Synthesis, Structure, and Optical Properties of 1,4-Dithiafulvene-Based Nonlinear Optic-phores

Abstract

Polyenic nonlinear optic (NLO)-phores with a proaromatic 1,4-dithiafulvene electron donor and the little explored 1,1,3-tricyano-2-phenylpropene acceptor have been synthesized. Their configurational and conformational features, ground state polarization, and linear and nonlinear optical properties have been determined experimentally and theoretically, and the results are compared to those of tetrathiafulvalene-related derivatives. The newly prepared compounds show close to optimal bond length alternation values for maximizing the first molecular hyperpolarizability, and one of them displays the highest mu beta0 value ever reported for a dithiafulvene-based NLO-phore. The first example of a dithiafulvenylmethylene transfer reaction is also reported.

New one- and two-dimensional 4H-pyranylidene NLO-phores

“…1). 14 It can be seen that the PhC-C(CN) bond adopts an s-trans conformation, like that found in a related derivative bearing a 1,3-dithiol-2-ylidene fragment, 15 and that the tricyanopropene moiety of 1e is appreciably distorted from planarity, as evidenced by dihedral angles C 8 -C 10 -C 17 -C 18 (17.1°) and C 9 -C 8 -C 10 -C 17 (29.3°), and by the angle between the best-fit planes of the pyran and the phenyl rings (67.6°). Moreover, the bond distances in the pyran ring of 1e are very similar to those of 1a.…”

Tetrathiafulvalene–Polychlorotriphenylmethyl Dyads: Influence of Bridge and Open‐Shell Characteristics on Linear and Nonlinear Optical Properties

“…Regarding the buildingb locks, the tetrathiafulvalene (TTF) moiety has been widely used as an efficient electron-donor unit for synthesizing TTF-p-A structures with appealing NLO properties.I ndeed, after the first example reported in 1998 by N. Martín, J. Garín and co-workers, [9] many otherT TF-based push-pull derivatives with closed-shell electronic structures exhibiting large NLO responses have been described. [10][11][12][13][14][15][16][17][18] On the other hand, molecular materials with open-shell electronics tructures have also aroused interest because of their high potentialitya sN LOphores. [19][20][21][22][23][24] Some of us previously reported the second-order nonlinearoptical(SONLO) response of afamily of polychlorotriphenylmethyl (PTM) radicald erivatives showingl arge b hyperpolarizability values.…”

Synthesis, Photophysical Properties and Two‐Photon Absorption Study of Tetraazachrysene‐based N‐Heteroacenes

“…[2][3][4][5][6][7][8][9][10][11][12][13] Benefiting from their diverse advantages including well-defined structurald iversity,f lexibility and functionality,f ast response, and variable band gap, organic p-conjugated compoundsh ave been widely explored as NLO materials to enhance TPAa bsorption cross-sections. [14][15][16][17][18][19][20][21][22] In particular, extended p-conjugated systems with the symmetrical substitution of electron-donating and electron-accepting units have been regarded as efficient TPAm olecules to exhibit larger TPAa bsorption cross-sectionsc ompared to the corresponding unsubstituted counterparts, indicating that the efficient intramolecular charge transfer (ICT), [23,24] caused by the donating and withdrawing abilities of electron donor and acceptor,p lays an important role in increasing their TPAc ross-sectionsv alues. [25][26][27] Effortst of urtheri ncrease the nonlinearity are usually focused on enlarging the conjugation length or increasing the strength of donors or acceptors or both.…”