Preparation and characterization of compounds between 18-crown-6 and two potassium mercurate(II) salts

Abstract

Reaction between 1,4,7,10,13,16-hexaoxacyclooctadecane (18-crown-6) and dipotassium tetraiodomercurate(II) and dipotassium tetrathiocyanatomercurate(II) in organic solvent mixture produces [K(18-crown-6)]2[Hg2I6]·2H2O (1) and [Hg(18-crown-6)](SCN)2 (2) respectively. These two products have been isolated and characterized by elemental analysis and infrared studies. Their crystal structures have been determined. Crystal data for 1: a=10.644(9), b=14.925(13), c=15.362(14) Å, β=103.7(1)°, U=2371.0 Å3, space group P21/c, Z=2; for 12: a=8.224(7), b=8.027(7), c=15.56(1) Å, β= 103.0(1)°, U=1000.8 Å3, space group P21/c, Z=2. Reflection data were collected on a diffractometer and the structures were solved by the heavy atom technique and refined by full-matrix least-squares. For 1 1159 independent reflections above background were refined by full-matrix least-squares to R=0.070 (Rw=0.075) and for 2 913 independent reflections above background were similarly refined to R=0.077 (Rw=0.083). 1 contains [K2- (18-crown-6)2]2+ centrosymmetric dimeric cations in which two [K(18-crown-6)]+ cations are linked via weak KO bonds and centrosymmetric [Hg2I6]2- anions. 2 contains centrosymmetric discrete [Hg(18-crown-6)(SCN)2] molecules in which the mercury atom has an eight-coordinate hexagonal bipyramidal environment, being bonded to the sulphur atoms of two thiocyanate groups as well as to six oxygen atoms of the 18-crown-6. © 1989.