A cw EPR and ENDOR investigation on a series of Cr(i) carbonyl complexes with relevance to alkene oligomerization catalysis: [Cr(CO)4L]+ (L = Ph2PN(R)PPh2, Ph2P(R)PPh2)
作者:Lucia E. McDyre、Tracy Hamilton、Damien M. Murphy、Kingsley J. Cavell、William F. Gabrielli、Martin J. Hanton、David M. Smith
DOI:10.1039/c0dt00127a
日期:——
The preparation and characterisation of the Cr(I) complexes [Cr(CO)4L]+ (L = Ph2PN(R)PPh2, Ph2P(R)PPh2), which are used as pre-catalysts for the selective oligomerization of ethylene, are reported. The electronic properties and structural features of these complexes in frozen solution have been established via continuous wave X-band Electron Paramagnetic Resonance (cw-EPR) and continuous wave 1H, 14N
Cr(I)配合物的制备与表征[Cr(CO)4 L] + (L = PH 2 PN(R)PPh 2, pH值2 P(R)PPH 2)用作选择性低聚反应的预催化剂 乙烯,均已报告。通过连续波X波段电子顺磁共振(cw-EPR)和连续波1 H建立了这些复合物在冷冻溶液中的电子性质和结构特征,14 N 和 31 P电子核双共振(cw-ENDOR)光谱。EPR谱主要受g各向异性的影响,两个等效项之间的P A耦合非常大31 P核。自旋哈密顿量参数(摹⊥(g xx = g yy)> g e >摹∥(g zz))与低旋转一致第5天具有C 2v对称性的系统,其中SOMO对所有配合物的金属贡献主要是d xy。对于含配体e,d,f和g的配合物,各向同性的费米接触项(P a iso,由EPR和ENDOR确定)最大,表明SOMO中31 P 3 s特性对于PNP型更高。配体比PCP类型。在配合物细微结构上的差异也通过在