Tc—P, bond distances

The structure of cis-[Tc(C0)2(P(0Et)2Ph)4]C104 shows the metal to be in a distorted octahedral geometry with a mean Tc-P bond distance of 2.41 A, and Tc-CO bond lengths of 1.90 A. Other reported Tc(I) compounds have also been stabilized by the presence of strong --acceptor ligands. These include Tc(C5H5)(CO)3139), [Tc(C5H5)2]2140),... 

Geometry optimizations of Tc2X4(PMej)4 reveal that the calculated Tc-Tc, Tc-X (X = Cl, Br), and Tc-P bond distances are in excellent agreement with the experimental values (Table 7.9) [61]. Calculations confirm the experimental observation that the Tc-Tc bond distance is identical in both... 

Table 7.9 Effective bond order, total bond order, and Tc-Tc, Tc-X, and Tc-P bond distances (A) for Tc2X4(PMej)4 (X = CI, Br) calculated at the CASPT2/VTZP level of theory.

An interesting mixed-ligand complex is [Tc(dppe)2(ox)j, prepared by the reduction of TCO4 by dppe in hot ethanol in the presence of oxalic acid. The average Tc-0 bond distances of 2.13(1) and 2.12(1) A in two independent molecules are somewhat longer than those found in other oxalato complexes (197). Reaction of (NH4)2[Tc Clg] with diethyl phenylphosphonite in the presence of BH4" yields the yellow octahedral rans-[Tc HPhP(OEt)2 4Cl2l, with Tc-P and Tc-Cl bond distances both 2.41(1) A. The low measured magnetic moment of 1.4 BM has been ascribed to partial decomposition (198). 

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