Crystal structure of trans-(1,8-dibutyl-1,3,6,8,10,13-hexa-aza-cyclo-tetra-decane-κ(4) N (3),N (6),N (10),N (13))bis-(thio-cyanato-κN)nickel(II) from synchrotron data.

Dae-Woong Kim,Dohyun Moon,Jong Won Shin,Jin Hong Kim,Jong Jin Kim

doi:10.1107/s205698901501110x

Abstract

The crystal structure of the title compound, [Ni(NCS)2(C16H38N6)], has been determined from synchrotron data. The asymmetric unit consists of two halves of the complex mol-ecules which have their Ni(II) atoms located on inversion centres. The Ni(II) ions show a tetra-gonally distorted octa-hedral coordination geometry, with four secondary amine N atoms of the aza-macrocyclic ligand in the equatorial plane and two N atoms of the thio-cyanate anions in the axial positions. The average equatorial Ni-N bond length [2.070 (5) Å] is shorter than the average axial Ni-N bond length [2.107 (18) Å]. Only half of the macrocyclic ligand N-H groups are involved in hydrogen bonding. The complex mol-ecules are connected via inter-molecular N-H⋯S hydrogen bonds into two symmetry-independent one-dimensional polymeric structures extending along the b-axis direction. One of the n-butyl substituents of the macrocycle exhibits conformational disorder with a refined occupancy ratio of 0.630:0.370.

Highlights

The crystal structure of the title compound, [Ni(NCS)2(C16H38N6)], has been determined from synchrotron data
The asymmetric unit consists of two halves of the complex molecules which have their NiII atoms located on inversion centres
The complex molecules are connected via intermolecular N—H S hydrogen bonds into two symmetry-independent one-dimensional polymeric structures extending along the b-axis direction

Summary

Chemical context

Coordination compounds, including those formed by macrocyclic ligands, have attracted wide interest of material sciences, because of their potential applications (Lehn, 1995; Zhou et al, 2012). NiII macrocyclic complexes having vacant sites in the axial positions have been used for the synthesis of new supramolecular materials with interesting properties, including chiral recognition (Ryoo et al, 2010) and gas storage (Suh et al, 2012). NiII complexes with alkyl-substituted tetra-azamacrocyclic ligands and anionic tetrazole derivatives, metal cyanide and azide (Shen et al., 2012; Kim et al, 2015) have been studied as magnetic materials and substrates for crystal engineering. We report the synthesis and crystal structure of an NiII complex with an azamacrocycle ligand and two thiocyanate anions, trans-(1,8-dibutyl-1,3,6,8,10,13-hexaazacyclotetradecane4N3,N6,N10,N13)bis(thiocyanato-N)nickel(II) (I). C2A, C3A and C2B, C3B atoms adopt a chair conformation, whereas the five-membered chelate rings involving C1A, C4A and C1B, C4B assume a gauche conformation (Min & Suh, 2001; Kim et al, 2015)

Structural commentary

Database survey

Synthesis and crystallization

Refinement