Polyhedral-Based Nonlinear Optical Materials. 2. 1 Theoretical Investigation of Some New High Nonlinear Optical Response Compounds Involving Polyhedral Bridges with Charged Aromatic Donors and Acceptors (original) (raw)
Related papers
Polyhedral-based nonlinear optical materials
Journal of Organometallic Chemistry, 2000
A calculational investigation using semiempirical methods of the molecular and electronic structures, along with the nonlinear optical responses, of a series of compounds in which icosahedral carborane polyhedra bridge charged aromatic donor and acceptor moieties, specifically tropyl (C 7 H 7 + ) and cyclopentadienyl (C 5 H 5 − ) groups, found that these molecules show exceptionally large calculated second-order responses. These compounds were found to give calculated first hyperpolarizabilities (i) ranging from 8.6 to 1226.0 ×10 − 30 cm 5 esu − 1 at 0.5 eV excitation energy. These nonlinear optical responses are understood within the framework of the two-state model using molecular orbital and electronic structure considerations.
…, 1997
2 ) dppe, X 2 ) C≡C, Y 2 ) (E)-CH)CH (12), C≡C (18); L 2 ) dppe, X 2 ) (E)-CH)CH, Y 2 ) C≡C , (E)-CH)CH (16); L 2 ) dppm, X 2 ) C≡C, Y 2 ) (E)-CH)CH (13); L 2 ) dppm, X 2 ) (E)-CH)CH, Y 2 ) C≡C (15), (E)-CH)CH (17)] are reported, the latter being donorbridge-acceptor complexes varying in bridge composition by replacement of yne with E-ene linkages, together with their cyclic voltammetric data, linear optical, and quadratic nonlinear optical response data. Ru II/III oxidation potentials increase on replacing yne linkage by E-ene linkage at the phenylene adjacent to the metal center, and on replacing dppe by dppm co-ligands. The low-energy optical absorption maxima occur in the region 20400-23300 cm -1 and are metal-to-ligand charge-transfer (MLCT) in origin; these bands undergo a blue-shift upon π-bridge lengthening by addition of phenyleneethynylene units, and on replacing E-ene linkages by yne linkages. Time-dependent density functional theory calculations on model complexes have suggested assignments for the low-energy bands. The optical spectra of selected oxidized species contain low-energy ligand-to-metal charge transfer (LMCT) bands centered in the region 9760-11800 cm -1 . Quadratic molecular nonlinearities from hyper-Rayleigh scattering (HRS) studies at 1064 nm reveal an increase in the two-level-corrected 0 value on π-bridge lengthening, a trend that is not seen with values because of the blue-shift in λ max for this structural modification. Replacing yne linkages by E-ene linkage at the phenylene adjacent to the metal center or dppm co-ligand by dppe results in an increase in and 0 values. In contrast, quadratic molecular nonlinearities by HRS at 1300 nm or electric field-induced secondharmonic generation (EFISH) studies at 1907 nm do not afford clear trends. Houbrechts, S.; Kauranen, M.; Clays, K.; Persoons, A.
Structure-Property Relationships in Organic Nonlinear Optical Materials
MRS Proceedings, 1999
ABSTRACTTuning the degree of bond-length alternation in organic nonlinear optical materials is a powerful paradigm for the design of organic materials with large molecular hyperpolarizabilities (β). Several research groups have employed this paradigm in the design and synthesis of NLO materials incorporating donor-acceptor polyenes. Increased bond-length alternation in polyenes leads to decreased barriers to rotation about C=C bonds and, hence, increased conformational flexibility. Since the degree of bond-length alternation is solvent dependent, so is the degree of conformational flexibility. In an effort to probe the influence of conformational flexibility on NLO response, we synthesized a series of simple donor-acceptor polyenes that are either conformationally flexible (la, 2a, 3a) or rigid (1b, 2b, 3b). For each pair of molecules ZINDO sum-over-states calculations predict a larger value of βμ, for the conformationally flexible isomer, but EFISH measurements (CHCl3) display mixe...
Semi-empirical calculations of the nonlinear optical properties of polycyclic aromatic compounds
Chemical Physics, 1994
A systematic study of factors influencing nonlinear optical properties, in particular the second hyperpolarizability ( y) , is conducted for a series of polycyclic aromatic hydrocarbons (PAHs). The HOMO-LUMO gap, polarizability (cu), first hyperpolarizability ( p), and second hyperpolarizability of polycyclic aromatic compounds are computed by using semi-empirical MNDO-FF calculation implemented in the MOPAC package. For linear polyacenes, the linear and nonlinear properties and total resonance energy are found to increase while the HOMO-LUMO gap and resonance energy per electron decrease as the number of six-membered rings increases. For nonlinear PAHs, the chain topology should be taken into account. An empirical formula is given to relate the computed ( y) and (cu ) . 0301-0104/94/S 07.00 0 1994 Elsevier Science B.V. All rights reserved. SSDZ 0301-0104(93)E0387-B
Chemistry-a European Journal, 1997
Donor-acceptor polyenes of various lengths, and that combine aromatic electron-donating moieties with powerful heterocyclic electron-withdrawing terminal groups, have been synthesized and characterized as efficient nonlinear optical (NLO) chromophores. Their linear and nonlinear optical properties have been investigated, and variations in these properties have been related to ground-state polarization (dipole p ) and structure. In particular, unprecedented quadratic hyperpolarizabilities (p) have been achieved (up to p(0) =I500 x 10-30esu) by reduction of the bondlength alternation (BLA) in the polyenic chain. In each series of homologous com-Chrm. 7 VCH Verlug.~g~.sell.s~huft n d H . 0-69451 Weinheim, l Y Y 7 OU47-6539/97/0307-1091 $ 17.50+ ,5010 N j VCII ~,i.ulu~s~i,scIl.~cha/t m h H , 0.69451 Weinheim, 1997 0947-653Y/Y7/0307-1UY2 $ 1 7 . 5 0 i .50]0
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2011
2-(4-Fluorophenyl)-1-(4-methoxyphenyl)-4,5-dimethyl-1H-imidazole (fpmpdi) was synthesised and its structure was characterized by 1 H, 13 C, mass, elemental analysis and X-ray techniques. It belongs to monoclinic crystal system having the lattice dimensions of monoclinic with point group, P 21 /c; a = 8.5132 (1)Å, b = 9.5128 (2)Å, c = 19.2610 (3)Å,ˇ= 96.798 (2). Since (fpmpdi) is highly sensitive to different external stimulations such as UV irradiation, heat, increasing pressure and changing the environmental pH causing color change and so they can be used as a "multi-way" optically switchable material. A prominent fluorescence enhancement was found in the presence of transition metal ions such as Hg 2+ , Pb 2+ and Cu 2+ and this was suggested to result from the suppression of radiationless transitions from the n-* state in the chemosensors. The optimized geometrical parameters obtained by DFT calculation is in good agreement with single crystal XRD data. The Mulliken, NBO charge analysis and the HOMO-LUMO energies were also calculated. The molecular electrostatic potential surface (MEP) and first static hyperpolarisability have also been employed theoretically which reveal that the fpmpdi have non-linear optical (NLO) behavior with non-zero values. Ground and excited states DFT calculations were carried out in order to find out dipole moment and energy.
Current Opinion in Solid State and Materials Science, 1996
Over the past two years, the field of molecular nonlinear optics has benefited from both upstream rejuvenation (the emergence of new molecular engineering guidelines) and downstream application-oriented breakthroughs, helping to bring the field closer to industrial developments. In the fundamentals areas, traditional perspectives based on the paranitroaniline 'molecular diode' template are being enlarged to encompass three-dimensional multicharge transfer 'multipolar' systems with dipolarless 'octupoles', demanding that earlier models and experiments be thoroughly revisited. Furthermore, the relevance of polar structures primarily targeted towards quadratic nonlimear optics has been extended to cubic all-optical processes based on a cascaded sequence of quadratic processes. In the application domain, progress in crystal growth is best illustrated by the demonstration of low threshold pulsed near-IR optical parametric oscillators based on stable organic or organomineral crystals. Functionalized polymers have confirmed their current supremacy as organic optoelectronic device materials with the reports of low voltage electro-optic modulation in integrated waveguide structures and high modulation bandwidth.
Organometallics, 2002
2 ) dppe, X 2 ) C≡C, Y 2 ) (E)-CH)CH (12), C≡C (18); L 2 ) dppe, X 2 ) (E)-CH)CH, Y 2 ) C≡C , (E)-CH)CH (16); L 2 ) dppm, X 2 ) C≡C, Y 2 ) (E)-CH)CH (13); L 2 ) dppm, X 2 ) (E)-CH)CH, Y 2 ) C≡C (15), (E)-CH)CH (17)] are reported, the latter being donorbridge-acceptor complexes varying in bridge composition by replacement of yne with E-ene linkages, together with their cyclic voltammetric data, linear optical, and quadratic nonlinear optical response data. Ru II/III oxidation potentials increase on replacing yne linkage by E-ene linkage at the phenylene adjacent to the metal center, and on replacing dppe by dppm co-ligands. The low-energy optical absorption maxima occur in the region 20400-23300 cm -1 and are metal-to-ligand charge-transfer (MLCT) in origin; these bands undergo a blue-shift upon π-bridge lengthening by addition of phenyleneethynylene units, and on replacing E-ene linkages by yne linkages. Time-dependent density functional theory calculations on model complexes have suggested assignments for the low-energy bands. The optical spectra of selected oxidized species contain low-energy ligand-to-metal charge transfer (LMCT) bands centered in the region 9760-11800 cm -1 . Quadratic molecular nonlinearities from hyper-Rayleigh scattering (HRS) studies at 1064 nm reveal an increase in the two-level-corrected 0 value on π-bridge lengthening, a trend that is not seen with values because of the blue-shift in λ max for this structural modification. Replacing yne linkages by E-ene linkage at the phenylene adjacent to the metal center or dppm co-ligand by dppe results in an increase in and 0 values. In contrast, quadratic molecular nonlinearities by HRS at 1300 nm or electric field-induced secondharmonic generation (EFISH) studies at 1907 nm do not afford clear trends. Houbrechts, S.; Kauranen, M.; Clays, K.; Persoons, A.
Optical Materials
In the current work a new third-order nonlinear optical organic single crystal of (2E)-3-(4-Methylphenyl)-1-(3-nitrophenyl) prop-2-en-1-one (ML3NC) has been grown with well-defined morphology using the slow evaporation solution growth technique. X-ray diffraction technique was used to confirm the crystal system. The presence of functional groups in the molecular structure was identified by robust FT-IR and FT-Raman spectra by experimental and theoretical analysis. The ultraviolet-visible-near infrared and photoluminescence studies shows that the grown crystals possess excellent transparency window and green emission band (~560 nm) confirms their use in green OLEDs. The third-order nonlinear and optical limiting studies have been performed using femtosecond (fs) Z-scan technique. The third-order nonlinear optical susceptibility (c (3)), second-order hyperpolarizability (g), nonlinear refractive index (n 2) and limiting threshold values are found to be 4.03 Â 10 À12 esu, 14.2 Â 10 À32 esu, À4.33 Â 10 À14 cm 2 /W and 2.41 mJ/cm 2 , respectively. Furthermore, the quantum chemical studies were carried out to achieve the ground state molecular geometry and correlate with experimental results. The experimental value of absorption wavelength (l abs ¼ 328 nm) is found to be in excellent accord with the theoretical value (l abs ¼ 328 nm) at TD-DFT/B3LYP/6-31G* level of theory. To understand the static and dynamic NLO behavior, the polarizability (a) and second hyperpolarizability (g) values were determined using TD-HF method. The computed second hyperpolarizability g(-3u; u,u,u) at 800 nm wavelength was found to be 0.499 Â 10 À32 esu which is in good agreement with experimental value at the same wavelength. These results confirms the applied nature of title molecule in optoelectronic and nonlinear optical devices.