Synthesis, characterization, and crystal structure of an iron(II) 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane macrocyclic complex

The synthesis and detailed characterization of the macrocyclic complex [Fe(meso)(CH₃CN)₂](ClO₄)₂·2CH₃CN (meso: 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane) based on analytical, spectrometric, spectroscopic and X-ray diffraction methods are reported herein. This is the first single crystal structure of an iron-meso complex ever reported in the literature. The molecular structure revealed a tetragonally distorted octahedral geometry with the iron(II) bound to four amine nitrogens in the equatorial plane, while the apical positions are occupied by acetonitrile molecules. The macrocycle adopts the most stable conformation with the six-membered rings in chair form, while the gauche conformation is seen for the five-membered rings. The compound crystallizes in the space group P2₁/n, with cell parameters a=10.139(1), b=12.237(1), c=13.311(1) ?, β=99.542(2)° and Z=2.Supplementary material CCDC-239983 contains the supplementary crystallographic data for this paper. These data can be obtained free of charge at [or from the Cambridge Crystallographic Data Centre (CCDC), 12 Union Road, Cambridge CB2 1EZ, UK; fax: +44(0)1223–336033; email: deposit@ccdc.cam.ac.uk].”