DESCRIPTION "Synthesis of organometallic molecules that can be used as markers of organic substances" The present invention concerns the synthesis of organometallic molecules used to recognise biological substances by spectroscopy or electrochemically. The determination of biological molecules (for example: nucleic acids, proteins, amino acids) is generally carried out through other biomolecules that have a very high and specific affinity with them. In particular the problem of specific recognition of DNA and RNA is very complex and represents an objective of great interest for research, due to the great application possibilities in the medical, diagnostic and therapeutic field. For example, the ability of DNA, RNA and more recently PNAs (peptide nucleic acids) to specifically recognise just complementary sequences of nucleic bases gives them a great potential both as antigen drugs (i.e. that interact with DNA preventing it from being transcribed) or as antisense drugs (i.e. that interact with RNA preventing its translation and therefore its proteic synthesis) , both in medical and alimentary diagnostics. For example, in this last field, by hybridising or not a known genetic sequence, they allow it to be established whether it has been artificially modified . Therefore, it is very important, for applications in diagnostics, to have simple, sensitive, quick and possibly inexpensive tests to determine the recognition of biological molecules. For the analysis of nucleic acids, the biomolecules most often used are nucleic acids themselves or else synthesis oligomers normally having from 10 to 20 monomeric units both carrying known base sequences. For the same purpose more recently peptide nucleic acids (PNAs) (figure 1) have been used, which are DNA peptido- mimetic, in the structure of which the sugar phosphate sequence, negatively charged, has been replaced by a neutral aminoethyl glycine chain to which the nucleobases are linked .

DNA PNA Figure 1 PNAs, synthesised- for the first time in 1991 (Nielsen et al. , 1991, Science 254, 1497, Nielsen, P.E.; Egholm, M. Peptide Nucleic Acids. Protocols and Applications, Horizon Scientific Press Norfolk, 1999.) , possess a very high affinity with DNA and RNA and form PNA/DNA (and PNA/RNA) duplexes characterised by high thermal stability. This property derives from the lack of electrostatic repulsion between the PNA and DNA (or RNA) filaments, with respect to that existing between two negatively charged DNA (or RNA) filaments. The thermal stability of the PNA/DNA duplexes depends heavily upon the presence of erroneous couplings in the bases. The presence of just one coupling error in the PNA/DNA duplex is much more destabilising than an analogous error present in the DNA/DNA duplex. This represents an advantage in the use of PNAs with respect to DJSTA in molecular biology, in gene therapy and in diagnostics. (Nielsen, P. E.; Current Opinion in Biotech. 2001, 12, 16, and ref. cit.; Wang J., Biosensors & Bioelectronics 13, 1998, 757-762) . As far as applications in diagnostics are concerned, the use of nucleic acids or their mimetics in the construction of biosensors is a challenging issue and of great interest in analytical chemistry, which is continually subject to advances linked to the development of new- increasingly efficient optics and microelectronics technologies. In one of the most common applications, biomolecules (known as biosensors) are immobilised on supports, for example glass or silicon plates or polymeric membranes, etc., so as to form the so-called microarrays. This type of sensor is very important both in gene diagnosis and for other purposes, and the recognition of a molecule can be detected through spectrometry, fluorimetric, electrochemical methods etc. (Wang J. Nucleic Acids Research, 28, 3011-3016,2000; Takenaka S. Bull. Chem. Soc. Jpn. , 74, 217-224, 2001; Weiler, J. ; Gausepohl, H.; Hauser, O.; Jensen, O.; Hoheisel, J. Nucleic Acids Research, 25, 2792-2799, 1997; Goffeau, A. Nature, 385, 202-203, 1997) . In particular, electrochemical sensors seem to possess potentialities such as to be able to surpass other sensors already existing in terms of sensitivity, speed and cost (De-los-Santos-Alvarez,P. ; Lobo-Castanόn, M.; Miranda-Ordieres, A.; Tunδn-Blanco, P. Anal. Bioanal. Chem., 2004, 378, 104-118. Umek R. M.; Lin S. W. ; Vielmetter J.; Terbrueggen R. H.; Irvine B; Yu C. J. ; Kayyem J. F.; Yowanto H.; Blackburn G. F.; Farkas D. H. ; Chen Y. P.; Journal of molecular diagnostics, 2001, May, 3(2), 74-84; Mukumoto Kosuke; Nojima Takahiko; Furuno Nobuaki; Takenaka Shigeori; Nucleic Acids Research. Supplement (2001) (2003), (3), 43-4; Yu, C. J.; Wan, Yanjian; Yowanto, Handy; Li, Jie; Tao, Chunlin; James, Matthew D.; Tan, Christine L.; Blackburn, Gary F.; Meade, Thomas J.; Journal of the American Chemical Society 2001, 123(45), 11155-11161) . In most cases the detection of the signal is obtained by introducing onto the biosensor suitable markers, such as fluorescent compounds or organometallic complexes (Fischer-Durand, N. Saδmain ,M.; Bogna, R. ; Vessieres, A.; Zakrwewski, J.; Jaouen, G. Chem. BioChem.,5, 519-525, 2004; Metzler-Nolte, N.; Angew. Chem. Int. Ed., 2001, 40, 6, 1040-1043; Verheijen, J. C; Van der Marel, G. A.; Van Boom, J. H.; Metzler-Nolte, N.; Bioconjugate Chemistry, 11, 6, 2000, 741-743;) . Much of the research in this field is aimed at increasing the sensitivity of the devices also by increasing the intensity of the signal emitted by the marker. The problem tackled by the present invention is that of obtaining markers for biological molecules capable of emitting signals of greater intensity and thus in principle capable of increasing its detectability threshold. The present invention, as described hereafter and claimed in the attached claims, is aimed at these objectives. In a first aspect, the present invention concerns organometallic compounds of formula (I) , their salts and solvates:

where n is from 0 to 5; A is selected from: O, N, S; R2, R3, R4 are selected from H and -(CH2)m-/ with m=0-8; R2, R3, R4 can never be simultaneously equal to H or to a radical -(CH2)m- with m=0; D is selected from: O, N, S; p is 1 when D is 0 or S; p is 1 or 2 when D is N; when p=2, the chains of formula R5-X-Y-OM can be equal or different; R5 is selected from H and -(CH2)0-5-; X is selected from the following groups: -(CH2) 0-5-/ -CO-, o 9 9 C-N , C-(CH2)L5 , C-S ;

Y is selected from the following groups: -(CH2) 0-5- , (CH2)L5-N-C ?\ o , (CH2)1-5—S—C ;

OM is selecteedd ffrroomm tthhee ffoollilcowing groups:

R1 is selected from the following groups : H, CO , o Il H COH , C — (CH2)i-6 — COOR7 , N — (CH2H-6 — COOR7, - COOR7 ; -CO-NH-

R7 is selected from the following groups: H, - (CH2) 1-

-C6F5, (CH2)o-5 Si(CH3)3/ -PhNO2, -CH2PhNO2,

: -OH; -SH; -NH2; -COOH; -S-S-

Preferably, n is from 0 to 2, more preferably it is

equal to 0. A is preferably selected from 0 and N.

R2, R3, R4 are preferably selected from H and

(CH2)1-3-, even more preferably they are a -CH2-

group.

D is preferably selected from N and O. R5 is preferably equal to -(CH2) 0-2-, more preferably it is - (CH2) 0-l~ • Preferably, when D is N, p is equal to 2 and R5 is a radical -CH2- • Preferably, X is selected from: -CO-, -(CH2) 0-2- and -CO-NH-; more preferably it is selected from: -CO-, -CH2- and -CO-NH-. Y is preferably selected from: - (CH2) 0-2-, -(CH2)X-S-NH-CO-; even more preferably it is selected from: (CH2) 0 and - (CH2)2-NH-CO- . OM is preferably selected from the following groups:

more preferably OM is selected from:

ably selected from : H, CO ,

-CO (CH2) 2COOR7 , -COOR7 , -CO-NH- (CH2) 2-4-Q and

R7 is preferably selected from: H, -CH2Ph, - (CH2) x.3 /

NO2Ph, -C6F5 , ; more preferably it is selected from: H, -CH2Ph, -C6F5, -S-S-

-OH,

In an embodiment A can be equal to NH. The most preferred organometallic compounds of formula (I) are: Tris(ferrocene methylene oxymethyl)aminomethane (20); N-Cbz-tris (ferrocene methylene oxymethyl)aminomethane (23); N-Cbz-bis(hydroxymethyl) (ferrocene methylene oxymethyl)aminomethane (21); N-Cbz-bis (ferrocene methylene oxymethyl) (hydroxymethyl)aminomethane (22); -V,jv'-diferrocencarbonyl-l,3-diamine-2-propanol (24) ; JV/JV'-dibenzoil chromotricarbonyl-1,3-diamine-2-propanol (25) ; N-succinyl-tris [ (phenyl chromotricarbonyl) carboxymethyl] aminomethane (26) ; N- (benzoil chromotricarbonyl) - [bis ( (phenyl chromotricarbonyl) carboxymethyl) - hydroxymethyl] aminomethane (27); 1,3-{bis [ ( (benzoil chromotricarbonyl) aminoethyl)aminocarbonyl methyl]amino}isopropanol (29) ; (2-ferrocene methylene oxy-1,1' -bis-ferrocene methylene oxymethylethyDcarbamic acid pentafluorophenyl ester (32); (2-ferrocene methylene oxy-1, 1'-bis-ferrocene methylene oxymethylethyDcarbamic acid N-succinimidyl ester (33); 1- (2-hydroxy-ethyl) -3- (2-ferrocene methylene oxy-1,1-bis- ferrocene methylene oxy methyl-ethyl) -urea (34) ; N- (2-ferrocene methylene oxy-1,1-bis-ferrocene methylene oxymethyl-ethyl) succinamic acid (35) . The compounds of formula (I) can be used as markers for the determination of biological molecules. By biological molecules we mean: nucleic acids, oligonucleotides, proteins, peptides, amino acids etc, preferably DNA and RNA. The biomolecules are DNA, RNA and PNA. Amongst the most preferred PNAs are PNAs having up to 20 monomeric units. Thanks to the presence of a polyfunctional unit containing many organometallic groups (for example ferrocenyl) , which are determined with an electrochemical method (for example: cyclic voltammetry) , the analysis sensitivity is substantially increased with respect to the corresponding substrates in which there is just one organometallic complex. Moreover, many organometallic groups are simultaneously linked to the biomolecule, through a single reaction, avoiding being able to replicate many times over the introduction reaction of the organometal. This translates into an economic and time advantage. The products of formula (I) can also be used as markers of substances of pharmaceutical interest, for example antibodies (Fischer-Durand, N. Salmain ,M. ; Bogna, R.; Vessieres, A.; Zakrwewski, J.; Jaouen, G. Chem. BioChem.,5, 519-525, 2004) or antiepileptics (Vessieres, A.; Salmain, M.; Brossier,P. ; Jaouen, G.; J. Pharm. Biomed. 21, 625-633,1999) or other drugs, for example antitumour drugs, so as to enhance the localisation or the interaction of the drug with cells and receptors. For example analogues of Tamoxifen (anitumour drug) containing a ferrocene group are known in literature. (Top, S.-; Vessieres, A.; Leclercq, G. ; Tang, J.; Vasserman, J.; Hunche, M.; Jaouen, G. Chemistry: A Europ. J., 21, 5223-5236, 2003) . Moreover, organometallie groups can increase the lipophily of the substance or molecule to which they are linked and increase their cellular permeability. In a second aspect, the present invention concerns the possibility of detecting biomolecules marked with the compounds of the invention through an electrode, preferably a microelectrode. Said electrode can be used by itself or else immobilised, together with other microelectrodes, on a support such as glass, silicon, gold or polymeric membranes, so as to construct the so- called microarrays. (Wang J. Nucleic Acids Research, 28, 3011-3016,2000) . The compounds of formula (I) are synthesised as described in scheme 1.

Scheme 1 In step (a) the compound (2) is reacted with the compound of general formula Rx-E (3) , where R1 is as described above and E is a leaving group, preferably halogen, more preferably Cl or Br, even more preferably Cl. The reaction conditions depend heavily upon the nature of the group R1 and are known in the field. For example, when R1 is equal to group -COOCH2Ph, a mixture of H2O and AcOEt at a temperature of about 200C is used as solvent vigorously shaking for about 5 hours. The desired product is obtained through separation of the pahses and extraction with solvent. The step (a) is optional; in some cases it is possible to start from the compound (4) in which R1 is equal to hydrogen and to carry out step (b) directly; or else the compound (4) , in which R1 is as described above, can be commercially available. The step (a) is preferably carried out when A is equal to N. In step b) the intermediate (4) is reacted with the reactant of general formula (5) , where R5, X,. Y and OM are as described above and Q is selected from OH and halogen, preferably it is selected from OH or Cl. The step (b) is preferably carried out in a solvent selected from: toluene, CH2Cl2, DMF, THF, dioxane or mixtures thereof, more preferably in mixtures of toluene/CH2Cl2 2:1, CH2Cl2 or DMF. These solvents are preferably anhydrides and the reaction is preferably carried out in an atmosphere of nitrogen or argon. The reaction temperature is generally between 150C and 1000C, preferably between 200C and 800C, even more preferably between 230C and 650C. The reaction can be conducted in the presence of acids or of bases which are preferably selected from, respectively, CF3COOH7 HCl, H2SO4, CH3COOH; PTSA, preferably CF3COOH, or Et3N, pyridine, KOH, N,N- dimethylaminopyridine, piperidine, K2CO3, Na2CO3, diisopropylamine, preferably Et3N. The duration of the reaction depends upon the starting products used. The reactant of formula (5) can be used in molar excess with respect to the intermediate (4) ; the amount used depends upon the number of lateral chains present in the reactant (4) (for example one from R2, R3 and R4 can be equal to H) and upon the type of end product that one intends to obtain, i.e. having one, two or three organometallic groups. For example, if one wishes to obtain a trisubstituted end product the reactant (5) can be used in molar excess of 4-5 times or more with respect to (4) . When R1 is different to H, the intermediate (6) can be deprotected and the compound (I) can be isolated. This reaction is carried out with the methods of the prior art according to the nature of the protective group. For example, when R1 is equal to -COOCH2Ph (group Cbz) , the removal can be carried out with Pd/C. Optionally, in the case in which A is equal to N, the product (6) can be deprotected and acylated in situ, for example by reaction with a base and then with an acylating reactant. In some cases after this treatment two products are formed: one acylated product and one intramolecular transacylation product (see example 5) . Alternatively, when A is equal to N and Rl is selected from: -CO- (CH2)i-6-COOR7, -CO-NH- (CH2)i-io-Q or -

COOR7, where R7 is selected from H, -C6F6, and Q is as described above, the compound of formula (I) can also be synthesised according to the synthetic procedure described in examples 9-12.

In the case in which D is equal to N and there is a second chain of formula: -R5-X-Y-OM, the synthesis of the product of formula (I) is carried out according to scheme 2.

(I)

Scheme 2

In step (d) the compound (7) is reacted with the

reactant (8) of formula R8-OH, where R8 is a linear or

branched alkyl group (Ci_8) , preferably it is a linear

alkyl group (CV3) , more preferably it is a methyl group.

The reaction takes place at a temperature generally

between 150C and 1000C, preferably between 250C and 750C,

more preferably at the reflux temperature of the reactant

(8) , if it is a liquid, or else at the reflux temperature of the solvent used. In step (e) , the intermediate (9) is reacted with the reactant (10) of general formula G- (CH2) 1-5-G, where G is selected from a group NH2 and SH, preferably it is a group NH2 and the group (CH2)1-5 is an ethylene group. The reaction temperature is between 150C and 1000C, preferably between 200C and 800C, even more preferably between 230C and 650C. The duration of the reaction depends upon the starting products used. Preferably, the reactant (10) is also used as solvent. In step (f) the intermediate (11) is reacted with (12) of general formula Q-CO-OM, where Q and OM are as defined above. The reaction conditions are the same as those foreseen for step (b) . Preferably, in the case of the reactions' described in scheme 2, one from R2, R3 and R4 is equal to H. The molecules of formula (I) are anchored to the biomolecule (amino acids, peptides, nucleic acids, preferably PNA, DNA, RNA, more preferably PNA) suitably derivatized according to the known methods for peptide synthesis, for example, by reaction with activated esters of carboxyliσ groups present in the biomolecule. In example 7 the synthesis of a PNA monomer labelled with a compound of formula (I) is displayed. This reaction can also be applied to PNA comprising many monomers and to nucleic acids. Optionally, as outlined in scheme 3, in the case in which A is equal to N, the compounds of formula (I) can be transformed into the corresponding isocyanate (13) that can react with amino or alcohol groups present in most biological and organic molecules. Example 8 shows the synthesis of glycine labelled with a compound of formula (I) . This example can be generalised for all amino acids.

© (13) Scheme 3 Other examples of reactions between organometallic compounds and biological molecules can be found in the following publications: Fish, Richard H. ; Jaouen, Gerard; Organometallics, 2003, 22(11), 2166-2177; Metzler-Nolte, N. ; Angewandte Chemie, International Edition, 2001, 40(6), 1040-1043; Fischer-Durand, Nathalie; Salmain, Michele; Rudolf, Bogna; Vessieres, Anne; Zakrzewski, Janusz; Jaouen, Gerard; ChemBioChem, 2004, 5(4), 519-525; Baldoli, Clara; Giannini, Clelάa; Licandro, Emanuela; Maiorana, Stefa.no; Zinzalla, Giovanna; Synlett 2004, 6, 1044-1048; Maiorana, Stefano; Licandro, Emanuela; Perdicchia, Dario; Baldoli, Clara; Vandoni, Barbara; Giannini, Clelia; Salmain, Michele; Journal of Molecular Catalysis A: Chemical, (2003), 204-205, 165-175; Baldoli, Clara; Maiorana, Stefano; Licandro, Emanuela; Zinzalla, Giovanna; Perdicchia, Dario; Organic Letters (2002), 4(24), 4341-4344; Salmain, Michele; Jaouen, Gerard; Comptes Rendus Chimie (2003), 6(2), 249-258; Sehnert, Jan; Hess, Alexandra; Metzler-Nolte, Nils; Journal of Organometallic Chemistry (2001), 637-639, 349- 355; Verheijen, Jeroen C; van der Marel, Gijs A.; van Boom, Jacques H.; Metzler-Nolte, Nils; Bioconjugate Chemistry, (2000), 11(6), 741-; The compounds of formula (I) and the biomolecule labelled with the products of formula (I) can also be synthesised with different methods to those described here without departing from the purposes of the present invention. Hereafter, some examples of synthesis of the compounds of the invention are described. SCHEME OF SYNTHESIS 1 EXAMPLE 1. Synthesis of Tris(ferrocene methylene oxymethyl) aminomethane (20) .

1) Synthesis of i\r-Cbz-tris(hydroxymethyl) aminomethane. A suspension of NaHCO3 (53 mmol, 1,5 eq, 4,4 g) and tris (hydroxymethyl)aminomethane (42 mmol, 12 eq, 5 g) in H2O (20 mL) and AcOEt (40 mL) , kept under stirring, is added to drop by drop with benzyl chloroformate (6 g, 35 mmol, 5,3 mL) , keeping the temperature at about 200C. The mixture is left in stirring for 5 hours at room temperature and, then, the solid is filtered and the two phases are left to separate. The aqueous phase is extracted with AcOEt (3x40 mL) and the combined organic phases are washed with H2O (40 mL) . After evaporation of the solvent, the residue is taken with diisopropyl ether (20 mL) and it is cooled with an ice bath. The white solid is filtered and 9.5 g (88% yield) of product is obtained. Melting point 101-1030C. 2) Synthesis of J\T-Cbz tris (ferrocene methylene oxymethyl) aminoπtethane (23) . In an atmosphere of nitrogen, a solution of ferrocenyl methanol (9.26 mmol, 2 g) in toluene (10 ml) and CH2Cl2 (5 ml) heated to 6O0C, is added to with a first portion of W-Cbz-tris (hydroxymethyl)aminomethane (0.12 g, 0.47 mmol,) and CF3COOH (0.2 ml of a solution 0.65 M in toluene) . It is heated again to the same temperature carrying out 4 further additions of the same amount of iV-Cbz-tris (hydroxymethyl)aminomethane and CF3COOH every 30 minutes. The heating to 600C for 27 h follows, carrying out another 4 additions of ferrocenyl methanol, each equal to 0.32 g (3.8 mmol), every 6 hours. After evaporation of the solvent the residue is taken with CH2Cl2 (20 ml) and washed with 50 ml of a saturated solution of NaHCO3. The aqueous phase is then extracted with CH2Cl2 (2x20 ml) and the combined organic phases are washed with H2O (50 ml), dried over Na2SO4 and evaporated. The crude product is purified on a chromatography column of silica gel (eluent MTBE/Etp, 2:8) to give 1.45 g (73%) of product as orange solid and, as by-product, 1.6 g of diferrocenylmethyl ether. M . p 115 - 117 0 C (pentane) . 1H NMR ( CDCl3 , δ) : 3 . 67 ( s , 6H, CH2O) ; 4 . 09 ( s , 15 H, Fc) ; 4 . 11 ( t , 6H, Fc) ; 4 . 16 (t , 6H , Fc ) ; 4 . 20 ( s , 6H , OGH2Fc) ; 5 . 02 ( s , 2H , CH2Ph) ; 5.2 (bs, NH); 7.32 (m, 5H, Ph); 13C NMR (CDCl3, δ) , 58.8; 66.1; 68.2; 68.4; 68.8; 69.0; 69.5; 83.8; 127.9; 128.0; 128.4; 137; 156; m/z (FAB+) 850 (M+) ; IR (Nujol, V cm"1) 1723 (NHCO) . 3) Synthesis of the compound of the title At room temperature, in an atmosphere of N2, Pd/C (10%, 0.3 g) and HCO2NH4 (0.3 g, 3.2 mmol) are added to a solution of JV-Cbz tris (ferrocenyloxymethyl) aminomethane (0.85 g, 1.0 mmol) in MeOH (10 ml) and CH2Cl2 (18 ml) . The mixture is stirred at room temperature for 20 minutes. The catalyst is filtered on celite panel washing with CH2Cl2 (10 ml) , the solvent is evaporated and the residue is taken with CH2Cl2 (50 ml) washing it with a saturated NaCl solution (2x50 ml) . The aqueous phase is extracted with CH2Cl2 (3x10 ml) . The combined organic phases are dried over Na2SO4 and evaporated at low pressure, the crude product is purified with a chromatography column on silica gel, eluent AcOEt (Rf= 0,25) . 0.65 g (90% yield) of orange solid is obtained. M. p. : 105-107 0C (pentane) . 1H NMR (CDCl3, δ): 2.28 (bs, 2H, NH2) ; 3.45 (s, 6H, CCiJ2O) ; 4.10-4.25 (m, 27H, Fc + 6H, OCH2Fc) . 13C NMR (CDCl3, δ) , 56.51; 68.2; 68.4; 69.08; 69.65; 71.48; 83.84; m/z (EI) 715 (M+) . IR (Nujol, V cm"1) 3093 (NH2) . EXAMPLE 2. Synthesis of N-Cbz- bis (hydroxymethyl) (ferrocene methylene oxymethyl)aminomethane (21); N-Cbz-bis (ferrocene methylene oxymethyl) (hydroxymethyl) aminomethane (22) ; N- Cbz-tris (ferrocene methylene oxymethyl)aminomethane (23) ;

(21) (22) (23)

Fc = At room temperature and in an atmosphere of nitrogen, a solution of ferrocenyl methanol (0.6 mmol, 0.13 g) in CH2Cl2 (12 ml) is added to with N-Cbz- tris (hydroxymethyl)aminomethane (0.2 mmol, 0.05 g) dissolved in CH2Cl2 (4 ml) and CF3COOH (10 μl). It is heated to 400C for 4 h, then ferrocenyl methanol (0.32 mmol, 0.07 g) is added again and it is heated for another 4h to 4O0C. It is left overnight at room temperature then 20 ml of an aqueous solution of 5% NaOH is added. The phases are separated removing the aqueous phase with CH2Cl2 (20 ml) . The combined organic phases are washed with H2O (40 ml) , dried over Na2SO4 and evaporated under vacuum. The crude reaction product is purified on a chromatography column of silica gel obtaining 3 fractions that contain the substituted mono- di- and tri ferrocenyl products as well as a by-product consisting of diferrocenylmethyl ether. N-Cbz-bis (hydroxymethyl) (ferrocene methylene oxymethyl) aminomethane; (27 % yield), Rf.= 0.28 (TBME/Etp=2/8) ; orange solid: m.p. 113- 115°C (dec.) (pentane) . 1H NMR (CDCl3, δ) : 3.53 (d, 2H, CH2OH, J = 11.6 Hz ) ; 3.58 (s, 2H, CH2OCH2Fc) ; 3.72 (d, 2H, CH2OH7 J = 11.6 Hz); 4.09 (s, 5H, CH Fc); 4.16 (t, 2H, CH Fc, J = 1.8 Hz) 4.18 (t, 2H, CH Fc, J= 1.8 Hz) ; 4.3 (s, 2H, OCH2Fc); 5.08 (s, 2H7 CH2Ph) ; 5.74 (s, NH) ; 7.35 (m, 5H, Ph) . 13C EMR (CDCl3, δ) 59.1; 64.5; 67; 68.7; 69.9; 70.8; 83.0; 128.0; 128.2; 128.5; 136; 156. M/Z (HRSM) : 453.12 (M+) . IR (Nujol, v cm"1) 3300 (OH), 1685 (CONH) . N-Cbz-bis (ferrocene methylene oxymethyl) (hydroxymethyl)aminomethane: (19 % yield) Rf = 0.25 (TBME/Etp=7/3) ; orange oil; .1H NMR (CDCl3, δ):3.48 (d, 2H, CH2OCH2FC, J = 9.16 Hz ); 3.63 (bs, OH); 3.69 (d, 2H, CH2OCH2FC; J = 9.16 Hz); 3.77 (d, 2H, CH2OH, J = 6.6 Hz) ; 4.10 (s, 1OH, CH Fc); 4.12 (t, 4H, CH Fc, J = 1.76 Hz) ; 4.17 (t, 4H, CH Fc, J= 1.76 HJZ) ; 4.21 (d, 2H, OCH2Fc,- J = 11.4 Hz) ; 4.27 (d, 2H, OCH2Fc, J = 11.4 Hz) ; 5.04 (s, 2H, CH2Ph) ; 5.4 (bs, NH) ; 7.35-7-38 (m, 5H, Ph); 13C NMR (CDCl3, δ) ; 59.1; 65.1; 66.6; 68.38; 69.49;; 69.01-69.08; 69.56; 69.71; 83.3; 128.0; 128.07; 128.5; 136; 156. M/z (HRSM) : 651.14; (M+); IR (liquid film, V cm"1) 3414 (OH) , 1714 (CONH) . N-Cbz-tris (ferrocene methylene oxymethyl)aminomethane: (36 % yield) Rf =0.47 (TBME/Etp=7/3) . EXAMPLE 3. N,N'-diferrocencarbonyl-1,3-diaπun.ino-2- propanol (24) .

At room temperature and in an atmosphere of nitrogen, oxalyl chloride (2 mmol, 0.17 ml) is dripped into a suspension of ferrocencarboxylic acid (0.25 g, 1 mmole) in anhydrous CH2Cl2 (5 ml) . A dark red coloured solution is obtained that is left under stirring for 30 minutes. The excess (COCl)2 is eliminated by distillation under vacuum and the dark oil residue, dissolved in anhydrous CH2Cl2 (5 ml) , is dripped at room temperature into a solution of 1,3-diamino-2-propanol (0.45 mmol, 40 mg) and Et3N (2 mmol, 0.3 ml) in CH2Cl2 (2 ml) . The solution is stirred for 2h and precipitation of an orange coloured solid is obtained. The solvent is evaporated and the residue is taken with 10 ml of a CH2Cl2/Et20 3:7 mixture and it is filtered, washing with 30 ml of the same mixture. 195 mg of orange solid is obtained with a yield of 94%. M. p. 176-177°C (pentane) . 1H NMR (DMSO, δ): 3.27 (m, 4H, CiJ2NHCOFc, OH) ; 3.74 (m, IH, CHOH) ; 4.17 (m, 1OH, CH Fc) ; 4.82 (t, 4H, CH Fc) ; 4.34 (t, 4H, CH Fc) ; 7.9 (t, 2H, NH) ; 13C NMR (DMSO, δ) : 43.08; 68.2; 69.2; 69.65; 69.9; 77.5 ; 170. M/Z (ESI) : 537 (M+Na+) ; 515 (M+l) ; IR (NUj Ol # V cm"1) 3294 (NH, OH) ; 1635 (CO) . EXAMPLE 4. Synthesis of N, N' -dibenzoil chromotricarbonyl l,3-diamine-2-propanol (25) .

At room temperature and in an atmosphere of nitrogen, the benzyl chromotricarbonyl acid (0.6 g, 2.32 mmol) is dissolved in anhydrous DMF, obtaining an orange solution that is heated to 6O0C. At this temperature the solid carbonyldiimidazol (0,38 g, 2,32 mmol) is added in portions over 5 minutes, the solution becomes deep red. It is heated to 6O0C for 30 minutes, noting the development of CO2. l,3-diamine-2-propanol (0.1 g, 1.16 mmol) dissolved in 0.5 ml of DMF is dripped into the solution, the colour goes from red to orange and one continues to heat to 600C for 2h. The DMF is evaporated under vacuum and the crude product is purified on a chromatography column (eluent AcOEt/MeOH, 9:1) obtaining the product as a dark yellow solid (50% yield) . M.p.: 203-205 0C (dec) (pentane) . 1H NMR (DMSO, δ): 3.21-3.32 (m, 4H, CH2N); 3.72-3.77 (m, IH, CH); 5.07 (d, OH, J= 6.0 Hz) ; 5.70-5.86 (m, 6H, PhCr(CO)3); 6.26-6.28 (m, 4H, PhCr(CO)3); 8.42-8.56 (m, 2H, NH) . M/z (ESI) : 593: (M+Na+) ; 457 (M+Na+-Cr(CO)3) ; IR (Nujol, V cm"1) 3338; 1980, 1883, 1646. EXAMPLE 5. Synthesis of N-succinyl-tris [(phenyl chromotricarbonyl)carboxymethyl] aminomethane (26) and N- (benzoil chromotricarbonyl) - [bis( (phenyl chromotricarbonyl) carboxymethyl) - hydroxymethyl] aminomethane (27);

1) Synthesis of N-Fmoc- tris (hydroxymethyl)aminomethane The same procedure used for the synthesis-of N-Cbz- tris (hydroxymethyl)aminomethane (example 1, 1) . 40% yield. M.p. 128-130 0C (pentane) . 1H NMR (200 MHz, CDCl3) : 3.18 (bs, 3H, OH); 3.68 (bs, 6H, (CH2O)3); 4.18-4.25 (m, IH, CH) ; 4.43-4.46 (m, 2H, CH2); 5.72 (bs, IH, NH) ; 7.26- 7.45 (m, 4H, arom) , 7.57-7.61 (m, 2H, arom) ; 7.76-7.79 (m, 2H, arom) . Elem. analysis. Calculated for C19H21NO5: C, 66,46; H, 6,16; N, 4,08; found C, 66,58; H, 6,10; N, 4,01. 2) N-Fmoc-tris (benzene chromotricarbonyl carboxymethyl) aminomethane. At room temperature and under nitrogen dimethylamine pyridine (0.050 g) is added to a solution of the product obtained in step 1) (0.5g, 0.90 mmol) and benzene chromotricarbonylic acid (0.80 g, 3.00 mmol) in CH2Cl2 (50 ml) . The orange solution is cooled to 00C and added to with N- (3-dimethyl aminopropyl)N' -ethylcarbodiimide (EDC) hydrochloride (0.60 g, 3.30 mmol) . The solution is stirred at room temperature for 2h and the colour turns from red to orange. The solvent is evaporated and the crude reaction product is purified on a chromatography column (eluent: AcOEt) to give 0.9 g of yellow solid (97%) R. f.=0.75. m.p. 117-119°C (pentane) 1H NMR (300 MHz, CDCl3) : 4.20-4.22 (m, IH, CH), 4.38 (bs, 2H, CH2 Fmoc) , 4.76 (bs, 6H, CH2O) , 5.24-5.32 (m, 6H, PhCr(CO)3) , 5.50 (bs, NH), 5.59-5.63 (m, 3H, PhCr(CO)3), 6.10-6.12 (m, 6H, PhCr(CO)3), 7.27-7.41 (m, 4H, arom) , 7.58-7.61 (m, 2H, arom) , 7.73-7.76 (m, 2H, arom) . 13C NMR (75 MHz, CDCl3) : 47.1, 63.3, 67.1, 89.2, 94.9, 95.2, 120.0, 125.1, 127.1, 127.7, 141.3, 143.8, 154.9, 164.9, 230.5. M/z (ESI) 1085.9 [M+Na+] , 950.1 [Mn-Na+-Cr(CO)3] , 814.1, [M+Na+- 2Cr(CQ)3] , 678.3 [M+Na+- 3Cr(CO)3] . IR (CHCl3, v cm'1) 1988, 1919. 3) Synthesis of the compounds of the title At room temperature and under nitrogen piperidine (0.16 g, 1.9 mmol) is added to a solution of the compound obtained in step 2) (0.1 g, 0.09 mmol) in CH2Cl2 (5 ml) . Upon the disappearance of the starting product (TLC: AcOEt) succinic anhydride (0.33 g, 3.3 mmol) is added and the solution is kept under stirring at room temperature for 24 hours. It is washed with a saturated NaHCO3 solution (4x5 ml) and the aqueous phases are then extracted with CH2Cl2 (5 ml) . The combined organic phases are treated in a separatory funnel with a solution of KHSO4 0.3M (3x5ml) , the organic phases are dried over Na2SO4 and evaporated. The crude reaction product is purified on a chromatography column (eluent: CH2Cl2/AcOEt/MeOH in increasing MeOH gradient) to give the product (26) in a yield of 63% and (27) as by-product in a yield of 23%. (26) : 1H NMR (200 MHz, CDCl3, d) : 2.16-2.49 (m, 4H, (CH2)2); 4.69-4.79 (m, 6H, CH2O); 5-29-5.60 (m, 10 H PhCr(CO)3); 6.14 (bs, 5 H PhCr(CO)3); 8.0 (bs, NH) . M/z (ESI) : 964 (M+Na+) , IR (nujol, cm-1) : 1893, 1973, 1724. (27) : 1H NMR (200 MHz, CDCl3, δ) : 3.92 (d, 2H, J=5.6, CH2OH); 4.56-4.69 (m, 4H, CH2O) ; 5.14 (t, IH, J=5.6, OH) ; 5.62-5.84 (m, 8H, PhCr(CO)3); 6.01 (t, 2H, J-I.A1 PhCr(CO)3); 6.29-6.33 (m, 5H, PhCr(CO)3); 7.90 (bs, IH, NH) . M/z (ESI) : 841 (M+) . IR (nujol, cm-1) : 3477, 3404, 1974, 1961, 1899, 1880, 1738, 1728. SCHEME OF SYNTHESIS 2. EXAMPLE 6. Synthesis of 2,3-{bis[ ( (benzoil chromotricarbonyl) aminoethyl)aminocarbonylmethy1] amino}is opropanol (29) .

(29) 1) Synthesis of { [3- (Bis-methoxycarbonyl methyl- amino) -2-hydroxy-propyl] -methoxycarbonyl methyl-amino}- methyl acetate. 1, 3-diamino-2-hydroxypropane-N,N,N' ,N' -tetracetic acid (5g, 15 mmol) is suspended in 20 ml of MeOH adding H2SO4 (96%, 0.5 ml) and it is heated under reflux for 20 hours. As the reaction progresses the solution becomes clear. The solvent evaporates under vacuum, and the residue is taken with 30 ml of CH2Cl2 and it is washed with a saturated NaHCO3 solution (3x20 ml) . The aqueous phases are once again removed with CH2Cl2 (2x25 ml) . The combined organic phases are washed with H2O (30 ml) and dried over Na2SO4. The solvent is evaporated and a pale yellow coloured oil is recovered that is used as such for the subsequent reactions. 1H NMR (CDCl3, δ) : 2.49-2.56 (m, 2H, CH2N); 2.75-2.80 (m, 2H, CH2N); 3.49-3.52 (m, 8H, NCH2CO2CH3);' 3.58-3.67 (m, 13H, CH + CO2CH3); 3.97 (bs, OH) . IR (liquid film, cm" x) 3461, 17Sl. 2) Synthesis of N- (2-amino-ethyl) -2- [ [ (2-amino- ethylcarbamoyl) -methyl] - (3-{bis- [ (2-amino- ethylcarbamoyl) -methyl] -amino}-2-hydroxy-propyl) -amino] - acetamide. A solution of the product obtained in 1) (Ig, 2,85 mmol) in ethylenediamine (10 ml) is heated to 6O0C for 8 hours and then is left at room temperature overnight. The excess ethylenediamine is distilled under vacuum, butanol is added (10 ml) and it is distilled under vacuum once again (repeating this operation 3 times- in order to eliminate the residual ethylenediamine) . The desired crude product is obtained as a pale yellow dense oil, which is used as such for the subsequent reactions. 1H NMR (CDCl3, δ) : 2.50-2.65 (m, 12H, CH2N); 2.75- 2.80 (m, 2H, CH2N) ; 3.07-3.15 (m, 17H, CH + NCH2CO2CH2) ; 3.70 (bs, OH) ; 8.20 (bs, 2H, NH + NH2) . IR (nujol, cm'1) 3354, 1662. M/z (ESI) : 491 [M+l] . 3) Synthesis of the compound of the title At room temperature (200C) a solution of benzyl chromotricarbonyl acid (0.2 g, 0.77 mmol) in anhydrous DMF (2 ml) is added to with the product obtained in 2) (0.13 g, 0.77 mmol) and diisopropyl carbodiimide (DIC) (0.1 g, 0.77 mmol, 120 ml) . The solution turns from orange to red. It is left under stirring for 30 minutes, then the tetramine (0.075 g, 0.15 mmol) dissolved in 0.5 ml anhydrous MeOH and the diisopropyl ethyl amine (0.2 g, 265 ml, 1.55 mmol) are dripped. It is heated to 35°C for 4 hours then it is left under stirring overnight at room temperature. The DMF is evaporated and the solid residue is suspended under stirring in CH2Cl2 and centrifuged eliminating the supernatant. The operation is repeated 4 times. The desired product is a lemon yellow solid, obtained after filtration in a yield of 67%. M.p. 197-200 (dec) . 1H NMR (CDCl3, δ) . : 2.72-3.34 (m, 28H, CH2N); 3".75-3.βO (m, IH, CH); 5.74-5.82 (m, 9H, PhCr(CO)3); 6.29-6.31 (m, 6H, PhCr(CO)3); 8.37 (bs, NH); 8.70 (bs, NH); IR (nujol, v cm"1) 3461, 1980, 1885, 1651. M/z (ESI) : 1452 (M+) . EXAMPLE 9. Synthesis of acid- (2-ferrocene methylene oxy- 1,1'-bis-ferrocene methylene oxymethylethyl)carbamiσ pentafluorophenyl ester (32) ;

Into a solution of bis (pentafluorophenyl) carbonate (115 mg, 0.30 mmol) in N-methyl pyrrolidone (1.5 ml), at 00C, the solid compound (20) (example 1) (210 mg, 0.30 mmol), diisopropylamine (DIPEA) (130 ml, 0.74 mmol) and DMF (0.3 ml) are added. It is left under stirring at O0C for Ih, to allow the formation of the compound of the title (Rf = 0.75, AcOEt/ETP, 6:4) . The compound (32) can be isolated and purified, for example, with chromotography or else used as such in the anchoring reaction with organic molecules (see example 12) . EXAMPLE 10. Synthesis of acid- (2-ferrocene methylene oxy- 1,1' -bis-ferrocene methylene oxymethylethyl)carbamic-N- succinimidyl ester (33) ;

Into a solution of N N' -disuccinimidyl carbonate (140 mg, 0.55 mmol) in anhydrous DMF (5 ml) at 00C, a solution of the compound (20) (example 1) (391 mg, 0.55 mmol) in DMF (5 ml) is slowly dripped. It is left under stirring for 15 minutes at O0C. The compound (33) , thus obtained, can be isolated and purified or used as such for the synthesis of the compound (34) (see example 11) . EXAMPLE 11. Synthesis of 1- (2-hydroxy-ethyl) -3- (2- ferrocene methylene oxy-l,l-bis-ferrocene methylene oxy methyl-ethyl) -urea (34).

(34 )

Into solution of N,N' -disuccinimidyl carbonate (140 mg, 0.55 mmol) in anhydrous DMF (5 ml) at 00C, a solution of the compound (20) (example 1) (391 mg, 0.55 mmol) in DMF (5 ml) is slowly dripped. After 15' at 00C 40 μl of 2-amino ethanol (0.67 mmol) are dripped. After about 30' an orange suspension forms and another 50 μl of 2-amino ethanol (0.84 mmol) are added. After two hours at room temperature the DMF is distilled under vacuum, the residue is taken with CH2Cl2 (30 ml) , washed with a saturated NaHCO3 solution (1x30 ml) and then with H2O (2x15 ml) . The organic phase is dried over Na2SO4, filtered and evaporated obtaining a dark yellow oil. IH NMR (CDCl3, δ) : 3.16 (m, 2H, CH2NH); 3.55 (m, 8H, CH2O+CH2OH); 4.10-4.22 (m, 33H, Fc + 6H, OCH2Fc). M/z (ESI+) 825.8 (M++Na) . EXAMPLE 12. Synthesis of N- (2-ferrocene methylene oxy-l,l-bis-ferrocene methylene oxymethyl-ethyl) succinamic acid (35) .

(35) A solution of the compound (20) (example 1) (112 mg, 0.16 mmol) in CH2Cl2 (2.5 ml) is dripped into a solution of succinic anhydride (25 mg, 0.26 mmol) in anhydrous CH2Cl2 (1 ml) , and a spatula tip of solid dimethylaminopyridine is added. It is left under stirring for 1 h at room temperature, the reaction mixture is diluted with CH2Cl2 (20 ml) and it is washed with NaHCO3 5% (15 ml) . The aqueous phase is extracted with CH2Cl2 (2x 20 ml) , the combined organic phases are washed with KHSO4 IN (2x15 ml) , dried over Na2SO4, filtered and evaporated under vacuum. The crude reaction product is purified through a chromatography column on silica gel (AcOEt; Rf = 0.55) and the product is isolated as a yellow solid in a yield of 73%. IH NMR (CDCl3; δ) : 2.4-2.6 (m, 4H, CH2-CH2) ; 3.59 (bs, 6H, C(CH2)3); 4.12-4.19 (m, 33 H, Fc + CH2Fc); 5.8 (bs, IH, NH); m/z (ESI+) 838 (M++Na) . EXJ-MPLES OF ANCHORING OF THE COMPOUNDS OF FORMULA (I) TO PNA AND TO OTHER BIOMOLECULES. EXAMPLE 7.Reaction of tris(ferrocenyloxymethyl) aminomethane with a tyrosine PNA monomer to give the product (30) .

A solution of bis (pentafluorophenyl) carbonate (0.38 g, 0.94 mmol) in CH2Cl2 (5 ml) is cooled to 00C, and the tyrosine PNA monomer is added (Sforza, S.; Nielsen, P. et al. Tetrahedron Lett. (1998), 39, 4707) (0.5 g, 0.93 mmol) . Diisopropylamine (DIPEA) (160 ml) is dripped into the suspension thus obtained and the solution becomes clear. It is left under stirring for 3h and a 5% NaHCO3 solution (2x1OmI) is added extracting the aqueous phase with CH2Cl2 (3x10 ml) . The combined organic phases are washed with H2O (20 ml) dried over Na2SO4 and evaporated up to about 2 ml. To one side, in an atmosphere of N2, a solution of tris (ferrocenyloxymethyl) aminomethane in CH2Cl2 (5 ml) cooled to 00C is prepared into which DIPEA (180 ml, 0.5 mmol) and the previous solution of pentafluoro ester are dripped. It is left under stirring at room temperature for 5 hours. It is washed with a 10% NaHCO3 solution (2x1OmI) removing the aqueous phase with CH2Cl2 (3x10 ml) . The combined organic phases are washed with H2O (20 ml) dried over Na2SO4 and evaporated. The crude product is purified with a chromatography column on silica gel, eluent AcOEt. 0,4 g (80%) of orange solid are obtained. m.p. 98-103 0C (pentane) . 1H NMR (CHCl3, δ) : 1.84 (s, 3H, CH3) ; 2.6 (d,lH, J= 10.5 Hz, CH2) ; 3.0-3.1 (m, 4H, CH2) ; 3.67 (bs, 6H; CH2OCH2Pc); 3.77 (s, 3H, COOCH3) ; 3.82-3.86 (m, 2H, CH + CH2) ; 4.11 (s, 9H, Pc) ; 4.14 (s, 6H, Fc) ; 4.19 (s, 6H, Fc) ; 4.24 (s, 6H, CH2Fc) ; 4.52 (d, IH, J= 16.2 Hz, CH2) ; 4.99 (d, IH, J = 12 Hz, CH2) ; 5.19 (d, IH, J= 12 Hz, CH2) ; 5.46 (bs, IH, NH) ; 5.61 (bs, IH, NH) ; 6.58 (s, IH, CH=) ; 7.02 (d, 2H, J= 8.47 Hz, PhO) ; 7.10 (d, 2H, J= 8.47 Hz, PhO) ; 7.25-7.35 (m, 5H, Ph) ; 8.01 (S, IH, NH) . 13C NMR (CHCl3, δ) : 12.3; 33.50; 39.03; 48.7; 49.5; 50.34; 60; 63.6; 66.9; 69.6; 68.5; 68.6; 69.2; 83.0; 110.8; 122.14; 127; 128.4; 129.9; 136; 141.0; 151.4; 155.0; 156.0; 164.1; 166.95; 172. M/z (HRSM) : 1279.30 (M+) . EXAMPLE 8. Reaction of tris (ferrocenyloxymethyl) aminomethanβ with glycine to give the product (31)

(31) 1) Synthesis of tris (ferrocenyloxymethyl)methyl isocyanate. A solution of COCl2 (0.45 mmol, 240 ml of 20% solution in toluene) is cooled to -5 0C and a solution of tris (ferrocenyloxymethyl) aminomethane (0.3 g, 0.42 mmol) in CH2Cl2 (20 ml) and TEA (0.9 mmol, 125 ml) are added simultaneously through two syringes. The disappearance of the reactant is followed by tic (eluent AcOEt/petrol ether, 6:4) . At the end of the addition it is left under stirring for 15 minutes. Nitrogen is bubbled into the solution for a few minutes and the solvent is evaporated. The crude reaction product is purified with a chromatography column on silica gel, (eluent AcOEt/petrol ether, 3:7) . 0.32 g (76%) of the product is obtained as an orange oil. 1H NMR (CDCl3, δ) : 3.46 (s, 6H, CH2O); 4.10-4.25 (m, 27H, FC + 6H, OCH2Fc) . IR (Nujol, V cm"1) 2249 (NCO) . M/z (ESI) 741 (M+ ) . 2) Synthesis of N- (tris (ferrocenyloxymethyl) methane aminocarbonyl)glycine. A solution of the product obtained in 1) (0.22 g, 0.3 mmol) in CH2Cl2 (5 ml) is added to with glycine methyl ester hydrochloride (0.04 g, 0.3 mmol) and triethylamine TEA (45 ml, 0.3 mmol) , it is left to react under stirring for 24 h at 300C. The disappearance of the reactant 1) is followed by tic (eluent AcOEt/petrol ether, 6:4) . At the end of the reaction the solvent is evaporated, the residue is taken with MeOH (5 ml) and CH2Cl2 (2ml), an aqueous solution of LiOH (0.08 g, 2 mmol in 0.5 ml of H2O) is added and it is left under stirring for 24 h at 300C. The solvent is evaporated, the residue is taken with 10 ml of CH2Cl2 and it is washed with a solution of KHSO4, (2x5 ml) at pH*= 1. The aqueous phases are extracted with CH2Cl2 (2x5 ml) and the combined organic phases washed with 5 ml of saturated NaCl solution. It is dried over Na2SO4, the solvent is evaporated, the residue is suspended in pentane and it is filtered obtaining the product as a yellow solid in a yield of 75%. 1H NMR (CDCl3, δ) : 3.46 (bs, 6H, CH2O); 3.82 (bs NCH2CO) ; 3.97-4.19 (m, 27H, Fc + 6H, OCH2Fc) . IR (Nujol, n cm-1) 2249 (NCO) . M/z (ESI) 816 (M+) . The formation of the duplex between the biomolecule labelled with the compounds of the invention and the nucleic acid to be analysed, for example in the case of ferrocenylic derivatives, can be determined through electrochemical measurements. As described hereafter, for this purpose cyclic volumetry measurements have been carried out in order to preliminarily investigate the efficiency of the analytical response. EXAMPLE 12. Reaction between the compound (32) and a PNA monomer (aminoethylglycinic monomer) to give {{2- [3- (2-ferrocene methylene oxy-1,1-bis-ferrocene methylene oxymethyl-ethyl) -ureido] -ethyl}- [2- (5- methy1-2,4-dioxo- 3,4-dihydro-2H-pyrimidine-l-il) -acetyl] -amino}- acetic acid methyl ester (36) .

(36 ) Into a solution of bis (pentafluorophenyl) carbonate (115 mg, 0.30 mmol) in N-methyl pyrrolidone (1.5 ml), at 00C, the solid compound (20) (example 1) (210 mg, 0.30 mmol), diisopropylamine (DIPEA) (130 μl, 0.74 mmol) and DMF (0.3 ml) are added. It is left under stirring at 00C for Ih, to allow the formation of the corxesponding pentafluorophenyl carbonate (Rf = 0.75, AcOEt/ETP, 6:4) . In a second balloon a solution of PNA aminoethylglycinic trifluoroacetate1 monomer (35 mg, 0.08 mmol) in DMF (0.5 ml) and DIPEA (0.35 ml, 2.0 mmol) is prepared in which the previously separated solution is slowly dripped, at room temperature. It is heated to 45°C for 2h, then the reaction mixture is diluted with CH2Cl2 (25 ml) and washing is carried out with a saturated NaHCO3 solution (3x15 ml) and H2O (2x30 ml) . The organic phase is dried over Na2SO4, filtered and evaporated under vacuum. The crude reaction product is purified through a chromatography column on silica gel (ETP/AcOEt,4 :6 progressively increasing the polarity in (AcOEt/ETP, 6:4 Rf = 0.1) obtaining 74 mg of product that is redissolved in CH2Cl2 (0.5ml) and repxecipitated from pentane. 6-3 mg of yellow solid are obtained, with a yield of 78%. 1H NMR (CDCl3, δ) : 1.8 (s, 3H, CH3) ; 3.3-3.4 (m, 4H, CH2CH2); 3.62 (s, 6H, C(CH2)3); 3.72 (s, 3H, OCH3); 3.96 (s, 2H, CH2COO); 4.10 (s, 15 H, Fc), 4.12 (t, 6H, Fc), 4.17 (t, 6H, Fc) , 4.20 (s, 6H, CH2Fc), 4.28 (s, 2H, CH2CO); 5.7 (bs, 2H, NH); 6.76 (s, IH, CH=); 8.11 (bs, IH, NH); 13C NMR (CDCl3, δ) : 12.3; 37.7; 48.8; 49.0; 49.5; 52.5; 58.9; 68.4-68.5; 69.3; 69.4; 69.7; 83.5; 110.0; 141 . 9 ; 150 . 9 ; 157 . 2 ; 163 . 9 ; 167 . 6 ; 170 . 1 . m/z (ESI+) 1039 (M+); 1062 (M++ "Na) IR- (nujol) (cm"1) 1651 (CO) , 1455- (NHCONH) .

1 Baldoli, Clara; Falciola, Luigi; Licandro, Emanuela; Maiorana, Stefano; Mussini, Patrizia; Ramani, Prasanna; Rigamonti, Clara; Zinzalla, Giovanna. J. Organomet. Chem. 2004, 689 (25) ,4791. EXAMPLE 13. Reaction between lysine and the compound (32) to give 2-carbobenzyloxyamino-6- [3- (2-ferrocene methylene oxy-l,l-bis-ferrocene methylene oxymethyl-ethyl) -ureido] hexanoic acid (37) .

(37) Into a solution of bis (pentafluorophenyl) carbonate (73 mg, 0.18 irunol) in anhydrous DMF (1 ml) at O0C a solution of the compound (20) (example 1) (120 mg, 0.17 mmol) in anhydrous DMF (1 ml) and DIPEA (31 μl, 0.18 mmol) is slowly dripped. It is left under stirring at 00C for Ih, to give the corresponding pentafluorophenyl carbamate. In a second reaction balloon a solution of (L) -N-Cbz lysine (73 mg, 0.25 mmol) in anhydrous DMF (0.5 ml), H2O (0.1 ml) and DIPEA (0.6 ml) is prepared. Into this solution the previously prepared solution is dripped slowly and at room temperature, maintaining the pH at 9-10. The solution is then heated to 45°C for 1 h. The mixture is then diluted with CH2Cl2 (30 ml) and washed with NaHCO3 5% (25 ml) . The aqueous phase is extracted with CH2Cl2 (3x20 ml), the combined organic phases are washed with a 0.3 M solution of KHSO4 (3x10 ml) and then with H2O (20 ml) , dried over Na2SO4, filtered and evaporated. The crude reaction product is purified through a chromatography column on silica gel (ETPrAcOEt,4/6) followed by CH2Cl2:MeOH, l/l to elute the product, which is precipitated from pentane. It is filtered recovering 135 mg of (37) as a yellow solid in a yield of 77%. 1H NMR (CDCl3; δ) : 1.2-1.8 (m, 6H, CH2) ; 2.9-3.0 (m, 2H, CH2NH) ; 3.6 (bs, 7H, CH2 + CH); 4.1-4.3 (m, 33-H,- Pc+ CH2Pc) ; 5.12 (bs, 2H, CH2Ph); 7.3-7.4 (m, 5H, Ph) . 13C(CDCl3,δ) : 22.32; 29.2; 32.11; 39.8; 53.1; 58.8; 66.7; 68.5-69.3; 69.6; 83.6; 128.0-128.3; 136.4; 156.1; 158.5; 177.m/z (ESI+) 1021 (M+); 1044 (M++Na) . M.p. 140-145 0C (dec) . VOLTAMMETRIC ANALYSIS Cyclic voltammetry measurements were carried, out in the case of the compounds (21) , (22) , (23) , (30) , ferrocenyl methanol, as starting product, and ferrocene as potential reference according to IUPAC recommendations. In graph 1 the voltammetric curves of the products (21) , (22) , (23) and ferrocenylmethanol are displayed. In graph 2 the voltammetric curve of the product (30) is displayed in comparison with the curve of tris- ferrocenyl derivate (23) and with ferrocenylmethanol. Voltammetric studies were conducted through a potentiostat/galvanostat Autolab PGSTAT 12 (EcoChemie, Netherlands) managed through a PC with dedicated GPES software, and equipped with a Metrohm 663 VA stand equipped with: rotating disc working electrodes made from Pt (radius 1 mm.) or glassy carbon (GC, radius 1 mm.); a graphite counter electrode; and a saturated calomelane reference electrode (SCE) with double jacket containing KCl 3 M in water. The stability and reproducibility of each system investigated were worked out by checking the coincidence of a reference voltammogram at the start and at the end of each measurement session. Solutioirs-σf DMF, ACN and CH2Cl2 (Merck, HPLC grade) deaerated with a flow of nitrogen (about 10 minutes) , and thermostatted at 298 K were used. Tetraethylammonium perchlorate TEAP and tetrabutylammonium perchlorate TBAP (> 99% Pluka) were used as support electrolytes. The compounds were studied: through cyclic voltammetry on electrodes made from Pt or GC with a non-rotating disc, at concentrations between 10"4 and ICT3 M, at different scanning speeds of the potential (from 20 to 500 mV/s) ; through low-speed scanning voltammetry (5 mV/s) on rotating disc working electrodes made from Pt or GC, at different rotation speeds (from 500 to 3000 revolutions per minute) . Both of the electrodes before being used underwent washing with HNO3 and H2O. The measurement cell was carefully washed with HNO3 and H2O, dried, and finally washed twice with the operative solvent. After thermostatting and deaeration, the cyclic voltammograms were recorded in sequence on a stationary electrode (first the bottom, then the bottom with the addition of the substance, at the different scanning speeds of the potential) , and then on a rotary electrode (at a single scanning speed of the potential but at different rotation speeds) . Some cyclovoltamme-tric curves, obtained in dimethylformamide, are displayed in graph 1. The analysis of such curves leads to the following considerations: the functionalisation of the ferrocenylic alcohol with formation of ether links leads to a small but significant displacement of the cyclovoltammetric characteristics of the ferrocenylic groups in the positive direction; as the ferrocenylic groups increase (from 1 to 3) passing from the compound (21) to (22) to (23) a modest widening of the voltammetric curves can be observed with simultaneous slight displacement of the peak potential towards more positive values, two effects that could be due to an indication of differentiation of the three ferrocenylic groups. On the other hand, the current density (and therefore the intensity of the signal) increases regularly as the number of ferrocenylic groups increases reaching a ratio of about 3 :1 between compound (23) and (21) , which is highly satisfactory for the purposes of detection. In graph 2, on the other hand, the curves obtained in CH3CN are compared relative to the compound (30) , to tris-ferrocenyl derivate (23), and to ferrocenylmethanol. Comparing the derivate (30) with the compound (23) it can be seen that the peak potentials are not significantly different, whereas the peak—current density of (30) , although decreased with respect to (23) (due to the greater molecular complexity and therefore the lower diffusion coefficient, determined by us during the course of the tests on a rotary disc electrode) , still remains very high, so much so that, repeating the same test at gradually lower concentrations, it was noticed that the compound (30) is detectable in cyclic voltammetry up to concentrations in the order of 10"7 M, and in pulsed voltammetry up to concentrations in the order of 10"8 M. ADVANTAGES The compounds of the invention, for example the ferrocenylic derivates when used as labels of biomolecules, determine an increase in the analytical sensitivity with the same amount of biological substance to be analysed. This result is obtained thanks to the presence of many organometallic groups that provide a current intensity that increases as the number of groups increases. Using the compounds of the invention there is also the advantage of being able to link many organometallic groups to the biological molecule through a single reaction, avoiding having to replicate many times the introduction reaction of the organometal; this saves time and money. Thanks to the increased analysis sensitivity, the compounds of the invention can also be used as labels of substances of. pharmaceutical interest (for example antibodies etc.) and of drugs, in order to easily determine their localisation; for example to check whether interaction of the drug with cells and receptors has or has not occurred. The presence of many organometallic groups linked to a drug can also substantially increase its lipophily and therefore its bioavailability.