Cation-π interactions. Synthesis and crystal structure of complexes [K(B18-C-6)]NCS and [K(DB18-C-6)]₂[Hg(SCN)₄]

2126-2131The reactions of benzo-18-crown-6 (B18-C-6) with K2[Cd(SCN)4] and dibenzo-18-crown-6 (DB 18-C-6) with K2[Hg(SCN)4] are reported here. The unexpected complex [K(B18-C-6)]NCS (1) and complex [K(DB18-C-6)]2 [Hg(SCN)4] (2) have been isolated and characterized by elemental analysis, IR and X-ray diffraction analysis. The complexes belong to monoclinic, space group P21/c and C2/c respectively with cell dimensions, 1: a = 9.960(3), b = 25.097(7), c = 8.374(2) Å, β = 106.519(3), V = 2006.7(10) Å3 , Z = 4, Dcalcd· = 1.356 g/cm3, F(000) = 864, R1 = 0.0429, wR2 = 0.0579 and 2: a= 30.187(17), b= 14.668(8), c = 25.467(15)Å, β= 99.517(10). V= 11119(11) Å3, Z = 8, Dcalcd = 1.414 g/cm3, F(000) = 4752, R1 = 0.0415, wR2 = 0.0805. Complex 1 forms one-dimensional infinite chain structure through K+-π interactions between neighboring molecules in the solid state. In complex 2, [K(DB 18-C-6)]2[Hg(SCN)4] molecules form a dimeric structure bridged by K+-π interactions between adjacent [K(DB18-C-6)] units