Synthesis and nonlinear optical properties of functionalised polydiacetylenes and their complexes with transition metals

New polydiacetylenes (PDAs) have been prepared in which a ligating 2,2'-bip yridyl substituent is incorporated in the side-chain, 3a-d. The formation o f complexes of these polymers, and of a related (diethylamino)alkyl substit uted PDA 4, with transition metals has been studied. Coordination polymers containing nickel(II) 5 a,b, copper(II) 5 c,d, ruthenium(II) 6 and molybden um(o) 7 a-c have been formed and characterised spectroscopically by compari son with appropriate model coordination compounds, including species derive d From corresponding monomeric 1,3-diynes 1. The nonlinear optical properti es of PDA 4 and the coordination polymers 5-7 in solution have been investi gated by the z-scan procedure. Values for the nonlinear absorption coemcien t, alpha(2), and the nonlinear refractive index, n(2), have been derived an d these are discussed in relation to the structures of the PDAs.