Design, crystal structures and enhanced frequency-upconverted lasing efficiencies of a new series of dyes from hybrid of inorganic polymers and organic chromophores

Abstract

A new series of hybrid dyes, trans-4-(4′-N,N-dialkylaminostyryl)-N-methyl pyridinium [Cd(SCN)₃⁻]_n [alkyl = Me(1), Et(2), Pr(3) and n–Bu(4)] have been successfully synthesized from hybrids of inorganic polymers and organic chromophores. The structures of four new hybrid dyes were characterized by single-crystal X-ray diffraction first. The particular features of the hybrid dyes are (1) the inorganic anions form isolated polymeric one-dimensional zig-zag chains of [Cd(SCN)₃⁻]_n with an extended π-conjugation system within the polymeric –[M–S–C≡N]–M… chain and high polarizabilities; and (2) the organic cationic chromophores determine their optical properties. Experimental results revealed that the TPA cross-section values and overall energy conversion efficiencies of hybrid dyes with different alkyl pendant groups have obviously increased from 1 to 4, and in particular, have been substantially enhanced compared to their corresponding iodide analogues 1′–4′. Therefore, we speculate that such increases are attributable to arrangements of infinite anionic [Cd(SCN)₃⁻]_n chains and synergic effects with chromophore cations.