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31.19

Hoá học

So sánh các tính toán lý thuyết hàm mật độ đối với năng lượng và sự khác nhau cấu trúc giữa các ligands E(PH3)2 và NHEMe của các phức chất tungsten pentacarbonyl (E = C, Si, Ge, Sn, Pb)

Comparison of density functional theory calculations for energy and structural differences between ligands E(PH3)2 and NHEMe of tungsten pentacarbonyl complexes (E = C, Si, Ge, Sn, Pb)

Hóa học

2014

5

602-609

0866-7144

A comparison of DFT is made for the calculation of geometry, bond dissociation energy (BDE), and dispersion interaction differences between complexes with ligand carbodiphosphorane-analogues (called tetrylones) [(CO)5W{E(PH3)2}] (W5-EP2) and complexes with ligand N-heterocyclic carbene-analogues (called tetrylenes) [(CO)5W{NHEMe}] (W5-NHEMe) when E = C - Pb. Gradient-corrected (BP86) density-functional calculations were chosen to study the structures and energies of two systems using quantum chemical calculations at BP86/TZVPP // BP86/SVP level of theory. The calculated equilibrium structures of the complexes [(CO)5W-{E(PH3)2}] show that the carbone ligand C(PH3)2 is bonded head-on to the metal fragment in the adduct W5-CP2, but the heavier homologues W5-SiP2 to W5-PbP2 have side-on bonded ligands E(PH3)2. The trend of the bond dissociations energies (BDEs) for the W-E bond in W5-EP2 system is W5-CP2 W5-SiP2 W5-GeP2 W5-SnP2 W5-PbP2. In contrast,.the complexes [(CO)5W{NHEMe}] (W5-NHEMe) possess end-on-bonded NHEMe ligands with E W5-NHSiMe W5-NHGeMe W5-NHSnMe W5-NHPbMe. The BDEs calculated for the W-E bonds in W5-EP2 and W5-NHEMe systems considering dispersion interactions show that the effect of bulky ligands E(PH3)2 and NHEMe influence the intrinsic W-E bond strength. These results suggest that this interesting class of compounds is worth further study.

TTKHCNQG, CVv 14