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1.
Formation of Long,Multicenter π‐[TCNE]22− Dimers in Solution: Solvation and Stability Assessed through Molecular Dynamics Simulations
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Dr. Marçal Capdevila‐Cortada Dr. Jordi Ribas‐Arino Dr. Alain Chaumont Prof. Georges Wipff Prof. Juan J. Novoa 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(47):17037-17046
Purely organic radical ions dimerize in solution at low temperature, forming long, multicenter bonds, despite the metastability of the isolated dimers. Here, we present the first computational study of these π‐dimers in solution, with explicit consideration of solvent molecules and finite temperature effects. By means of force‐field and ab initio molecular dynamics and free energy simulations, the structure and stability of π‐[TCNE]22? (TCNE=tetracyanoethylene) dimers in dichloromethane have been evaluated. Although the dimers dissociate at room temperature, they are stable at 175 K and their structure is similar to the one in the solid state, with a cofacial arrangement of the radicals at an interplanar separation of approximately 3.0 Å. The π‐[TCNE]22? dimers form dissociated ion pairs with the NBu4+ counterions, and their first solvation shell comprises approximately 20 CH2Cl2 molecules. Among them, the eight molecules distributed along the equatorial plane of the dimer play a key role in stabilizing the dimer through bridging C?H???N contacts. The calculated free energy of dimerization of TCNE . ? in solution at 175 K is ?5.5 kcal mol?1. These results provide the first quantitative model describing the pairing of radical ions in solution, and demonstrate the key role of solvation forces on the dimerization process. 相似文献
2.
Capdevila-Cortada M Novoa JJ Bell JD Moore CE Rheingold AL Miller JS 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(34):9326-9341
The α, β, and δ polymorphs of [TTF][TCNE] (TTF=tetrathiafulvalene; TCNE=tetracyanoethylene) exhibit a new type of long, multicenter bonding between the [TTF]δ+ and [TCNE]δ? moieties, demonstrating the existence of long, hetero‐multicenter bonding with a cationicδ+???anionicδ? zwitterionic‐like structure. These diamagnetic π‐[TTF]δ+[TCNE]δ? heterodimers exhibit a transfer of about 0.5 e? from the TTF to the TCNE fragments, as observed from experimental studies, in accord with theoretical predictions, that is, [TTFδ+???TCNEδ?] (δ?0.5). They have several interfragment distances <3.4 Å, and a computed interaction energy of ?21.2 kcal mol?1, which is typical of long, multicenter bonds. The lower stability of [TTF]δ+[TCNE]δ? with respect to typical ionic bonds is due, in part, to the partial electron transfer that reduces the electrostatic bonding component. This reduced electrostatic interaction, and the large interfragment dispersion stabilize the long, heterocationic/anionic multicenter interaction, which in [TTFδ+???TCNEδ?] always involves two electrons, but have ten, eight, and eight bond critical points (bcps) involving C? C, N? S, and sometimes C? S and C? N components for the α, β, and δ polymorphs, respectively. In contrast, γ‐[TTF][TCNE] possesses [TTF]22+ and [TCNE]22? dimers, each with long, homo‐multicenter 2e?/12c (c=center, 2 C+4 S) [TTF]22+ cationic+???cationic+ bonds, as well as long, homo‐multicenter 2e?/4c [TCNE]22? anionic????anionic? bonding. The MO diagrams for the α, β, and δ polymorphs have all of the features found for conventional covalent C? C bonds, and for all of the previously studied multicenter long bonds, for example, π‐[TTF]22+ and π‐[TCNE]22?. The HOMOs for α‐, β‐, and δ‐[TTF][TCNE] have 2c C? S and 3c C? C? C orbital‐overlap contributions between the [TTF]δ+? and [TCNE]δ? moieties; these are the shortest intra [TTF???TCNE] separations. Thus, from an orbital‐overlap perspective, the bonding has 2c and 3c components residing over one S and four C atoms. 相似文献
3.
Orientational Preference of Long,Multicenter Bonds in Radical Anion Dimers: A Case Study of π‐[TCNB]22− and π‐[TCNP]22−
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Dr. Marçal Capdevila‐Cortada Prof. Joel S. Miller Prof. Juan J. Novoa 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(17):6420-6432
The similar shape and electronic structure of the radical anions of 1,2,4,5‐tetracyanopyrazine (TCNP) and 1,2,4,5‐tetracyanobenzene (TCNB) suggest a similar relative orientation for their long, multicenter carbon?carbon bond in π‐[TCNP]22? and in π‐[TCNB]22?, in good accord with the Maximin Principle predictions. Instead, the two known structures of π‐[TCNP]22? have a D2h(θ=0°) and a C2(θ=30°) orientation (θ being the dihedral angle that determines the rotation of one radical anion relative to the other along the axis that passes through center of the two six‐membered rings). The only known π‐[TCNB]22? structure has a C2(θ=60°) orientation. The origin of these preferences was investigated for both dimers by computing (at the RASPT2/RASSCF(30,28) level) the variation with θ of the interaction energy (Eint) and the variation of the Eint components. It was found that: 1) a long, multicenter bond exists for all orientations; 2) the Eint(θ) angular dependence is similar in both dimers; 3) for all orientations the electrostatic component dominates the value of Eint(θ), although the dispersion and bonding components also play a relevant role; and 4) the Maximin Principle curve reproduces well the shape of the Eint(θ) curve for isolated dimers, although none of them reproduce the experimental preferences. Only after the (radical anion).? ??? cation+ interactions are also included in the model aggregate are the experimental data reproduced computationally. 相似文献
4.
Andrew Hempel Norman Camerman Zbigniew Dauter Donald Mastropaolo Arthur Camerman 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(4):455-456
The crystal structure of the title compound, C19H26NO+·Cl? (common name: N,N‐diethyl‐2‐[(4‐phenylmethyl)phenoxy]‐ethanamine hydrochloride), contains one molecule in the asymmetric unit. The planes through the two phenyl rings are roughly perpendicular. Protonation occurs at the N atom, to which the Cl? ion is linked via an N—H?Cl hydrogen bond. The molecule adopts an eclipsed rather than extended conformation. 相似文献
5.
By alternating‐current electrochemical technique crystals of copper(I) π‐complex with 1‐allylpyridinium chloride of [C5H5N(C3H5)][Cu2Cl3] ( 1 ) composition have been obtained and structurally investigated. Compound 1 crystallizes in monoclinic system, space group C2/c a = 24.035(1) Å, b = 11.4870(9) Å, c = 7.8170(5) Å, β = 95.010(5)°, V = 2150.0(2) Å3 (at 100 K), Z = 8, R = 0.028, for 4836 independent reflections. In the structure 1 trigonal‐pyramidal environment of π‐coordinated copper(I) atom is formed by a lengthened to 1.376(2) Å C=C bond of allyl group and by three chlorine atoms. Other two copper atoms are tetrahedrally surrounded by chlorine atoms only. The coordination polyhedra are combined into an original infinite (Cu4Cl62—)n fragment. Structural comparison of 1 and the recently studied copper(I) chloride π‐complexes with 3‐amino‐, 2‐amino‐, 4‐amino‐1‐allylpyridinium chlorides of respective [LCu2Cl3] ( 2 ), [L2Cu2Cl4] ( 3 ), and [LCuCl2] ( 4 ) compositions allowed us to reveal the trend of the inorganic fragment complication which depends on pKa (base) value of the corresponding initial heterocycle. 相似文献
6.
Osamu Takahashi Katsuyoshi Yamasaki Yuji Kohno Kazuyoshi Ueda Hiroko Suezawa Motohiro Nishio 《化学:亚洲杂志》2006,1(6):852-859
Ab initio molecular‐orbital (MO) calculations were carried out, at the MP2/6‐311++G(d,p)//MP2/6‐31G(d) level, to investigate the conformational Gibbs energy of alkyl 1‐cyclohexylethyl ketones, cyclo‐C6H11CHCH3? CO? R (R=Me, Et, iPr, and tBu). In each case, one of the equatorial conformations was shown to be the most stable. Conformers with the axial CHCH3COR group were also shown to be present in an appreciable concentration. Short C? H???C?O and C? H???O?C distances were found in each stable conformation. The result was interpreted on the grounds of C? H???π(C?O) and C? H???O hydrogen bonds, which stabilize the geometry of the molecule. The ratio of the diastereomeric secondary alcohols produced in the nucleophilic addition to cyclo‐C6H11CHCH3? CO? R was estimated on the basis of the conformer distribution. The calculated result was consistent with the experimental data previously reported: the gradual increase in the product ratio (major/minor) along the series was followed by a drop at R=tBu. The energy of the diastereomeric transition states in the addition of LiH to cyclo‐C6H11CHCH3? CO? R was also calculated for R=Me and tBu. The product ratio did not differ significantly in going from R=Me to tBu in the case of the aliphatic ketones. This is compatible with the above result calculated on the basis of the conformer distribution. Thus, the mechanism of the π‐facial selection can be explained in terms of the simple premise that the geometry of the transition state resembles the ground‐state conformation of the substrates and that the nucleophilic reagent approaches from the less‐hindered side of the carbonyl π face. 相似文献
7.
Masood Parvez Shaun T. Mesher Peter D. Clark 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(5):574-576
The structure of 2,5‐bis(methylthio)‐1,4‐benzoquinone, C8H8O2S2, is composed of an essentially planar centrosymmetric benzoquinone substituted with two methylthio groups. The important bond distances are S—Csp3 1.788 (2) and S—Csp2 1.724 (2) Å, and the two Csp2—Csp2 distances are 1.447 (3) and 1.504 (3) Å, which differ significantly. There are short S?S interactions of 3.430 (1) Å and Csp2—H?O‐type contacts forming a dimeric motif with graph set R22(8). The structure of 2‐methyl‐3‐(methylsulfonyl)benzo[b]thiophene, C10H10O2S2, is composed of an essentially planar benzothiophene moiety substituted with methyl and methylsulfonyl groups. The mean values of the important bond distances are endocyclic S—Csp2 1.734 (3), S=O 1.434 (4) and C—Caromatic 1.389 (10) Å. The exocyclic S—Csp2 and S—Csp3 distances are 1.759 (4) and 1.763 (5) Å, respectively. 相似文献
8.
Daphne E. Keller Huub Kooijman Antoine M. M. Scheurs Jan Kroon Eugeniusz Grech 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(4):479-480
The structure of the title compound, C14H19N2+·C9H3Cl6O4?·H2O, consists of singly ionized 1,4,5,6,7,7‐hexachlorobicyclo[2.2.1]hept‐5‐ene‐2,3‐dicarboxylic acid anions and protonated 1,8‐bis(dimethylamino)naphthalene cations. In the (8‐dimethylamino‐1‐napthyl)dimethylammonium cation, a strong disordered intramolecular hydrogen bond is formed with N?N = 2.589 (3) Å. The geometry and occupancy obtained in the final restrained refinement suggest that the disordered hydrogen bond may be asymmetric. Water molecules link the anion dimers into infinite chains via hydrogen bonding. 相似文献
9.
F. L. Oliveira P. C. Huber W. P. Almeida J. R. Sabino R. Aparicio 《Acta Crystallographica. Section C, Structural Chemistry》2013,69(2):119-122
The ZnII center in the dicationic complex of the title compound, [Zn(C10H7N3S)3](NO3)2·0.5C2H5OH·H2O, is in a distorted octahedral environment with imperfect noncrystallographic C3 symmetry. Each 2‐(1,3‐thiazol‐2‐yl)‐1H‐benzimidazole ligand coordinates in a bidentate manner, with the Zn—N(imidazole) bond lengths approximately 0.14 Å shorter than the Zn—N(thiazole) bond lengths. Charge‐assisted hydrogen bonds connect cations, anions and water molecules. A lattice void is occupied by an ethanol solvent molecule disordered about a crystallographic inversion center and π‐stacking is observed between one type of symmetry‐related benzene rings. 相似文献
10.
Colm Crean John F. Gallagher Albert C. Pratt 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(1):o36-o38
The title complex, C17H9N5·C6H4S4, contains π‐deficient bis(dinitrile) and TTF molecules stacked alternately in columns along the a‐axis direction; the interplanar angle between the TTF molecule and the isoindolinyl C4N[C(CN)2]2 moiety is 1.21 (4)°. The N‐allyl moiety in the TCPI molecule is oriented at an angle of 87.10 (10)° with respect to the five‐membered C4N ring, and the four C[triple‐bond]N bond lengths range from 1.134 (3) to 1.142 (3) Å, with C—C[triple‐bond]N angles in the range 174.3 (3)–176.9 (2)°. In the TTF system, the S—C bond lengths are 1.726 (3)–1.740 (3) and 1.751 (2)–1.763 (2) Å for the external S—C(H) and internal S—C(S) bonds, respectively. 相似文献
11.
Resonance Character of Copper/Silver/Gold Bonding in Small Molecule⋅⋅⋅MX (X=F,Cl, Br,CH3, CF3) Complexes
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Prof. Guiqiu Zhang Huanjing Yue Dr. Frank Weinhold Hui Wang Hong Li Dezhan Chen 《Chemphyschem》2015,16(11):2424-2431
The resonance character of Cu/Ag/Au bonding is investigated in B???M?X (M=Cu, Ag, Au; X=F, Cl, Br, CH3, CF3; B=CO, H2O, H2S, C2H2, C2H4) complexes. The natural bond orbital/natural resonance theory results strongly support the general resonance‐type three‐center/four‐electron (3c/4e) picture of Cu/Ag/Au bonding, B:M?X?B+?M:X?, which mainly arises from hyperconjugation interactions. On the basis of such resonance‐type bonding mechanisms, the ligand effects in the more strongly bound OC???M?X series are analyzed, and distinct competition between CO and the axial ligand X is observed. This competitive bonding picture directly explains why CO in OC???Au?CF3 can be readily replaced by a number of other ligands. Additionally, conservation of the bond order indicates that the idealized relationship bB???M+bMX=1 should be suitably generalized for intermolecular bonding, especially if there is additional partial multiple bonding at one end of the 3c/4e hyperbonded triad. 相似文献
12.
Fiona Brady John F. Gallagher Carol Murphy 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(3):365-368
The title compounds, C12H13NO4, are derived from l ‐threonine and dl ‐threonine, respectively. Hydrogen bonding in the chiral derivative, (2S/3R)‐3‐hydroxy‐2‐(1‐oxoisoindolin‐2‐yl)butanoic acid, consists of O—Hacid?Oalkyl—H?O=Cindole chains [O?O 2.659 (3) and 2.718 (3) Å], Csp3—H?O and three C—H?πarene interactions. In the (2R,3S/2S,3R) racemate, conventional carboxylic acid hydrogen bonding as cyclical (O—H?O=C)2 [graph set R22(8)] is present, with Oalkyl—H?O=Cindole, Csp3—H?O and C—H?πarene interactions. The COOH group geometry differs between the two forms, with C—O, C=O, C—C—O and C—C=O bond lengths and angles of 1.322 (3) and 1.193 (3) Å, and 109.7 (2) and 125.4 (3)°, respectively, in the chiral structure, and 1.2961 (17) and 1.2210 (18) Å, and 113.29 (12) and 122.63 (13)°, respectively, in the racemate structure. The O—C=O angles of 124.9 (3) and 124.05 (14)° are similar. The differences arise from the contrasting COOH hydrogen‐bonding environments in the two structures. 相似文献
13.
Dr. Jingjun Hao Prof. Arnold L. Rheingold Marzieh Kavand Dr. Kipp J. van Schooten Prof. Christoph Boehme Dr. Marçal Capdevila‐Cortada Prof. Juan J. Novoa Eva Wöss Prof. Günther Knör Prof. Joel S. Miller 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(35):12312-12315
The reaction of 2,3,5,6‐tetracyanopyridine (TCNPy) and Cr(C6H6)2 forms diamagnetic σ‐[TCNPy]22? possessing a 1.572(3) Å intrafragment sp3–sp3 bond. This is in contrast to the structurally related 1,2,4,5‐tetracyanobenzene and 1,2,4,5‐tetracyanopyrazine that form π‐dimer dianions possessing long, multicenter bonds. 相似文献
14.
Ondrej Kysel Šimon Budzák Miroslav Medveď Pavel Mach 《International journal of quantum chemistry》2008,108(9):1533-1545
Geometry, thermodynamic, and electric properties of the π‐EDA complex between hexamethylbenzene (HMB) and tetracyanoethylene (TCNE) are investigated at the MP2/6‐31G* and, partly, DFT‐D/6‐31G* levels. Solvent effects on the properties are evaluated using the PCM model. Fully optimized HMB–TCNE geometry in gas phase is a stacking complex with an interplanar distance 2.87 × 10?10 m and the corresponding BSSE corrected interaction energy is ?51.3 kJ mol?1. As expected, the interplanar distance is much shorter in comparison with HF and DFT results. However the crystal structures of both (HMB)2–TCNE and HMB–TCNE complexes have interplanar distances somewhat larger (3.18 and 3.28 × 10?10 m, respectively) than our MP2 gas phase value. Our estimate of the distance in CCl4 on the basis of PCM solvent effect study is also larger (3.06–3.16 × 10?10 m). The calculated enthalpy, entropy, Gibbs energy, and equilibrium constant of HMB–TCNE complex formation in gas phase are: ΔH0 = ?61.59 kJ mol?1, ΔS = ?143 J mol?1 K?1, ΔG0 = ?18.97 kJ mol?1, and K = 2,100 dm3 mol?1. Experimental data, however, measured in CCl4 are significantly lower: ΔH0 = ?34 kJ mol?1, ΔS = ?70.4 J mol?1 K?1, ΔG0 = ?13.01 kJ mol?1, and K = 190 dm3 mol?1. The differences are caused by solvation effects which stabilize more the isolated components than the complex. The total solvent destabilization of Gibbs energy of the complex relatively to that of components is equal to 5.9 kJ mol?1 which is very close to our PCM value 6.5 kJ mol?1. MP2/6‐31G* dipole moment and polarizabilities are in reasonable agreement with experiment (3.56 D versus 2.8 D for dipole moment). The difference here is due to solvent effect which enlarges interplanar distance and thus decreases dipole moment value. The MP2/6‐31G* study supplemented by DFT‐D parameterization for enthalpy calculation, and by the PCM approach to include solvent effect seems to be proper tools to elucidate the properties of π‐EDA complexes. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008 相似文献
15.
Site‐Directed Dimerization of Bowl‐Shaped Radical Anions to Form a σ‐Bonded Dibenzocorannulene Dimer
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Dr. Sarah N. Spisak Dr. Alexander V. Zabula Melisa Alkan Dr. Alexander S. Filatov Prof. Dr. Andrey Yu. Rogachev Prof. Dr. Marina A. Petrukhina 《Angewandte Chemie (International ed. in English)》2018,57(21):6171-6175
Designed site‐directed dimerization of the monoanion radicals of a π‐bowl in the solid state is reported. Dibenzo[a,g]corannulene (C28H14) was selected based on the asymmetry of the charge/spin localization in the C28H14.? anion. Controlled one‐electron reduction of C28H14 with Cs metal in diglyme resulted in crystallization of a new dimer, [{Cs+(diglyme)}2(C28H14?C28H14)2?] ( 1 ), as revealed by single crystal X‐ray diffraction study performed in a broad range of temperatures. The C?C bond length between two C28H14.? bowls (1.560(8) Å) measured at ?143 °C does not significantly change upon heating of the crystal to +67 °C. The single σ‐bond character of the C?C linker is confirmed by calculations. The trans‐disposition of two bowls in 1 is observed with the torsion angles around the central C?C bond of 172.3(5)° and 173.5(5)°. A systematic theoretical evaluation of dimerization pathways of C28H14.? radicals confirmed that the trans‐isomer found in 1 is energetically favored. 相似文献
16.
Susim Maiti Monika Mukherjee Bidisha Nandi Madeleine Helliwell Nitya G. Kundu 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(8):992-994
The title compound, C26H21NO2S2, which consists of a benzothiazole skeleton with α‐naphthylvinyl and tosyl groups at positions 2 and 3, respectively, was prepared by palladium–copper‐catalyzed heteroannulation. The E configuration of the molecule about the vinyl C=C bond is established by the benzothiazole–naphthyl C—C—C—C torsion angle of 177.5 (4)°. The five‐membered heterocyclic ring adopts an envelope conformation with the Csp3 atom 0.380 (6) Å from the C2NS plane. The two S—C [1.751 (4) and 1.838 (4) Å] and two N—C [1.426 (5) and 1.482 (5) Å] bond lengths in the thiazole ring differ significantly. 相似文献
17.
Tuncer Hkelek Selen Bilge emsay Demiriz Bilgehan
zgü Zeynel Kl 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(11):o803-o805
The title compound {systematic name: 2,2′‐[1,3‐propanediyldioxydi‐o‐phenylenebis(nitrilomethylidyne)]diphenol}, C29H26N2O4, exists as the phenol–imine form in the crystal, and there are strong intramolecular O—H⋯N hydrogen bonds, with O⋯N distances of 2.545 (2) and 2.579 (2) Å. The C=N imine bond distances are in the range 1.276 (2)–1.279 (2) Å and the C=N—C bond angles are in the range 123.05 (16)–124.64 (17)°. The configurations about the C=N bonds are anti (1E). 相似文献
18.
Alison J. Edwards Eric Wenger 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(4):m230-m231
The crystal and molecular structures of the title compound, 3‐bromo‐3‐(dibenzylphenylphosphonio)‐2,2‐diphenyl‐5‐trifluoromethyl‐1H‐benzo[e][1,2]phosphanickelepine, [NiBr(C22H17F3P)(C20H19P)], which was obtained as the major regioisomer from insertion of HCCCF3 into the Ni—C bond of the five‐membered phosphanickelacycle [NiBr(o‐C6H4CH2PPh2‐κ2C,P){PPh(CH2Ph)2}], have been determined. Principal geometric data include the Ni—X bond lengths Ni—Br 2.3343 (4) Å, Ni—P 2.1867 (7) and 2.2094 (7) Å, and Ni—C 1.882 (3) Å, and the two trans angles P—Ni—P 171.55 (3)° and Br—Ni—C 176.88 (9)°. 相似文献
19.
Pranav R. Shirhatti Prof. Dilip K. Maity Surjendu Bhattacharyya Prof. Sanjay Wategaonkar 《Chemphyschem》2014,15(1):109-117
The C?H???Y (Y=hydrogen‐bond acceptor) interactions are somewhat unconventional in the context of hydrogen‐bonding interactions. Typical C?H stretching frequency shifts in the hydrogen‐bond donor C?H group are not only small, that is, of the order of a few tens of cm?1, but also bidirectional, that is, they can be red or blue shifted depending on the hydrogen‐bond acceptor. In this work we examine the C?H???N interaction in complexes of 7‐azaindole with CHCl3 and CHF3 that are prepared in the gas phase through supersonic jet expansion using the fluorescence depletion by infra‐red (FDIR) method. Although the hydrogen‐bond acceptor, 7‐azaindole, has multiple sites of interaction, it is found that the C?H???N hydrogen‐bonding interaction prevails over the others. The electronic excitation spectra suggest that both complexes are more stabilized in the S1 state than in the S0 state. The C?H stretching frequency is found to be red shifted by 82 cm?1 in the CHCl3 complex, which is the largest redshift reported so far in gas‐phase investigations of 1:1 haloform complexes with various substrates. In the CHF3 complex the observed C?H frequency is blue shifted by 4 cm?1. This is at variance with the frequency shifts that are predicted using several computational methods; these predict at best a redshift of 8.5 cm?1. This discrepancy is analogous to that reported for the pyridine‐CHF3 complex [W. A. Herrebout, S. M. Melikova, S. N. Delanoye, K. S. Rutkowski, D. N. Shchepkin, B. J. van der Veken, J. Phys. Chem. A 2005 , 109, 3038], in which the blueshift is termed a pseudo blueshift and is shown to be due to the shifting of levels caused by Fermi resonance between the overtones of the C?H bending and stretching modes. The dissociation energies, (D0), of the CHCl3 and CHF3 complexes are computed (MP2/aug‐cc‐pVDZ level) as 6.46 and 5.06 kcal mol?1, respectively. 相似文献
20.
M. Sc. Benjamin Scheibe Clemens Pietzonka M. Sc. Otto Mustonen Prof. Dr. Maarit Karppinen Prof. Dr. Antti J. Karttunen Prof. Dr. Mihail Atanasov Prof. Dr. Frank Neese Dr. Matthias Conrad Prof. Dr. Florian Kraus 《Angewandte Chemie (International ed. in English)》2018,57(11):2914-2918
The D2h‐symmetric dinuclear complex anion [U2F12]2? of pastel green Sr[U2F12] shows a hitherto unknown structural feature: The coordination polyhedra around the U atoms are edge‐linked monocapped trigonal prisms, the UV atoms are therefore seven‐coordinated. This leads to a U–U distance of 3.8913(6) Å. A weak UV–UV interaction is observed for the dinuclear [U2F12]2? complex and described by the antiferromagnetic exchange Jexp of circa ?29.9 cm?1. The crystalline compound can be easily prepared from SrF2 and β‐UF5 in anhydrous hydrogen fluoride (aHF) at room temperature. It was studied by means of single crystal X‐ray diffraction, IR, Raman and UV/VIS spectroscopy, magnetic measurements, and by molecular as well as by solid‐state quantum chemical calculations. 相似文献