New chemistry of the triply bonded divanadium (V2 4+) unit and reduction to an unprecedented V2 3+ core.
New chemistry of the triply bonded divanadium (V2 4+) unit and reduction to an unprecedented V2 3+ core.
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三键合钒 (V2 4 ) 单元的新化学成分并还原为前所未有的 V2 3 核心。
DOI：
10.1021/ic034646e
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发表时间：
2003
影响因子：
4.6
通讯作者：
Xiaoping Wang
中科院分区：
文献类型：
--
作者：
F. Cotton;E. Hillard;C. A. Murillo;Xiaoping Wang
本文报道了七个新的具有轮状结构的含氮配体桥连的双钒化合物的合成和表征。其中5个含有抗磁性V（2）（4+）核，其短V-V距离小于2.0 A，与形式三键一致。V-V距离随桥接配体的碱性而变化;碱性更强的配体如胍基型配体具有更短的金属-金属分离，而碱性更弱的甲脒基具有更长的分离。V（2）（DPhF）（4）（DPhF = N，N ′-二苯基甲脒的阴离子）被还原一个电子，得到两个结构[K（THF）（3）]V（2）（DPhF）（4）和[K（18-冠-6）（THF）（2）]V（2）（DPhF）（4）.它们具有前所未有的V（2）（3+）核心，其中每个钒原子的形式氧化态为+1.5。在还原物种的V-V键距和多线EPR光谱的减少提供证据，这两个分子包含一个键的顺序3.5。
We report here the synthesis and characterization of seven new divanadium compounds with the paddlewheel geometry bridged by nitrogen-donating ligands. Five of these contain the diamagnetic V(2)(4+) core with short V-V distances of less than 2.0 A, consistent with a formal triple bond. The V-V distances vary with the basicity of the bridging ligands; more basic ligands such as those of the guanidinate type have the shorter metal-metal separations, and those with the less basic formamidinate groups have longer separations. One compound, V(2)(DPhF)(4) (DPhF = the anion of N,N'-diphenylformamidine), has been reduced by one electron, and two structures, [K(THF)(3)]V(2)(DPhF)(4) and [K(18-crown-6)(THF)(2)]V(2)(DPhF)(4), have been obtained. These have an unprecedented V(2)(3+) core where the formal oxidation state of each vanadium atom is +1.5. The decrease in V-V bond distance and the multiline EPR spectrum in the reduced species provide evidence that these two molecules contain a bond of order 3.5.