Journal ArticleDOI
Polyazamacrocycles. Part 7. Kinetics of aquation of trans-dichloro and trans-chloro (nitro) complexes of cobalt (III) with tetra-aza macrocycles
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In this article, the authors show that very large aquation rate enhancements in cobalt (III) complexes of 14-membered macrocycles are possible only if gem-dialkyl groups are present.Abstract:
Kinetic studies on the aquation of trans-[CoLCl2]+ and trans-[CoL(NO2)+](L = tetra-aza macrocycle) complexes show large variation in rates. The dependence of aquation rates on conformational strain energy is true only for a limited number of compounds. The rate enhancements can be rationalised in terms of the ability of the macrocycle to fold across a fold axis. The large-ringed macrocyclic complexes trans-[CoL6Cl2]+(L6= 1,4,8,11 -tetra-azacyclohexadecane) and trans-[CoL7Cl2]+(L7= 1,4,8,11 -tetra-azacycloheptadecane) aquate at much lower rates due to curtailed folding ability. The N ⋯ N bite distances also suggest a lower aquation rate for these complexes. The complexes of 2,5,5,7,9,12,12,14-octamethyl- and 5,7,12,14-tetraethyl-5,12-dimethyl-1,4,8,11 -tetra-azacyclotetradecane aquate with low rates lying in a narrow range. No specific trends can be identified in these complexes. These studies also show that very large aquation rate enhancements in cobalt (III) complexes of 14-membered macrocycles are possible only if gem-dialkyl groups are present.read more
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Journal ArticleDOI
Axial ligand substitution in diastereoisomeric trans-[Co(Me8 14ane)Cl2]+ complexes and their anti-fungal activities
Tapashi G. Roy,Saroj K. S. Hazari,Benu K. Dey,R. K. Sutradhar,Lucky Dey,Nural Anowar,Edward R. T. Tiekink +6 more
TL;DR: Three isomeric Me8 14anes, LA, LB and LC, on aeration with cobalt(II) acetate tetrahydrate and subsequent treatment with concentrated HCl and HClO4, give green trans-[CoLCl2]ClO 4 diastereoisomers as mentioned in this paper.
Journal ArticleDOI
Configurational isomerism of 2,5,5,7,9,12,12,14-octamethyl-1,4,8,11-tetraazacyclotetradecane and its compounds
TL;DR: The Cahn Ingold Prelog (CIP) priority rules have been used to characterize cyclic tetraamine 2.5,5,7,9,12, 12,14,Octamethyl-1,4,8,11-tetraazacyclotetradecane.
Journal ArticleDOI
Synthesis of Some Octahedral Nickel(II) Complexes of One Isomer of Isomeric Me8[14]anes: X-ray Structure of Diisothiocyanato(3,10-C-meso-3,5,7,7,10,12,14,14-octamethyl-1,4,8,11-tetraazacyclotetradecane, LC)nickel(II), [NiLC(NCS)2]
TL;DR: One isomer, LC of the isomeric Me8[14]anes, LA, LB and LC; on reaction with Ni(NCS)2 produces a six coordinate octahedral diisothiocyanato complex as mentioned in this paper.
Journal ArticleDOI
Reassignment, Isolation, Spectral and X-ray Characterization of Diastereoisomers of the Macrocyclic Ligand 3,10-meso-3,5,7,7,10,12,14,14-Octamethyl-1,4,8,11-tetraazacyclotetradecane and their NiII and CuII Complexes
TL;DR: In this paper, the diastereoisomeric macrocycles and their NiII and CuII complexes have been characterized and confirmed by IR, UV/Vis, and NMR spectroscopy as well as X-ray crystallography.
References
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Journal ArticleDOI
Polyazamacrocycles. V. Structure of Isomeric 3,5,7,7,10,12,14,14-Octamethyl-1,4,8,11-tetraazacyclotetradecanes
Ramesh Bembi,Sham M. Sondhi,Ashok K. Singh,Amrit K. Jhanji,Tapashi G. Roy,J. William Lown,Richard G. Ball +6 more
TL;DR: In this article, the structure of one isomer has been confirmed by X-ray crystallography, which is a diastereomeric Me8[14]diene that can be separated through fractional crystallization from xylene and has been established on the bseis of their NMR spectra.
Journal ArticleDOI
Ring size effects among metal complexes with macrocyclic ligands. The kinetics of aquation of dichlorotetraamine complexes of cobalt(III) involving macrocyclic ligands
Yann Hung,Daryle H. Busch +1 more
Journal ArticleDOI
The kinetics and stereochemistry of spontaneous aquation of trans-[Co(en)2N3(Me2SO)]2+, [Co(en)2N3(DMF)]2+,[Co(en)2N3Br]+ and [Co(en)2N3Cl]+
William G. Jackson,C. M. Begbie +1 more
TL;DR: In this paper, the synthesis of trans-solvento complexes trans-[Co(en)2(sol)N3](ClO4)2 (sol = Me2SO,Me2N·CHO (DMF)) are described.