Feb 13, 2014 - Solvent effects on polarizability and hyperpolarizability of spirobifluorene derivative. Hai-Peng Li & Xiao-Peng Shen & Kui Han & Gang Tang.
J Mol Model (2014) 20:2126 DOI 10.1007/s00894-014-2126-7
ORIGINAL PAPER
Solvent effects on polarizability and hyperpolarizability of spirobifluorene derivative Hai-Peng Li & Xiao-Peng Shen & Kui Han & Gang Tang
Received: 17 October 2013 / Accepted: 20 December 2013 / Published online: 13 February 2014 # Springer-Verlag Berlin Heidelberg 2014
Abstract We studied the solvent effect on the geometric structure and (hyper)polarizability of spirobifluorene derivative by using quantum chemistry calculations. We found that the geometric structure is slightly affected by the solvent polarity. However, solvent polarity significantly influences first hyperpolarizability and second hyperpolarizability respectively. In addition, the linear polarizability is less affected by the solvent than the hyperpolarizabilities. We also first studied the solvent effect on frontier molecular orbitals and found that the frontier molecular orbitals energy gap is strongly influenced by the surrounding solvent. Our results demonstrate frontier molecular orbitals energy gap and molecular hyperpolarizabilities can be tuned by a suitable choice of the solvent respectively. Such findings have crucial implications for organic nonlinear optical materials applications. Keywords Geometric structure . Quantum chemistry calculations . Second hyperpolarizability . Solvent effect . Spirobifluorene derivative
interaction through the spirolinkage [5], that is, spiroconjugation efffect [6]. As a typical spirocompound, spirobifluorene has excellent third-order NLO properties [8]. Most of the earlier investigations of the NLO response of the spirobifluorene derivatives considered the first hyperpolarizability [3–7]. By comparison, very little theoretical effort has been directed to the second hyperpolarizability of such molecular species. In experiments, the hyperpolarizability is generally measured in solution which raises the possibility of solvent influencing the observed NLO response of the solute. In theory, the solvent effects on the NLO properties of various push-pull molecules have been investigated by several authors [9–15]. However, no study has yet been reported in the solvent-dependent NLO properties of spiroconjugated compounds. In this work, we use quantum chemistry calculations to study the solvent effect on geometric structure and NLO properties of 2,2′-diamino-7,7′-dinitro-9,9′-spirobifluorene (ANSF) (Fig. 1). Our results demonstrate that the NLO properties of ANSF studied are strongly influenced by the surrounding medium and thus can be tuned by a suitable choice of the solvent.
Introduction The development of novel organic materials for nonlinear optical (NLO) applications has been a very active field of research for a number of years [1, 2]. Recently, great attention has been paid to spiroconjugated molecular systems because spirocompounds exhibit both large NLO properties and excellent transparency compared to the corresponding monomers [3–8]. The enhancement of first hyperpolarizability of spirocompounds has been explained based on the orbital H.
