Selective Substitution of One of the Substituents on Germanium in Coordinatively Unsaturated Ruthenium Germyl Complexes

The coordinatively unsaturated tri-p-tolylgermyl
complex RuCl­(Ge­[p-tolyl]3)­(CO)­(PPh3)2 (1) is obtained in good yield through
the reaction between HGe­(p-tolyl)3 and
RuCl­(Ph)­(CO)­(PPh3)2. On treatment of 1 with 1 equiv of NaS2CNR′2 (R′
= Et, Me), the chloride ligand is displaced and the corresponding
coordinatively saturated complexes Ru­(κ2-S2CNR′2)­(Ge­[p-tolyl]3)­(CO)­(PPh3)2 (2a, R′ =
Et; 2b, R′ = Me) are formed. One of the PPh3 ligands in 2a is labile and undergoes substitution
readily on addition of CO to give the cis-dicarbonyl
complex Ru­(κ2-S2CNEt2)­(Ge­[p-tolyl]3)­(CO)2(PPh3) (3). On addition of NaS2CNMe2 to 2b, a PPh3 ligand is displaced by one sulfur atom
while the other sulfur atom displaces one of the p-tolyl groups on germanium to give Ru­(κ2(Ge,S)-Ge­[p-tolyl]2S2CNMe2)­(κ2-S2CNMe2)­(CO)­(PPh3) (4). Complex 4 is
also formed on addition of excess NaS2CNMe2 to 1. Treatment of 1 with pyridine and ethanol under
ambient conditions also results in cleavage of one of the germyl p-tolyl groups, and the product formed is the coordinatively
unsaturated, ethoxy-substituted germyl complex RuCl­(Ge­[OEt]­[p-tolyl]2)­(CO)­(PPh3)2 (5). The ethoxy group in 5 is labile, and on contact
with n-propanol in solution, alkoxy group exchange
slowly occurs to give RuCl­(Ge­[OnPr]­[p-tolyl]2)­(CO)­(PPh3)2 (6). This reaction is reversible, and treatment of 6 with ethanol returns 5. In a related reaction, treatment
of 5 with water gives the hydroxy–germyl analogue
RuCl­(Ge­[OH]­[p-tolyl]2)­(CO)­(PPh3)2 (7). The single-crystal X-ray structures
of 1, 2a, 3, and 4 are presented.

通过HGe(p-tolyl)3与RuCl(Ph)(CO)(PPh3)2的反应，成功获得高收率的配位不饱和三(对甲苯基)锗基钌配合物RuCl-(Ge[p-tolyl]3)-(CO)-(PPh3)2 (1)。将1与等摩尔的NaS2CNR′2 (R′ = Et, Me)反应，氯配体被取代，生成了相应的配位饱和配合物Ru-(κ2-S2CNR′2)-(Ge[p-tolyl]3)-(CO)-(PPh3)2 (2a, R′ = Et; 2b, R′ = Me)。在2a中，一个PPh3配体易解离，在加入CO后，发生取代反应，生成顺式二羰基配合物Ru-(κ2-S2CNEt2)-(Ge[p-tolyl]3)-(CO)2(PPh3) (3)。向2b中加入NaS2CNMe2，一个PPh3配体被一个硫原子取代，而另一个硫原子取代了锗上的一个对甲苯基，从而得到Ru-(κ2(Ge,S)-Ge[p-tolyl]2S2CNMe2)-(κ2-S2CNMe2)-(CO)-(PPh3) (4)。在向1中加入过量NaS2CNMe2的情况下，也能得到配合物4。在常温条件下，用吡啶和乙醇处理1，导致其中一个锗基对甲苯基的断裂，生成的产物是配位不饱和、乙氧基取代的锗基配合物RuCl-(Ge-OEt-[p-tolyl]2)-(CO)-(PPh3)2 (5)。在5中，乙氧基易解离，与溶液中的正丙醇接触时，烷氧基交换缓慢发生，生成RuCl-(Ge-OnPr-[p-tolyl]2)-(CO)-(PPh3)2 (6)。该反应是可逆的，用乙醇处理6可恢复5。在另一相关反应中，用水分解5，得到羟基-锗基类似物RuCl-(Ge-OH-[p-tolyl]2)-(CO)-(PPh3)2 (7)。1、2a、3和4的单晶X射线结构也被展示。