Ligands containing alternating 2,6-linked pyridine and 2,5-linked thiophene units

A variety of linear assemblies of alternating pyridine (2,6-linked) [P] and thiophene (2,5-linked) [T] units have been generated with up to seven unit s and their macrocyclisation investigated The optimal methods involved the palladium(0) catalysed reaction of thienyl Grignard reagents with bromopyri dines. In this way were made TPT, TPTPT, TPTPTPT, BrPTPBr and various XCH2P TPTPCH2X derivatives (X = H, Br, OH, OR and SBu-t). Alternative routes wher eby pyridine units were 2,6-linked by CH2SCH2 units, with the intention of converting the bridge groups into thiophenes by a Hinsberg reaction, were-a lso studied. The latter products. {(HOCH2[P]CH2)(2)S and (HOCH2[P]CH2SCH2)( 2)[P]} proved to be highly effective ligands for transition metals, especia lly divalent ones such as Co2+, Ni2+ and Zn2+. No macrocyclisations were ef fective.