prevents further study. The M(CO)5 series M = W, Mo, Cr promote downfield shifts of α-ring protons and upfield shifts of β-ring protons, thus behaving more like anionic ML5 units (M(CN)53−, M(hedta)−; FeII and RuII), toward N-heterocyclic ligands. An isomer with M(CO)5 attached to the π-cloud, in addition to the N-bound complexes, was obtained only for Mo(CO)5(2,6-Me2pz). Reasons for the η2 attachment
吡嗪系列的配合物M(CO)5(
PZR n),M = W,Mo或Cr;R = CH 3,
PZR Ñ =
吡嗪(Ñ = 0),
2-甲基吡嗪(Ñ = 1),
2,3-二甲基吡嗪和
2,6-二甲基吡嗪(Ñ = 2)和2,3,6-三甲基(Ñ = 3)已经通过在
丙酮中的UV光解来制备。在CDCl 3和C 6 D 6中获得了M(CO)5(
PZR n)系列,游离
配体PZR n及其共轭酸
PZR n H +的NMR光谱。
PZRn个环质子相对于其他没有选择性与环C-H键缔合的溶剂,经历C 6 D 6的高场迁移。移位差, = δ(CDCL 3 -C 6 d 6),被衰减随甲基化(Σ Ñ)作为分子的两个体积的函数和电子因子正比于哈米特常数σ p为CH 3。因此, = Ç Ò +(0.56 σ p + BV)Σ Ñ其中Ç Ò = 0.58,σ p = -0.129,BV = -0.069为
吡嗪类。
路易斯酸M(CO)5(M