SYNTHESIS AND REACTIVITY OF MOPT BIMETALLIC SYSTEMS CONTAINING THE LIGAND 2-OXACYCLOPENTYLIDENE

Oxidative addition of P-H bonds of primary/ secondary phosphines, bound to Mo-2-oxacyclopentylidene systems, to Pt(0) complexes results in the transfer of the 2-oxacyclopentylidene ligand from the Mo to the Pt center. The cationic 2-oxacyclopentylidene complexes cis-[Cp(OC)2Mo(COCH2CH2CH2)-(PPh2H)]BPh4 and irans-[Cp(OC)2Mo(COCH2CH2CH2)(PCy2H)]BPh4, obtained from the reaction of Cp(OC)3Mo(CH2CH2CH2Br) with PR2H and NaBPh4> react (i) with Pt(C2H4)2(PCy3) to give [Cp-(OC)2Mo(M-PR2)(M-H)Pt(COCH2CH2CH2)(PCy3)]BPh4 and (ii) with Pt(C2H4)(PPh3)2 to give equimolar mixtures of[Cp(OC)2Mo(M-PR2)(M-H)Pt(COCH2CH2CH2)(PPh3)]BPh4, Cp(OC)2Mo(R2PCOCH2CH2CH2), and [PtH(PPh3)3]BPh4. Reaction of Cp(OC)2Mo(COCH2CH2CH2)(PCyH2)]BPh4 with Pt(C2H4)(PPh3)2 gives a mixture of trans(Mo),cis(Pt)-[Cp(OC)2Mo(COCH2CH2CH2)(M-PCyH)PtH(PPh3)2]BPh4 and [Cp-(OC)2Mo(Z-PCy(CHOCH2CH2CH2))(Z-H)Pt(PPh3)2]BPh4. The complexes Cp(OC)2Mo-(R2PCOCH2CH2CH2) are readily obtained from the reaction of 7 or 8 with base (Proton Sponge). Themolecular structure o[Cp(OC)2Mo(M-PPh2)(M-H)Pt(COCH2CH2CH2)(PCy3)]BPh4-CH2Cl2 (10a) has been determined by single-crystal X-ray diffraction. Crystal data for 10a: C66H76BCl2Mo03P2Pt, fw = 1352.0, monoclinic, space group P2Jc, Z = 17.920 (3) A, b = 19.605 (4) A, c = 18.301 (3) Z, Z = 108.95 (1)°, V = 6081 A3, Du = 1.48 g cm“3 for Z = 4; Å(wÅ) = 0.052 (0.051) for 5973 reflections with F 6 Z{Z). The structure of 10a contains square-planar Pt and distorted 4:3 “piano-stool” Mo centers, which are linked by bridging diphenylphosphido and hydrido ligands with Pt-(μ-P)-Mo and Pt-(μ-H)-Mo bond angles of 81.28 (9) and 149 (7)°, respectively. The Pt-Mo separation (3.063 (1) A) is long and weak. © 1990, American Chemical Society. All rights reserved.