Novel phosphine ligands bearing 3(5)-pyrazolyl and 4-(2-amino)pyrimidinyl groups: Synthesis and coordination chemistry

Novel triphenyl phosphine ligands bearing pyrazole or 2-aminopyrimidine groups in the ortho or meta position of one or three of the phenyl rings were obtained starting from the corresponding acyl derivatives Ph2P(o-C6H4-COCH3), Ph2P(m-C6H4-COCH3), or P(m-C6H4-COCH3)3. Conversion of the acyl groups into 3-dimethylamino-2-propen-1-onyl units was achieved by reaction with HC(OMe)2NMe2 which underwent ring closing with hydrazine or guanidine to yield the desired heterocycles. Two palladium complexes were synthesized using the coordinatively labile precursor (PhCN)2PdCl2, one of them could be characterized by X-ray structure analysis.