Training Module 1 : Using Stata for Survey Data Analysis
The equilibrium geometries and bond dissociation energies of 16-valence-electron(VE) complexes (PMe(3))(2)Cl(2)M(E) and 18-VE complexes (PMe(3))(2)(CO)(2)M(E) with M=Fe, Ru, Os and E=C, Si, Ge, Sn were calculated by using density functional theory at the BP86/TZ2P level. The nature of the M-E bond was analyzed with the NBO charge decomposition analysis and the EDA energy-decomposition analysis. The theoretical results predict that the heavier Group 14 complexes (PMe(3))(2)Cl(2)M(E) and (PMe(3))(2)(CO)(2)M(E) with E=Si, Ge, Sn have C(2v) equilibrium geometries in which the PMe(3) ligands are in the axial positions. The complexes have strong M-E bonds which are slightly stronger in the 16-VE species 1ME than in the 18-VE complexes 2ME. The calculated bond dissociation energies show that the M-E bonds become weaker in both series in the order C>Si>Ge>Sn; the bond strength increases in the order FeE pi-acceptor bonds, which are not degenerate. The shape of the frontier orbitals reveals that the HOMO-2 sigma MO and the LUMO and LUMO+1 pi MOs of 1ME are very similar to the frontier orbitals of CO.