Mercury coordination chemistry of a nitrogen/thioether sulfur ligand having an internal hydrogen bond donor: Generation of a thioether-coordinated dimercurous complex

Abstract

Admixture of the chelate ligand bmnpa (N,N-bis(2-methylthio)ethyl-N-((6-neopentylamino-2-pyridyl)methyl)amine) with an equimolar amount of Hg(ClO4)2·3H2 Oi n CH 3OH/CH2Cl2, followed by recrystallization from CH3CN/Et2O, yielded the Hg(II) perchlorate complex ((bmnpa)Hg(ClO4)2 )( 1). Addition of an equimolar amount of Me4NOH·5H2 Ot o aC H 3CN solution of 1, followed by recrystallization from CH3OH/Et2O, yielded the dinuclear Hg2 2+ complex ((bmnpaHg)2)(ClO4)2 (4). X-ray crystallographic characterization of 1·0.5CH3CN revealed a mononuclear structure having a primary coordination number of two with a distorted linear geometry, and four secondary bonds for an effective coordination number of six. The 1 H NMR spectrum of 1 in CD3CN shows distinctive 3 J199Hg−1H coupling in the benzylic -CH2 - and thioether −SCH3 resonances. Complex 4·CH3OH exhibits a structure in the solid state wherein each mercury center of the Hg2 2+ ion displays thioether coordination and a distorted tetrahedral geometry. Complex 4 is the first dimercurous complex for which J199Hg−1H coupling involving a -SCH3 appendage is reported.