NEW METHOXO-BRIDGED, HYDROXO-BRIDGED AND PYRAZOLATE-BRIDGED PLATINUM(II) COMPLEXES - CRYSTAL-STRUCTURE OF [NBU4]2[(PT(C6F5)2)2(MU-OH)-(MU-DMPZ)] (DMPZ = 3,5-DIMETHYLPYRAZOLATE)

The hydroxo complex [{Pt(C6F5)2(mu-OH)}2]2- reacts with azoles (1:1 molar ratio) in benzene to give the double bridged complexes [{Pt(C6F5)2}2(mu-OH)(mu-L-L)]2- [L-L = pyrazolate (pz) 1, 3,5-dimethylpyrazolate (dmpz) 2, 3-methylpyrazolate (mpz) 3 or indazolate(indz) 4]. When the same reaction is carried out in methanol with the reactants in 1;2 molar ratio the corresponding di-mu-azolate derivatives [{Pt(C6F5)2(mu-L-L}2]2- [L-L = pz 5, dmpz 6, mpz 7 or indz 8] are obtained. On treatment of [{Pt(C6F5)2(mu-OH)}2]2- with methanol the di-mu-methoxo complex [{Pt(C6F5)2(mu-OMe)}2]2- 9 was obtained. The di-mu-azolate complexes 5-8 can be alternatively prepared by treatment of 9 with the respective azoles (1:2 molar ratio) in methanol. Reaction of complex 1 with methanol leads to the formation of [{Pt(C6F5)2}2(mu-OMe)(mu-pz)]2- 10. All the complexes have been isolated as the [NBu4]+ salts. Spectroscopic (IR, H-1 and F-19 NMR) data have been used for structural assignments, and an X-ray structure determination carried out for [NBu4]2[{Pt(C6F5)2}2(mu-OH)(mu-dmpz)] has established the binuclear nature of the anion. The structure was solved and refined to R = 0.057 and R' = 0.089 based on 10057 observed reflections. The Pt atoms are four-co-ordinated, Pt(1)-O 2.113(7), Pt(1)-N(1) 2.04(1), Pt(1)-C(10) 2.02(1), Pt(1)-C(20) 1.96(2), Pt(2)-O 2.077(9), Pt(2)-N(2) 2.075(9), Pt(2)-C(30) 1.97(2), Pt(2)-C(40) 2.00(1) angstrom, and show deviations from a square-planar arrangement towards a tetrahedral disposition.