| dc.creator |
Kinunda, Grace |
|
| dc.date |
2018-09-25T13:49:17Z |
|
| dc.date |
2018-09-25T13:49:17Z |
|
| dc.date |
2018 |
|
| dc.date.accessioned |
2021-05-03T13:19:56Z |
|
| dc.date.available |
2021-05-03T13:19:56Z |
|
| dc.identifier |
GA Kinunda - Tanzania Journal of Science, 2018 |
|
| dc.identifier |
ISSN 0856-1761, e-ISSN 2507-7961 |
|
| dc.identifier |
http://hdl.handle.net/20.500.11810/4922 |
|
| dc.identifier.uri |
http://hdl.handle.net/20.500.11810/4922 |
|
| dc.description |
The rate of displacement of the chloride ligands by three neutral nucleophiles (Nu) of different steric demands, namely thiourea (TU), N,N’-dimethylthiourea (DMTU) and N,N,N,’Ntetramethylthiourea (TMTU) in the complexes viz; [Pt(II)(bis(2-pyridylmethyl)amine)Cl]ClO4, (Pt1), [Pt(II){N-(2-pyridinylmethyl)-8-quinolinamine}Cl]Cl, (Pt2), [Pt(II)(bis(2-pyridylmethyl)sulfide)Cl]Cl, (Pt3) and [Pt(II){8-((2-pyridylmethyl)thiol)quinoline}Cl]Cl, (Pt4) was studied under pseudo first-order conditions as a function of concentration and temperature using a stopped-flow technique and UV-Visible spectrophotometry. The observed pseudo first order rate constants for substitution reactions obeyed the simple rate law kobs =[Nu] k2. The results have shown that the chloro ligand in Pt(N^S^N) complexes is more labile by two orders of magnitude than Pt(N^N^N) complexes due to the high trans labilizing effect brought by the S donor atom. The quinoline based Pt(II) complexes (Pt2 and Pt4) have been found to be slow than their pyridine counterparts Pt1 and Pt3 due to poor π-acceptor ability of quinoline. Second-order kinetics and large negative activation entropies support an associative mode of activation. |
|
| dc.language |
en |
|
| dc.publisher |
College of Natural and Applied Sciences (CoNAS) of the University of Dar es Salaam (UDSM) |
|
| dc.subject |
Substitution |
|
| dc.subject |
nucleophiles |
|
| dc.subject |
pseudo first-order |
|
| dc.subject |
associative |
|
| dc.subject |
entropy |
|
| dc.title |
A trans influence and π-conjugation effects on ligand substitution reactions of Pt(II) complexes with tridentate pendant N/S-donor ligands |
|
| dc.type |
Journal Article, Peer Reviewed |
|