Crystal Engineering in [(12C4)₂Na][Cd(SCN)₃]:  First Example of an Anionic Cadmium Thiocyanate Coordination Solid with a Sandwich [(12C4)₂Na]⁺ Cation as Spacer/Controller, Resulting in a Hexagonal Arrangement of Antiparallel Zigzag [Cd(SCN)₃^-]_∞ Chains

Abstract

This paper reports the synthesis, characterization, and structure of [(12C4)(2)Na][Cd(SCN)(3)] (3). The title compound 3 represents the first example of an anionic cadmium thiocyanate coordination solid in which a sandwich [(12C4)(2)Na](+) monocation serves as the spacer/controller, giving rise to a hexagonal array of antiparallel infinite zigzag [Cd(SCN)(3)(-)](infinity) chains with the cations occupying the triangular channels. The title compound 3 crystallizes in a monoclinic unit cell of P2(1)/n space group symmetry with lattice parameters of 13.204(2) Å, 10.692(2) Å, 21.036(1) Å, 95.520(8) degrees, and Z = 4. A detailed comparison of the title structure (3) with that of [(18C6)(2)Na(2)(H(2)O)(2)](1/2)[Cd(SCN)(3)] (1) and [(18C6)K][Cd(SCN)(3)] (2) revealed that the arrangement and the alignment of the infinite anionic [Cd(SCN)(3)(-)](infinity) zigzag chains are dictated by the dimensions and symmetry, respectively, of the cations. The infinite anionic [Cd(SCN)(3)(-)](infinity) chains in 1 and 2 form an approximate tetragonal array, creating square channels which are filled with the dimeric [(18C6)(2)Na(2)(H(2)O)(2)](2+) (in 1) or with two monomeric [(18C6)K](+) (in 2) cations while the infinite anionic [Cd(SCN)(3)(-)](infinity) chains in 3 adopt an approximate hexagonal arrangement with the triangular channels filled by the smaller [(12C4)(2)Na](+) cations (the dimension effect). The relative alignment (either parallel or antiparallel) of the anionic chains is dictated by the symmetry or approximate symmetry of the cations. Thus, both the dimeric cation in 1 and the sandwich cation in 3 give rise to antiparallel alignment of the anionic [Cd(SCN)(3)(-)](infinity) chains with the centrosymmetric space group P2(1)/n whereas the disklike cation in 2 gives rise to parallel alignment of [Cd(SCN)(3)(-)](infinity) chains with noncentrosymmetric space group Cmc2(1) (the symmetry effect).

Bird-like spiro-metallacyclic complexes based on a bent oxadiazole bridging ligand

“…The Cd-N bond distances lie in the range of 2.329(3)-2.356(3) A, which is comparable with the corresponding Cd-N bond lengths found in 4. The axial Cd-S bond length (Cd(1)-S(2) ¼ 2.7395 (10) A) is slightly longer than that of the equatorial one (Cd(1)-S(1) ¼ 2.6678 (10) A), which is similar to that observed in [(12C4) 2 Na][Cd(SCN) 3 ]. 10 The ligand itself bends markedly inward and converges at the Cd(II) center to generate a metallocycle.…”

“…The axial Cd-S bond length (Cd(1)-S(2) ¼ 2.7395 (10) A) is slightly longer than that of the equatorial one (Cd(1)-S(1) ¼ 2.6678 (10) A), which is similar to that observed in [(12C4) 2 Na][Cd(SCN) 3 ]. 10 The ligand itself bends markedly inward and converges at the Cd(II) center to generate a metallocycle. In addition, a pair of metallocycles are double-linked together by two SCN À co-ligands into a pseudospiro-metallocycle (Fig.…”

Three green luminescent cadmium complexes containing 8-aminoquinoline ligands: Syntheses, crystal structures, emission spectra and DFT calculations

“…Two crystallographically inequivalent SCN À anions are linear and the C20-N5-Cd1 angle is 176.0(6)1, while the C19-N6-Cd1 angle is 161.9(6)1. The Cd-N bond lengths range from 2.110(6) to 2.218(6) Å , which are somewhat shorter than those previously reported [37][38][39]. As illustrated in Fig.…”

Synthesis and crystal structure of two novel polymeric PbII compounds: [Pb(phen)(N3)2]n and [Pb(deta)(N3)·(N3)]n

“…In transition metal complexes the structural and electronic versatility of these bridges have been used to explore magnetic materials, photo-devices, liquid crystals, catalysts and other functional materials [7][8][9][10][11][12]. However, the corresponding non-transition metal complexes are still few and the majority of the development in the non-transition metals are with the Group 12 metals: zinc, cadmium and mercury [13][14][15][16][17][18][19]. The lead(II) complexes with N-donor bridging agent have been studied in some details [20,21].…”