N-functionalized, cyclam-based unsymmetrical dicompartmental binuclear copper(II) complexes containing 4- and 6-coordination sites: electrochemical, magnetic, catalytic, and antimicrobial studies

Abstract

A series of unsymmetrical dicompartmental binuclear copper(II) complexes have been prepared by Schiff-base condensation of 1,8-[bis(3-formyl-2-hydroxy-5-bromo)benzyl]-l,4,8,11-tetraazacyclotetradecane (L) with aliphatic and aromatic diamines, copper(II) perchlorate and triethylamine. The complexes were characterized by elemental and spectral analysis. Electronic spectra of the complexes show d-d transitions in the range 663-786 nm. Electrochemical studies of the complexes in DMF show two irreversible one electron reduction processes E 1 pc ¼ À0.62 to À0.77 V and E 2 pc ¼ À0.94 to À1.17 V. Cryomagnetic investigations of the binuclear complexes show À2J values in the range of 154 to 236 cm À1 . The rate constants for hydrolysis of 4-nitrophenylphosphate are in the range of 2.27 Â 10 À2 to 9.21 Â 10 À2 min À1 and for catecholase activity in the range of 3.06 Â 10 À2 to 8.35 Â 10 À2 min À1 . All the complexes were screened for antifungal and antibacterial activity.

Synthesis and Crystal Structure of a 4,4’-bipyridine Linked Dinuclear Copper(II) Complex Derived from 2-{[2-(2-hydroxyethylamino)ethylimino] methyl}-6-methylphenol

“…23 The strong absorption band at 1637 cm -1 can be attributed to ν(C=N). 24 The C-O (phenolic) stretching band is observed at 1221 cm -1 in the complex. 25 Nitrato complexes show IR bands in the range 1410-1448 (ν 5 ), 1290-1322 (ν 1 ), and 1073-1077 cm -1 (ν 2 ) due to NO stretches.…”

The stabilities and formation kinetics of some macrocycles with copper(II): crystal structures of some pendant arm macrocycles

“…The closer the fit between the metal ion and the size of the cavity, the better the fit, thus higher the stability of the complex. This provides the opportunity to develop specific metal ion sensors by manipulating the structure of macrocycles [7][8][9][10][11].…”

“…Pendant arms can be attached directly to the donor atoms which can affect the nature of its metal ion coordination [1]. Pendant arms may consist of flexible components such as alkyl chain containing any number of functional groups including amines, alcohols, amides and carboxyl or aromatic groups with other additional donors [2][3][4][5][6][7][8]. The stability of macrocyclic complex is affected by a number of structural characteristics.…”