Theoretical study on the structure and UV–visible spectrum of pyridine–chloranil charge-transfer complex

A new cross-conjugated mesomeric betaine

“…Spectrophotometric 23,24 and theoretical 25 studies of the CT complex formed by pyridine derivatives have been reported earlier. For studying CT complex of imidazo[1,2- a ]pyridine with DMAD, we selected two variables, namely relative concentrations of the donor (imidazo[1,2- a ]pyridine) and acceptor (DMAD) ( Table 2 ) and time by taking 1 : 1 concentrations of the two reactants.…”

One and Multiple Bonds Interatomic Spin-Spin Coupling inη6-Cymene Ru(II) of 3,5-Dimethyl-, 3,5-Dicarboxylic-, and 5-Phenyl-pyrazole Derivatives

“…DFT PBE exchange functional has been found to be good for the optimization of metal complexes and give similar results with hybrid functional PBE0 and mPW1PW91 [24]. It is also good for studying weak-interacting systems [25] but just like any other DFT methods, it is limited in the study of noncovalent intermolecular interactions because of its long-range deficiency which makes hybrid DFT preferable [26][27][28]. Even though all the properties of interest are purely intramolecular interaction, the NMR, spin-spin coupling constants J(A, B) [29,30], and other stationary properties were computed using B3LYP hybrid DFT method which is Becke's threeparameter exchange [31] and Lee-Yang-Parr's correlation nonlocal functional.…”

Structure of the Pyridine–Chloranil Complex in Solution: A Surprise from Depolarized Hyper-Rayleigh Scattering Measurements

“…Thus, the structure could either be T-shaped or cofacial. If we assign the structure of the PYRÀCHL complex as T-shape, as assigned from Li's calculation, 12 we will be in serious disagreement with the nonlinear optical properties, β HRS , D, and D 0 as computed using Zerner's intermediate neglect of differential overlap correction vector (ZINDO-CV) programs. 21 In order to compute linear and nonlinear optical properties, the geometry of the pyridineÀchloranil (PYRÀCHL) complex was optimized in the gas-phase and in a solvent dielectric (chloroform).…”

“…Formation of a weak CT complex between chloranil and pyridine derivatives in solution has been reported earlier by various spectroscopic and thermochemical methods, − but those studies were not directed toward structure/geometry elucidation of the complex. Some idea about the geometry of the pyridine–chloranil 1:1 complex came recently from a theoretical calculation by Li et al where they have shown that pyridine binds to chloranil via an effective σ–π type interaction to form an inclined T-shape structure, with the pyridine plane making an angle of 77.8° to the chloranil plane in which the nitrogen atom of pyridine is pointed toward the center of the chloranil molecule. This is an interesting prediction since the proposed structure is close to the T-shape structure, which is rare in occurrence among organic aromatic molecular complexes.…”