Two series of highly efficient and thermally stable nonlinear optical chromophores based on the (4diarylamino)phenyl electron donors have been synthesized and systematically investigated. A modular approach has been employed to synthesize these electron donors with tunable size, shape, and electrondonating abilities. Efficient conjugated bridges were extended from these donors and coupled with very strong CF 3 -TCF electron acceptors to afford chromophores with very high β values (up to 7077 × 10 -30 esu at 1.907 µm). These chromophores possess much higher thermal stability (with their onset decomposition temperatures all above 220 °C) than those substituted with (4-dialkylamino)phenyl donors. Most importantly, the high molecular hyperpolarizability of these chromophores can be effectively translated into very large electro-optic (E-O) coefficients (r 33 ) in poled polymers through suitable shape engineering. Exemplified by the chromophore B4, which has a fluorinated aromatic substituent anchored at its donor end, it showed a very large r 33 (169 pm/V) at 1.31 µm. This value is almost 1 order higher than the E-O activities usually reported for (4-diarylamino)phenyl-substituted NLO chromophores.

Abstract. In situ liquid secondary ion mass spectrometry (SIMS) enabled by system for analysis at the liquid vacuum interface (SALVI) has proven to be a promising new tool to provide molecular information at solid-liquid and liquid-vacuum interfaces. However, the initial data showed that useful signals in positive ion spectra are too weak to be meaningful in most cases. In addition, it is difficult to obtain strong negative molecular ion signals when m/z>200. These two drawbacks have been the biggest obstacle towards practical use of this new analytical approach. In this study, we report that strong and reliable positive and negative molecular signals are achievable after optimizing the SIMS experimental conditions. Four model systems, including a 1,8-diazabicycloundec-7-ene (DBU)-base switchable ionic liquid, a live Shewanella oneidensis biofilm, a hydrated mammalian epithelia cell, and an electrolyte popularly used in Li ion batteries were studied. A signal enhancement of about two orders of magnitude was obtained in comparison with non-optimized conditions. Therefore, molecular ion signal intensity has become very acceptable for use of in situ liquid SIMS to study solid-liquid and liquid-vacuum interfaces.

Iridium pincer complexes (POCOP)Ir(CO) (POCOP = κ 3 -C 6 H 3 -1,3-[OP( t Bu) 2 ] 2 ) and substituted POCOP derivatives catalyze deoxygenation of glycerol to npropanol and 1,3-propanediol in good yield under moderate conditions (acidic aqueous dioxane, 200 °C, 80 bar H 2 ). Catalyst solubility in the polar reaction mixture is improved by incorporation of a polar moiety in the para position of the POCOP phenyl ring, with the best results obtained with a dimethylamino substituent.

Application of bis(propylenedioxythiophene) (bis(ProDOT)) π-conjugated bridges bearing alkyl or aryl substituents in electro-optic (EO) chromophores is presented. A series of three bis(ProDOT)-based chromophores and a bithiophene-based control chromophore were prepared and fully characterized with regard to EO applications. The highly planar bis(ProDOT) bridge results in slightly larger (∼10%) molecular hyperpolarizability ( ) values as compared to the bithiophene bridge, as measured by hyperRayleigh scattering at a variety of wavelengths. In amorphous polycarbonate guest-host films, however, the bulky substituents on the bis(ProDOT) bridge result in significantly larger (∼70%) poling-induced EO coefficient (r 33 ) values, as measured by simple reflection ellipsometry at 1310 nm. This can be attributed to a roughly 2-fold enhancement in poling efficiency due to reduced intermolecular dipole-dipole interactions. This chromophore architecture also exhibits excellent temporal alignment stability and photochemical stability as compared to benchmark AJL8, FTC, and CLD chromophore systems. Incorporation of the strong CF 3 -phenyl-substituted tricyano-furan (TCF) acceptor into a bis(ProDOT)-based chromophore resulted in a zzz (-2ω;ω,ω) value at 1907 nm of 5700 ( 400 × 10 -30 esu and an r 33 value of 69 ( 14 pm/V at 32.8 total chromophore weight %.

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This article describes the high-yielding and selective oxidatively induced formation of ethane from mono-methyl palladium complexes. Mechanistic details of this reaction have been explored via both experiment and computation. On the basis of these studies, a mechanism involving methyl group transmetalation between Pd(II) and Pd(IV) interediates is proposed.

We have synthesized a new class of highly efficient nonlinear optical (NLO) chromophores based on the novel tricyanopyrroline (TCP) electron acceptor. Molecular linear and nonlinear optical properties of the prototypical chromophores were measured and calculated to understand structure-property relationships. One such chromophore showed molecular first hyperpolarizability (β) of (8700 ( 702) × 10 -30 esu at excitation wavelengths of 1.9 µm, and another showed macroscopic electro-optic (EO) coefficients (r 33 ) of 51 pm/V at 1.55 µm with 20 wt % chromophore loading when poled with 65 V/µm in amorphous polycarbonate film. Synthetic strategies for extending the utility of the acceptor and chromophores are discussed.

A macrocyclic trichromophore bundle 1 with parallel-aligned dipole moments has been synthesized to study the influence of aggregation and orientation of a nonlinear optical (NLO) chromophore on its optical properties. The linear and nonlinear optical properties of 1 and a single chromophore standard 2 have been studied by UV-vis absorption, fluorescence, solvatochromic spectrometry, and hyper-Rayleigh scattering (HRS). Reduced first-order hyperpolarizability beta, hypsochromic shift, enhanced solvatochromic shifts, and fluorescence quenching for individual chromophores were observed when 1 was compared with 2. Analysis of the data showed that the transition dipole moment changes only slightly when the chromophores are parallel aligned in the bundle architecture. However, the apparent hyperpolarizability of the individual chromophores decreased significantly by about 20%. The reduction in beta for the individual chromophores in 1 is largely due to the hypsochromic shift, i.e., excitation energy increase of the interband (charge-transfer) energy gap and the reduced difference between the ground-state and excited-state dipole moments. The hypsochromic shift and fluorescence quenching are consistent with exciton theory. Possible reasons for the enhanced solvatochromic shift are discussed.