Organometallic Compounds Containing a Guanidinium Group. Phenylmercury(II) Derivatives of Creatine and Creatinine

Phenylmercury(II) replaces a proton of creatine, H2NC+(NH2)NMeCH2C02-, in basic solution to form the zwitterionic complex PhHgNHC+(NH2)NMeCH2CO2-. Creatine and creatinine (C4H7N30) react with PhHg((OH)N03)I/2 in aqueous ethanol to form a 2:l complex [(PhHg)2(C4H6N30][N03] which exists in two crystalline forms. Creatinine forms a 1:l complex [PhHg(C4H7N30)][N03].1/2H20 at pH 1.4 on reaction with PhHg((OH)N03)l/2 in the presence of nitric acid. The 1:l and 2:l complexes may be interconverted. Creatinine hydronitrate, [H2NCNMeCH2CONH][NO3], and the PhHg(II) complexes of creatinine have similar infrared (including deuterated derivatives) and 1H NMR spectra, consistent with retention of the creatinine ring and presence of a guanidinium group in the complexes. An X-ray structural analysis of one crystalline form of the 2:l complex shows bonding of PhHg(II) groups to the exocyclic and ring nitrogens of creatinine to form the cation [PhHgNHCNMeCH2CONHgPh]+.