[(5SR,7RS,12RS,14RS)-5,7,12,14-Tetramethyl-1,4,8,11-tetraazacyclotetradecane]nickel(II) Diperchlorate

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 (1a versus 1b) and/or the coordination geometry of the macrocycle (1a/1b versus 2). These observations are extended to related ferric cis- and trans-dichloro macrocyclic complexes.

Structural Analysis of All the Nickel 14-Membered Tetraaza Macrocycles in the Cambridge Structural Database

One hundred and thirty-nine nickel complexes containing the 1,4,8,11-tetraazacyclotetradecane backbone were found in the Cambridge Structural Database. Cluster analysis was used to separate the structures according to their macrocyclic configurations, using their conformations as a separation criteria. The most commonly found configuration was the trans III configuration. The amount of trans I macrocycles relative to trans III macrocycles was found to be higher for square-planar complexes than octahedral ones. Molecular mechanical conformational searches were done for select structures found in the Cambridge Structural Database.