Palladium(II) Schiff Base Complexes Derived from Allylamine and Vinylaniline

Abstract

Condensation of salicylaldehyde <TEX>$(2-HOC_6H_4C(O)H)$</TEX> with allylamine afforded the unsaturated salicylaldimine, <TEX>$2-HOC_6H_4C(H)=NCH_2CH=CH_2$</TEX>. Similar reactivity was observed with substituted salicylaldehydes. Further reaction of these Schiff bases with palladium acetate or <TEX>$Na_2PdCl_4$</TEX> afforded complexes of the type <TEX>$PdL_2$</TEX>, where L = deprotonated Schiff base. The molecular structure of the parent salicylaldimine palladium complex <TEX>$[trans-(2-OC_6H_4C(H)=NCH_2CH=CH_2)_2Pd]$</TEX> (1) was characterized by an X-ray diffraction study. Crystals of 1 were monoclinic, space group <TEX>$P2_1/n,\;a\;=\;14.0005(9)\;{\AA},\;b\;=7.2964(5)\;{\AA},\;c\;=\;17.5103(12)\;{\AA},\;{\beta}\;=\;100.189(1)^{\circ}$</TEX>, Z = 4. Analogous chemistry with 4-vinylaniline also gave novel palladium complexes containing a pendant styryl group. Crystals of <TEX>$[trans-(2-HOC_6H_4C(H)=N-4-C_6H_4CH=CH_2)_2Pd]$</TEX> (4) were monoclinic, space group <TEX>$P2_1/c$</TEX>, a = 13.7710(14) <TEX>${\AA}$</TEX>, b = 11.0348(11) <TEX>${\AA}$</TEX>, c = 7.8192(8) <TEX>${\AA}$</TEX>, <TEX>${\beta}\;=\;98.817(2)^{\circ}$</TEX>, Z = 2.