Density functional theory prediction of geometry and vibrational circular dichroism of bridged triarylamine helicenes

Pandith, Altaf Hussain; Islam, Nasarul; Syed, Zeeshan Fatima; Rehman, Suhail-ul; Bandaru, Sateesh; Anoop, Anakuthil

doi:10.1016/j.cplett.2011.09.074

Cited by 16 publications

(15 citation statements)

References 45 publications

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“…Spassova et al [58] reported a theoretical investigation on the electronic circular dichroism spectra of bridged TAHs. In our earlier work, we reported on the conformational analysis and vibrational circular dichroism of TAH and its camphanate derivative [59].…”

Section: Introductionmentioning

confidence: 99%

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

Islam

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.

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Section: Introductionmentioning

confidence: 99%

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

Islam

Pandith

2014

J Mol Model

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“…The B3PW91 functional was chosen based on numerous earlier studies which suggest it to be efficient and reasonably accurate in predicting ground and excited state energies of a broad range of organic molecules and inorganic complexes [38,42,43,61,62].…”

Section: Computational Detailsmentioning

confidence: 99%

“…Recently, quantum chemical computations on transition metal complexes, applying the Density functional theory (DFT) method, have been reported [32][33][34][35][36][37][38][39][40][41][42][43][44]. According to Amer et al [15], electronic properties of [Ru(L) 3 ] 2+ complexes can be effectively manipulated by ligand exchange or modification.…”

Section: Introductionmentioning

confidence: 99%

“…The unique nature of VCD spectroscopy results from the combination of a number of vibrational transitions spanning the (3N-6) vibrational modes of a chiral molecule, N, being the number of atoms in the molecule [50]. Extending the application of ab initio analysis, computationally, VCD and IR band assignments in the gas and liquid phases were evaluated for a large number for transition metal complexes [39][40][41][42][43][44][51][52][53].…”

Section: Introductionmentioning

confidence: 99%

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

Islam

Pandith

2014

Journal of Coordination Chemistry

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Density functional theory calculations were performed on [Ru(L) 3 ] 2+ (L = 1,10-phenanthroline, 2,2′-bipyridine, 2,2′-bipyrimidine, 2,2′-bipyrazine) complexes by employing B3PW91 functional and LAN2DZ basis set to predict their spectra and nonlinear optical response. The geometrical and coordination energy studies explained that the stability of [Ru(L) 3 ] 2+ metal complexes depends on the extent of interaction of the dπ orbitals of Ru 2+ with the π* ligand orbitals, which is maximum for 1,10-phenanthroline. The two enantiomers of the [Ru(L) 3 ] 2+ show IR absorption peaks in the region of 1100-1800 cm −1 , and a slight shift occurs to lower frequency by solvent. The vibrational circular dichroism peaks of [Ru(phen) 3 ] 2+ had major contribution from out-of-phase stretching of 1,10-phenanthroline rings and a minor contribution from H-C=C-H wagging and C=C stretching of rings. Maximum hyperpolarizability was observed for [Ru(phen) 3 ] 2+ due to stronger anharmonicity in the π-electron system. Among the [Ru(L) 3 ] 2+ (L = bpy, bpm, and bpz) complexes, [Ru(bpm) 3 ] 2+ shows enhanced hyperpolarizability due to increase in the dipole along the X-direction. In derivative Ru 2+ complexes, we found that hyperpolarizability depends on electron-donating capability of the substituent. As per FMOs study, the HOMO is predominantly metal fragment based, the LUMO is primarily ligand based, and the larger value of hyperpolarizability corresponds to the lower E LUMO -E HOMO gap, reflecting that nonlinear optical response is a consequence of additive dipolar responses of charge transfer and hyperpolarizability.

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“…26,[77][78][79][80] The ground state structures of rutaecarpine as monomers, p-stacked dimers and N-HÁ Á ÁO linear dimers are fully optimized in gas phase by using hybrid density functional M06-2X 51,52 at the 6-31+g(d,p) level. 26,[77][78][79][80] The ground state structures of rutaecarpine as monomers, p-stacked dimers and N-HÁ Á ÁO linear dimers are fully optimized in gas phase by using hybrid density functional M06-2X 51,52 at the 6-31+g(d,p) level.…”

Section: Theoretical Calculationsmentioning

confidence: 99%

Investigating the molecular and aggregated states of a drug molecule rutaecarpine using spectroscopy, microscopy, crystallography and computational studies

Dandpat

Sarkar

2015

Phys. Chem. Chem. Phys.

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The photophysical properties of a potential drug molecule rutaecarpine have been investigated in molecular as well as aggregated states. All systems have been characterized by various spectroscopic, microscopic and dynamic light scattering (DLS) techniques. The investigation has been carried out by keeping the fact in mind that hydrophobic organic molecules have a strong tendency to form aggregates in aqueous solution. A blue shift in the absorption spectrum of rutaecarpine has been observed for aggregates (compared to molecular solution) indicating the formation of H-type aggregates. The intermolecular interactions responsible for such aggregation have been further investigated through crystallographic and computational studies. It has been observed that π-π stacking interactions among the monomer units play an important role in the formation of H-type aggregates. Quantum mechanical calculations also substantiate the blue shift in the absorption that has been observed for aggregates. In the present case, enhanced emission for aggregates as compared to the molecular solution of rutaecarpine has also been observed. The observed enhanced emission upon aggregation is attributed to the decrease of the non-radiative rate constant (knr) upon aggregation. The effect of a surface active ionic liquid (SAIL), 1-dodecyl-3-methylimidazolium bromide ([C12mim]Br), on the aggregation of rutaecarpine has been investigated. Interestingly, in addition to the decrease in the particle size, a change in the morphology of the aggregates has also been observed with gradual addition of [C12mim]Br to the colloidal solution of rutaecarpine. The present study demonstrates that a SAIL can effectively be used as a medium for dissociation of colloidal aggregates and encapsulation of molecular species, which in turn would be helpful in influencing the drug activity.

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Density functional theory prediction of geometry and vibrational circular dichroism of bridged triarylamine helicenes

Cited by 16 publications

References 45 publications

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

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

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

Investigating the molecular and aggregated states of a drug molecule rutaecarpine using spectroscopy, microscopy, crystallography and computational studies

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Density functional theory prediction of geometry and vibrational circular dichroism of bridged triarylamine helicenes

Cited by 16 publications

References 45 publications

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

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

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

Investigating the molecular and aggregated states of a drug molecule rutaecarpine using spectroscopy, microscopy, crystallography and computational studies

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