Syntheses and structures of blue-luminescent mercury(II) complexes with 2,6-bis(imino)pyridyl ligands.

Seven five-coordinate 2,6-bis(imino)pyridyl mercury complexes, [2,6-(ArN horizontal lineCMe)(2)C(5)H(3)NHgCl(2).nCH(3)CN] (Ar = C(6)H(5), n = 1.5, 1; Ar = 2,6-(i)Pr(2)C(6)H(3), n = 0, 2; Ar = 2,6-Me(2)C(6)H(3), n = 1, 3; Ar = 2-MeC(6)H(4), n = 1, 4; Ar = 4-MeC(6)H(4), n = 1, 5; Ar = 2,4,6-Me(3)C(6)H(2), n = 1, 6; Ar = 2,6-Et(2)C(6)H(3), n = 0, 7), were synthesized by reactions of the corresponding bis(imino)pyridine ligands with HgCl(2) in CH(3)CN, and in good yield. The structures of complexes 1-6 were determined by single-crystal X-ray diffraction. In all complexes, the metal center is tridentately chelated by the ligand and further coordinated by two chlorine atoms, resulting in a distorted trigonal bipyramidal geometry. All complexes have blue luminescence at room temperature in solution and the solid state. At 293 K in a CH(2)Cl(2) solution, the fluorescent emission maxima for complexes 1-7 are at lambda = 395, 400, 407, 403, 427, 415, and 403 nm, respectively, which can be attributed to ligand-centered pi* --> pi transitions.