Influence of substituents on bond lengths

Hayd, H.; Savin, H.; Stoll, A.; Preuß, H.; Becker, Gerd

doi:10.1016/0166-1280(88)87008-8

Cited by 7 publications

(5 citation statements)

References 25 publications

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“…Furthermore, from subsequent ab initio calculations some controversy , arose about the early interpretation and especially the role of d orbitals. Only about 10 years ago, a correct description of this phenomenon has been achieved with pseudopotential SCF calculations; additionally, the substitution effects turned out to be simulated very well by an external electrostatic fielda result confirming the simple model 14 mentioned above.…”

Section: Introductionsupporting

confidence: 54%

Element−Element Bonds. IX.¹ Structures of Tetrakis(trifluoromethyl)diphosphane and -diarsane: Experimental and Theoretical Investigations

et al. 1999

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X-ray structure determinations of tetrakis(trifluoromethyl)diphosphane (2c, mp -82 degrees C, triclinic, P&onemacr;; Z = 1, a = 529.7(3) pm, b = 681.6(2) pm, c = 802.8(3) pm, alpha = 108.58(1) degrees, beta = 99.66(1) degrees, gamma = 103.29(1) degrees, wR2 = 0.204) and -diarsane (3c, mp -52 degrees C, monoclinic, P2(1)/c; Z = 2, a = 769.5(3) pm, b = 750.0(3) pm, c = 960.7(2) pm, beta = 105.26(1) degrees, wR2 = 0.115), both at -100(3) degrees C, reveal the molecules to adopt the trans conformation in the solid. Compared with the tetramethyl derivatives, the E-E (224.6(2)/246.3(1) pm, E = P, As) and E-C (188.3(4)/201.3(7) pm) bonds are elongated by 4.5/4.8 pm and 3.4/3.4 pm, respectively. From gas electron diffraction studies of diphosphane 2c a mixture of 85(10)% trans and 15(10)% gauche conformers can be deduced; diarsane 3c shows the trans form exclusively. The molecular parameters (E-E, 224.8(11)/245.2(6); E-C, 189.6(4)/ 201.2(4) pm) agree excellently with those determined for the crystalline state. As a result of quantum chemical calculations at Hartree-Fock and hybrid density functional levels of theory using 6-311+G basis sets, the gauche conformer of hydrazine derivative 1c and the trans conformer of diarsane 3c are clearly lowest in energy. However, for diphosphane 2c the gauche and not the trans form is found to be slightly more stable. Variations of calculated E-E and E-C bond lengths are analyzed and compared with corresponding values of the parent compounds E(2)H(4) (1a to 3a) as well as the tetramethyl derivatives 1b to 3b.

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Section: Introductionsupporting

confidence: 54%

Element−Element Bonds. IX.¹ Structures of Tetrakis(trifluoromethyl)diphosphane and -diarsane: Experimental and Theoretical Investigations

et al. 1999

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“…These values are also consistent with the similar studies [22][23][24][25][26]. The changes in the bond length of the C-H bond on substitution may be due to a change in the charge distribution on the carbon atom of the benzene ring [27][28][29][30][31]. The C-Cl bond lengths (1.738 and 1.741 Å) are in good agreement with the mean value (1.741 ± 0.016 Å) [25].…”

Section: Molecular Geometrysupporting

confidence: 90%

“…The C-Cl bond lengths (1.738 and 1.741 Å) are in good agreement with the mean value (1.741 ± 0.016 Å) [25]. The optimized bond lengths of C-H and C-Cl for B3LYP with 6-311++G(d,p) method were also in good agreement for similar molecules [27,28,30,32]. In general, calculated geometric parameters are in good agreement with those obtained from experimental results.…”

Section: Molecular Geometrysupporting

confidence: 65%

Synthesis, characterization, crystal structure and theoretical studies of N-(2,4-dichlorobenzylidene)-3-methylbenzenamine

Aytekin¹,

Elmalı²,

Berber³

et al. 2016

AUBTD-A

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N-(2,4-dichlorobenzylidene)-3-methylbenzenamine (L6) was synthesized as single crystal and characterized by FT-IR, Raman, 1 H NMR, 13 C NMR and UV-VIS spectroscopy. The thermal stability of the title compound was also studied by thermogravimetric analysis (TGA) and differential thermal analysis (DTA) analyses. The optimized geometric parameters, conformational analysis, normal mode frequencies and corresponding vibrational assignments of L6 was theoretically examined by means of density functional theory (DFT) method using the Becke-3-Lee-Yang-Parr (B3LYP) exchangecorrelation functional and the 6-311G++(d, p) basis sets. The DFT based nuclear magnetic resonance (NMR) calculations were also performed to be used for assigning the 1 H and 13 C NMR chemical shifts of L6. Reliable vibrational assignments were investigated by the potential energy distribution analysis and the highest occupied and the lowest unoccupied molecular orbitals (HOMO and LUMO) of L6 was predicted. A good consistency were obtained between the theoretically predicted structural parameters, vibrational frequencies and those obtained experimentally.

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“…For meta -substituted derivatives the correlation is worse (cc = 0.879), but the slope is still positive. Despite the fact that the electron-withdrawing substituents can make bonds longer by weakening them, these results can also be rationalized by a simple electrostatic model. , The three fluorine atoms in CF 3 cause the carbon atom to carry a high positive net charge. If another substituent at the para or meta position is electron-withdrawing, this makes the benzene ring partially positive.…”

Section: Resultsmentioning

confidence: 99%

Toward a Physical Interpretation of Substituent Effects: The Case of Fluorine and Trifluoromethyl Groups

et al. 2014

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The application of ab initio and DFT computational methods at six different levels of theory (MP2/cc-pVDZ, MP2/aug-cc-pVTZ, B3LYP/cc-pVDZ, B3LYP/aug-cc-pVTZ, M06/cc-pVDZ, and M06/aug-cc-pVTZ) to meta- and para-substituted fluoro- and trifluoromethylbenzene derivatives and to 1-fluoro- and 1-trifluoromethyl-2-substituted trans-ethenes allowed the study of changes in the electronic and geometric properties of F- and CF3-substituted systems under the impact of other substituents (BeH, BF2, BH2, Br, CFO, CHO, Cl, CN, F, Li, NH2, NMe2, NO, NO2, OH, H, CF3, and CH3). Various parameters of these systems have been investigated, including homodesmotic reactions in terms of the substituent effect stabilization energy (SESE), the π and σ electron donor-acceptor indexes (pEDA and sEDA, respectively), the charge on the substituent active region (cSAR, known earlier as qSAR), and bond lengths, which have been regressed against Hammett constants, resulting mostly in an accurate correspondence except in the case of p-fluorobenzene derivatives. Moreover, changes in the characteristics of the ability of the substituent to attract or donate electrons under the impact of the kind of moiety to which the substituent is attached have been considered as the indirect substituent effect and investigated by means of the cSAR model. Regressions of cSAR(X) versus cSAR(Y) for any systems X and Y allow final results to be obtained on the same scale of magnitude.

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Influence of substituents on bond lengths

Abstract: Pseudopotential SCF calculations for YaC-X, Y =H, F; X=H, F, CI, PH 2 , PF 2 and a simple model, simulating the substituents by a homogeneous, electric field, are presented in order to rationalize the substitution effect on the C-X bond.

Cited by 7 publications

References 25 publications

Element−Element Bonds. IX.¹ Structures of Tetrakis(trifluoromethyl)diphosphane and -diarsane: Experimental and Theoretical Investigations

Element−Element Bonds. IX.¹ Structures of Tetrakis(trifluoromethyl)diphosphane and -diarsane: Experimental and Theoretical Investigations

Synthesis, characterization, crystal structure and theoretical studies of N-(2,4-dichlorobenzylidene)-3-methylbenzenamine

Toward a Physical Interpretation of Substituent Effects: The Case of Fluorine and Trifluoromethyl Groups

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Influence of substituents on bond lengths

Abstract: Pseudopotential SCF calculations for YaC-X, Y =H, F; X=H, F, CI, PH 2 , PF 2 and a simple model, simulating the substituents by a homogeneous, electric field, are presented in order to rationalize the substitution effect on the C-X bond.

Cited by 7 publications

References 25 publications

Element−Element Bonds. IX.1 Structures of Tetrakis(trifluoromethyl)diphosphane and -diarsane: Experimental and Theoretical Investigations

Element−Element Bonds. IX.1 Structures of Tetrakis(trifluoromethyl)diphosphane and -diarsane: Experimental and Theoretical Investigations

Synthesis, characterization, crystal structure and theoretical studies of N-(2,4-dichlorobenzylidene)-3-methylbenzenamine

Toward a Physical Interpretation of Substituent Effects: The Case of Fluorine and Trifluoromethyl Groups

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Product

Resources

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Element−Element Bonds. IX.¹ Structures of Tetrakis(trifluoromethyl)diphosphane and -diarsane: Experimental and Theoretical Investigations

Element−Element Bonds. IX.¹ Structures of Tetrakis(trifluoromethyl)diphosphane and -diarsane: Experimental and Theoretical Investigations