6 Y. Yamamoto, T. Tanase, H. Ukaji, M. Hasegawa, T. Igoshi and
within the range assigned as P trans to S. The spectrum also
showed another resonance at 48.36 ppm, which is assigned to
Pa. The 1H NMR spectrum showed peaks at 2.44 and 2.22 ppm
assignable to the S-methyl and acetyl protons of the bound
amino acid shifted to low field upon coordination through
sulfur.61 This indicates the formation of the monofunctional
adduct [Pt(triphos)(AcMet-S)]ϩ, 8.
K. Yoshimura, J. Organomet. Chem., 1995, 498, C23.
7 T. Tanase, H. Toda and Y. Yamamoto, Inorg. Chem., 1997, 36,
1571.
8 K. D. Tan, R. Uriarte, T. J. Mazanec and D. W. Meek, J. Am. Chem.
Soc., 1979, 101, 6614.
9 J. Chatt, R. Mason and D. W. Meek, J. Am. Chem. Soc., 1975, 97,
3826.
10 B. Longato, G. Pilloni, G. Valle and B. Corain, Inorg. Chem., 1988,
27, 956.
Reaction of [PtAu(triphos)Cl3], 4, with thiols. The reaction of
[PtAu(triphos)Cl3] and GSH in 1:1 molar ratio in DMF–D2O
(4:1) at ca. pH 3 (uncorrected meter reading) gave rise to
a white precipitate that was filtered off. The 31P NMR spec-
trum of the clear solution showed two peaks at 88.05 ppm,
J(P–Pt) = 3099 Hz, and 42.99 ppm, J(P–Pt) = 2442 Hz, for
which reasonable assignments are to Pb and Pa, respectively,
of complex 2, [Pt(triphos)Cl]ϩ. After the addition of 2 molar
equivalents of GSH in the same solvent system at pH 7.53,
the 31P NMR spectrum of the reaction mixture showed peaks
at 90.60 ppm, J(P–Pt) = 2319 Hz, and 45.45 ppm, J(P–Pt) =
2559 Hz, these peaks are assigned to Pb and Pa, respectively,
of [Pt(triphos)(GS)]ϩ adduct, 5, which arises from the further
reaction of 2 with GSH.
11 (a) B. Longato, G. Pilloni, G. M. Bonera and B. Corain, J. Chem.
Soc., Chem. Commun., 1986, 1478; (b) B. Longato, B. Corain,
G. M. Bonera and G. Pilloni, Inorg. Chim. Acta, 1987, 137, 75.
12 (a) B. Lippert, Prog. Inorg. Chem., 1989, 37, 1; (b) B. Lippert, Gazz.
Chim. Ital., 1989, 118, 153 and references therein.
13 G. Bandoli, G. Trovo, A. Dolmela and B. Longato, Inorg. Chem.,
1992, 31, 45.
14 A. Habtemariam and P. J. Sadler, Chem. Commun., 1996, 1785.
15 N. Margiotta, A. Habtemariam and P. J. Sadler, Angew. Chem., Int.
Ed. Engl., 1997, 36, 1185.
16 P. Sevillano, A. Habtemariam, A. Castiñeiras, M. E. García and
P. J. Sadler, Polyhedron, 1998, 18, 383.
17 C. E. Housecroft, B. A. M Shaykh and A. C. Rheingold, Acta
Crystallogr., Sect. C, 1990, 46, 1549.
18 E. G. Hope, W. Levason and N. A. Powell, Inorg. Chim. Acta, 1986,
115, 187.
The reaction of [PtAu(triphos)Cl3], 4 with N-acetyl--
cysteine in 1:1 molar ratio at ca. pH 3 in DMF–D2O (4:1) led
to the formation of a white precipitate. After the filtration of
the solid, 31P NMR spectrum of the solution was recorded
(Table 4). It showed two peaks at 88.06 ppm, J(P–Pt) = 3095
Hz, and 42.93 ppm, J(P–Pt) = 2444 Hz, assignable to Pb and Pa
of complex 2, [Pt(triphos)Cl]Cl, respectively. After the addition
of the 2 molar equivalents of amino acid (ca. pH 7.21),
the 31P NMR spectra of the reaction mixture showed two peaks
at 90.96 ppm, J(P–Pt) = 2292 Hz, and 45.12 ppm J(P–Pt) =
2569 Hz. These peaks were assigned to Pb and Pa of
[Pt(triphos)(AcCys)]ϩ, 7, respectively. Thus the high affinity of
Au() for thiolates62 dominates reactions of complex 4 with
thiols and Au() is readily extracted from the bimetallic com-
plexes allowing chelate ring closure.
19 R. Colton and V. Tedesco, Inorg. Chim. Acta, 1992, 202, 95.
20 R. Colton and T. Whyte, Aust. J. Chem., 1991, 44, 525.
21 W. H. Baddley, F. Basolo, H. B. Gray, C. Nölting and A. J. Poë,
Inorg. Chem., 1963, 2, 921.
22 S. J. Berners-Price and P. J. Sadler, Inorg. Chem., 1986, 25, 3822.
23 E. F. de Assis and C. A. L. Filgueiras, Transition Met. Chem., 1994,
19, 484.
24 Enraf-Nonius. CAD4-Express Software, Version 5.1, Enraf-
Nonius, Delft, The Netherlands, 1995.
25 A. L. Speck, HELENA, A Program for Data Reduction of CAD4
Data, University of Ultrech, The Netherlands, 1997.
26 A. L. Spek, PLATON, A Multipurpose Crystallographic Tool,
University of Ultrech, The Netherlands, 1997.
27 G. M. Sheldrick, Acta Crystallogr., Sect. A, 1983, 39, 158.
28 G. M. Sheldrick, SHELXL97, Program for the Refinement of
Crystal Structures, University of Göttingen, Germany, 1997.
29 International Tables for X-ray Crystallography, Kluwer Academic
Publishers, Dordrecht, The Netherlands, 1995, vol. C.
30 E. Keller, SCHAKAL 92, A Computer Program for the Graphic
Representation of Molecular and Crystallographic Models,
University of Freiburg, Germany, 1992.
Conclusion
We have shown that Au() can induce chelate ring-opening in
Pd() and Pt() triphos complexes to give novel bimetallic com-
plexes which were shown by X-ray crystallography to contain
square-planar Pd() and Pt() and linear Au() centres. It was
possible to reverse chelate ring-opening via Au() abstraction
from the bimetallic complex 4, [PtAu(triphos)Cl3] using thiols
such as the tripeptide glutathione. We also have shown that
thiolate adducts of [Pt(triphos)]2ϩ have good aqueous solu-
bility. Substitution of the thiol by the nucleotide 5Ј-GMP
in [Pt(triphos)(GS)]ϩ was observed in the presence of Au().
These studies provide the basis for further investigation of the
biological activity of this class of complexes.
31 L. Zsolnai, ZORTEP, A Program for the Presentation of Thermal
Ellipsoids, University of Heidelberg, Germany, 1997.
32 J. Casier and A. M. Glaze, J. Appl. Crystallogr., 1986, 19, 205.
33 W. Clegg, Acta Crystallogr., Sect. A, 1981, 37, 22.
34 G. M. Sheldrick, SHELXTL V. S., Siemens Analytical X-ray
instruments, Madison, Wisconsin, 1995.
35 D. J. Watkin, C. K. Prout, P. W. Betteridge and J. R. Curruthers,
CRYSTALS, Issue 10, Chemical Crystallography Laboratory,
University of Oxford, 1996.
36 N. Walken and D. Stuart, Acta Crystallogr., Sect. A, 1983, 39, 158.
37 R. B. King, P. N. Kapoor and R. N. Kapoor, Inorg. Chem., 1971,
10. 1841.
38 A. K. Al-Sa’ady, C. A. McAullife, R. V. Parish and J. A. Sandbank,
Inorg. Synth., 1985, 23, 191.
39 A. Albinati, F. Lianza, H. Berger, P. J. Pregosin, H. Rüegger and
R. W. Kunz, Inorg. Chem., 1993, 32, 478.
40 W. J. Geary, Coord. Chem. Rev., 1971, 7, 81.
Acknowledgements
We thank Xunta de Galicia (projects XUGA 20903A93 and
XUGA 20906A98), Predoctoral Grant for P. S., BBSRC and
EPSRC for their support for this work. We also acknowledge
assistance of Dr Lesley Yellowlees (The University of
Edinburgh) with the use of the electrochemical equipment.
41 A. Handler and P. Peringer, J. Chem. Soc., Dalton Trans., 1990,
3725.
42 G. K. Anderson, H. C. Clark and J. A, Davies, Inorg. Chem., 1983,
83, 434.
43 P. E. Garrou, Chem. Rev., 1981, 81, 229.
44 K. D. Tau, R. Uriarte, T. J. Mazanec and D. W. Meek, J. Am. Chem.
Soc., 1979, 101, 6614.
45 R. G. Pearson, Inorg. Chem., 1973, 12, 713.
46 W. McFarlane and J. Cass, J. Chem. Soc., Dalton Trans., 1974, 324.
47 C. J. Smith, V. S. Reddy and V. Katti, Chem. Commun., 1996, 2557.
48 G. I. Bertinsson, Acta Crystallogr., Sect. C, 1983, 39, 563.
49 F. H. Allen, O. Kennard and R. Taylor, Acc. Chem. Res., 1983, 16,
143.
References
1 F. A. Cotton and B. Hong, Prog. Inorg. Chem., 1992, 40, 179.
2 S. J. Berners-Price and P. J. Sadler, Struct. Bonding, 1988, 70, 27.
3 C. Bolm, D. Kaufmann, S. Gesslers and K. Harms, J. Organomet.
Chem., 1995, 502, 47.
4 D. L. DuBois, A. Miedaner and R. C. Haltiwanger, J. Am. Chem.
Soc., 1991, 113, 8753.
5 R. E. Rülke, J. G. P. Delis, A. M. Groot, C. J. Elsevier, P. W. N. M.
van Leeuwen, K. Vrieze, K. Groubitz and H. Schenk, J. Organomet.
Chem., 1996, 508, 109.
50 W. C. Hamilton, Structural Chemistry and Molecular Biology,
ed. A. Rich and N. Davison, Freeman, San Francisco, 1968, p. 466.
51 C. Navarro-Ranninger, F. Zamora, I. Lopez-Solera, A. Mengl and
J. R. Masaguer, J. Organomet. Chem., 1996, 506, 149.
52 A. Habtemariam, P. J. Sadler, S. Parsons, A. Castiñeiras,
J. Chem. Soc., Dalton Trans., 1999, 2861–2870
2869