Bicyclic cyclopalladated complexes derived from N-benzyl-substituted Schiff's bases

Article abstract of DOI:10.1016/S0022-328X(97)00377-X

2-Benzylamino-2-penten-4-one (Hacac-bn) reacts with Pd(MeCO₂)₂ and [Pd(MeCO₂)₂(SPrⁱ₂)₂] in benzene at 50°C to give an N,O-chelated complex, [Pd(acac-bn)₂] and a bicyclic cyclopalladated complex, [Pd(acac-NCH₂C₆H₄)(SPrⁱ₂)], respectively. Diisopropyl sulfide ligand in the latter complex is replaced easily by PPh₃, giving [Pd(acac-NCH₂C₆H₄)(PPh₃)]. N-(Salicylidene)benzylamine (Hsal-bn) also reacts similarly with Pd(MeCO₂)₂ and [Pd(MeCO₂)₂(SPrⁱ₂)₂] at 50°C to afford [Pd(sal-bn)₂] and [Pd(sal-NCH₂C₆H₄)(SPrⁱ₂)], respectively. N-(3,5-Dichlorosalicylidene)benzylamine (Hdcsal-bn) reacts with [Pd(MeCO₂)₂(SPrⁱ₂)₂] and Pd(MeCO₂)₂ in the presence of PPh₂(OMe) at 50°C to yield cyclopalladated complexes, [Pd(dcsal-NCH₂C₆H₄)(SPrⁱ₂)] and [Pd(dcsal-NCH₂C₆H₄){PPh₂(OMe)}], respectively. [Pd(MeCO₂)₂(dmpy)₂] (dmpy = 3,5-dimethylpyridine) reacted with Hdcsal-bn in 1:1 and 1:2 molar ratios at 50°C to give [Pd(dcsal-bn)(MeCO₂)(dmpy)] and [Pd(dcsal-bn)₂], respectively. The functions of SPrⁱ₂ and dmpy in these reactions are discussed.