Title

Substitution Reactions of Five-coordinate Complexes. 2. Mechanism of Ligand Replacement in Trigonal-bipyramidal Nickel(ii) and Platinum(ii) Complexes Containing the Tetradentate Ligand Tris(o-(diphenylarsino)phenyl)arsine

Abstract

Ligand replacement of the monodentate ligand in a series of trigonal-bipyramidal nickel(II) complexes containing the tetradentate ligand tris(o-(diphenylarsino)phenyl)arsine, QAS, is reported for methanol solutions. Entering ligands replacing Br- in order of decreasing rate were SC(NH2)2 ≫ CN-, > N3- > SCN- > I- > NO2 - ≫ PPh3. CN- replacement of leaving groups in order of decreasing rate were NCS- > N3 - > Cl- > Br- > NO2 - > I-. A second consecutive decomposition was observed to be several orders of magnitude slower than ligand replacement when CN- was the entering ligand. The kinetic data obtained at 0.050 M ionic strength and 25.0°C are consistent with either an associative interchange, Ia, mechanism or a mechanism involving formation of a four-coordinate intermediate via partial dissociation of the tetradentate ligand.

Department(s)

Chemistry

International Standard Serial Number (ISSN)

00201669

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 1980 American Chemical Society, All rights reserved.


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