Zeise’s salt figure

The adoption of a planar structure in these adducts, rather than the sterically more favourable tetrahedral one, is in keeping with a platinum(II) oxidation state. The side-on bonding of the 02 molecule is believed to involve two components, as in Zeise s salt (Figure 3.18). 

Figure 3.63 Platinum-alkene bonding in Zeise s salt. (Reproduced with permission from S.A. Cotton and F.A. Hart, The Heavy Transition Elements, Macmillan Press Ltd, 1975, p. 126.)...

FIGURE 16.10 The structure and bonding in the anion of Zeise s salt. A cr-bond results from the overlap of a dsp2 hybrid orbital on the metal and the 7T orbital on ethylene. Back donation from a d orbital on the metal to the -k orbital on ethylene gives some 7r bonding (shown in (c)). 

FIGURE 21.8 The 7r bonding that occurs between ethylene and Pt in Zeise s salt. 

The utility of fragment orbitals can be documented in many different situahons. Here only two examples, ahcene ML and CpMLs complexes, are covered. We start with Zeise s salt, ethylene PtCls. A PtCls fragment is d the electron occupancy for the five fragment orbitals is shown on the left side of Figure 18(a). The empty 2ai PtCft" hybrid interacts with and stabihzes the n orbital of the ethylene hgand while filled b2 is stabihzed by ethylene tt. The same basic pattern... 

Figure 18 Orbital interaction diagrams for (a) Zeise s salt and (b) ethylene-Fe(CO)4...

Generate and display the molecular orbitals of the anion of Zeise s salt, shown in Figure 13-4. Identify the molecular orbitals that show how the it and tt orbitals of ethylene interact with orbitals on platinum. 

The UV absorption curves of all the present complexes have peaks with e=ea.l03M-1cm- from 31,000 to 45,000 cm-1. Denning, Hartley and Venanzi assigned the absorption bands of Zeise s salt in this region to d-ir (ethylene) transition. (12) We have observed CD peaks with Ac s -1.3 and +3.3 at ea.35,000 and 39,500 cm-1 for the tetraphenylphosphonium salt of [PtCl3(5,5-tbn)] in acetonitrile. 13) The peak at 35,000 cm l must correspond to the same transition as that of the main CD band of Figure 10 (and Figure... 

Figure 19.19 Slmcture of the anion of Zeise s salt, [Ptiij -CzHjlClj] standard deviations are Pt-Cl 0.2 pm Pi-C 0.3 pm, and C-C 0.4pm.

M. J. S. Dewar proposed a model (Figure 1) to describe the bonding of an olefin to silver(i) or copper(i). The model suggested that, in addition to cr-donation of olefin 7r-bonding electrons to the metal, d electrons on the metal would also interact with antibonding orbitals of 7r-symmetry on the olefin. No experimental evidence was provided to support this proposal nor, indeed, was explicit mention made of Zeise s salt or other platinum-olefin complexes. From a study of Chemical Abstracts 41 (1947)-75 (1971), it would appear that Dewar did not follow up his proposal with more detailed studies, possibly indicating that this was not a prime focus of his own interests in MO theory and its application to... 

Figure 3 Early proposal by J. Chatt of bonding between ethylene and platinum ii) in Zeise s salt taken from ref 13)...

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