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.

配位不饱和的三对甲苯基锗基配合物RuCl(Ge[p-甲苯基]₃)(CO)(PPh₃)₂（编号1）可由HGe(p-甲苯基)₃与RuCl(Ph)(CO)(PPh₃)₂反应高产率制得。将配合物1与1当量的二烷基二硫代氨基甲酸钠NaS₂CNR′₂（R′为乙基Et、甲基Me）反应，其配位的氯配体被取代，得到相应的配位饱和配合物Ru(κ²-S₂CNR′₂)(Ge[p-甲苯基]₃)(CO)(PPh₃)₂（2a：R′=Et；2b：R′=Me）。2a中的一个三苯基膦配体具有配位不稳定性，通入一氧化碳（CO）后易发生取代反应，生成顺式二羰基配合物Ru(κ²-S₂CNEt₂)(Ge[p-甲苯基]₃)(CO)₂(PPh₃)（3）。向2b中加入NaS₂CNMe₂时，一个三苯基膦配体被其中一个硫原子取代，同时另一个硫原子取代了锗原子上的一个对甲苯基，最终得到配合物Ru(κ²(Ge,S)-Ge[p-甲苯基]₂S₂CNMe₂)(κ²-S₂CNMe₂)(CO)(PPh₃)（4）。向1中加入过量NaS₂CNMe₂时，同样可得到配合物4。在室温条件下将1与吡啶和乙醇共同处理，会断裂锗基上的一个对甲苯基，生成配位不饱和的乙氧基取代锗基配合物RuCl(Ge[OEt][p-甲苯基]₂)(CO)(PPh₃)₂（5）。5中的乙氧基配体具有配位不稳定性，在溶液中与正丙醇接触时，会缓慢发生烷氧基交换反应，生成RuCl(Ge[OnPr][p-甲苯基]₂)(CO)(PPh₃)₂（6）。该反应为可逆反应，将6与乙醇共同处理即可得到5。在类似反应中，将5与水反应可得到其羟基锗基类似物RuCl(Ge[OH][p-甲苯基]₂)(CO)(PPh₃)₂（7）。本文还报道了配合物1、2a、3及4的单晶X射线衍射结构。