Synthesis and characterization of new potentially hydrosoluble pincer ligands and their application in Suzuki-Miyaura cross-coupling reactions in water

Three water soluble pincer ligands, 2,6-bis[(diethanolamine)methyl]pyridine hydrobromide (1:2) (1), 3,11,17,18-Tetraazatricyclo[11.3.1.1(5,9)]octadeca-1(17),5,7,9(18),13,15-hexaene,3,11-bis(dihydroxymethylmethyl) hydrobromide (1:2) (2), and 1,3-bis[(diethanolamine)methyl]benzene (3) were synthesized and unequivocally characterized by a number of analytical techniques including single crystal X-ray diffraction analyses. Mixtures of these ligands with PdCl2 proved to be efficient in catalyzing the Suzuki-Miyaura cross couplings in water. Being the most efficient system that including ligand (1). Further experiments using this catalytic system were performed to assess the effects of varying temperature, reaction times, and nature of the base, finding the optimal operational conditions of this system. (C) 2013 Elsevier Ltd. All rights reserved.