Tertiary phosphine complexes of cyclopentadienylmolybdenum carbonyl halides. Stereoselective syntheses and isomer separations

Abstract

Pure cis and trans isomers of CpMo(CO) 2(L)X (Cp = η 5-C 5H 5, L = PPh 3 or PBu 3, X = Br, or I) have been separated by chromatography and characterized by infrared and proton NMR spectroscopy. The reactions of trans-CpMo(CO) 2(L)CH 3 with HgX 2 (X = Cl, Br, I, SCN) afford cis-CpMo(CO) 2(L)X in high yield. Both linkage isomers are obtained in the reaction with Hg(SCN) 2, L = PPh 3. The mercuric halides react with CpMo(CO) 2(L)COCH 3 to form the metalmetal bonded derivatives trans-CpMo(CO) 2(L)HgX. Reactions of CpMo(CO) 2(L)CH 3 or CpMo(CO) 2(L)COCH 3 with bromine or iodine yield the halide complexes CpMo(CO) 2(L)X (X = Br and I, respectively), the product mixtures containing high proportions of the trans isomers.