Cooney Shannon E, Marinho Thompson V, Duggan S Genevieve, Shiels Dominic, Brennessel William W, Miro Pere, Matson Ellen M
Department of Chemistry, University of Rochester, Rochester, New York 14627, United States.
Department of Chemistry, University of Iowa, Iowa City, Iowa 542240, United States.
JACS Au. 2025 Jun 12;5(7):3433-3443. doi: 10.1021/jacsau.5c00482. eCollection 2025 Jul 28.
The synthesis of a niobium-(V) substituted polyoxovanadate-alkoxide (NbPOV-alkoxide; [NbVO(OCH)]) is reported. Addition of 5,10-dihydrophenazine to [NbVO(OCH)] results in formation of the 2 H/e reduced assembly, [NbVO(OH)-(OCH)], via proton-coupled electron transfer. [NbVO(OH)-(OCH)] has a bond dissociation free energy (BDFE-(O-H)) of 62.3 kcal mol, resembling that of its homometallic congener, [VO(OH)-(OCH)] (BDFE-(O-H) = 62.3 kcal mol). Single-crystal X-ray diffraction reveals that [NbVO(OH)-(OCH)] exists as a mixture of two structural isomers, with the vanadium-aquo moiety formed in either the - or - positions relative to the Nb-(V) dopant. The formation of two regioisomers is a departure from prior observations of H-atom uptake at the surface of heterometal-doped polyoxovanadate-alkoxides, and is credited to distortions in intercluster metal oxygen bond lengths. Improved selectivity for the - isomer is achieved by decreasing the dielectric constant of the reaction solvent. Computational analysis predicts the preferential formation of -[NbVO(OH)-(OCH)] in solvents with low dielectric constants as a result of changes to the dispersed charge across the assembly.
报道了一种铌（V）取代的多氧钒酸醇盐（NbPOV-醇盐；[NbVO(OCH)]）的合成。将5,10-二氢吩嗪添加到[NbVO(OCH)]中，通过质子耦合电子转移形成2H/e还原组装体[NbVO(OH)-(OCH)]。[NbVO(OH)-(OCH)]的键解离自由能（BDFE-(O-H)）为62.3 kcal/mol，与其同金属类似物[VO(OH)-(OCH)]（BDFE-(O-H)=62.3 kcal/mol）相似。单晶X射线衍射表明，[NbVO(OH)-(OCH)]以两种结构异构体的混合物形式存在，钒-水部分相对于Nb-(V)掺杂剂在α或β位置形成。两种区域异构体的形成与之前在杂金属掺杂的多氧钒酸醇盐表面氢原子摄取的观察结果不同，这归因于簇间金属-氧键长度的扭曲。通过降低反应溶剂的介电常数，可以提高α异构体的选择性。计算分析预测，由于组装体上分散电荷的变化，在低介电常数的溶剂中优先形成α-[NbVO(OH)-(OCH)]。
