A DFT study on 1,4‐dihydro‐1,4‐azaborinine annulated linear polyacenes: Absorption spectra, singlet‐triplet energy gap, aromaticity, and HOMO–LUMO energy modulation

Abstract

Linear polyacene (LPA) mimics containing multiple heterocycles have been computationally designed by annulating 1,4-dihydro-1,4-azaborinine moieties to benzene (aB -aB ), naphthalene (aN -aN ), anthracene (aA -aA ), and tetracene (aT -aT ) cores. DFT studies conducted on them using M06L/6-311++G(d,p) method reveal a perfect planar structure for all and suggest the utilization of nitrogen lone pairs for aromatic π-electron delocalization. The computed values of aromaticity indices such as HOMA, NICS, and dehydrogenation energy (E ) of heterocycles support strong aromatic character for each six-membered ring in the LPA mimics. On the basis of the minimum value of the molecular electrostatic potential (V ) observed on each LPA unit in the LPA mimics, the extended delocalization of π-electrons is verified. The energetic parameter E showed strong linear correlation with HOMA, NICS and V parameters, which strongly supports the multidimensional character of aromaticity in LPA mimics. The electronic property modification is shown by the theoretical absorption spectra data and singlet-triplet energy gap (ΔE ). The bandgap and ΔE tunings are achieved for LPA mimics by selecting appropriate number of azaborinine type units and the size of LPA core used for annulation. © 2017 Wiley Periodicals, Inc.

Doping Effects on the Reactivity of the MVO5– (M = V–Zn) Clusters in CO Oxidation Reaction

“…Herein, we defined the principles in selecting the pair of active orbitals to donate (an occupied orbital) and accept (an unoccupied orbital) the transferred electron during CO oxidation, as illustrated in Figures a,b, S13, and S14. DFT sometimes generates wrong results for absolute energy gaps, whereas it has been demonstrated that DFT calculations are convincing to predict the relative energy gaps of frontier orbitals for related materials and then facilitate the modulation of their properties to be more optimal in applications. − For CO oxidation by MVO 5 – , the O t atom bonded with M prefers to be removed. Thus, such an O t (2p)-centered and occupied orbital of MVO 5 – on the top is selected as the active orbital to donate electron, for instance, the HOMO of MnVO 5 – is selected (Figure a), whereas the HOMO – 2 of ZnVO 5 – is selected (Figure b).…”

Six-Membered Rings With Two or More Heteroatoms With at Least One Boron

“…The computed values of aromaticity indices and dehydrogenation energy of heterocycles suggest strong aromatic character for each six-membered ring in the linear polyacene mimics. 42…”

Molecular electrostatic potential analysis: A powerful tool to interpret and predict chemical reactivity

“…Later, LPA mimics with multiple heterocycles were considered by extending the 1, 4-dihydro-1, 4-azaborinine systems. 224 Yet, another study showed that Clar's sextet theory of aromaticity can be extended to develop multitopic NHC ligands. Here, the change in electron releasing power of the ligands with the annulation of heterocycle or branching through C sp 3 linkage could be monitored by the V min corresponding to the (3, +3) CP at the lone pair of carbene.…”