Synthetic, spectroscopic and structural behavior of unsaturated functionalized N -heterocyclic carbene complexes of group 11

Abstract A series of unsaturated functionalized silver(I) N -heterocyclic carbenes [{(κ C -C 7 N 2 H 10 )AgCl} 2 ] ( 1a ), [{(κ C -C 8 N 2 H 12 ) 2 } 2 Ag][Ag 2 Cl 4 ] ( 1b ), [{(κ C -C 9 N 2 H 14 ) 2 Ag} 2 ][Ag 2 Cl 4 ] ( 1c ), and [{(κ C -C 12 N 2 H 14 ) 2 Ag} 2 ][Ag 2 Cl 4 ] ( 1d ) have been synthesized and used as transmetalation agents to form the corresponding Au(I) and Cu(I) complexes. The reactions of 1a-d with [Au(SMe 2 )Cl] or CuI produced the mixed-metal biscarbene compounds [(κ C -C 7 N 2 H 10 ) 2 M][AgCl 2 ] (M = Au 2a ; Cu 3a ), [{(κ C -C 8 N 2 H 12 ) 2 } 2 M][Ag 2 Cl 4 ] (M = Au 2b ; Cu 3b ), [{(κ C -C 9 N 2 H 14 ) 2 M} 2 ][Ag 2 Cl 4 ] (M = Au 2c ; Cu 3c ), and [{(κ C -C 12 N 2 H 14 ) 2 } 2 M][Ag 2 Cl 4 ] (M = Au 2d ; Cu 3d ). The carbene complexes were fully characterized by IR, NMR and mass spectrometry, and the molecular structures of 1a , 1b , 2b and the imidazolium salt [PMIM][PF 6 ] ( L2′ ) were determined by single crystal X-ray diffraction studies. Compounds L4 , 1d and 2d were used as monomeric units to carry out free-radical polymerization (FRP) reactions using AIBN as initiator.