HETEROATOMIC CHELATION OF MIXED PHOSPHINE (OR ARSINE) AND PHOSPHINE OXIDE LIGANDS WITH RHENIUM(V) - SYNTHESIS, CHARACTERIZATION, AND X-RAY STRUCTURAL INVESTIGATIONS OF NEW RHENIUM(V) METALLACYCLIC COMPOUNDS - (O)PPH2(CH2)NEPH2RE(O)CL3 (E = P, AS)

The reactions of (O)PPh2CH2PPh2 (1) and (O)PPh2CH2CH2AsPh2 (3) with ReOC14-, generated from NH4ReO4 and concentrated HCI, produced (O)PPh2CH2PPh2Re(O)Cl3 (2) and (O)PPh2CH2CH2AsPh2Re(O)Cl3 (4), respectively. The monoethoxy derivatives (O)PPh2CH2PPh2Re(O)(OEt)Cl2 (5) and (O)PPh2CH2CH2AsPh2Re-(O)(OEt)Cl2 (6) were prepared by performing the above reactions in ethanol medium. The Re(V) complex Re-(O)Cl3(PPh3)2 (7) undergoes ligand-exchange reactions with 1 or 3 to produce 2 and 4, respectively. The chemical compositions of all the new complexes have been established by analytical data and H-1 NMR, P-31 NMR, and IR spectroscopic data. The structure of 2 has been confirmed by an X-ray crystallographic study. The structure comprises the neutral monomeric complex (O)PPh2CH2PPh2Re(O)CI3 With two crystallographically independent molecules in the asymmetric unit and a cocrystallized molecule of tetrahydrofuran. Crystal data: monoclinic space group P2(1)/c, a = 19.689 (4) angstrom, b = 20.030 (3) angstrom, c = 14.776 (4) angstrom, beta = 91.329 (10)-degrees, V = 5825.7 (22) angstrom3, Z = 8. The structure was solved by direct methods and was refined to R = 0.048.