Ligand exchange reactions in cyclopalladated complexes of benzylideneanilines. Crystal structure of [Pd(C6H4CHNC6H5)Br(PPh3)2]
- 1 January 1986
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in J. Chem. Soc., Dalton Trans.
- No. 9,p. 1785-1790
- https://doi.org/10.1039/dt9860001785
Abstract
The ligand exchange reactions between [{[graphics omitted]C6H5)(O2CMe)}2] and the free imines p-RC6H4CHNC6H5(R = H, Cl, NMe2, or NO2)(N[graphics omitted]CH) in acetic acid have been studied. The substitution process is favoured when the incoming ligand contains electron-withdrawing substituents. From the results obtained a new mechanism involving a bis-cyclometallated complex ([graphics omitted]P[graphics omitted])] as intermediate is proposed. The dimeric cyclopalladated compounds are obtained by metallation of the imines by Pd(O2CMe)2; by reaction with phosphines PR′3 and LiBr, [[graphics omitted]C6H5)Br(PR′3)] and [Pd(p-RC6H3CHNC6H5)Br(PR3′)2] are formed (R′= Ph or Et). All the compounds have been fully characterized and their 1H and 13C n.m.r. spectroscopic data recorded. The molecular structure of [Pd(C6H4CHNC6H5)Br(PPh3)2] has been determined by a single-crystal X-ray analysis. The crystals are monoclinic, space group P21/a, a= 17.427(3), b= 24.790(4), c= 10.424(2)Å, β= 98.91(2)°, and Z= 4; R= 0.053 for 6 579 reflections. The palladium atoms are five-co-ordinated, the Pd–N distance being 2.710(6)Å.Keywords
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