Carbonyl and nitrosyl diruthenium compounds: Crystal structure of [Ru2(O2CMe)(DPhF)3(CO)]BF4 · CH2Cl2 and its isomorphous nitrosyl analogue

The reaction of [Ru2(O2CMe)(DPhF)3(H2O)]BF4 (DPhF = N,N′-diphenylformamidinate) with CO gas leads to [Ru2(O2CMe)(DPhF)3(CO)]BF4 (1), that is the first isolated carbonyl complex containing the Ru25+ unit. The nitrosyl analogue [Ru2(O2CMe)(DPhF)3(NO)]BF4 (2) is prepared by reaction of Ru2Cl(O2CMe)(DPhF)3 with NOBF4. However, the attempts to obtain the cyanide derivative by reaction of Ru2Cl(O2CMe)(DPhF)3 or [Ru2(O2CMe)(DPhF)3(H2O)]BF4 with NaCN were unsuccessful. The structure of compounds 1 · CH2Cl2 and 2 · CH2Cl2 are described. Both compounds are isomorphous. The magnetic measurements at variable temperature demonstrate that 1 is paramagnetic with one unpaired electron in all range of temperature, in contrast to the three unpaired electrons usually present in Ru25+ complexes. The analogous nitrosyl compound 2 is diamagnetic.