very small. The rates and activation parameters of these isomerisation reactions presumably proceeding by the twist mechanism (ΔS‡ highly negative) have been determined. The factors controlling geometrical preference of oxidation states viz., metal–phosphorus back-bonding and PPh3⋯ PPh3 steric repulsion are considered in relation to the osmium analogues reported previously.
Na [S 2 CNEt 2 ]与[Ru(PPh 3)3 Cl 2 ]的反应生成顺式-[RuL 2(PPh 3)2 ](L = S 2 CNEt 2),其在被
铈(IV)氧化时得到反式-[RuL 2(PPh 3)2 ] +,分离为其PF 6 –盐。两种复合物均以接近定量的产率获得。三价复合物显示单电子顺磁性和菱形冷冻溶液EPR光谱,已对其进行了分析,分别提供了≈8000和菱形畸变参数≈8000和≈1700 cm –1。在6450 cm –1处观察到Kramers双峰内的
配体场跃迁,预测值为≈7000 cm –1。变温度(253-303 K)的伏安研究已经揭示,电极反应进行在stereoretentive方式[ ë ½(顺式),0.23和È ½(反式), - 0.09 V与饱和甘
汞电极(SCE)],但顺式-[RuL 2(PPh 3)2 ] +和反式-[RuL 2(PPh 3)2 ]种类不稳定且