Structural models for [M(CO)3(H2O)3]+ (M=Tc, Re): fully aqueous synthesis of technetium and rhenium tricarbonyl complexes of tripodal oxygen donor ligands

The reaction of [M(H2O)3(CO)3]+ (M=Tc, Re) with Na[CpCo[PO(OR)2]3] (NaLOR; R=Me, Et) in water produced the compounds M(CO)3(LOR), all of which were yellow solids, in yields varying from 55 to 89%. The two compounds M(CO)3(LOEt) were structurally characterized by single crystal X-ray crystallography. In both cases, the ligand LOEt was bound to the metal center in a tridentate fashion utilizing an {OOO} donor set. The ligands LOR can be used as models for facially coordinated triaqua groups owing to their position in the spectrochemical series. Therefore, these four compounds, M(CO)3(LOR), can be considered structural models for [M(H2O)3(CO)3]+. Crystal data for Tc(CO)3(LOEt) are as follows: molecular formula C20H35CoO12P3Tc, MW=717.32, monoclinic, a=11.5661(11) Å, b=18.671(2) Å, c=13.7852(13) Å, β=92.770(2)°, V=2973.5(5) Å3, space group P21/n, Z=4, final R1=0.0669, wR2=0.1361. Crystal data for Re(CO)3(LOEt) are as follows: molecular formula C20H35CoO12P3Re, MW=805.52, monoclinic, a=11.5113(7) Å, b=18.6022(12) Å, c=13.7397(8) Å, β=92.7580(10)°, V=2938.7(3) Å3, space group P21/n, Z=4, final R1=0.0384, wR2=0.0760.