Density functional studies of the n·aσ charge-transfer complexes between NH 3 and BrX (X=Cl, Br)

García, Antón; Elorza, J. M.; Ugalde, Jesús M.

doi:10.1016/s0166-1280(99)00431-5

Cited by 14 publications

(7 citation statements)

References 27 publications

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“…A first inspection of the results, focusing the attention on E GKS b and ∆ GKS , confirms the finding, well established in literature [49,51,53,54,56,89], that hybrid functionals outperform semilocal ones for the calculation of interaction energies of ground-state chargetransfer complexes. In fact, BHLYP with a MARE of 16.63% is the most accurate method.…”

Section: Embedding Energysupporting

confidence: 84%

“…This suggests that a strong error cancellation occurs for embedding calculations using semilocal functionals, while the cancellation is much less in the case of hybrid approaches. The reason for this behavior can be traced back to the fact that, in general, conventional semilocal functionals overestimate significantly the binding energy of charge-transfer complexes [42,49,[51][52][53][54]56] (MSE is largely positive) while, on the other hand, when used in methods based on the FDE theory they show usually a tendency to produce too low interaction energies (∆E is negative in most cases). On the contrary, hybrid functionals are quite accurate for the calculation of the interaction energies of chargetransfer complexes and, at the same time, corresponding embedding calculations reproduce with good accuracy the parent supermolecular GKS calculations.…”

Section: Embedding Energymentioning

confidence: 99%

“…As a consequence, the description of ground-state charge-transfer complexes is very challenging for conventional semilocal XC functionals because of the SIE inherent in these methods. On the other hand, a good performance is generally obtained for hybrid functionals, especially when rather large portions of Hartree-Fock exchange are included [49][50][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65]. Similar results also concern the charge transfer between organic molecules and metal substrates [66,67].…”

Section: Introductionmentioning

confidence: 97%

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Semilocal and hybrid density embedding calculations of ground-state charge-transfer complexes

Laricchia

Fabiano

Sala

2013

The Journal of Chemical Physics

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We apply the frozen density embedding method, using a full relaxation of embedded densities through a freeze-and-thaw procedure, to study the electronic structure of several benchmark ground-state charge-transfer complexes, in order to assess the merits and limitations of the approach for this class of systems. The calculations are performed using both semilocal and hybrid exchange-correlation (XC) functionals. The results show that embedding calculations using semilocal XC functionals yield rather large deviations with respect to the corresponding supermolecular calculations. Due to a large error cancellation effect, however, they can often provide a relatively good description of the electronic structure of charge-transfer complexes, in contrast to supermolecular calculations performed at the same level of theory. On the contrary, when hybrid XC functionals are employed, both embedding and supermolecular calculations agree very well with each other and with the reference benchmark results. In conclusion, for the study of ground-state charge-transfer complexes via embedding calculations hybrid XC functionals are the method of choice due to their higher reliability and superior performance.

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Section: Embedding Energysupporting

confidence: 84%

Section: Embedding Energymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

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Semilocal and hybrid density embedding calculations of ground-state charge-transfer complexes

Laricchia

Fabiano

Sala

2013

The Journal of Chemical Physics

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“…Based on the experience gained from the previous investigations on H 3 N···ClF, four basis sets were used: 6-31++G(d,p), 6-311++G(2d,2p), 6-311++ G(3df,2p), − and aug-cc-pVTZ. − With these four basis sets, the structures of the complexes were optimized at the MP2 level and with three DFT methods (B3LYP, − PW91PW91, and BH&HLYP as implemented in Gaussian 98). This choice was motivated by the previously observed acceptable performance of B3LYP for the methylated amine···F 2 complexes, by a recent use of PW91PW91 in the pure van der Waals system (N 2 ) 2 , and by a recent study of the charge-transfer complexes of NH 3 with BrCl and Br 2 in which the use of the BH&HLYP method was recommended. The counterpoise (CP) correction to the basis set superposition error (BSSE) including the contribution of geometry relaxation was computed in all cases at the conventionally optimized complex equilibrium geometries.…”

Section: Methods Of Calculationmentioning

confidence: 99%

Charge-Transfer Complexes between the Amines (CH₃)_nNH_3-_n (n = 0−3) and the ClF Molecule: An ab Initio and Density Functional Study on the Intermolecular Interaction

Karpfen

2001

J. Phys. Chem. A

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The intermolecular interactions between the amines NH 3 , CH 3 NH 2 , (CH 3 ) 2 NH, and (CH 3 ) 3 N and the ClF molecule were investigated with the aid of ab initio calculations performed at different levels of Møller-Plesset perturbation theory and coupled cluster expansions. In addition, three density functional theory approaches were probed. Medium-sized to extended polarized basis sets were applied. Distinct and very systematic differences occur for the calculated complex properties in this series when applying different electron correlation methods. In these four complexes, the computed intramolecular ClF distance is substantially widened relative to that of the isolated ClF molecule by about 0.07-0.15 Å, whereas the calculated intermolecular N‚‚‚Cl distance is substantially contracted by about 0.2-0.3 Å upon going from H 3 N‚‚‚ClF to (CH 3 ) 3 N‚‚‚ ClF, in agreement with the experimentally observed trend. Computed dipole moments range from about 5.7 D in H 3 N‚‚‚ClF to about 7.6 D in (CH 3 ) 3 N‚‚‚ClF, indicating an increasingly polar structure. Successive methyl substitution modifies the interaction energy between the amine and ClF systematically from about -9 kcal mol -1 in H 3 N‚‚‚ClF to about -20 kcal mol -1 in the (CH 3 ) 3 N‚‚‚ClF complex. These complexes can be described best as charge-transfer complexes with modest intramolecular structure relaxations in the amine and with an important contribution originating from a significant stretching of the ClF molecule.

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“…DFT has a wide range of applications, including providing complete and precise structural features of CT, hydrogen-bonded, and coordination complexes [ 23 , 24 ]. The CT complexation was recently investigated using DFT calculations to describe the donor and acceptor molecules in the CT complex [ 25 , 26 ]. Furthermore, the time-dependent density functional theory (TD-DFT) was applied to compute the electronic absorption spectra of the studied CT complexes [ 14 , 27 ].…”

Section: Introductionmentioning

confidence: 99%

New Charge Transfer Complexes of K+-Channel-Blocker Drug (Amifampridine; AMFP) for Sensitive Detection; Solution Investigations and DFT Studies

et al. 2021

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UV–Vis spectroscopy was used to investigate two new charge transfer (CT) complexes formed between the K+-channel-blocker amifampridine (AMFP) drug and the two π-acceptors 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) and tetracyanoethylene (TCNE) in different solvents. The molecular composition of the new CT complexes was estimated using the continuous variations method and found to be 1:1 for both complexes. The formed CT complexes’ electronic spectra data were further employed for calculating the formation constants (KCT), molar extinction coefficients (εCT), and physical parameters at various temperatures, and the results demonstrated the high stability of both complexes. In addition, sensitive spectrophotometric methods for quantifying AMFP in its pure form were proposed and statistically validated. Furthermore, DFT calculations were used to predict the molecular structures of AMFP–DDQ and AMFP–TCNE complexes in CHCl3. TD-DFT calculations were also used to predict the electronic spectra of both complexes. A CT-based transition band (exp. 399 and 417 nm) for the AMFP–TCNE complex was calculated at 411.5 nm (f = 0.105, HOMO-1 → LUMO). The two absorption bands at 459 nm (calc. 426.9 nm, f = 0.054) and 584 nm (calc. 628.1 nm, f = 0.111) of the AMFP–DDQ complex were theoretically assigned to HOMO-1 → LUMO and HOMO → LUMO excitations, respectively.

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Density functional studies of the n·aσ charge-transfer complexes between NH 3 and BrX (X=Cl, Br)

Cited by 14 publications

References 27 publications

Semilocal and hybrid density embedding calculations of ground-state charge-transfer complexes

Semilocal and hybrid density embedding calculations of ground-state charge-transfer complexes

Charge-Transfer Complexes between the Amines (CH₃)_nNH_3-_n (n = 0−3) and the ClF Molecule: An ab Initio and Density Functional Study on the Intermolecular Interaction

New Charge Transfer Complexes of K+-Channel-Blocker Drug (Amifampridine; AMFP) for Sensitive Detection; Solution Investigations and DFT Studies

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Density functional studies of the n·aσ charge-transfer complexes between NH 3 and BrX (X=Cl, Br)

Cited by 14 publications

References 27 publications

Semilocal and hybrid density embedding calculations of ground-state charge-transfer complexes

Semilocal and hybrid density embedding calculations of ground-state charge-transfer complexes

Charge-Transfer Complexes between the Amines (CH3)nNH3-n (n = 0−3) and the ClF Molecule: An ab Initio and Density Functional Study on the Intermolecular Interaction

New Charge Transfer Complexes of K+-Channel-Blocker Drug (Amifampridine; AMFP) for Sensitive Detection; Solution Investigations and DFT Studies

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Charge-Transfer Complexes between the Amines (CH₃)_nNH_3-_n (n = 0−3) and the ClF Molecule: An ab Initio and Density Functional Study on the Intermolecular Interaction