Goncharova-Zapata Olga, Chatterjee Pabitra B, Hou Guangjin, Quinn Laurence L, Li Mingyue, Yehl Jenna, Crans Debbie C, Polenova Tatyana
Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA. ; Tel. +1-302-831-1968.
Department of Chemistry, Colorado State University, Fort Collins, CO 80523-1872, USA. Tel. +1-970-491-7635.
CrystEngComm. 2013 Nov 21;15(43). doi: 10.1039/C3CE41322E.
A series of vanadium(V) complexes with o-dioxolene (catecholato) ligands and an ancillary ligand, (-(salicylideneaminato)ethylenediamine) (hensal), were investigated using V solid-state magic angle spinning NMR spectroscopy (V MAS NMR) to assess the local environment of the vanadium(V). The solid-state V NMR parameters of vanadium(V) complexes with a related potentially tetradentate ancillary ligand (-salicylidene-'-(2-hydroxyethyl)ethylenediamine) (hshed) were previously shown to be associated with the size of the HOMO-LUMO gap in the complex, and as such provide insights on the interaction between metal ion and ligand (P. B. Chatterjee, et al., 50 (2011) 9794). Our results show that the modification of the ancillary ligand does not impact the observed trend between complexes ranging from catechols with electron rich to electron poor substituents. However, the ancillary ligand does impact the size of the HOMO-LUMO separation in the parent complex and thus the solid-state vanadium NMR chemical shift of the unsubstituted vanadium complex. For these complexes significant changes observed in the isotropic shifts and more modest changes detected in the reflect the electronic changes in the complex as the catechol is varied. However, no obvious trend was observed in the chemical shift anisotropies (δ and η) with the variation in the catechol. The electronic changes in the coordination environment of the vanadium can be described using solid-state V NMR spectroscopy.
使用钒固态魔角旋转核磁共振光谱（V MAS NMR）研究了一系列含有邻二氧杂环戊烯（儿茶酚）配体和辅助配体（-（亚水杨基氨基）乙二胺）（hensal）的钒（V）配合物，以评估钒（V）的局部环境。先前已表明，含有相关潜在四齿辅助配体（-亚水杨基-'-（2-羟乙基）乙二胺）（hshed）的钒（V）配合物的固态V NMR参数与配合物中HOMO-LUMO能隙的大小有关，因此能提供有关金属离子与配体之间相互作用的见解（P. B. Chatterjee等人，50（2011）9794）。我们的结果表明，辅助配体的修饰不会影响从具有富电子到贫电子取代基的儿茶酚的配合物之间观察到的趋势。然而，辅助配体确实会影响母体配合物中HOMO-LUMO间距的大小，从而影响未取代钒配合物的固态钒NMR化学位移。对于这些配合物，随着儿茶酚的变化，在各向同性位移中观察到显著变化，在[此处原文缺失相关内容]中检测到更适度的变化，这反映了配合物中的电子变化。然而，随着儿茶酚的变化，在化学位移各向异性（δ和η）中未观察到明显趋势。钒配位环境中的电子变化可以用固态V NMR光谱来描述。
