Analysis of vibrational spectra (FT-IR and VCD) and nonlinear optical properties of [Ru(L) 3 ] 2+ complexes

Pandith

2014

J Mol Model

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This work involved the design of a new series of triarylaminehelicenes (TAH) with significant hole transport capacity and enhanced nonlinear optical response. The geometries, electronic properties and nonlinear response of TAH derivatives were studied using density functional theory at the B3PW91/6-311++G (2d, 2p) level. Charge transfer and nonlinear optical response were analyzed and correlated with modifications in geometry and energy levels. Calculations indicated that trivial changes in the torsional angle occur in TAH derivatives with electron-donating substituents as compared to those with electron-withdrawing substituents, resulting in lower reorganization energies for TAH derivatives 2-6. TAH derivatives with an -N(CH3)2 group have the greatest highest occupied molecular orbital (HOMO) level, and thus the least ionization potential, indicating significant hole transfer efficiency as compared to unsubstituted TAH. A decrease in the HOMO-LUMO gap occurs upon substitution with electron-releasing groups, whereas there is an increase in the case of -NO2, -COOH, and -CN TAH derivatives. Topological analysis of the HOMOs of the neutral molecules revealed that these orbitals are concentrated mainly in the helicene backbone, with an important contribution from fused phenyl rings, nitrogen atoms and carbonyl groups. However, the lowest unoccupied molecular orbitals (LUMO) are invariably constituted by fused phenyl rings without any contribution from the central nitrogen atom. Studying the effect of substitution on the nonlinear optical response of TAH derivatives, the calculated polarizability and hyperpolarizability at B3PW91/6-311++G (2d,2p) level of theory exhibited a prominent improvement as compared to unsubstituted TAH. Both electron-donating groups and electron-withdrawing groups result in a red shift in the electronic absorption bands of the substitution derivatives, in particular those with -N(CH3)2 and -NH2 groups.

Section: Nonlinear Responsementioning

confidence: 99%

“…The total static dipole moment (μ), average linear polarizability (α) and first-order hyperpolarizability (β) using the x, y, z components of the compound from Gaussian 03 W [60] output were calculated by Eqs. 4-6 [61][62][63][64][65][66][67][68][69][70][71][72][73][74][75][76][77].…”

Section: Introductionmentioning

confidence: 99%

Optoelectronic and nonlinear optical properties of triarylamine helicenes: a DFT study

Pandith

2014

J Mol Model

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“…Polarizability and hyperpolarizability characterises the response of a system in an applied field. It is well known for various studies that the molecular polarizability, hyperpolarizability and dipole moments are important for active nonlinear performance of the chemical system [64,65]. Helical system (TOH and TTH) contained sp 2 -hybridised carbon, the electron in the p z -orbital of each sp 2 -hybridised carbon atom will form p-bonds with the neighbouring p z -electrons.…”

Section: Frontier Molecular Orbitals Uv-visible Spectra Charge Tranmentioning

confidence: 99%

Spectral and optoelectronic studies on 7,12,17-trioxa and 7,12,17-trithia [11] helicenes: a DFT view

Chimni

2017

Indian J Phys

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Density functional theory has been used to analyse the structural, spectral, charge transport and nonlinear properties of 7,12,17-trioxa [11] helicene and 7,12,17-trithia [11] helicene. The optimised geometries of TOH and TTH shows that carbon-carbon bond lengths of inner fused rings vary from terminal rings, as a consequence of generated torsional strain. The IR-spectra displays characteristics peaks in the region of 750-1550 cm -1 in TOH and a slight shift occurs to lower frequency in case of TTH. The vibrational circular dichroism peaks have major contributions from in and out of plane bending and minor contribution from C=C stretching of fused aromatic rings. From ionisation and reorganization energy values it is evident that TOH and TTH can act as hole transport material for OLED device. As a consequence of extended conjugation in studied system, the higher values of polarizability and hyperpolarizability reflects their role in NLO devices.

“…Currently, considerable attention has been focused on the studies of organic molecules capable of exhibiting organic light emitting properties or massive NLO susceptibilities. Researchers have observed that the presence of extended π-electron delocalization is the key element in the design of organic molecules exhibiting either the OLED or NLO applications (Geffroy et al, 2006 ; Sasabe and Kido, 2011 , 2013a , b ; Jin and Tang, 2013 ; Sekine et al, 2014 ; Islam and Pandith, 2014a ; Romain et al, 2015 ).…”

Section: Introductionmentioning

confidence: 99%

“…Octaphyrin (1.1.1.1.1.1.0.0) ( OP ), being a conjugated π system may be the excellent candidate for the materials science. Many research groups have reported the synthesis and structural properties of isomers of Octaphyrin (1.1.1.1.1.1.0.0) (Franck and Nonn, 1995 ; Latos-Grazynski, 2004 ; Shimizu et al, 2005 ; Rath et al, 2005b ; Geffroy et al, 2006 ; Hiroto et al, 2006 ; Kumar et al, 2007 ; Misra and Chandrashekar, 2008 ; Anaka et al, 2011 ; Sasabe and Kido, 2011 , 2013a , b ; Mori et al, 2012a ; Jin and Tang, 2013 ; Kido et al, 2013 ; Naoda and Osuka, 2014 ; Sekine et al, 2014 ; Islam and Pandith, 2014a ; Anguera et al, 2015 ; Romain et al, 2015 ). According to Chandershaker et al the core-modified expanded porphyrins containing 26, 36, and 54 π electrons because of their exceptionally massive two-photon absorption cross- sections may be considered among the most effective appropriate candidates, particularly as organic NLO materials (Pushpan and Chandrashekar, 2002 ).…”

Section: Introductionmentioning

confidence: 99%

Computational Studies on Optoelectronic and Nonlinear Properties of Octaphyrin Derivatives

Lone²

2017

Front. Chem.

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The electronic and nonlinear optical (NLO) properties of octaphyrin derivatives were studied by employing the DFT/TDFT at CAM-B3LYP/6-311++G (2d, 2p) level of the theory. Thiophene, phenyl, methyl and cyano moieties were substituted on the molecular framework of octaphyrin core, in order to observe the change in optoelectronic and nonlinear response of these systems. The frontier molecular orbital studies and values of electron affinity reveals that the studied compounds are stable against the oxygen and moisture present in air. The calculated ionization energies, adiabatic electron affinity and reorganization energy values indicate that octaphyrin derivatives can be employed as effective n-type material for Organic Light Emitting Diodes (OLEDs). This character shows an enhancement with the introduction of an electron withdrawing group in the octaphyrin framework. The polarizability and hyperpolarizability values of octaphyrin derivatives demonstrate that they are good candidates for NLO devices. The nonlinear response of these systems shows enhancement on the introduction of electron donating groups on octaphyrin moiety. However, these claims needs further experimental verification.