New “X-type” second-order nonlinear optical (NLO) dendrimers: fewer chromophore moieties and high NLO effects

Abstract

New types of “X-type” NLO dendrimers, C2 and C3, in which the chromophore moieties were arranged in order, were rationally designed. The special topology of the chromophore moieties contributed a great deal to the good NLO performance of C2 and C3: the d₃₃ value of C2 (containing only five chromophore moieties) was 157.4 pm V⁻¹, while that of C3 (containing nine chromophore moieties) achieved 195.2 pm V⁻¹, much larger than that of C1 (74.7 pm V⁻¹, containing three chromophore moieties) and the fifth generation dendrimer (G5) (193.1 pm V⁻¹, bearing 62 pieces of chromophore moieties). Through careful experimental and theoretical analysis, their structure–property relationship was explained, and discussed in detail.