顺磁性五坐标复合离子[ML(S)] 2+(M = Co II或Ni II ; L = 1,4,8,11-tetramethyl-1 ,4,8,11-四氮杂环十四烷,S = NCMe或OH 2)表明镍(II)配合物比钴(II)类似物更不稳定。对于乙腈溶剂交换,镍(II)和钴(II)配合物的ΔS ‡值较大而为负,而ΔH ‡值较低,这与缔合交换(I a)机理相符。以前的通过15 N nmr证实了[NiL(NCMe)] 2+离子的13 C nmr线扩展结果,并且对高自旋[CoL(NCMe)] 2进行了类似的13 C和15 N线扩展研究。 +离子给出(在298.2 K时):10 –5 k ex。= 5.65±0.50 s –1, ΔH ‡ = 19.5±0.8 kJ mol –1, ΔS ‡ = –69.5±3.5 JK –1 mol –1。与母体六溶剂化金属离子的比较表明,四方大环配体(L)显着降低了ΔH
DOI:
10.1039/dt9800000574
作为产物:
描述:
在
4-bromoanilinium tetrafluoroborate 作用下,
以
not given 为溶剂,
生成
参考文献:
名称:
Comparison of Cobalt and Nickel Complexes with Sterically Demanding Cyclic Diphosphine Ligands: Electrocatalytic H2 Production by [Co(PtBu2NPh2)(CH3CN)3](BF4)2
摘要:
The cyclic diphosphine ligands (P2N2ph)-N-tBu and (P2N2Bz)-N-tBu have been synthesized and used to prepare new complexes of Co(II) and Ni(II) with the formula [M((P2N2R)-N-tBu)(CH3CNn](BF4)(2) (n = 2,3). The products have been characterized by variable-temperature NM R data, X-ray diffraction studies, and cyclic voltammetry, and properties of the new complexes have been compared with those of previously studied complexes containing (P2N2R)-N-ph ligands. The variation of either phosphorus or nitrogen substituents in these ligands can result in significant differences in the structure, electrochemistry, and reactivity of the metal complexes. [Co((P2N2Ph)-N-tBu)(CH3CN](3)](BF4)(2) is found to be an effective electrocatalyst for the formation of hydrogen using bromoanilinium tetrafluoroborate as the acid, with a turnover frequency of 160 s(-1) an overpotential of 160 mV. These cobalt derivatives are a promising class of catalysts for further study and optimization.