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Role of bridging diamine linkers on the rate of ligand substitution in a series of dinuclear Pt II complexes
Author(s) -
Jaganyi D.,
Munisamy V. M.,
Reddy D.
Publication year - 2006
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/kin.20152
Subject(s) - chemistry , thiourea , diamine , associative substitution , substitution reaction , ligand (biochemistry) , reactivity (psychology) , platinum , substitution (logic) , bridging ligand , nucleophilic substitution , stereochemistry , medicinal chemistry , crystallography , polymer chemistry , organic chemistry , crystal structure , catalysis , receptor , medicine , alternative medicine , pathology , computer science , programming language , biochemistry
Abstract A series of dinuclear platinum II complexes of the type [{ trans ‐Pt(H 2 O)(NH 3 ) 2 } 2 ‐NH 2 (CH 2 ) n H 2 N] 4+ (where n = 2, 3, 4, and 6) were synthesized to investigate the influence of the bridging diamine linker on the reactivity of the platinum centers. The p K a values were determined, and the rates of substitution of the aqua moieties by a series of neutral nucleophiles viz. thiourea, 1,3‐dimethyl‐2‐thiourea, and 1,1,3,3‐tetramethyl‐2‐thiourea were studied as a function of concentration and temperature. All reactions studied gave excellent fits to a single exponential and obeyed the simple rate law, k obs = k 2 [Nu]. Negative activation entropies support an associative mode of substitution. The results obtained suggest that the rate of substitution is definitely influenced by the length of the diamine chain, with the rate of substitution decreasing as the length of the diamine chain increases. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 202–210, 2006