Geometric isomers of dichloridoiron(III) complexes of CTMC (5,7,12,14‐tetramethyl‐1,4,8,11‐tetraazacyclotetradecane)

Both trans and cis iron–CTMC complexes, namely, trans‐dichlorido[(5SR,7RS,12RS,14SR)‐5,7,12,14‐tetramethyl‐1,4,8,11‐tetraazacyclotetradecane]iron(III) tetrachloridoferrate, [Fe(C14H32N4)Cl2][FeCl4] (1a), the analogous chloride methanol monosolvate, [Fe(C14H32N4)Cl2]Cl·CH3OH (1b), and cis‐dichlorido[(5SR,7RS,12SR,14RS)‐5,7,12,14‐tetramethyl‐1,4,8,11‐tetraazacyclotetradecane]iron(III) chloride, [Fe(C14H32N4)Cl2]Cl (2), were successfully synthesized and structurally characterized using X‐ray diffraction. The coordination geometry of the macrocycle is dependent on the stereoisomerism of CTMC. The packing of these complexes appears to be strongly influenced by extensive hydrogen‐bonding interactions, which are in turn determined by the nature of the counter‐anions (1aversus1b) and/or the coordination geometry of the macrocycle (1a/1bversus2). These observations are extended to related ferric cis‐ and trans‐dichloro macrocyclic complexes. Dichloridoiron(III) complexes of two stereoisomers of a tetraazamacrocycle are examined. The stereoisomerism of the macrocycle is shown to determine the geometric isomerism of the resulting metal complex, and these results are compared to relevant previous reports.