macrocyclic heterobinuclear zn(ii)–cu(ii) complexes with phenol based dicompartmental ligands possessing contiguous hexa- and penta-coordination sites were prepared by a stepwise procedure. the ligands include similar n4o2 and dissimilar n(imine)3o2 and n(amine)3o2 coordination sites sharing two phenolic oxygen atoms. the six-coordination site comprises two pyridyl pendant arms on the amine nit...

The macrocyclic amine, 1,5,9,18,22,26-hexaaza [11.11]-p-cyclophane (1) contains two dipropylenetriamine units which make the molecule highly basic. Owing to this basicity, 1 can be highly protonated in acidic media and can form supramolecular assemblies with different anions. Two new supramolecular structures arise from self-assembly of the salt of 1 with fumaric acid and of the N-methyl deriva...

Macrocyclic heterobinuclear Zn(II)–Cu(II) complexes with phenol based dicompartmental ligands possessing contiguous hexa- and penta-coordination sites were prepared by a stepwise procedure. The ligands include similar N4O2 and dissimilar N(imine)3O2 and N(amine)3O2 coordination sites sharing two phenolic oxygen atoms. The six-coordination site comprises two pyridyl pendant arms on the amine nit...

Two new mixed-ligand copper(II) complexes, [Cu(dipn)(NN)]Br2(1-2) [dipn=dipropylenetriamine, NN=ethylenediamine (en) (1) and propylenediamine (pn) (2)], have been synthesized. These complexes were characterized by spectroscopic and thermal techniques. Crystal structure for 2 shows a distorted trigonal-bipyramidal geometry around Cu(II) ion with one solvate water molecule. Antimicrobial and anti...

Two copper(II) complexes, 1 and 2, of two tridentate N-donor ligands, L(1) and L(2) [L(1) = dansyl derivative of bis-[3-(dimethylamino)-propyl]amine; L(2) = dansyl derivative of dipropylenetriamine] were synthesized and characterized. The quenched fluorescence intensity of complexes 1 and 2, in degassed methanol or aqueous (buffered at pH 7.2) solution, was found to reappear on exposure to nitr...

We have observed that the superoxide anion reacts with VO(salen), but not with VO(saldpt), where H2(salen) and H2(saldpt) are Schiff base ligands derived from salicylaldehyde and ethylenediamine or dipropylenetriamine, respectively. Based on the electrochemical, ESR, and UV spectroscopic studies of the reaction mixture, it was concluded that the superox­ ide anion reacts with VO(salen) to oxidi...

Ethylenediamine (en), putrescine (pu), diethylenetriamine (dien), dipropylenetriamine (dpta), spermidine (spmd) and their Cu(II) compounds as well as the Schiff bases with 2-furaldehyde (dienOO), 2- thiophenecarboxaldehyde (dienSS) and pyrrole-2-carboxaldehyde (dienNN) of dien and that of dpta with 2- thiophenecarboxaldehyde (dptaSS), were prepared and characterised. They were tested against Ba...

It is commonly believed that the activity of NO synthase (NOS) solely controls NO production from its substrates, L-Arg and O(2). The Michaelis-Menten constant (K(m)) of NOS for L-Arg is in the micromolar range; cellular levels of L-Arg are much higher. However, evidence strongly suggests that cellular supply of L-Arg may become limiting and lead to reduced NO and increased superoxide anion (O(...