Structural Properties of Some Cyanoethenes with Optical Nonlinearity

Abstract

An α-cyanostilbene crystal showing optical nonlinearity was examined to be compared with a non-optically active crystal, with emphasis on the structural aspect. It was suggested that the introduction of bulky substituents such dimethylamino and methoxy groups into the cyanostyrene conjugation system was effective to get macroscopic optical nonlinearity, based on the chemical synthesis and structural analysis. It was also stressed that the quadrupole interaction in α-cyanostilbenes was one of the important factors responsible for a nonsymmetric molecular arrangement for the second order optical nonlinearity.

The chalcone derivative (E)-1-(4-fluorophenyl)-3-(4-hydroxy-3-methoxyphenyl)prop-2-en-1-one monohydrate

“…1. A cis disposition of the olefinic and carbonyl functional groups about the C1-C8 single bond is observed, which is the conformation found for chalcone itself in the crystalline state (Rabinovich, 1970;Ohkura et al, 1973;Arai et al, 1994;Wu et al, 2006) and for most of its simple derivatives. The trans orientation of olefinic and carbonyl functional groups about the enone single bond is observed less frequently (Teh et al, 2006;Yathirajan, et al, 2006;Yathirajan, et al, 2007;Butcher et al, 2007) in the crystalline state for chalcones, possibly because it is less conducive to stabilizing intermolecular π-π stacking interactions (see below).…”

(E)-1-(4-Bromophenyl)-3-(2-methoxyphenyl)prop-2-en-1-one

“…For SHG conversion efficiencies, see: . For related structures, see: Arai et al (1994); Shettigar et al (2006); Rosli et al (2006); Ng et al (2006); Harrison et al (2006); Patil et al (2007); Li et al (1992); Loh et al (2010). For standard bond lengths, see: Allen et al (1987).…”

(E)-3-(4-Methoxyphenyl)-1-[4-(piperidin-1-yl)phenyl]prop-2-en-1-one

“…For antiinflammatory chalcones, see: Nowakowska (2007). For related structures, see: Ahmad et al(2010); Arai et al(1994); Jasinski et al (2010); Li et al (1992); Patil et al (2007); Shettigar et al (2006). For standard bond lengths, see; Allen et al (1987).…”

“…The synthesis and biological evaluation of simple methoxylated chalcones as anticancer, anti-inflammatory and antioxidant agents is recently reported (Bandgar et al, 2010). The crystal structures of some related chalcones containing methoxy substituents, viz., 4-bromo-4′-methoxy-chalcone (Li et al, 1992), 4-bromo-4′-methoxychalcone (Arai et al, 1994), 1-(4bromophenyl)-3-(4-methoxyphenyl)prop-2-en-1-one (Shettigar et al, 2006) and 1-(4-bromophenyl)-3-(3-methoxyphenyl) prop-2-en-1-one (Patil et al, 2007), a monoclinic polymorph of 1-(4-chlorophenyl)-3-(4-methoxyphenyl)prop-2en-1-one (Jasinski et al, 2010) and (E)-3-(3-chlorophenyl)-1-(4-methoxyphenyl) prop-2-en-1-one (Ahmad et al, 2010) have been reported. Hence in continuation with the synthesis and crystal structure of chalcones and their derivatives, this new chalcone containing the piperidine moiety was synthesized and its crystal structure is reported herein.…”