A Straightforward Modular Approach to NLO-Active β -Amino Vinyl Nitrothiophenes § (original) (raw)
Related papers
2007
In this work, we present a comparative study of the second order nonlinear optical properties of a series of chromophores containing a fused terthiophene, namely dithienothiophene (DTT), as electron relay with either D-π-A or D-π-D substitution patterns. The effect of the acceptor/donor strength and the solvent polarity confirm the possibility of fine-tuning optical non-linearities in the asymmetric samples. The geometrical and electronic properties calculated in solution reveal that push-pull chromophores become highly polarized as the dielectric constant of the solvent increases. Theoretical NLO calculations furthermore reveal a moderate nonlinear optical activity for the symmetric samples.
In this work, we present a comparative study of the second order nonlinear optical properties of a series of chromophores containing a fused terthiophene, namely dithienothiophene (DTT), as electron relay with either D-π-A or D-π-D substitution patterns. The effect of the acceptor/donor strength and the solvent polarity confirm the possibility of finetuning optical non-linearities in the asymmetric samples. The geometrical and electronic properties calculated in solution reveal that push-pull chromophores become highly polarized as the dielectric constant of the solvent increases. Theoretical NLO calculations furthermore reveal a moderate nonlinear optical activity for the symmetric samples.
Linear and Nonlinear Optics of Organic Materials VII, 2007
In this work, we present a comparative study of the second order nonlinear optical properties of a series of chromophores containing a fused terthiophene, namely dithienothiophene (DTT), as electron relay with either D-π-A or D-π-D substitution patterns. The effect of the acceptor/donor strength and the solvent polarity confirm the possibility of finetuning optical non-linearities in the asymmetric samples. The geometrical and electronic properties calculated in solution reveal that push-pull chromophores become highly polarized as the dielectric constant of the solvent increases. Theoretical NLO calculations furthermore reveal a moderate nonlinear optical activity for the symmetric samples.
A series of push-pull chromophores built around thiophene-based -conjugating spacers and bearing various types of amino-donors and cyanovinyl-acceptors have been analyzed by means of UV-Vis-NIR spectroscopic measurements. Density functional theory (DFT) calculations have also been performed to help the assignment of the most relevant electronic features and to derive useful information about the molecular structure of these NLO-phores. The effects of the donor/acceptor substitution in the electronic and molecular properties of the -conjugated spacer have been addressed. The effectiveness of the intramolecular charge transfer (ICT) has also been tested as a function of the nature of the end groups (i.e., electron-donating or electron-withdrawing capabilities). _______________________________________________________________________ María Moreno Oliva et. al. 2 investigated for their . These push-pull NLO-phores are basically constituted by an electron-donor (D) and an electron-acceptor (A) group interacting through a S-conjugated spacer.
Synthesis and electro-optic properties of amino-phenyl-thienyl donor chromophores
Optical Materials, 2008
In order to explore the effects of incorporation of an amino-phenyl-thienyl (APT) donor moiety into state-of-the art donor-bridge-acceptor organic NLO chromophores, two new materials were synthesized and characterized. Density functional theory (DFT) quantum-mechanical modeling indicates that this structural modification, producing enhanced ground-state electron density asymmetry and increased conjugation length, should lead to appreciable enhancement in first molecular hyperpolarizability (β). Previous empirical data suggests that such an approach to enhancements in nonlinearity may overcome the tradeoffs in nonlinearity with optical absorption and thermal stability, often encountered in organic NLO chromophore design. Material properties were evaluated in terms of poling-induced electro-optic coefficients normalized against applied poling field (r33/Ep), DFT calculated β and gas-phase dipole moment, experimentally determined βHRS, absorption maxima, and thermal stability. These data were then compared against those from benchmark materials. Experimental data were determined to reflect enhancements in nonlinearity with little detriment to thermal stability and optical absorption, making them excellent candidates for use in electro-optic polymer applications. The most active material (C3) demonstrated highly reproducible values of r33=130pm/V.
Tetrahedron, 2012
Two series of novel pushepull 1-(4-(thiophen-2-yl)phenyl)-1H-pyrroles 3e5 were designed to explore the consequence of using different electron accepting moieties linked to the thiophene at the arylthiophene bridge or to the pyrrole heterocycle, which plays the role of donor group. Compound 2 showed a different reactivity behavior in the presence of the Vilsmeier reagent or with tetracyanoethylene (TCNE) giving compounds 4a and 4b functionalized, respectively, at the 2 or on the 3-position of the pyrrole heterocycle. Their optical (linear and first hyperpolarizability), electrochemical, and thermal properties have been examined. Hyper-Rayleigh scattering (HRS) in dioxane solutions using a fundamental wavelength of 1064 nm was employed to evaluate their second-order nonlinear optical properties. Of these systems, thiobarbituric acid derivative 5b functionalized in the thiophene ring exhibits the largest first hyperpolarizability (b¼2480Â10 À30 esu, T convention) compared to the corresponding compound 4c substituted on the pyrrole heterocycle (b¼290Â10 À30 esu, T convention). Good to excellent thermal stabilities were also obtained for pushepull compounds 4 and 5 (270e288 C). This multidisciplinary study shows that modulation of the optical and electronic properties can be achieved by introduction of the acceptor groups in the thiophene of the arylthiophene bridge. The measured molecular first hyperpolarizabilities and the observed electrochemical behavior are quite sensitive to the position of acceptor group on the heterocyclic system (on the thiophene or on the pyrrole ring) as well as the strength of the acceptor moieties. Moreover, the combination of their good nonlinearity and high thermal stability make them good candidates for second-order nonlinear optical applications.
Nonlinear optical chromophores containing dithienothiophene as a new type of electron relay
Journal of Materials Chemistry, 1999
Nonlinear optical (NLO) donor-acceptor (D-A) chromophores containing a fused terthiophene, namely dithienothiophene (DTT) as electron relay, and various strength acceptors were synthesized to evaluate the relay's role in the solvatochromism as well as in the molecular nonlinearity, mb(0). Their solvatochromic behavior, which is dependent on acceptor strength, is correlated to their mb(0). The static quadratic hyperpolarizability, b(0), of DTTcontaining chromophores was determined by EFISH measurements. From the comparison of mb(0) values of D-A chromophores based on oligothiophenes, it was assessed that DTT as relay is significantly more efficient compared to bithiophene (the same number of conjugated double bonds) and terthiophene. An additional merit of DTT is that chromophores containing DTT have a noticeably high thermal stability.
Proceedings of SPIE - The International Society for Optical Engineering, 2011
The synthesis and characterization of new chromophores with second-order nonlinearities containing thienylpyrrole 1a, 2a-b, bithiophene 3 and arylthiophene 4 as π-conjugated bridges and indanonedicyanovinyl acceptor group are reported. The effect of placing the acceptor group at thiophene or pyrrole rings on the optoelectronic properties was also evaluated for thienylpyrrole derivatives 1a and 2a-b. The linear optical properties (absorption and emission) for all compounds were evaluated in dioxane solutions. In addition, the hyperpolarizabilities β of chromophores 1-4 were measured using hyper-Rayleigh scattering in dioxane solutions and thermogravimetric analysis (TGA) was used to evaluate their thermal stability. The experimental results indicate that chromophores 1-4 are endowed with both excellent optical nonlinearities and high thermal stability making them interesting candidates for nonlinear optical (NLO) applications.