A preliminary study of poly(p‐phenylene) based nonlinear optical materials

Abstract

This paper describes preliminary work exploring the feasibility of preparing high-performance nonlinear optical (NLO) materials based on the poly@-phenylene (PPP) backbone. Three new monomer/NLO-phores of the general formula: 4-RS0,C,H4C= C(4-XC6HS (where R = 2,5-dichlorophenyl; 2a, X = H; 2b, X = OCH,; 2c, X = N(CH,)d were synthesized and then homopolymerized using catalytic nickel and stoichiometric zinc to produce the poly@-phenylenes), 3 a-c, respectively, as lowmolecular-weight materials (number-average molecular weight a,, = 1 800-6000). NLOphores 2 b-c and low-molecular-weight oligomers of 3c were dispersed in a poly(methy1 methacrylate) (PMMA) host. Spin-cast films of these guest-host systems were subjected to corona poling above the glass transition temperature Tg. Following poling, both monomer NLO-phore/PMMA guest-host systems displayed optical nonlinearity with second-order nonlinear optical susceptibility x(') values of 1.7 pm/V and 0.9 pm/V for 2c and 2b, respectively. Both systems exhibited good temporal stability at room temperature, with about 12% loss in second harmonic signal over more than 100 h. However, the oligomeric material 3c dispersed in PMMA showed a smaller NLO signal when poled above Tg.Attempts to induce dipolar asymmetry in the homopolymers 3 b and 3 c were unsuccessful. The observed response during poling and the relaxation of the chromophore orientation following poling, have been discussed in terms of structure and composition of these systems.

2,5-Dichloro-1-(ROSO2)benzene [R=C6H5, C6F5, and CH2(CF2)4H]: Synthesis, molecular structure, and solubility in supercritical CO2

“…Several attempts at polymerizing compounds 1a-1c were made using nickel-catalysis and stoichiometric zinc. We have previously shown that 2,5-dichlorosulfonyl monomers do nicely polymerize under these conditions [15]; however, for each of the monomers prepared in this study we were unable to isolate a poly-p-phenylene product for further analysis. Tables 2 and 3 list the isopleths, solution densities, and the type of transitions for PDBS-CO 2 and FPDBS-CO 2 mixtures investigated in this study from approximately room temperature to 100 8C.…”

“…Chemical synthesis and molecular structure Phenyl 2,5-dichlorobenzenesulfonate (PDBS) [14] and pentafluorophenyl 2,5-dichlorobenzenesulfonate (FPDBS) are prepared in high yield from the inexpensive and commercially available 2,5-dichlorobenzenesulfonyl chloride, which has proven a valuable synthetic launching point for several poly ( p-phenylene) monomer syntheses prior to this work [15].…”

Synthesis and Characterization of Poly(p-phenylene)s with Nonlinear Optical Side Chains

“…The crude solids were left to air-dry overnight before drying in a vacuum oven until a constant weight measurement was obtained (18.67 g, 45% yield); mp 132.2°C (DSC). 1 Polymerization. Ni(0) coupling chemistry was used to polymerize the rigorously purified monomer.…”

“…The crude solids were left to air-dry overnight before drying in a vacuum oven until a constant weight measurement was obtained (18.67 g, 45% yield); mp 132.2 °C (DSC). 1 H NMR (CDCl3): σ (ppm) 8.00 (s,1,-CONHAr) 7.90 (s, 1, aromatic-H) 7.78 (d,1, ortho aromatic -H of anilide) 7.54 (t,1, meta aromatic -H of anilide) 7.40 (s, 2, aromatic-H) 7.34 (t,1, para aromatic-H of anilide). 13 Preparation of 4′-(N,N-Diethylamino)-2,5-dichlorobenzophenone (2).…”

“…4,15 The resulting dark green material was purified by repeated crystallization from ethanol to afford pale green plates (8.99 g, 41.1% yield); mp 73 °C (DSC). 1 H NMR (CDCl3): σ (ppm) 7.66 (d,1) 7.35 (m, 3) 6.62 (d, 1) 3.45 (q, 2, CH2) 1.23 (t, 3, CH3). 13 Polymerization.…”