Ancillary Ligand Effects upon Dithiolene Redox Noninnocence in Tungsten Bis(dithiolene) Complexes

作者：Yan Yong; Keating Christopher; Chandrasekaran Perumalreddy; Jayarathne Upul; Mague Joel T; DeBeer Serena; Lancaster Kyle M; Sproules Stephen; Rubtsov Igor V; Donahue James P^*

来源：Inorganic Chemistry, 2013, 52(11): 6743-6751.

DOI：10.1021/ic4009174

An expanded set of compounds of the type [W(S2C2Me2)(2)L1L2](n) (n = 0: L-1 = L-2 = CO, 1; L-1 = L-2 = (CNBu)-Bu-t, 2; L-1 = CO, L-2 = carbene, 3; L-1 = CO, L-2 = phosphine, 4; L-1 = L-2 = phosphine, 5. n = 2-: L-1 = L-2 = CN-, [6](2-)) has been synthesized and characterized. Despite isoelectronic formulations, the compound set reveals gradations in the dithiolene ligand redox level as revealed by intraligand bond lengths, upsilon(CCchelate)) and rising edge energies in the sulfur K-edge X-ray absorption spectra (XAS). Differences among the terminal series members, 1 and [6](2-), are comparable to differences seen in homoleptic dithiolene complexes related by full electron transfer to/from a dithiolene-based MO. The key feature governing these differences is the favorable energy of the tungsten d orbitals and exert an oxidizing effect on both metal and too high in energy to mix effectively with tungsten and thus leave how, and the degree to which, the redox level of a noninnocent CO pi* orbitals, which are suitably positioned to overlap with tungsten d orbitals and exert an oxidizing effect on both metal and dithiolene ligand via pi-backbonding. The CN- pi* orbitals are too high in energy to mix effectively with tungsten and thus leave the filled dithiolene pi* orbitals unperturbed. This work shows how, and the degree to which, the redox level of a noninnocent ligand can be modulated by the choice of ancillary ligands(s).

• 出版日期2013-6-3