A Strong Metal-to-Metal Interaction in an Edge-Sharing Bioctahedral Compound that Leads to a Very Short Tungsten–Tungsten Double Bond
详细信息 查看全文
- 作者：Gina M. Chiarella ; F. Albert Cotton ; Carlos A. Murillo ; Qinliang Zhao
- 刊名：Inorganic Chemistry
- 出版年：2014
- 出版时间：February 17, 2014
- 年：2014
- 卷：53
- 期：4
- 页码：2288-2295
- 全文大小：457K
- ISSN：1520-510X
文摘
An ionic edge-sharing bioctahedral (ESBO) species has been prepared having a tetramethylated bicyclic guanidinate with two fused six-membered rings characterized by a fairly flat N鈥揅(N)鈥揘 skeleton and abbreviated as TMhpp. The anion has two WIV atoms bridged by two oxo groups; the metal atoms are also spanned by two bridging guanidinate ligands, and each has two monodentate chlorine atoms. The complex formulated as (H2TMhpp)2[W(渭-O)(渭-TMhpp)Cl2]2 has the shortest W鈥揥 distance (2.3318(8) 脜) of any species with a 蟽2蟺2 electronic configuration. The anion and cations are connected by hydrogen bonds. To unambiguously ascertain the existence of the double-bonded W2(渭-O)2 entity, density functional theory calculations and natural bond orbital analyses were done on an analogous but hypothetical species with a W2(渭-OH)2 core having trivalent tungsten atoms and a possible 蟽2蟺2未2 electronic configuration. The calculations decidedly support the presence of tungsten鈥搊xo instead of tungsten鈥揾ydroxo groups and thus the existence of the double-bonded W2(渭-O)2 core. The strong bonding interaction between metal atoms is a clear indication that under certain circumstances the two octahedra in ESBO species do not behave as the sum of two mononuclear compounds.