Question

5. cis-[Pt(PEt3)2C12] is normally stable in benzene solution. Upon the addition of a trace amount of PPh3, however, it rapidly converts to a mixture of the cis and trans isomers. Draw a mechanism that accounts for this behavior

Answer 1

This question is explained as follows:

Sol This before question going to is based on trans effect of ligands, the solution, let us discurs flew (i) Trans effect series in order of decreasing strength CN-, CO, NO, CHA > PR3, ASR₂, H > CH₃, SC (NH2), > C6H5 , NO2, I-, SCN-> Be > ce > Py> RNH₂, NH₂> F-> OH > H₂O (ii) The replacement of ligands is based on trans effect i e, capability of a ligand to add a new ligand at a position trans to itself. Thus, ce has a power to welcome a group on its trans position if the groups like Py, RNH₂, NH3, F, I OH, HO' are already present on the position trans - to it. e.gr fa ja 7 ly a an at e NHL {due to ce > NH3 G Cin) In a reaction: once a group is removed never add it again and once a once a group group as is added never remove it again. We are it is ligant given a in werit that PPhz is present in non; although trace amount but as being a powerful trans effect; it can remove all the groups already present in complex.

This purcharge is responsible El a 7 PPhz I Php +2 Pet+2 ce Benzone Php - PPh₃ (I ) 2pet, Phat prt 3 PEt3 > PP hz petz CP feis - isomer) PPh, 72+ e a Teap Phz Php (PPh ppha ) Setzha 7 (petz PPh Php AP (ce > PPh ₂) 12 tot , Cl is less powerful, lut (traus - isomer) in any 1+w; demend points ci)& ci).