| Title
| - Synthesis and Antimicrobial Activities of Isomers ofN(4),N(11)-Dimethyl-3,5,7,7,10,12,14,14-octamethyl-1,4,8,11-tetraazacyclotetradecaneand Their Nickel(II) Complexes
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| Abstract
| - Two isomeric 1,8-dimethyl-1,4,8,11-tetraazacyclotetradecanes (L) and their complexes with Ni2+, viz. [NiL](ClO4]2 and [NiL(X)2][ClO4]2 (X = Cl, Br, I, SCN), have been synthesized. In crystals of [NiL][ClO4]2, the ligand is present either in a 2:1 mixture of the un- and dimethylated forms (centrosymmetric space group) or as a mixture of 73% of the mono- and 27% of unmethylated forms (acentric space group).
- The reactions of two isomers of 3,5,7,7,10,12,14,14-octamethyl-1,4,8,11-tetraazacyclotetradecane (differing in theorientation of the methyl groups on the chiral carbon atoms), designated as LB and LC, with CH3I in the ratio of 1:4resulted in the substitution of the N(4) and N(11) protons by CH3 groups, forming the dimethyl derivatives LBZ andLCZ, respectively. These ligands, on interaction with nickel(II) acetate tetrahydrate and subsequent addition of lithiumperchlorate, produce square-planar yellow [NiLBZ][ClO4]2 and orange [NiLC‘Z][ClO4]2. These nickel complexes undergoaxial ligand addition reactions with NCS-, Cl-, Br-, and I- as X- to form six-coordinate trans-diisothiocyanato,-dichloro, -dibromo, and -diiodo complexes of formula [NiLX2], where L = LBZ or LC‘Z, and X = SCN, Cl, Br, or I.All these compounds have been characterized on the basis of analytical, spectroscopic, conductometric, andmagnetochemical data. The structures of LBZ and two variants of [Ni“LBZ”][ClO4]2 (crystallizing in the space groupP21/n and Pn, respectively; “LBZ” symbolizes partially methylated ligand) have been determined by single-crystalX-ray analyses. The antifungal and antibacterial activities of these compounds have been studied against somephytopathogenic fungi and bacteria.
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