Synthesis, structural, spectral, electrochemical and spin equilibrium studies of hexaaza macrotricyclic complexes

The synthesis, crystal structures and antimicrobial studies of C‐methyl‐substituted hexaaza macrocycle of Cu(II) having aromatic pendant arm

“…The wileyonlinelibrary.com/journal/aoc appearance of a single broad d-d band in the visible spectrum of square-planar or tetragonally distorted octahedral complexes containing neutral macrocyclic diimine ligands is common. [56,57] We have observed one broad d-d transition bands at λ max 505 and 506 nm for complexes 1 and 2, respectively, contributing from the CuN 4 square-planar based coordination environment, which indicates that the Cu-X (where X = ClO 4 − and PF 6 − ) bonds are entirely dissociated. [58] Similar behavior has also been reported by Kang et al [59,60] This can be adequately explained as a d-d…”

Synthesis, Crystal Structure, and Spectroscopic Properties of Cu(II) Complex with 14-Membered Hexaazamacrocyclic Ligands

“…2 B 2g transition which was consistent with a tetragonally distorted octahedral. This distortion was supported by the single X-ray diffraction data that the axial bonds Cu-O was longer than the Cu-N bonds of the square-planar basal plane as a result from the Jahn-Teller effect with z-out elongation [1,35,50,53]. The solid state electronic absorption band was measured using the diffused reflectance technique and was similar to the spectrum obtained in liquid state above indicating the environment around the metal ion was under similar field strength in both states (Fig.…”

“…The broad vibration band at 1100 cm -1 which split into two bands at 1140 and 1068 cm -1 was assigned to perchlorate ions (ClO 4 -). The splitting of this band clearly indicated the presence of coordinated perchlorate [1,50,51]. As a result, the perchlorate bending vibration was seen as a sharp band at 621 cm -1 [35].…”

“…5. The energy level sequence will depend on the amount of tetragonal distortion due to ligand field and Jahn-Teller effects [2,50,52].…”

Chelation-controlled molecular morphology: aminal to imine rearrangements

“…15 Indeed, the isolated product need not even have the 1 : 1 carbonyl : amine stoichiometry expected for an imine, perhaps the best-known example of this being the case of the formaldehyde : ammonia adduct hexamethylenetetramine (urotropine; 1,3,5,7-tetra-azaadamantane), 15,16 and another example is provided by "hydrobenzamide", 17 although much more common are the cases, such as the family of triazacyclohexanes, 15 where 1 : 1 stoichiometry does apply. Both urotropine and the triazacyclohexanes are aminals, and the aminal unit is found in a great variety of more complicated systems including polycyclic ( poly)amine derivatives 18 (some used as explosives precursors 19 ), both macrocyclic 8c,8d, 20 and macrobicyclic 8c,21 ligand metal ion complexes, and intermediates for the selective alkylation of polyamines 22 or for amine exchange in bioactive materials. 23 Aminal-N is a good donor and an extensive coordination chemistry is known for aminal ligands, both preformed 18a,b,20,24-29 and as generated in template reactions, 3a,8b,c,d,30 coordination of the former sometimes resulting in metal-ion-induced rearrangement to imine species.…”