Syntheses, Crystal Structures, and Magnetic Properties of Two Cyano‐Bridged Cr III M II (M = Cu, Ni) Bimetallic Assemblies with Macrocyclic Ligands

Synthesis and characterization of a macrocyclic copper complex containing the 14-membered 1,3,5,8,10,12-hexaazacyclotetradecane unit

In this work, a new macrocyclic copper complex, [Cu(ACE)(SCN)2]; ACE: 1,3,6,10,12,15-hexaazatricyclo[13.3.1.16,10]eicosane, was prepared and characterized by elemental analysis, FT-IR, Raman spectroscopy and single-crystal X-ray diffraction. X-ray analysis of [Cu(ACE)(SCN)2] reveals an elongated octahedral geometry around the copper atom in a centrosymmetric CuN6 environment.

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

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.

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-(5-methyltetra-zolato-κN)nickel(II) from synchrotron data

The structure of the title compound, [Ni(C2H3N4)2(C16H38N6)], has been characterized from synchrotron radiation. The asymmetric unit consists of one half of the Ni(II) complex mol-ecule, which is related to the other half-mol-ecule by an inversion center. The Ni(II) ion is coordinated by four secondary N atoms of the macrocyclic ligand in a square-planar fashion in the equatorial plane and by two N atoms of the 5-methyltetra-zolate anions in axial positions, resulting in a tetra-gonally distorted octa-hedral geometry. The average equatorial Ni-N bond length [2.060 (8) Å] is shorter than the axial Ni-N bond length [2.2183 (11) Å]. An intra-molecular N-H⋯N hydrogen bond between the secondary amine N atom of the macrocyclic ligand and the non-coordinating N atom of the 5-methyltetra-zolate ion stabilizes the mol-ecular structure. Moreover, an inter-molecular N-H⋯N hydrogen bond between the macrocyclic ligand and 5-methyltetra-zolate group gives rise to a supra-molecular sheet structure parallel to the bc plane.

Crystal structures and magneto-structural correlation analysis for several cyano-bridged bimetallic complexes based on MnIII–FeIII systems

The rotation of subunits and its influence on the magnetic coupling in Mn^III–Fe^III systems.