Rational synthesis, structural characterization and theoretical exploration on third-order nonlinear optical properties of isolated Agn (n = 5, 8, 12) alkynyl clusters

Abstract Three silver(Ι) alkynyl compounds, [Ag 5 (C C t Bu)(CF 3 COO) 7 ( n Bu 4 N) 3 ·H 2 O] ( 1 ), [Ag 8 (C C t Bu) 2 (CF 3 COO) 10 (Et 3 N) 4 ] ( 2 ), and [Ag 12 (C C t Bu) 6 (CF 3 COO) 8 ( n Bu 4 N) 2 (Et 3 N) 2 (CF 3 COO) 2 ] ( 3 ), have been obtained. Concomitantly, isolated [Ag 5 (C C t Bu)(CF 3 COO) 7 ] 3– , [Ag 8 (C C t Bu) 2 (CF 3 COO) 10 ] 4– and [Ag 12 (C C t Bu) 6 (CF 3 COO) 8 ] 2– clusters ( Ag 5 , Ag 8 and Ag 12 for short) appear in 1 – 3 , respectively. The synthesis of 1 – 3 demonstrates silver(I) alkynyls are better systems for the study of the template effect. ESI-MS analysis indicates compounds 1 – 3 can stably exist in methanol, and they have been proved to be potential wide gap semiconductor materials by the reflectance spectra. Notably, the second hyperpolarizabilities ( γ values) of Ag 5 , Ag 8 and Ag 12 have been studied by using time-dependent density functional theory (TDDFT) calculations and the finite filed (FF) approach combining CAM-B3LYP. The calculated results show that they can be applied as potential third-order nonlinear optical (NLO) materials owing to their second hyperpolarizabilities rising from 39.1 × 10 −36 , 60.3 × 10 −36 to 97.7 × 10 −36  esu with the growth of the number of Ag atoms and C C groups.