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2-CN-C4H3S
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Nitrogen
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Nuclear
Quadrupole Coupling Constants |
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in 2-Cyanothiophene |
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Calculation of the nitrogen nqcc tensor in 2-cyanothiophene was made
here on molecular structures given by B3PW91/6-31G(2d,2pd) and B3P86/6-31G(3d,3p)
optimization. Calculated and (limited) experimental nqcc's are compared in Table 1. Structure
parameters are given in Table 2,
rotational constants in Table 3. |
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In Table 1, subscripts a,b,c refer to the principal axes of the inertia
tensor, subscripts x,y,z to the principal axes of the nqcc tensor.
The nqcc y-axis is chosen coincident with the inertia c-axis, these
are perpendicular to the plane of the molecule. Ø (degrees)
is the angle between its subscripted parameters. ETA = (Xxx
- Xyy)/Xzz. RSD is the residual standard deviation
of calibration of the B3PW91/6-311+G(df,pd) model for calculation of
the efg's/nqcc's. |
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Table
1. 14N nqcc's in 2-Cyanothiophene
(MHz). |
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Calculation was made on |
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the [a] B3PW91/6-31G(2d,2pd) opt structure, and |
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the [b] B3P86/6-31G(3d,3p) opt structure. |
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Calc. [a]
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Calc. [b] |
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Expt. [1]
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Xaa |
-
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4.139
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4.150
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-
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4.04(16)
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Xbb |
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2.548
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2.560
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Xcc |
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1.591
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1.591
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|Xab| |
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0.548
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0.537
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RSD |
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0.030 (1.3 %)
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0.030 (1.3 %) |
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Xxx |
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2.593
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2.602
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Xyy |
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1.591 |
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1.591 |
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Xzz |
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4.184
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4.193
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ETA |
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0.239
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0.241
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Øz,a |
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4.65
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4.55
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Øa,CN |
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4.82
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4.79
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Øz,CN |
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0.17
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0.24
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| Table 2. 2-Cyanothiophene and Thiophene. Structure parameters
(Å and degrees). |
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B3P86 |
B3PW91 |
B3PW91 |
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X = CN |
X = CN |
X = H |
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S(1)C(2) |
1.7254 |
1.7334 |
1.7197 |
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C(2)C(3) |
1.3772 |
1.3760 |
1.3660 |
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C(3)C(4) |
1.4118 |
1.4142 |
1.4229 |
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C(4)C(5) |
1.3699 |
1.3693 |
1.3660 |
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C(5)S(1) |
1.7039 |
1.7122 |
1.7197 |
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C(2)X(2) |
1.4112 |
1.4134 |
1.0787 |
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X(2)N
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1.1594
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1.1607
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C(3)H(3) |
1.0821 |
1.0806 |
1.0816 |
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C(4)H(4) |
1.0822 |
1.0808 |
1.0816 |
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C(5)H(5) |
1.0805 |
1.0792 |
1.0787 |
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C(5)S(1)C(2) |
91.56 |
91.43 |
91.95 |
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S(1)C(2)C(3) |
111.35 |
111.26
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111.42 |
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C(2)C(3)C(4) |
112.34 |
112.54
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112.60 |
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C(3)C(4)C(5) |
112.42 |
112.55
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112.60 |
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C(4)C(5)S(1) |
112.32 |
112.23
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111.42 |
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S(1)C(2)X(2) |
121.20 |
120.97
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119.93 |
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C(2)X(2)N |
179.98
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179.87
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S(1)C(5)H(5) |
119.59 |
119.46
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119.93 |
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C(3)C(4)H(4) |
124.13 |
123.92
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124.04 |
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C(4)C(3)H(3) |
125.03 |
124.80
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124.04 |
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| Table 3. 2-Cyanothiophene. Rotational Constants (MHz). |
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[a] B3PW91/6-31G(2d,2pd)
opt structure. |
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[b] B3P86/6-31G(3d,3p)
opt structure. |
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Calc [a] |
Calc [b] |
Expt. [1] |
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A
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5400.6
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5421.5
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5402.469(14)
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B
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1815.6
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1822.8
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1816.231(3)
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C
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1358.8
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1364.2
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1358.588(3)
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[1] J.Wiese, L.Engelbrecht, and H.Dreizler, Z.Naturforsch. 32a,152(1977).
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T.K.Avirah, T.B.Malloy Jr., and R.L.Cook, J.Mol.Struct. 29,47(1975).
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Thiophene |
2-Cyanofuran |
2-Bromothiophene |
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3-Chlorothiophene |
3-Bromothiophene |
2-Chlorothiophene
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3-Cyanothiophene
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Table of Contents |
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Molecules/Nitrogen |
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2CNThiophene.html |
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Last
Modified 11 June 2014 |
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