Crystal structure of trans-(1,8-dibutyl-1,3,6,8,10,13-hexaazacyclotetradecane-κ4N3,N6,N10,N13)bis(thiocyanato-κN)nickel(II) from synchrotron data

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 molecules which have their NiII atoms located on inversion centres. The NiII ions show a tetragonally distorted octahedral coordination geometry, with four secondary amine N atoms of the azamacrocyclic ligand in the equatorial plane and two N atoms of the thiocyanate 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 molecules are connected via intermolecular 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.

Keywords

• crystal structure
• azamacrocyclic ligand
• Jahn–Teller distortion
• sodium thiocyanate
• hydrogen bonding
• synchrotron data