Ligand exchange at square planar

Only for nickel(II) does the prospect of prereaction geometry change pose a potential complication and since more examples of faster associative nucleophilic ligand exchange at square-planar complexes (rather than their tetrahedral, 5-coordinate, or octahedral alterna-... 

Associative Ligand Exchange at Square-Planar Platinum(II)... 

A main objective of this work is to develop the relationship between the many reaction pathways leading to ligand substitution at square-planar molecules. Concentrating on more recent results to illustrate the processes under discussion, we examine in detail the evidence for operation of the less common and sometimes controversial routes such as dissociative ligand exchange (6). It cannot be stressed too much, however, that the field is still dominated by associative reactions, so to maintain a balance, as well as to provide the now necessary comparative evidence, we also cover the essential features of nucleophilic ligand replacements. 

Examinations of possible correlations between the volume of activation and the entropy of activation for series of similar reactions have been reported for reactions of transition metal coordination compounds, such as solvent exchange, ligand substitution, or isomerization.163 167 A limiting factor in a potential correlation may be the lack of precision that often attends experimental determination of the entropy of activation. Attention has been drawn specifically to the qualitative nature of the correlations between the two parameters for solvent exchange at some 3 + cations, and at square planar Pd2+ and Pt2+ ions.168... 

The link between nucleophilic attack at square-planar complexes en route to ligand exchange, and electrophilic attack en route to oxidative additions, is nowhere... 

Several examples of ligand exchange at gold(m) in square-planar organo-metallic derivatives will be found in the appropriate section of Part IV, Chapter 1. 

The general molecular orbital energy level schemes arrived at for square planar complexes are given in Fig. 2 (case 1) and Fig. 3 (case 2). Group molecular orbital overlap integrals (for Ni(CN)42-) and ligand exchange interactions are summarized in Table II. 

---