On The Reactivity Of Platina-Beta-Diketone And Acetylplatinum(Ii) Complexes Toward 2-(Diphenylphosphanyl)Benzaldehyde And Its Dioxolane Derivative

The dinuclear platina--diketone [Pt-2{(COMe)(2)H}(2)(-Cl)(2)] (1) reacts with four and two equivalents of 2-[2-(diphenylphosphanyl)phenyl]-1,3-dioxolane (L1) to yield [Pt(COMe)Cl(PPh2{o-C6H4CH(O2C2H4)}-P)(2)] (3) and [Pt(COMe)Cl(PPh2{o-C6H4CH(O2C2H4)}-P,O)] (4), respectively. The weak Pt-O bond in 4 can be easily broken up by stronger donors. Thus, complex 4 reacts with PPh3 to yield [Pt(COMe)Cl(PPh3)(PPh2{o-C6H4CH(O2C2H4)}-P)] (5) and [Pt(COMe)Cl(PPh3)(2)] (6) as well as with L1 to yield 3. Diacetylbis(amine)platinum(II) complexes cis-[Pt(COMe)(2)(NH2R)(2)] (R = Bn, 2a; R = Et, 2b; Bn = benzyl) react with L1 with the substitution of one amine ligand to yield [Pt(COMe)(2)(NH2R)(PPh2{o-C6H4CH(O2C2H4)}-P)] (R = Bn, 7a; R = Et, 7b). The unprotected 2-(diphenylphosphanyl)benzaldehyde (L2) reacts with the platina--diketone 1 by oxidative C-H addition followed by reductive elimination of acetaldehyde to form [PtCl{PPh2(o-C6H4CO)-P,C}{PPh2(o-C6H4CHO)-P}] (8). On the other hand, the reactions of diacetylbis(amine)platinum(II) complexes 2a/b and L2 proceeded with Schiff base formation and, thus, yielded complexes bearing hemiaminal-phosphane ligands, [Pt(COMe)(2)(PPh2{o-C6H4CH(OH)(NHR)}-P,N)] (R = Bn, 9a; R = Et, 9b), and imine-phosphane ligands, [Pt(COMe)(2){PPh2(o-C6H4CH=NR)-P,N}] (R = Bn, 10a; R = Et, 10b). The identities of all platinum complexes were unambiguously proved by microanalyses, high-resolution mass spectrometric investigations, NMR (H-1, C-13, P-31, Pt-195) and IR spectroscopy, and single-crystal X-ray diffraction analyses (for 4, 9a). The differences in the reactivity of the aldehyde-phosphane L2 and its acetal-protected derivative L1 are discussed.