scholarly journals Semiempirical Calculation of the Rotational Barrier and Valence Force Constants in Fluorocarbonylsulfenyl Chloride

1983 ◽  
Vol 38 (1) ◽  
pp. 61-63
Author(s):  
A. H. Jubert ◽  
C. O. Della Védova ◽  
E. L. Varetti ◽  
O. E. Piro ◽  
P. J. Aymonino
Keyword(s):  
Semiempirical Calculation ◽  
Rotational Barrier ◽  
Force Constants ◽  
Cndo Method ◽  
Normal Coordinate ◽  
Valence Force ◽  
Related Compounds ◽  
Normal Coordinate Calculation

Abstract The rotational barrier about the C-S bond in fluorocarbonylsulfenyl chloride [FC(O)SCl] is investigated using the CNDO method. The results confirm the existence of planar eis and trans conformers and the higher stability of the latter, as suggested by previous vibrational results. The valence force constants in FC(O)SCl were also calculated and the values obtained compare favourably with results from a previous normal coordinate calculation and with those of related compounds.

Raman Spectra of Gases. XXII. (CH3)3SiCl, (CD3)3SiCl and Some Normal Coordinate Calculations on (CH3)3SiNCO and (CH3)3SiNCS

1979 ◽  
Vol 33 (4) ◽  
pp. 364-371 ◽  
Author(s):  
J. R. Durig ◽  
M. Jalilian
Keyword(s):  
Force Field ◽  
Raman Spectra ◽  
Force Constants ◽  
Normal Coordinate ◽  
Vibrational Coupling ◽  
Valence Force ◽  
Vibrational Assignments ◽  
Valence Force Field ◽  
Normal Coordinate Calculation

The Raman spectra (0 to 3600 cm−1) of gaseous (CH3)3SiCl and (CD3)3SiCl have been recorded. It was possible to resolve the symmetric and antisymmetric SiC3 deformations. The spectra are discussed in detail and previous vibrational assignments are compared. A normal coordinate calculation has been carried out utilizing a modified simple valence force field. The extent of the vibrational coupling has been determined. It is believed that the main force constants should be transferable to other substituted trimethylsilyl compounds and this transferability is demonstrated by some normal coordinate calculations for trimethylsilylisocyanate and trimethylsilylisothiocyanate.

Darstellung und Schwingungsspektren von cis- und trans-[OsXY(acac)2], X ≠ Y = Cl, Br, I sowie Normalkoordinatenanalyse von trans-[OsClBr(acac)2]/Synthesis and Vibrational Spectra of cis- and trans-[OsXY(acac)2], X ≠ Y = Cl, Br, I, and Normal Coordinate Analysis of trans-[OsClBr(acac)2]

1998 ◽  
Vol 53 (2) ◽  
pp. 227-231
Author(s):  
K. Dallmann ◽  
W. Preetz
Keyword(s):  
Normal Coordinate Analysis ◽  
Force Constants ◽  
Vibrational Modes ◽  
Normal Coordinate ◽  
Valence Force ◽  
Valence Force Field ◽  
Stretching Vibrations ◽  
Cis And Trans ◽  
Ir And Raman ◽  
Good Agreement

Abstract In the reaction of K2[OsX3 Y3] with boiling water/acetylacetone (1:1) the six mixed com­plexes cis-and trans-[OsX2 (acac)2] (X ≠ Y = Cl, Br, I) are formed, which have been purified by column chromatography with toluene on silica gel. The IR and Raman spectra (10K) show the intraligand vibrations of the acac groups with nearly constant frequencies and the stretching vibrations of OsO in the range 460-696, of OsCl at 315-345, of OsBr at 210-225, and of Osl at 160-175 cm-1 . A normal coordinate analysis based on a modified valence force field was performed for trans-[OsClBr(acac)2] and the vibrational modes have been assigned. With a set of 32 force constants, taking into account the intraligand vibrations, a good agreement between observed and calculated frequencies has been achieved. The valence force constants are fd (OsCl•) = 1.75, fd(OsBr′) = 1.63 and fd (OsO) = 3.27 mdyn/Å.

Kristallstrukturen, Schwingungsspektren und Normalkoordinatenanalysen von trans-[PtX2(acac)2], X = CI, Br, I, SCN / Crystal Structures, Vibrational Spectra and Normal Coordinate Analyses of trans-[PtX2(acac)2], X = Cl, Br, I, SCN

1996 ◽  
Vol 51 (10) ◽  
pp. 1400-1406 ◽  
Author(s):  
D. Rickert ◽  
W. Preetz
Keyword(s):  
Crystal Structures ◽  
Normal Modes ◽  
Force Constants ◽  
Monoclinic Space Group ◽  
Normal Coordinate ◽  
Triclinic Space Group ◽  
Valence Force ◽  
Space Group ◽  
X Ray ◽  
Modes Of Vibration

The crystal structures of trans-[PtCl2(acac)2](monoclinic, space group P21/c, a - 7.616(5), b = 12.759(5), c = 7.892(5) Å, β = 118.459(5)°, Z = 2), trans-[PtBr2(acac)2] (triclinic, space group P1̅, a = 7.502(5), b = 7.665(5), c = 8.155(5) Å, α = 114~508(5), β = 94.537(5), γ = 117.669(5)°. Z = 1) and trans-[Pt(SCN)2(acac)2] (triclinic, space group P1̅ , a = 7.9095(10), b = 7.9393( 10), c = 7.9631 Å, a = 114.051 (10), β = 100.955(10), γ = 100.573(10)°, Z = 1) have been determined by single crystal X-ray diffraction analysis. The crystal structure of trans- [Ptl2(acac)2] is known from the literature. To enhance the spectroscopic resolution, the IR and Raman spectra of the four complexes have been measured at low temperature (10 K). Using the X-ray data, normal coordinate analyses based on a modified valence force field have been performed and the normal modes of vibration for the octahedral skeleton [PtX2O4] have been assigned. With a set of 19 or 23 force constants taking into account the inner-ligand vibrations a good agreement between observed and calculated frequencies has been achieved. The valence force constants are e.g.fd (PtCl) = 2.16, fd (PtBr) = 1.45, fd (PtI) = 1.01, fd (PtS) = 1.80 mdyn/Å, and fd (PtO) ranges from 1.89 to 1.91 mdyn/Å.

Kristallstrukturen, Schwingungsspektren und Normalkoordinatenanalysen von Tetrahalogenooxalatoosmaten (IV), [OsX4(ox)]2-, X = Cl, Br, I / Crystal Structures, Vibrational Spectra and Normal Coordinate Analyses of Tetrahalogenooxalatoosmates (IV), [OsX4(ox)]2-, X = Cl, Br, I

1997 ◽  
Vol 52 (3) ◽  
pp. 315-322 ◽  
Author(s):  
W. Preetz ◽  
A. Krull
Keyword(s):  
Crystal Structures ◽  
Normal Modes ◽  
Force Constants ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Normal Coordinate ◽  
Valence Force ◽  
Space Group ◽  
X Ray ◽  
Modes Of Vibration

Abstract The crystal structures of [(C5H5N)2CH2][OsCl4(ox)] (monoclinic, space group I2/m, a = 10.260(5), b = 13.841(5), c = 12.273(5) Å, β = 92.050(5)°, Z = 4), [(C5H5N)2CH2][OsBr4(ox)]·H2O(monoclinic, space group P21/n, a = 11.666(3),b = 11.591(5), c = 14.926(2) Å, β = 102.45(2)°, Z = 4) and [P(C6H5)4]2 [OsI4(ox)]·2CH2Cl2 (triclinic, space group P1̄, a = 14.597(2), b = 11.9185(9), c = 22.5624(14) Å, α = 80.284(8), β = 78.903(8), γ = 69.432(8)°, Z = 2) have been determined by single crystal X-ray diffraction analysis. The IR and Raman spectra of the three complexes were measured at room temperature. Using the molecular parameters of the X-ray determinations normal coordinate analyses based on a modified valence force field have been performed and the normal modes of vibration are assigned. With a set of 25 force constants and taking into account the innerligand vibrations a good agreement between observed and calculated frequencies has been achieved. The valence force constants of the X-Os-X axis are fd(OsCl) = 1.77, fd(OsBr) = 1.48, fd(OsI) = 1.0 mdyn/Å, of the X′-Os-O• axes are fd(OsCl′) = 1.88, fd(OsBr′) = 1.6, fd(OsI′) =1.1 mdyn/Å and fd(OsO•) ranges from 2.7 to 2.8 mdyn/Å.

Kristallstrukturen, Schwingungsspektren und Normalkoordinaten- analysen von cis- und trans-[OsX2(acac)2], X = Cl, Br, I / Crystal Structures, Vibrational Spectra and Normal Coordinate Analyses of cis- and trans-[OsX2(acac)2], X = Cl, Br, I

1997 ◽  
Vol 52 (8) ◽  
pp. 965-974 ◽  
Author(s):  
K Dallmann ◽  
W Preetz
Keyword(s):  
Crystal Structures ◽  
Normal Modes ◽  
Force Constants ◽  
Monoclinic Space Group ◽  
Normal Coordinate ◽  
Triclinic Space Group ◽  
Valence Force ◽  
Space Group ◽  
X Ray ◽  
Modes Of Vibration

The crystal structures of trans-[OsCl2(acac)2] (triclinic, space group P1̄, a = 7.4114(5), b = 7.6419(9), c = 7.9944(6) Å, α = 62.692(7), β = 87.687(6), γ = 60.667(6)°, Z = 1), trans-[OsBr2(acac)2] (triclinic, space group P1̄, a = 7.467(3), b = 7.621(3), c = 8.260(3) Å, α = 115.03(3), β = 92.78(3), γ = 117.91(3)°, Z = 1), cis-[OsCl2(acac)2] (monoclinic, space group C2/c, a = 13.8532(13), b = 7.7990(8), c = 13.6202(12) Å, β = 108.375(10)°, Z = 4) and cis-[OsBr2(acac)2] (monoclinic, space group C2/c, a = 13.944(2), b = 8.0347(13), c = 13.743(2) Å, β = 106.757(12)°, Z = 4) have been determined by single crystal X-ray diffraction analysis. To enhance the spectroscopic resolution, the IR and Raman spectra of the six complexes have been measured at low temperature (10 K). Using the molecular parameters of the X-ray determinations normal coordinate analyses based on a modified valence force field have been performed for trans-[OsCl2(acac)2], trans-[OsBr2(acac)2] and cis-[OsCl2(acac)2], and the normal modes of vibration assigned. With sets of 31 or 32 force constants, taking into account the innerligand vibrations, a good agreement between observed and calculated frequencies has been achieved. The valence force constants for the X-Os-X axes are fd(OsCl) = 1.81, fd(OsBr) =1.61 mdyn/Å, and for the Cl′-Os-O* axis are fd(OsCl’) = 1.94, fd(OsO*) = 2.81 mdyn/Å and fd(OsO) ranges from 3.27 to 3.31 mdyn/Å.

Normalkoordinatenanalyse an Oktaederkomplexen des Typs [MXnY6-n]z-, M = Ru, Rh, Os, Ir, Pt; Χ ≠ Y = F, Cl, Br; n = 0-6; z = 1 -3 / Normal Coordinate Analysis on Octahedral Complexes of the Type [ΜΧnΥ6-n]z-, M = Ru, Rh, Os, Ir, Pt; Χ ≠ Y = F, Cl, Br; n = 0-6; z = 1-3

1991 ◽  
Vol 46 (9) ◽  
pp. 1200-1206 ◽  
Author(s):  
K. Irmer ◽  
W. Preetz
Keyword(s):  
Force Field ◽  
Normal Coordinate Analysis ◽  
Force Constants ◽  
Geometric Isomers ◽  
Normal Coordinate ◽  
Valence Force ◽  
Valence Force Field

Normal coordinate analyses for all compounds of the series [MXnY6-1]z-, M = Ru, Rh, Os, Ir, Pt; Χ ≠ Y = F, Cl, Br; n = 0-6; z = 1-3, including the geometric isomers for n = 2, 3, 4 have been performed, based on a general valence force field. For the isostructural species of the point symmetries Oh (n = 0, 6), D4h (2,4, trans), C4v (1, 5), C3v (3, fac), C2v (2,4, cis; 3, mer) sequences of decreasing frequencies are established. Due to the different trans influences X < Y (F < Cl < Br) in asymmetric axes X′–M–Y′, the M–Y′ bonds are strengthened and the M – X′ bonds are weakened, as indicated by valence force constants for M – Y′ up to 21 % higher (Pt–Cl′), for M–X′ down to 18% lower (Pt–F′), as compared with the values calculated for symmetrical X–M–X and Y–M–Y axes, respectively. The influence of the different central ions and their oxidation numbers on the force field is discussed.

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