Homonuclear and Heteronuclear Complexes of Calix[4]-bis-monothiacrown-5 with Oligomer and Polymer Structures

Abstract

Homo- and heteronuclear complexes (1–7) of calix[4]-bis-monothiacrown-5 (L) with mercury(II), cadmium(II), copper(I), and potassium(I) salts adopting dimer, tetramer, one-dimensional (1D), and two-dimensional (2D) polymer structures with different coordination modes and connectivity patterns were prepared and structurally characterized. Reactions of L with mercury(II) iodide and mercury(II) thiocyanate afforded a dimer complex [Hg4(L)2I8]·CH2Cl2 (1) and a 1D coordination polymer {[Hg2(L)(SCN)4]·CH2Cl2}n (2), respectively, in which the exocyclic dimercury(II) complex units of L are doubly linked by the anions. Reactions of L with cadmium(II) iodide in the absence and the presence of mercury(II) iodide gave isostructural 1D coordination polymers [Cd2(L)I4]n (3) and {[Cd2(L)I4][CdHg(L)I4]}n (4), respectively. In the isostructure of 3 and 4, the ligands are alternately linked by the exocyclic M-I2-M squares via monocadmium(II)-mediated and dicadmium(II)-mediated modes, respectively. Reaction of L with copper(II) thiocyanate in the presence of potassium(I) thiocyanate afforded a discrete complex {[(K2L)4Cu6(SCN)10][K2L]2[Cu(SCN)3]3·2CH2Cl2·CH3CN} (5) consisting of three separated parts: dipotassium(I) tetramer part linked with a oligomer copper(I) thiocyanate backbone, dipotassium(I) monomer part, and trithiocyanato copper(I) complex part. When a mixture of mercury(II) thiocyanate and potassium(I) thiocyanate was used, a grid-type 2D heteronuclear polymer complex [Hg3(K2L)(SCN)8]n (6) in which the 1D mercury(II) thiocyanato backbones cross-linked by endocyclic dipotassium(I) complex units of L was isolated. One pot reaction of L with a mixture of iodide salts of potassium(I), mercury(II), and cadmium(II) gave a binary mixed product of a discrete complex [(K2L)2(Cd3I8)][Cd4I10] (7) and a heteronuclear 2D network (8) which can be manually separated because of the colorless platy and orange–yellow block shapes of the crystals, respectively. In 7, the endocyclic dipotassium(I) complex of L is linked by Cd3I8 clusters.