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![TABLE 4 . Average First Hyperpolarizabilities h [au] c of Azoles with...](profile/Aggelos-Avramopoulos/publication/233748235/figure/tbl1/AS:668684074893317@1536438115670/Average-First-Hyperpolarizabilities-h-au-c-of-Azoles-with-DFT-and-MSINDO-Optimized_Q320.jpg)
Density functional theory (DFT) is used to study the static electronic dipole moments, polarizabilities,
polarizability anisotropies, and first- and second-order hyperpolarizabilities of azoles. These properties are
obtained with a finite field approach implemented in the DFT program ALLCHEM. The calculations were of
all-electron type using a local...
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Context 1
... The structures of thiophene, pyrrole, and furan and the considered series of azoles, diazoles, and triazoles are illustrated in Figures 1 and 2. These figures contain also the direction and relative magnitude of the permanent dipole moments. ...
Citations
... On the other hand, in 2014, the García Mancheño group developed a new family of helical triazole-based HB-donors 7 as anion-binding catalysts. 38 1,2,3-Triazoles are heterocycles with interesting properties such as large dipole moment (m = 4.38 D) 39 and highly polarizable C-H bonds, 40 what makes them promising HB-donor moieties for anion-binding catalysis. 41 The chirality in the triazole catalysts 7 is introduced by a chiral trans-1,2-diamine unit that acts as a central backbone to pre-orientate the formation of the chiral helical structure upon binding to the substrate counter-anion. ...
Catalytic asymmetric dearomatization of heteroaromatic compounds has received considerable attention in the last few years, since it allows for a fast expansion of the chemical space by converting relatively simple, flat molecules into complex, three dimensional structures with added value. Among different approaches, remarkable progress has been recently achieved by the development of organocatalytic dearomatization methods. In particular, the anion-binding catalysis technology has emerged as a potent alternative to metal catalysis, which together with the design of novel, tunable anion-receptor motifs, has provided new entries for the enantioselective dearomatization of heteroarenes through a chiral contact ion pair formation by activation of the electrophilic reaction partner. In this feature, we provide an overview of the different methodologies and advances in anion-binding catalyzed dearomatization reactions of different heteroarenes.
... Thus, provided that there is a dipole moment change during a normal molecular vibration, rotation, and molecular rotation-vibration or from combinations, chemical compounds can absorb IR and are said to be IR active.Table 6shows the dipole moments of C4H5N isomers at the G4 method.The highest calculated dipole moment was found to be 4.6130 D for 2-cyanopropene and the lowest value was observed for Nvinylethyleneimine (0.9296 D). The dipole moment of pyrrole (1.8628 D) in this study agrees well with the experimental reported literature data of Karl and Sandro[25]. ...
The isomers of C4H5N consisting of eleven members (2-vinyl-2H-azirene, Isocyanocyclopropane, Ally isocyanide, N-vinylethyleneimine, Cyanocyclopropane, 2H-pyrrole, 3H-pyrrole, Ally cyanide, 2-cyanopropene, 2-butenenitrile, Pyrrole) have been studied computationally using the Gaussian-4 (G4) compound model with the Gaussian 09 suite of programs. Quantum chemical parameters such as standard enthalpy of formation, vibrational frequencies, rotational constants, bond distance and angle, and dipole moment were obtained and compared with experimental values (where available). Pyrrole was predicted to be the most stable among the C4H5N isomers with the least standard enthalpy of formation of 24.1kcal/mol. The calculated bond distances and angles for pyrrole were observed to be in excellent agreement with the measured experimental values. Also, the calculated rotational constants (A= 9.1392127, B=9.0066121, C=4.5362140) and dipole moment (1.8628D) for pyrrole were accurately predicted when compared to the experimentally determined values. Thus, the high accuracy obtained from this quantum chemical calculation indicates that other isomers of C4H5N with no experimental values are well predicted with the Gaussian-4G4 compound model.
... The three nitrogen atoms of the triazole ring cause a strong polarization of the aromatic π system, resulting in a partial positive charge on the carbon atoms and N1 while the N2 and N3 nitrogen atoms should show partial negative charges. This model is supported by experimental and computational data and further confirmed by the relatively large dipole moment, of almost 5 Debye calculated for the triazole moiety [16,17]. ...
Chemosensors are synthetic chemical compounds that have the ability to selectively bind with analytes of interest and produce detectable changes in, for example, their color, fluorescence, or redox potential. In this review, the latest developments in the field of chemosensors based on click generated triazoles used for a range of metal cations, anions, and neutral analytes have been summarized. The detection of metal ions has become a major field of research due to their medicinal, biological, and environmental impact. Recently, the number of articles published in this area of research has significantly increased, which have reported more reliable and sophisticated triazole-based chemosensors for a variety of analytes of interest. From this perspective, a constant accumulation of research work is needed (or acceptable) so as to produce a collection of chromophores that will assist researchers to rapidly access the current developments in this research field. This feature article focuses on the development of chemosensors based on click generated triazoles reported between 2012 and 2020, including metal cations, anions, and other small organic molecules due to their advantages over other chemosensors, which include ease of recognition, simple instrumentation, high selectivity, and high sensitivity.
... 39 This polarization is easily seen when comparing the resonance contributors of the most relevant tautomers of 1H-1,2,3-triazole (Scheme 3). In the contributors of the 1H-1,2,3-triazole tautomer (a), the carbon atoms and position 1 nitrogen have positive partial charge density, while positions 2 and 3 nitrogen have negative charge density, generating a high polarization and a dipole moment of 4.55 D. 40,41 By contrast, in the contributors of the 2H-1,2,3-triazole tautomer (b), the carbon atoms and nitrogen of position 2 have a positives partial charge density and nitrogen at positions 1 and 3 have a negative partial charge, which causes a lower polarization and a smaller dipole moment of 0.12 D. 40,41 Scheme 7. Cycloaddition mechanism proposed by Huisgen. Adapted from Bräse, 2010. ...
... 39 This polarization is easily seen when comparing the resonance contributors of the most relevant tautomers of 1H-1,2,3-triazole (Scheme 3). In the contributors of the 1H-1,2,3-triazole tautomer (a), the carbon atoms and position 1 nitrogen have positive partial charge density, while positions 2 and 3 nitrogen have negative charge density, generating a high polarization and a dipole moment of 4.55 D. 40,41 By contrast, in the contributors of the 2H-1,2,3-triazole tautomer (b), the carbon atoms and nitrogen of position 2 have a positives partial charge density and nitrogen at positions 1 and 3 have a negative partial charge, which causes a lower polarization and a smaller dipole moment of 0.12 D. 40,41 Scheme 7. Cycloaddition mechanism proposed by Huisgen. Adapted from Bräse, 2010. ...
... It was recognized a long time ago 1 that this can enable IM to form linear structures in non-polar solvents. Furthermore, IM is a strongly polar 2 (p=3.7 D) and polarizable 3,4 (=7.4 Å 3 ) molecule and this, alongside the formation of the strong N-H···N bond, has been predicted to endow IM oligomers with very large dipole moments [5][6][7][8][9] (see Figs. 1b,c). ...
Deuterated imidazole (IM) molecules, dimers and trimers formed in liquid helium nanodroplets are studied by the electrostatic beam deflection method. Monitoring the deflection profile of (IM)D+ provides a direct way to establish that it is the primary product of the ionization-induced fragmentation both of (IM)2 and (IM)3. The magnitude of the deflection determines the electric dipole moments of the parent clusters: nearly 9 D for the dimer and 14.5 D for the trimer. These very large dipole values confirm theoretical predictions and derive from a polar chain bonding arrangement of the heterocyclic imidazole molecules.
... Hence, in this paper, we present the synthesis and properties of a new laser dye crystal, rhodamine 590 acid phthalate. Although different materials have earlier been studied for their nonlinear properties, 47 this new crystal has high optical nonlinearity. To explore the possibility of NLO application of the new rhodamine 590 acid phthalate crystal, we have calculated its (i) first-order and second-order hyperpolarizabilities theoretically by performing quantum chemical computations and (ii) second-order hyperpolarizability experimentally by measuring the two-photon absorption (TPA) cross section using intensity-modulated light fields. ...
The synthesis and crystal structure of rhodamine 590 acid phthalate (RhAP) have been reported. This novel solid-state rhodamine derivative not only has a longer fluorescence lifetime compared to rhodamine solid-state matrixes where emission is quenched but also possesses strong nonlinear optical characteristics. The static and dynamic first- and second-order hyperpolarizabilities were calculated using the time-dependent density functional theory at the B3LYP/6-31+G* level. The computed static values of β and γ of RhAP by the X-ray diffraction (XRD) structure were 31.9 × 10–30 and 199.0 × 10–36 esu, respectively. These values were about 62 times larger than the corresponding values in urea, an already well-known nonlinear optical material. The second-order hyperpolarizability of the compound was determined experimentally by measuring the two-photon absorption cross section using intensity-modulated light fields. The reported compound, excitable at near-infrared, exhibited frequency upconversion with the two-photon absorption coefficient enhanced by two orders of magnitude compared to that of the dye solution. Hosting the dye in the solid, at high concentrations, exploits the nonlinearity of the dye itself as well as results in significant excitonic effects including formation of broad exciton band and superradiance.
... This order agrees with the well-known order or the decreasing aromaticity for heterocycles: pyrrole > furan. Jug et al. 46 performed the structure−polarization relationship study for a series of azoles by relating the average α, β, and γ tensors to, among others, the number of resonance structures of the studied molecules. The order of the average β values displayed in Table 2 is CR (200.1) ...
Static electric properties, from the dipole moment to the second-hyperpolarizability tensor γ, of the 3-membered, isoelectronic ring molecules, fluorene (FL), carbazole (CR), and dibenzofuran (DBF), have been calculated at various levels of approximation. The electron correlation effects have been included at the coupled-cluster (CC) level, using CCSD and CC2 versions of the method. DFT calculations with the CAM-B3LYP functional have also been performed, and the results are compared to the CC values. The electric property-tailored Pol basis set and its more compact Z3Pol version have been employed in all static calculations. Differences between dipole polarizability values computed at the Pol and Z3Pol bases have been found to be almost negligible. Therefore, all components of the frequency-dependent dipole polarizability tensor α(-ω;ω) have been determined at the CAM-B3LYP/Z3Pol level. Divergence occurring at electronic resonances has been eliminated using the complex polarization propagator (CPP) formalism, explicitly introducing an imaginary iΓ parameter to account approximately for the finite lifetime of the excited state. The imaginary part of the dipole polarizability
Im
α(-ω;ω) has been calculated for a wide range of external radiation energies up to 10 eV, and its maxima have been compared to the calculated vertical electronic excitation energies.
... We shall review the electronic and the pure vibrational contributions to the hyperpolarizabilities of pyrrole [50]. The original article involved also dipole moment and polarizabilities. ...
... These have been computed with the HF, MP2, CCSD and CCSD(T) methods and the Pol basis set. Correlation at the CCSD(T) level increases " and " by 50.2% and 17.4%, respectively [50] (Table 5. [50]. The first of those is computed by using first-order dipole moment derivatives and cubic force constants. ...
... These have been computed with the HF, MP2, CCSD and CCSD(T) methods and the Pol basis set. Correlation at the CCSD(T) level increases " and " by 50.2% and 17.4%, respectively [50] (Table 5. [50]. The first of those is computed by using first-order dipole moment derivatives and cubic force constants. ...
This article reviews some recent works, which deal with state-of-the-art results linear and nonlinear (L&NLO) properties of molecules (organic and inorganic). The electronic correlation, vibrational and relativistic contributions have been computed. Correlation has been taken into account by employing a series of methods e.g. MP2, CCSD, CCSD(T), CASPT2. The vibrational contributions have been computed by using the Bishop and Kirtman perturbation theory as well as the Numerov-Cooley integration. The relativistic correction has been computed by using the Douglas-Kroll method. It is noted that vibrational contribution has been calculated by taking into account both correlation and relativistic corrections. The properties are mainly static, but to a smaller extent, we have also considered frequency dependent properties. The main emphasis of the reviewed works was to use all the computational tools currently available in order to calculate property values as accurate as it is currently possible. The accuracy of the employed approximations is evaluated and discussed. Several interesting features and trends have been observed, for example the relativistic effects significantly reduce the magnitude of the vibrational corrections (coinage metal hydrides). An extensive study of fullerenes and endohedral fullerenes has been performed and reviewed. Of particular interest is the effect of the endohedral atom (e.g. Li) on the L&NLO properties of the system. The reviewed works have employed a large variety of systems (e.g. heavy metal-Group IIb-sulfides, coinage metal hydrides, ketones, thiones etc.).
... The pertinent cross section may be estimated by the above-mentioned correlation with the electronic polarizability. 66 The latter was in turn estimated from that reported for imidazole (7.495 Å 3 ), 67 by adding the group contribution of (CH 2 ) 2 (3.6 Å 3 ). 68 The resulting value of σ is 16.4 ± 2.5 Å 2 , and the partial pressures derived thereafter are also reported in Table 3. ...
The evaporation/decomposition behaviour of the imidazolium ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BMImPF6) was investigated in the overall temperature range 425 - 551 K by means of the molecular-effusion-based techniques Knudsen Effusion Mass Loss (KEML) and Knudsen Effusion Mass Spectrometry (KEMS), using effusion orifices of different size (from 0.2 to 3 mm in diameter). Specific effusion fluxes measured by KEML were found to depend markedly on the orifice size, suggesting the occurrence of a kinetically delayed evaporation/decomposition process. KEMS experiments revealed that other species are present in the vapor phase besides the intact ion pair BMImPF6(g) produced by the simple evaporation BMImPF6(l) = BMImPF6(g), with relative abundances depending on the orifice size – larger the orifice, larger the contribution of the BMImPF6(g) species. By combining KEML and KEMS results, the conclusion is drawn that in the investigated temperature range, when small effusion orifices are used a significant part of the mass loss/volatility of BMImPF6 is due to molecular products formed by decomposition/dissociation processes rather than to evaporated intact ion pairs. Additional experiments performed by non-isothermal Thermogravimetry-Differential Thermal Analysis (TG-DTA) further support the evidence of simultaneous evaporation/decomposition, although the conventional decomposition temperature derived from TG curves is much higher than temperatures covered in effusion experiments. Partial pressures of the BMImPF6(g) species were derived from KEMS spectra and analyzed by the second- and third-law methods giving a value of = 145.3 ± 2.9 kJ mol–1 for the standard evaporation enthalpy of BMImPF6. A comparison is done with the behavior of the 1-butyl-3-methylimidazolium bis(trifluoromethyl)sulfonylimide (BMImNTf2) ionic liquid.
... However, the accurate estimation of the influence of the vibrational motion of nuclei on dipole moment and polarizability for polyatomic molecules is more complicated and resource-demanding, as far as this requires, in the general case, the detailed exploration of corresponding potential energy surface (PES) (with calculation of the energy of rovibrational levels and corresponding wave functions) as well as the dipole moment surface (DMS) and dipole polarizability surface (DPS) applying accurate quantum chemical methods [37][38][39][40][41][42]. It should be emphasized that frequently upon the determination of state-specific electric properties of polyatomic structures only the effect of zero-point vibrational (ZPV) motion is explored or approximate methods are used [32,[43][44][45][46][47][48]. However, for many applications, both in chemistry and in physics, it is necessary to know the state-specific electric properties of molecules and clusters both in low and in high vibrational states [4,[49][50][51]. ...
... It is known that in order to get highly accurate results for polarizability of polyatomic systems, the calculations must involve, along with a careful choice of the function basis set and a proper inclusion of electronic correlation effects, the appropriate vibrational contributions [45,48]. Even if one interested in the value of polarizability at low temperature only, the zero-point motion can result in a considerable correction of the total polarizability of molecule or cluster. ...
... Therefore, it would be interesting to survey the performance of elaborated approximations in view of applicability to larger atomic systems. In doing so, we compared the values, obtained with the use of equations (14) and (16) for several large polyatomic structures, comprising dozens of atoms (including azoles, hydrocarbons, fullerenes, and nitroanilines), with the available literature data [14,18,45,48,[129][130][131][132] (see figure 9). ...
Dipole moment and static dipole polarizability surfaces for 50 polyatomic molecules, that are important for material science, combustion, and atmospheric chemistry, are explored in the vicinity of their equilibrium nuclear configurations by using density functional theory. The effective values of dipole moment and static polarizability of these molecules in individual vibrational states are determined using the calculated data on the electric properties and potential energy surfaces. Special attention is paid to the effect of the zero-point vibrations on the electric properties. The simple approximation scheme, allowing low-cost estimation of the zero-point vibrational corrections to polarizability, applicable for wide range of polyatomic compounds, are developed on the basis of the obtained data. The influence of the excitation of vibrational states on the dipole moment and dipole polarizability of polyatomic molecules are discussed with respect to the possible change of some important properties of molecular gases, such as refractive index, diffusion coefficients, and rates of chemical reactions.
