Multireference Configuration Interaction Study of Bromocarbenes

Standard, Jean M.; Steidl, Rebecca J.; Beecher, Matthew C.; Quandt, Robert W.

doi:10.1021/jp107688v

Cited by 16 publications

(44 citation statements)

References 48 publications

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“…As aforementioned, systematic investigation on the basis sets and various correlation effects in the calculations should be necessary for determination of accurate spectroscopic constants. As shown in Figure , the S‐T gap shows a decreasing tendency as the electronegativity of the X substituent decreases, ie, Δ E S‐T (NI) < Δ E S‐T (NBr) < Δ E S‐T (NCl) < Δ E S‐T (NF), which is similar as that of halocarbenes . Our results of S‐T gaps are in excellent agreement with experimental results for NXs.…”

Section: Resultssupporting

confidence: 87%

“…Similar analyses suggest that all the values of spectroscopic constants of the excited singlet states converge to a certain value respectively with the rise of basis set scale. Apparently, larger basis set would result in more accurate constants, as discussed in a series of carbenes and nitrenes . In the following sections, all the calculations were performed with the CBS basis set.…”

Section: Resultsmentioning

confidence: 99%

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Accurate spectroscopic constants of the lowest three electronic states in halonitrenes with multireference configuration interaction

Shan

Yin

Liu

et al. 2018

Int J of Quantum Chemistry

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Internally contracted multireference configuration interaction (icMRCI) calculations of the ground state (X 3 R 2 ), the first excited state (a 1 D) as well as the second excited state (b 1 R 1 ) have been performed for a series of halogenated nitrenes NXs (X 5 Cl, Br, and I). Accurate spectroscopic constants of these lowest three electronic states of each NX were obtained in this work using MRCI methods with aug-cc-pVXZ (X 5 T, Q, 5) basis sets and complete basis set (CBS) limit. In addition, various corrections, including the Davidson correction, scalar relativistic effect, corevalence correlation, and spin-orbit coupling effect, have been studied in calculating spectroscopic constants, especially for heavy-atom nitrenes. Comparisons have been made with previous computational and experimental results where available. The icMRCI 1 Q calculations presented in this work provide a comprehensive series of results at a consistent high level of theory for all of the halogenated nitrenes. K E Y W O R D Score-valence correlation, icMRCI1Q, nitrenes, scalar relativistic effect, spectroscopic constants, spin-orbit coupling effect 1 | I N TR ODU C TI ON Halogenated nitrenes NXs (X 5 F, Cl, Br, I) are sextet, neutral, and highly reactive molecular species where the nitrogen atom shows a monovalent nature. Derived from the photochemical process of the halogen azides XN 3 !N 2 1 NX (X 5 F, Cl, Br, I), [1][2][3] the radical NXs play an important photochemical role in the upper atmosphere and interstellar space because of their relatively high contents of the constituent elements in the space. [4,5] Halogenated nitrenes are also expected to be a possible candidate for the application in chemical energy storage sources since there exists two metastable excited states, a 1 D and b 1 R 1 of NXs. [6][7][8] Particularly, the a 1 D state of NF or NCl could be used for pumping the 2 P 1/2 -2 P 3/2 transition of atomic iodine in a successful demonstration of an efficient chemical laser. [9][10][11][12][13] Accurate spectroscopic information about these low-lying electronic states is essential to understand the dynamics and kinetics of chemical processes involving halogenated nitrenes.As analogs to halogenated carbenes, the two unpaired electrons of NX can couple either as a singlet or triplet state very close in energy. Being iso-valent with O 2 , all halogenated nitrenes studied to date have a triplet ground state of X 3 R 2 . The two low-lying excited singlet states, a 1 D and b 1 R 1 , resulting from the same electron configuration (p 4 p* 2 ), could exhibit quite different reactivity comparing to the triplet ground electronic state.The spectroscopy of these low-lying states, the singlet-triplet energy splitting, as well as their reactivity, has been the subject of a myriad of investigations in the literature. [14] The spectroscopic study of NXs could date back to more than 70 years ago when the emission spectrum of NBr (later assigned to the b 1 R 1 -X 3 R 2 transition [15] ) was first observed by Elliott. [16] After that, the stru...

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Section: Resultssupporting

confidence: 87%

Section: Resultsmentioning

confidence: 99%

Accurate spectroscopic constants of the lowest three electronic states in halonitrenes with multireference configuration interaction

Shan

Yin

Liu

et al. 2018

Int J of Quantum Chemistry

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“…The computed geometries and frequencies of theX,ã andÃ states are consistent with the theoretical literature values [23,[29][30][31]65,[68][69][70].…”

Section: Thex( 1 a )ã( 3 A ) Andã( 1 A ) States Of Cbri CCLI And Cfisupporting

confidence: 88%

“…demonstrate, have little effect on the singlet-triplet splitting, ∼0.2 kcal mol −1 at most (in CBrI). Consequently, the singlet-triplet separations computed in this work are not too different from those obtained at lower levels of theory [23,31,64,69]. Surprisingly though, in the case of CFI there is a noticeable discrepancy between the current result of 27.3 kcal mol −1 and the value of 25.1 kcal mol −1 (8777 cm −1 ) that has been recently reported by Sun et al [70] computed at a comparable level of theory with that employed here.…”

Section: Singlet-triplet Splittingscontrasting

confidence: 75%

Spectroscopy and heats of formation of CXI (X = Br, Cl, F) iodocarbenes: quantum chemical characterisation of the X̃(¹ A′), ã(³ A″) and Ã(¹ A″) states

Bacskay

2015

Molecular Physics

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The equilibrium energies of the iodocarbenes CXI (X = Br, Cl, F) in theirX( 1 A ),ã( 3 A ) andÃ( 1 A ) states and their atomisation and dissociation energies in the complete basis limit were determined by extrapolating valence correlated (R/U)CCSD(T) and Davidson corrected multi-reference configuration interaction (MRCI) energies calculated with the augcc-pVxZ (x = T,Q,5) basis sets and the ECP28MDF pseudopotential of iodine plus corrections for core and core-valence correlation, scalar relativity, spin-orbit coupling and zero-point energies. Spin-orbit energies were computed in a large basis of configurations chosen so as to accurately describe dissociation to the 3 P and 2 P states of C and of the halogens X and I, respectively. The computed singlet-triplet splittings are 13.6, 14.4 and 27.3 kcal mol −1 for X = Br, Cl and F, respectively. The enthalpies of formation at 0 K are predicted to be 97.4, 82.6 and 38.1 kcal mol −1 with estimated errors of ±1.0 kcal mol −1 . TheÃ ←X excitation energies (T 00 ) in CBrI and CClI are calculated to be 41.1 and 41.7 kcal mol −1 , respectively. The Renner-Teller intersections in both molecules are predicted to be substantially higher than the dissociation barriers on theÃ surfaces. By contrast, in CFI theÃ state is found to be unbound with respect to dissociation.

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“…In general, carbenes are classified as either singlets or triplets depending upon their electronic structure there [10]. Carbenes play important roles both as reactive intermediates and also as ligands; consequently, considerable effort has been devoted to understand their molecular and electronic structures [11][12][13][14][15]. Special interest is associated with carbenes that feature the attachment of donor groups to the carbenic carbon since they behave as nucleophiles and, in some instances, can be isolated.…”

Section: Introductionmentioning

confidence: 99%

Characteristics and nature of the intermolecular interactions in boron-bonded complexes with carbene as electron donor: an ab initio, SAPT and QTAIM study

Esrafili

2011

J Mol Model

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We report geometries, stabilization energies, symmetry adapted perturbation theory (SAPT) and quantum theory of atoms in molecules (QTAIM) analyses of a series of carbene-BX(3) complexes, where X = H, OH, NH(2), CH(3), CN, NC, F, Cl, and Br. The stabilization energies were calculated at HF, B3LYP, MP2, MP4 and CCSD(T)/aug-cc-pVDZ levels of theory using optimized geometries of all the complexes obtained from B3LYP/aug-cc-pVTZ. Quantitatively, all the complexes indicate the presence of B-C(carbene) interaction due to the short B-C(carbene) distances. Inspection of stabilization energies reveals that the interaction energies increase in the order NH(2) > OH > CH(3) > F > H > Cl > Br > NC > CN, which is the opposite trend shown in the binding distances. Considering the SAPT results, it is found that electrostatic effects account for about 50% of the overall attraction of the studied complexes. By comparison, the induction components of these interactions represent about 40% of the total attractive forces. Despite falling in a region of charge depletion with nabla(2)ρ(BCP) >0, the B-C(carbene) bond critical points (BCPs) are characterized by a reasonably large value of the electron density (ρ(BCP)) and H(BCP) <0, indicating that the potential energy overcomes the kinetic energy density at BCP and the B-C(carbene) bond is a polar covalent bond.

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Multireference Configuration Interaction Study of Bromocarbenes

Cited by 16 publications

References 48 publications

Accurate spectroscopic constants of the lowest three electronic states in halonitrenes with multireference configuration interaction

Accurate spectroscopic constants of the lowest three electronic states in halonitrenes with multireference configuration interaction

Spectroscopy and heats of formation of CXI (X = Br, Cl, F) iodocarbenes: quantum chemical characterisation of the X̃(¹ A′), ã(³ A″) and Ã(¹ A″) states

Characteristics and nature of the intermolecular interactions in boron-bonded complexes with carbene as electron donor: an ab initio, SAPT and QTAIM study

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Multireference Configuration Interaction Study of Bromocarbenes

Cited by 16 publications

References 48 publications

Accurate spectroscopic constants of the lowest three electronic states in halonitrenes with multireference configuration interaction

Accurate spectroscopic constants of the lowest three electronic states in halonitrenes with multireference configuration interaction

Spectroscopy and heats of formation of CXI (X = Br, Cl, F) iodocarbenes: quantum chemical characterisation of the X̃(1 A′), ã(3 A″) and Ã(1 A″) states

Characteristics and nature of the intermolecular interactions in boron-bonded complexes with carbene as electron donor: an ab initio, SAPT and QTAIM study

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Spectroscopy and heats of formation of CXI (X = Br, Cl, F) iodocarbenes: quantum chemical characterisation of the X̃(¹ A′), ã(³ A″) and Ã(¹ A″) states