Plot of geometrical change (dihedral angle) with the Hammett Parameter, for the series of studied DMB derivates.

<p>Plot of geometrical change (dihedral angle) with the Hammett Parameter, for the series of studied DMB derivates.</p

Plot of Hammett Parameter with (a) electron affinity (eV) and (b) ionization potential (eV).

<p>Plot of Hammett Parameter with (a) electron affinity (eV) and (b) ionization potential (eV).</p

Schematic diagram of a two-layered OLED device.

<p>Schematic diagram of a two-layered OLED device.</p

Sketch of aryldimesityl borane (DMB) derivatives study using DFT at B3PW91/6-311++G (d,p)level of theory.

<p>Sketch of aryldimesityl borane (DMB) derivatives study using DFT at B3PW91/6-311++G (d,p)level of theory.</p

Results of TDDFT calculations at B3PW91/6-311++G (d, p) level of theory for the electron transitions of DMB systems.

<p>Results of TDDFT calculations at B3PW91/6-311++G (d, p) level of theory for the electron transitions of DMB systems.</p

Selected geometrical parameters (bond angles and bond lengths) of aryldimesityl borane (DMB) derivatives in neutral and anionic states calculated at B3PW91/6-311++G (d, p) level.

<p>Selected geometrical parameters (bond angles and bond lengths) of aryldimesityl borane (DMB) derivatives in neutral and anionic states calculated at B3PW91/6-311++G (d, p) level.</p

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

<div><p>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 d<i>π</i> orbitals of Ru²⁺ with the <i>π</i>* 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 <i>π</i>-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 <i>X</i>-direction. In derivative Ru²⁺ 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.</p></div

DFT calculated HOMO, LUMO energies, Ionisation potentials (Ip) and Electron affinity (EA) of studied aryldimesityl borane(DMB) derivative calculated.

a<p>Δ(HOMO)  = E(_{HOMO DMB derivative}) – E(HOMO_DMB),</p>b<p>Δ(LUMO)  = E(_{LUMO DMB derivative}) – E(HOMO_DMB),</p>c<p>Ip = E⁺(G)⁰- E⁰(G)⁰ and ^dEA(eV)  = E^-(G)⁰- E⁰(G)⁰.</p><p>DFT calculated HOMO, LUMO energies, Ionisation potentials (Ip) and Electron affinity (EA) of studied aryldimesityl borane(DMB) derivative calculated.</p

Electron Transport and Nonlinear Optical Properties of Substituted Aryldimesityl Boranes: A DFT Study

<div><p>A comprehensive theoretical study was carried out on a series of aryldimesityl borane (DMB) derivatives using Density Functional theory. Optimized geometries and electronic parameters like electron affinity, reorganization energy, frontiers molecular contours, polarizability and hyperpolarizability have been calculated by employing B3PW91/6-311++G (d, p) level of theory. Our results show that the Hammett function and geometrical parameters correlates well with the reorganization energies and hyperpolarizability for the series of DMB derivatives studied in this work. The orbital energy study reveals that the electron releasing substituents increase the LUMO energies and electron withdrawing substituents decrease the LUMO energies, reflecting the electron transport character of aryldimesityl borane derivatives. From frontier molecular orbitals diagram it is evident that mesityl rings act as the donor, while the phenylene and Boron atom appear as acceptors in these systems. The calculated hyperpolarizability of secondary amine derivative of DMB is 40 times higher than DMB (<b>1</b>). The electronic excitation contributions to the hyperpolarizability studied by using TDDFT calculation shows that hyperpolarizability correlates well with dipole moment in ground and excited state and excitation energy in terms of the two-level model. Thus the results of these calculations can be helpful in designing the DMB derivatives for efficient electron transport and nonlinear optical material by appropriate substitution with electron releasing or withdrawing substituents on phenyl ring of DMB system.</p></div

Reorganization energy (λ_-) for electron transport (eV) calculated by using DFT at B3PW91/6-311++G (d, p) level of theory and Hammett value (σ) of DMB derivatives.

<p><b>*</b>reference <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0114125#pone.0114125-Leffler1" target="_blank">[48]</a></p><p>Reorganization energy (λ_-) for electron transport (eV) calculated by using DFT at B3PW91/6-311++G (d, p) level of theory and Hammett value (σ) of DMB derivatives.</p