RHENIUM CARBONYL-COMPLEXES WITH BIS(DIPHENYL PHOSPHINO)METHANE - X-RAY CRYSTAL-STRUCTURE OF [REBR(CO)2(PH2PCH2PPH2)(PH2PCH2P'PH2).0.43[REBR(CO)2(PH2PCH2PPH2)(PH2PCH2P(O)PH2)]

The reaction of fac-[ReBr(CO)3(dppm)] (dppm = Ph2PCH2PPh2) with dppm in refluxing xylene gave the dicarbonyl cis-mer-[ReBr(CO)2(dppm-P)(dppm-P,P')] (Id) in which one dppm is monodentated. This compound reacted with oxygen in xylene at room temperature to give first the P-oxide derivative cis-mer-[ReBr(CO)2(dppm-P)(dppm-P,PO)] (II), that subsequently decomposes with formation of Ph2P(O)CH2P(O)PPh2. The X-ray structure of I has been determined in a crystal containing 30% of II. The reaction of I with TlPF6 in CH2Cl2 gave the cationic cis-[Re(CO)2(dppm-P)2]PF6 (III).