Next Article in Journal
Determination of Trace Level of cAMP in Locusta Migratoria Manilensis Meyen by HPLC with Fluorescence Derivation
Previous Article in Journal
"Int. J. Mol. Sci. 2006, 7, 131-154" is republished as "Int. J. Mol. Sci. 2006, 7, 231-254"
 
 
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

A Comparative X-ray Diffraction Study and Ab Initio Calculation on RU60358, a New Pyrethroid

by
Fodil Hamzaoui
1,
Abdelkader Chouaih
1,
Philippe Lagant
2,
Ouassila Belarbi
1 and
Gérard Vergoten
2,*
1
Laboratoire SEA2M, Département de Chimie, Université de Mostaganem, 27000 Mostaganem, Algeria
2
UMR CNRS 8576 Glycobiologie Structurale et Fonctionnelle, Université des Sciences et Technologies, 59655 Villeneuve d’Ascq, France
*
Author to whom correspondence should be addressed.
Int. J. Mol. Sci. 2006, 7(8), 255-265; https://doi.org/10.3390/i7080255
Submission received: 28 February 2006 / Revised: 12 April 2006 / Accepted: 30 July 2006 / Published: 9 August 2006

Abstract

:
The crystal structure of RU60358, C20H21NO3, has been determined using X-ray diffraction to establish the configuration and stereochemistry of the molecule around the C15-C16 triple bond. The compound crystallises in the orthorhombic space group P212121, a = 7.7575, b = 11.3182, c = 21.3529Å, V = 1874.80Å3 and Z = 4. The structure has been refined to a final R = 0.068 for the observed structure factors with I ≥ 3σ (I). The refined structure was found to be significantly non planar. A comparative study, using the ab initio calculations of the structure at B3LYP/6-31G** levels of theory, shows good geometrical agreement with the X-ray diffraction data. Standard deviations between the calculated and experimental bond values have been shown to be 0.01 Å and 0.5° for bond angles. Vibrational wavenumbers were obtained from a normal mode analysis using the ab initio calculations.

1. Introduction

The structures of pyrethroids compounds obtained from experimental X-ray diffraction data has been investigated by several authors [1,2,3,4]. Considerable progress has been made in relating the structure of pyrethroids with their biological activity, but improvement of such concepts requires reliable information on molecular shape (configuration, bond lengths and angles and conformation). Biological activity in pyrethroids is related to molecular structure and depends strongly on the stereochemistry adopted by the asymmetric centers [5,6,7]. In this context the compound RU60358 appears as an useful intermediate in the synthesis of some pyrethroid insecticides [8]. The study of the conformation of this molecule may yield information about the mechanism of its biological activity [9,10]. In this paper, we propose a comparative study between the experimental X-ray diffraction data and the optimized geometry predicted from ab initio molecular orbital calculations performed on the compound RU60358. Vibrational wavenumbers were then consequently predicted and correct assignments obtained.
Ijms 07 00255 i001

2. Results and discussion

2.1. Description of the crystal structure

The displacement ellipsoid plot with the numbering scheme for the title compound is shown in Figure 1. Figure 2 shows a perspective view of the crystal packing in the unit cell. Selected X-ray diffraction data summarize bond lengths in Table 1 and bond angles in Table 2.
Figure 1. Perspective view of the molecule showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as small spheres of arbitrary radii.
Figure 1. Perspective view of the molecule showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as small spheres of arbitrary radii.
Ijms 07 00255 g001
Figure 2. A perspective view of the crystal packing in the unit cell.
Figure 2. A perspective view of the crystal packing in the unit cell.
Ijms 07 00255 g002
Table 1. Selected bond distances (Å) by X-ray and theoretical calculations
Table 1. Selected bond distances (Å) by X-ray and theoretical calculations
Atom 1Atom 2Distance (Å)
X-rayB3LYP/6-31G**
C1C21.395 (10)1.433
C1 C101.395 (11)1.381
C1 C111.474 (12)1.472
C2C31.410 (09)1.416
C2C71.395 (11)1.433
C3C41.395 (13)1.388
C4C51.395 (10)1.428
C4 C151.429 (10)1.428
C5C61.395 (10)1.371
C6C71.395 (09)1.422
C7C81.395 (11)1.418
C8C91.395 (11)1.375
C9 C101.395 (09)1.412
C11N1.278 (13)1.290
C11 C121.514 (15)1.497
C12O11.292 (10)1.351
C12O21.152 (10)1.210
C13O11.439 (12)1.436
NO31.376 (09)1.374
C14O31.427 (11)1.467
C15 C161.163 (13)1.213
C16 C171.467 (12)1.459
C17 C181.439 (12)1.548
C17 C191.469 (11)1.541
C17 C201.531 (13)1.549
Table 2. Selected bond angles (°) by X-ray and theoretical calculations
Table 2. Selected bond angles (°) by X-ray and theoretical calculations
Atom 1Atom 2Atom 3Angle (°)
X-rayB3LYP/6-31G**
C2C1 C10120.0 (8)119.8
C2C1 C11123.5 (5)121.1
C10C1 C11116.2 (8)119.1
C1C2C3120.2 (6)122.6
C1C2C7120.0 (7)118.5
C3C2C7119.8 (7)118.7
C2C3C4120.0 (5)121.5
C3C4C5120.0 (5)119.2
C3C4 C15122.1 (6)120.9
C5C4 C15117.9 (8)119.9
C4C5C6120.0 (8)120.4
C5C6C7120.4 (7)121.2
C2C7C6119.8 (9)118.8
C2C7C8120.0 (5)119.6
C6C7C8120.2 (6)121.6
C7C8C9120.0 (5)120.6
C8C9 C10120.0 (7)120.1
C16 C17 C19111.5 (9)109.4
C16 C17 C20107.7 (9)109.3
C18 C17 C19110.5 (8)109.7
C18 C17 C20107.3 (5)109.6
C19 C17 C20107.2 (4)109.5
C1 C10C9120.0 (6)121.2
C1 C11N126.9 (8)125.7
C1 C11 C12121.6 (5)121.4
N C11 C12111.5 (4)112.9
C12O1 C13117.0 (9)115.0
NO3 C14108.5 (5)109.2
C11NO3110.8 (7)112.6
C11 C12O1110.6 (7)110.5
C11 C12O2126.0 (9)125.7
O1 C12O2123.4 (5)123.8
C4 C15C16174.8 (9)180.5
C15 C16C17179.3 (6)180.1
C16 C17C18112.6 (7)109.6

2.2. Optimized geometry

Calculated geometric parameters at B3LYP/6-311G** are equally displayed into Table 1 and Table 2. From the theoretical values, it is noteworthy that most of the optimized bond lengths have slightly larger values than the corresponding experimental ones, due to the fact that theoretical calculations imply isolated molecules in gaseous phase state while experimental results refer to molecules in the solid state. Comparing theoretical bond angles with those given in experimental data, the B3LYP calculated values correlate in a good agreement. In spite of the differences, calculated geometric parameters represent a good approximation and can provide a starting point to calculate other parameters, such as vibrational wavenumbers, as will be described below.

2.3. Vibrational wavenumbers

The theoretically derived DFT vibrational wavenumbers corresponding to the optimized geometry can be expressed in the more convenient internal coordinate space for a description of the potential energy distribution (PED) via the Redong Program [11]. This algorithm uses least square methods to fit the theoretical vibrational wavenumbers to the experimental ones by introducing scaling factors associated to the various types of force constants.
Table 3 displays the potential energy distribution among internal coordinates obtained for the scaled DFT normal modes analysis (scaling factor = 0.962). This last value is currently recommended to obtain correct vibrational wavenumbers and adequate assignments of the PED [12].
The νC=N stretching mode of the imine part is generally observed in the 1665-1675 cm-1 range by Raman spectroscopy. The presence of neigbouring aryl groups lowers this value by 10-20 cm-1. Using a general scaling factor of 0.962 leads to the 1594 cm-1 DFT theoretical wavenumber (1657 cm-1 without scaling). This assignment is in accordance with the Raman wavenumbers as reported by Dollish et al. [13]. The imine moiety participates also to Raman bands around 1274 cm-1, presently calculated at 1266 cm-1. Other vibrational modes of interest implying the imine group are predicted to occur at 314 cm-1 (δ(N-O-CH3), at 971.6 cm-1 (νN-O) and at 997 cm-1 for the (νO-CH3) stretching mode.
The alkyne νCΞC stretching mode displays intense Raman bands in the 2220-2240 cm-1 range. The DFT corresponding wavenumber is obtained presently at 2243 cm-1. Keeping the same 0.962 scaling factor, the δC-CΞC in plane bending mode is predicted to occur at 474.6 cm-1, this frequency being quite comparable to the experimental range centered at 484 cm-1[13].
The ester group gives a predicted DFT νC=O stretching mode located at 1749 cm-1 corresponding to current experimental bands obtained in the 1730-1750 cm-1 range. The associated νC-O stretching mode is predicted at 1215 cm-1, this value appearing quite consistent with experimental data (1200-1220 cm-1). The in plane δ(O-C=O) bending mode is observed in the 750-775 cm-1 range using Raman spectroscopy and the DFT derived corresponding wavenumber is obtained here at 752 cm-1. The δ(C-C=O) and δ(C-O-CH3) in plane bending motions are predicted to stand at 374 and 298 cm-1 respectively, these two wavenumbers being very close to the experimental data (300-340 cm-1).
For the aromatic part of the molecule, we can observe a rough accordance between the DFT predicted wavenumbers (and corresponding vibrational assignments) and the experimental data obtained from vibrational analyses on benzene derivatives [14]. The pyrethoid molecule displays numerous and complex mixings of vibrational modes between the two rings and their substituents.
The ν8 degenerate (8a, 8b) mode (in Wilson’s notation) [14] implying νCA-CA ring stretching motions is generally observed around 1596 cm-1. DFT calculations predict contributions from these two modes at 1558 and in the1582-1594 cm-1 range.
νCA-CA and δCH modes related to the δ19 degenerate mode [14] give rise to experimental vibrational bands around 1485 cm-1. The DFT derived 1484.6 cm-1 wavenumber corresponds correctly to such an assignment.
The mode 4 of benzene generally gives rise to weak Raman and strong IR bands. This out of plane mode (γCH) is generally observed to occur around 693 cm-1. The DFT wavenumber obtained presently at 738 cm-1 could correspond to this mode.
The intense νCA-CA (ν1 in Wilson’s notation) ring stretching mode appears in Raman spectra at 992 cm-1. This mode has been identified as being slightly dependent of δCH bending motions. Due to large mixings of vibrational motions taking place between the two rings, an attempt in the assignment of this mode from DFT calculation is given here at 971.6 cm-1.
From DFT vibrational analyses, out of plane γCH motions display in and out of phase motions depending on the ring. These modes are predicted at 819 and 825 cm-1. Other contributions to the out of plane motions have been also obtained theoretically at 887 and 933 cm-1. An attempt to assign these wavenumbers to the ν5, 10a and 10b normal modes as observed for benzene derivatives [13,14,15] remains however difficult.
Table 3. Normal modes analysis of RU60358 from DFT (RB3LYP/6-31G (d, p).
Table 3. Normal modes analysis of RU60358 from DFT (RB3LYP/6-31G (d, p).
ν (cm-1)*Assignmentsν (cm-1)* Assignments
10.6τC17CT, τC1C11, δC4,C15,C16702.1νCACA, νC1C11, δCACACA, δCT,O,N
13.8τC1C11723.4νsCT(CH3)3 (tBu)
24.7τC11C12738.1γCAH, γCACA, τCACA
30.9δCA,C4,C15 749.6γC12=O2, γC11N, δC12=O2
35.4τC4C15, τC1C2, δC15,C16,C17752.2γC12=O2, δC12=O2, δC12O1CT, νC12O1
61.9τC1C11, τC1CA, τC4C15778.7γCAH, γC1C11, γCACA
67.2τNO, γC11N819.0γCAH#, γCACA
98.1τC14O, τNO 825.3δCACACA(ring 1), γCAH##, νCACA
102.4δC15,C16,C17, τC6C7 832.4δCACACA, νC16C17, νC17CT
108.4δC12,C11,N, τO1C13, δC1,C11,C12873.0γC3H, τ CACA
112.8τO1C13887.1γCAH(ring 1)
129.4δC4,C15,C16, τO1C12 897.4νO3N, νO3CT, νO1C12, νO1CTC17CT
158.9τC2C7, τC2C3, τC7C8 897.8νC17CT, ρ(tBu)
163.6τO1C12, τO3C14, τON899.7νC17CT
173.9τON, δC4,C15,C16, τO3C14926.0νC17CT, νNO3, νC4CA, δCACACA
185.2τC6C7, τC1C2, τC4C15933.0γCAH( all rings)
218.6νC4C15, νC16C17, δC3,C4,C5933.8ρ(tBu)
221.9τC17CH3 (tBu)942.9γCAH(all rings)
246.0δC12,O1,C13, δO1,C12,C11, τC4C15971.6νO3N, νCACA, δCACACA, δCAH, δC11,N,O3
269.5τC17CH3(tBu)996.9νCTO1, νO3CT
276.5τC17CH3(tBu)1013.9ρ(tBu)
279.4δC12,O1,C13, νC1C11, δC1,C11,C121014.1ρ(tBu)
297.8τC11N, δC12,O1,C13, τO1C121045.1νCACA, νO3CT, νO3N
314.3δC14,O,N, νC1C11, τC11N, δCACACA1060.2νO3CT, νCACA, νO3N
332.4δCT,C17,CT(tBu) 1095.2νC12O1, νCTO1, δC11,N,O3, νO3CT
336.7δCT,C17,CT(tBu)1130.9ρC14H3
357.3δCT,C17,CT(tBu), δC1,C2,C3, δC6,C7,C81133.8ρC13H3
367.4νC11C12, δC11,N,O, δC12,C11,N1134.5δCAH, νCACA(ring 2)
373.6δC11,C12,O2, δC12,O1,C13 1148.6δCAH, νCACA(ring 1)
387.9τC4C15, τC4CA, γC6C71163.1ρC13H3
424.2δCT,C17,CT(tBu)1172.1ρC14H3
425.2τCACA, γCAH1181.6ρ(tBu)
474.6δC4,C15,C16, δC16,C17,CT, γC-N1183.4ρ(tBu)
501.5δC16,C17,CT, δCA,C4,C15, δCACACA1184.8νO1C12, ρC14H3, νC4C15, ρC13H3, ρ(tBu)
512.7δC16,C17,CT, δC15,C16,C17, τCACA1196.4νCACA, δCAH
528.1γCACA, τCACA, γC1C11, δC14,O3,N1215.3δCAH, νO1C12
545.3τC4C15, δC15,C16,C17, δC16,C17,CTCACA, γC4C151241.2δCAH(ring 2)
550.4δC4,C15,C16, δC16,C17,CT1266.0νC11C12, νC1C11, νO1C12, δCAH(ring 1)
583.3τC11N, νC16C17, δCA,C1,C11, γC11N, γC12=O21270.9νC16C17, νC4C15, δCAH(ring 1)
590.2γC11N, τC11C12, γC12=O2, g C4C151303.8νCACA, δCAH
616.1δCACACA, δCT,O,N, νC17CT1352.3νCACA
652.7γC4C15, γC1C11, τCACA, γCAH1353.7dsCH3(tBu)
1354.4dsCH3(tBu)2243.4νC15C16
1364.7νCACA, δCAH2925.2νsCH3 (tBu)
1384.7δsCH3(tBu)2925.8νsCH3(tBu)
1416.2δsC14H32931.6νsC14H3
1421.4δsC13H32931.8νsC14H3, nsCH3(tBu)
1423.3δsC13H32947.1νsC13H3
1433.6δaCH3(tBu)2996.8νaCH3(tBu)
1434.7δaC14H32997.4νaCH3(tBu)
1436.2νCACA, δCAH 3002.5νaCH3 (tBu)
1437.8δaC13H33006.2νaC14H3
1443.9δaCH3 (tBu)3006.8νaCH3(tBu)
1444.4δaCH3(tBu)3010.2νaCH3(tBu)
1451.5δaC13H33010.9νaCH3(tBu)
1456.3δaCH3(tBu)3020.7νaC13H3
1456.8δaCH3(tBu) 3041.2νaC14H3
1457.4δaC14H33054.8νaC13H3
1474.6δaCH3(tBu)3056.3νCAH(all rings)
1484.6νCACA, δCAH3059.4νCAH(all rings)
1557.7νCACA, δCAH3068.8νCAH(ring 1)
1582.1νC11N, νCACA3083.6νCAH(ring 1)
1593.9νC11N, νCACA3087.9νCAH(ring 2)
1609.1νCACA3096.9νCAH(ring 2)
1749.0νC12=O2
(tBu) : Tertiobutyl group. ring 1 is defined by atoms C1, C2, C7, C8, C9 and C10 . ring 2 is defined by atoms C2, C3, C4, C5, C6 and C7# CA-H out of plane bending (in phase in each ring but out of phase between rings)## CA-H out of plane bending in phase for both rings. ν : stretching modes (νs : symmetric, νa : antisymmetric)δ : in plane valence angle bending, (δs : symmetric, δa : antisymmetric). τ, γ, ρ : torsion, out of plane wagging and rocking deformations respectively(*scaled vibrational frequencies originate from application of a general scaling factor (0.962) applied to all types of internal force constants).

3. Experimental Section

3.1 X-ray structure determination

A needle-shaped crystal of dimensions 0.32 ´ 0.27 ´ 0.10 mm was mounted on a Philips Enraf Nonius four-circle diffractometer. Data were collected with MoKa radiation. Intensities for 3082 reflections were measured by the w/2q scan method, scan width = 1.4°, scan speed 0.02°s-1 and 0 < h < 10, 0 < l < 15, 0 < k < 30. Lattice parameters from 25 reflections (2 < q < 30). Three standard reflections monitored every two hours, no significant variation was observed. The data were corrected for Lorentz and Polarization effects, but not for absorption or extinction. The structure was determined by considering 1583 reflections with I ≥ 3σ(I).
The structure was solved by direct methods implemented in Shelxs [16]. A Fourier synthesis revealed the complete structure, which was refined by full-matrix least squares. All non-H atoms refined anisotropically. The H atoms were located from a difference Fourier map and included in the refinement with the isotropic temperature factor of the carrier atom. Fig. 1 shows the atomic numbering of the molecule.
The final least-squares cycle using Shelxl [17] gave R = 0.068 for all reflections with I ≥ 3σ(I), wR = 6.8%, S = 1.25, w =1. (Δρ)min= -0.271 eÅ-3 , (Δρ)max = 0.380 eÅ-3.
Atomic scattering factors for heavy atoms were taken from International Tables for X-ray Crystallography [18] while the factors for H were those of Stewart, Davidson & Simpson [19]. A summary of the key crystallographic information is given in Table 4.
Crystallographic data has been deposited with the Cambridge Crystallographic Data Centre with the deposition number CCDC 272 478. These data can be obtained free of charge from The Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.

3.2. Computational methods

Molecular modeling, geometry optimizations, harmonic wavenumbers for the normal modes of vibration and force field in cartesian coordinates were calculated on RU60358 using the Density Functional Theory and the B3LYP [20,21] (Becke’s three parameter Hybrid Functional using the LYP correlation Functional) functional together with the 6-31G(d,p) basis set. Such combination is being used with good results for organic molecules [22] and hydrogen-bonded systems [23,24,25], and represents a good compromise between economy of computational resources, accuracy and applicability to many-atoms molecules. All the calculations were made with the Gaussian 03 set of programs [26]. Ab initio geometry optimization on RU60358 was performed starting from the geometry found in the X-ray refinement.
Table 4. Crystallographic data and experimental details for C20H21NO3
Table 4. Crystallographic data and experimental details for C20H21NO3
Crystal data
FormulaC20H21NO3
Molecular weight 323.34
Crystal system Orthorhombic
Space groupP212121
Unit cell determinationLeast-squares fit from 25 reflections (2° < q < 30°)
a (Å)7.7575
b (Å)11.3182
c (Å)21.3529
V (Å3)1874.80
Z4
dcalc(g. cm-3)1.16
mu (mm-1) 0.077
Crystal colourColourless
Crystal size 0.32 ´ 0.27 ´ 0.10 ( mm)
Experimental data
Technique Four circles diffractometer, CAD4 Enraf Nonius kappa geometry
Graphite oriented monochromator : Moka
λ = 0.71070 Å, ω/2q scan
Scanning range for θ2.04 ¾ 29.96
Number of reflections measured 3082
Number of reflections observed 1583 (I ≥ 3σ(I)criterion)
Limiting indicesh 0 ® 10
k 0 ® 15
l 0 ® 30
T (K)293
Refinement data
Refinement methodFull-matrix least-squares on F
Final R indicesR=0.068, wR=0.068
S1.249
H atoms constrained refinement
Parameters 224
(Δ/σ)max0.380
(Δρ)min-0.271 eÅ-3
(Δρ)max0.380 eÅ-3
Extinction No extinction correction applied

References

  1. Baert, F.; Guelzim, A. X-ray Structure of the Pyrethroid Insecticide { 1R-[1 α(S*),2α] }-2-(2,2-Dichlorovinyl)-3,3-dimethylcyclopropanecarboxylic Acid Cyano(3-phenoxyphenyl)methyl Ester (RU 24501). Acta Cryst. C 1991, 47, 606–608. [Google Scholar] [CrossRef]
  2. Baert, F.; Guelzim, A.; Germain, G. Structure of Two Pyrethroid Insecticides: Acrynathryn (RU 38702) and a Derivative (RU 38181). Acta Cryst. C 1991, 47, 768–771. [Google Scholar] [CrossRef]
  3. Hamzaoui, F.; Lamiot, J.; Baert, F. X-ray Structure of a New Pyrethroid RU 52259. Acta Cryst. C 1993, 49, 818–820. [Google Scholar] [CrossRef]
  4. Hamzaoui, F.; Baert, F. A New Pyrethroid Insecticide RU41414. Acta Cryst. C 1996, 52, 689–690. [Google Scholar] [CrossRef]
  5. Tessier, J. Recent Advances in the Chemistry of Insect Control; Janes, N.F., Ed.; The Royal Society of Chemistry: London, 1985; pp. 26–52. [Google Scholar]
  6. Tessier, J.; Teche, A.; Demoute, J. P. Pesticide Chemistry: Human Welfare and the Environment; Miyamoto, J., Kearney, P.C., Eds.; Pergamon Press: Oxford, New York, 1983; Vol. 1, pp. 95–100. [Google Scholar]
  7. Tessier, J.; Teche, A.; Demoute, J. P. Proceedings of the 5th IUPAC International Congress of Pesticide Chemistry; Miyamoto, J., Kearney, P.C., Eds.; Pergamon Press: Oxford, New York, 1983; pp. 197–202.
  8. Babin, D.; Demassey, J.; Demoute, J. P.; Dutheil, P.; Terrie, I.; Tessier, J. A New Way toward Zα,β Unsaturated Esters: A Pyrethroid Application. J. Org. Chem. 1992, 57, 584–589. [Google Scholar] [CrossRef]
  9. Elliott, M. The Relationship between the Structure and the Activity of Pyrethroids. Bull. Wld Hlth Org. 1970, 44, 315–324. [Google Scholar]
  10. Elliott, M.; Farnham, A. W.; Janes, N. F.; Needham, P. H.; Pulman, D. A. Insecticidal Activity of the Pyrethrins and Related Compounds. Pestic. Sci. 1975, 6, 537–542. [Google Scholar] [CrossRef]
  11. Allouche, A.; Pourcin, J. Ab initio calculation of vibrational force fields: Determination of non-redundant symmetry coordinates by least-square component analysis. Spectrochim. Acta, Part A 1993, 49, 571–580. [Google Scholar] [CrossRef]
  12. Pulay, P. Possibilities and limitations of ab initio calculation of vibrational spectra. J. Mol. Struct. 1995, 347, 293–308. [Google Scholar] [CrossRef]
  13. Dollish, F. R.; Fateley, W. G.; Bentley, F. F. Characteristic Raman Frequencies of Organic Compounds; John Wiley& Sons: New York, 1974. [Google Scholar]
  14. Varsányi, G.; Szöke, S. Vibrational Spectra of Benzene Derivatives; Academic Press: New York, 1969. [Google Scholar]
  15. Wilson, E. B., Jr. The Normal Modes and Frequencies of Vibration of the Regular Plane Hexagon Model of the Benzene Molecule. Phys. Rev. 1934, 45, 706–714. [Google Scholar] [CrossRef]
  16. Sheldrick, G.M. SHELXS97: Program for crystal structure determination; University of Göttingen: Germany, 1997. [Google Scholar]
  17. Sheldrick, G. M. SHELXL97: Program for crystal structure determination; University of Göttingen: Germany, 1997. [Google Scholar]
  18. Brown, P. J.; Fox, A. G.; Maslen, E. N.; O'Keefe, M. A.; Willis, B. T. M. International Tables for X-ray Crystallography; Wilson, A. J.C., Prince, E., Eds.; Kluwer Academic Publishers: Dordrecht, 1999; Vol. C, pp. 548–589. [Google Scholar]
  19. Stewart, R. F.; Davidson, E. R.; Simpson, W. T. Coherent X-Ray Scattering for the Hydrogen Atom in the Hydrogen Molecule. J. Chem. Phys. 1965, 42, 3175–3187. [Google Scholar] [CrossRef]
  20. Becke, A. D. Density-functional thermochemistry. III. The role of exact exchange. J. Chem. Phys. 1993, 98, 5648–5652. [Google Scholar] [CrossRef]
  21. Lee, C.; Yang, W.; Parr, R. G. Development of the Colle-Salvetti correlation-energy formula into a functional of the electron density. Phys. Rev. B 1988, 37, 785–789. [Google Scholar]
  22. Rauhut, G.; Pulay, P. Transferable scaling factors for density functional derived vibrational force fields. J. Phys. Chem. 1995, 99, 3093–3100. [Google Scholar] [CrossRef]
  23. Gómez Marigliano, A. C.; Varetti, E. L. Self-Association of Formamide in Carbon Tetrachloride Solutions: An Experimental and Quantum Chemistry Vibrational and Thermodynamic Study. J. Phys. Chem. A 2002, 106, 1100–1106. [Google Scholar] [CrossRef]
  24. Gómez Marigliano, A.C.; Varetti, E.L. Unpublished results.
  25. Sim, F.; St.-Amant, A.; Papai, I.; Salahub, D. R. Gaussian density functional calculations on hydrogen-bonded systems. J. Am. Chem. Soc. 1992, 114, 4391–4400. [Google Scholar] [CrossRef]
  26. Frisch, M. J.; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.; Robb, M. A.; Cheeseman, J. R.; Montgomery, J. A., Jr.; Vreven, T.; Kudin, K. N.; Burant, J. C.; Millam, J. M.; Iyengar, S. S.; Tomasi, J.; Barone, V.; Mennucci, B.; Cossi, M.; Scalmani, G.; Rega, N.; Petersson, G. A.; Nakatsuji, H.; Hada, M.; Ehara, M.; Toyota, K.; Fukuda, R.; Hasegawa, J.; Ishida, M.; Nakajima, T.; Honda, Y.; Kitao, O.; Nakai, H.; Klene, M.; Li, X.; Knox, J. E.; Hratchian, H. P.; Cross, J. B.; Adamo, C.; Jaramillo, J.; Gomperts, R.; Stratmann, R. E.; Yazyev, O.; Austin, A. J.; Cammi, R.; Pomelli, C.; Ochterski, J. W.; Ayala, P. Y.; Morokuma, K.; Voth, G. A.; Salvador, P.; Dannenberg, J. J.; Zakrzewski, V. G.; Dapprich, S.; Daniels, A. D.; Strain, M. C.; Farkas, O.; Malick, D. K.; Rabuck, A. D.; Raghavachari, K.; Foresman, J. B.; Ortiz, J. V.; Cui, Q.; Baboul, A. G.; Clifford, S.; Cioslowski, J.; Stefanov, B. B.; Liu, G.; Liashenko, A.; Piskorz, P.; Komaromi, I.; Martin, R. L.; Fox, D. J.; Keith, T.; Al-Laham, M. A.; Peng, C. Y.; Nanayakkara, A.; Challacombe, M.; Gill, P. M. W.; Johnson, B.; Chen, W.; Wong, M. W.; Gonzalez, C.; Pople, J. A. Gaussian 03, Revision A.1. Gaussian, Inc.: Pittsburgh PA, 2003. [Google Scholar]

Share and Cite

MDPI and ACS Style

Hamzaoui, F.; Chouaih, A.; Lagant, P.; Belarbi, O.; Vergoten, G. A Comparative X-ray Diffraction Study and Ab Initio Calculation on RU60358, a New Pyrethroid. Int. J. Mol. Sci. 2006, 7, 255-265. https://doi.org/10.3390/i7080255

AMA Style

Hamzaoui F, Chouaih A, Lagant P, Belarbi O, Vergoten G. A Comparative X-ray Diffraction Study and Ab Initio Calculation on RU60358, a New Pyrethroid. International Journal of Molecular Sciences. 2006; 7(8):255-265. https://doi.org/10.3390/i7080255

Chicago/Turabian Style

Hamzaoui, Fodil, Abdelkader Chouaih, Philippe Lagant, Ouassila Belarbi, and Gérard Vergoten. 2006. "A Comparative X-ray Diffraction Study and Ab Initio Calculation on RU60358, a New Pyrethroid" International Journal of Molecular Sciences 7, no. 8: 255-265. https://doi.org/10.3390/i7080255

Article Metrics

Back to TopTop