|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
CH2FCN
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Nitrogen
|
|
|
Nuclear
Quadrupole Coupling Constants |
|
|
|
in Monofluoroacetonitrile |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Calculation of the nitrogen nqcc's was made
here on a molecular structure derived ab initio
(see below). These are compared with the experimental nqcc's [1] in
Tables 1 and 2. Structure parameters and atomic coordinates respectively
are given in Tables 3 and 4. |
|
|
|
|
|
|
|
|
|
|
|
|
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 symmetry plane of the molecule. Ø (degrees)
is the angle between its subscripted parameters. ETA = (Xxx
- Xyy)/Xzz. |
|
|
|
|
|
|
|
|
|
|
|
|
RMS is the root mean square
difference between calculated and experimental nqcc's (percentage of
average experimental nqcc). RSD is the residual stand deviation
of calibration of the B3PW91/6-311+G(df,pd) model for calculation of
the nqcc's. |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
|
|
|
|
|
|
|
|
Table 1. Nitrogen nqcc's
in CH2FCN (MHz). |
|
| |
|
|
|
|
|
|
|
|
|
|
|
Calc. |
|
Expt. [1] |
|
| |
|
|
|
|
|
|
|
|
14N |
Xaa |
- |
3.707 |
- |
3.7039(26) |
|
|
|
Xbb |
|
1.948 |
|
1.8918(26) |
|
|
|
Xcc |
|
1.759 |
|
1.8122(37) |
|
|
|
|Xab| |
|
2.237 |
|
2.119 |
|
|
|
|
|
|
|
|
|
|
|
RMS |
|
0.045 (1.8 %) |
|
|
|
|
|
RSD |
|
0.030 (1.3 %) |
|
|
|
|
|
|
|
|
|
|
|
|
|
Xxx |
|
2.726 |
|
2.604 |
|
|
|
Xyy |
|
1.759 |
|
1.812 |
|
|
|
Xzz |
- |
4.485 |
- |
4.416 |
|
|
|
ETA |
- |
0.216 |
|
|
|
|
|
Øz,a |
|
19.17 |
|
|
|
|
|
Øa,CN |
|
19.26 |
|
|
|
|
|
Øz,CN |
|
0.08 |
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
|
|
|
|
|
|
|
|
Table 2. Nitrogen nqcc's
in CD2FCN (MHz). |
|
| |
|
|
|
|
|
|
|
|
|
|
|
Calc. |
|
Expt. [1] |
|
| |
|
|
|
|
|
|
|
|
14N |
Xaa |
- |
3.793 |
- |
3.7858(49) |
|
|
|
Xbb |
|
2.034 |
|
1.9731(41) |
|
|
|
Xcc |
|
1.759 |
|
1.8127(64) |
|
|
|
|Xab| |
|
2.124 |
|
|
|
|
|
|
|
|
|
|
|
|
|
RMS |
|
0.047 (1.9 %) |
|
|
|
|
|
RSD |
|
0.030 (1.3 %) |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Molecular Structure
|
|
|
|
|
|
|
|
|
|
|
|
|
The molecular structure was optimized
at the MP2/6-311G(d,p) level of theory assuming Cs symmetry.
The optimized CC and CN bond lengths were then corrected using
equations obtained from linear regression analysis of the data given
in reference [3]. Likewise, the optimized CF bond lengths were corrected
by regression analysis of the data given in reference [4]. The
CH bond lengths were corrected using r = 1.001 ropt, where
ropt is obtained by MP2/6-31G(d,p) optimization [5]. |
|
|
|
|
|
|
|
|
|
|
|
|
| |
|
|
|
|
|
| Table 2. Molecular structure
parameters (Å and degrees). |
|
|
|
|
|
|
|
|
|
CF |
|
1.372 |
|
|
|
CH |
|
1.090 |
|
|
|
CC |
|
1.467 |
|
|
|
CN |
|
1.1555 |
|
|
|
CCF |
|
110.30 |
|
|
|
CCH |
|
109.14 |
|
|
|
CCN |
|
179.33 |
|
|
|
|
|
|
|
|
|
CN tilts away from F. |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| Table 3. Atomic Coordinates. |
| (More figures are
show than are significant.) |
|
|
|
|
|
|
|
|
|
|
|
a (Å) |
|
b (Å) |
|
c (Å) |
|
|
|
|
|
|
|
|
|
F |
- |
1.461842 |
- |
0.420235 |
|
0.0 |
|
H |
- |
0.736357 |
|
1.232818 |
± |
0.891965 |
|
C |
- |
0.575756 |
|
0.627256 |
|
0.0 |
|
C |
|
0.803399 |
|
0.127238 |
|
0.0 |
|
N |
|
1.894240 |
- |
0.253878 |
|
0.0 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
[1] M.Andolfatto, H.Krause, D.H.Sutter, M.H.Palmer, Z.Naturforsch.
43a,651(1988). |
|
|
[2] W.Kasten, H.Dreizler, B.E.Job, and
J.Sheridan, Z.Naturforsch 38a,1015(1983). |
|
|
[3] J.Demaison, J.Cosléou, R.Bocquet,
and A.G.Lesarri, J.Mol.Spectrosc. 167,400(1994). |
|
|
[4] R.M.Villamañan, W.D.Chen, G.Wlodarczak,
J.Demaison, A.G.Lesarri, J.C.López, and J.L.Alonso, J.Mol.Spectrosc.
171,223(1995) |
|
|
[5] J.Demaison and G.Wlodarczak, Structural
Chem. 5,57(1994). |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
CHF2CN |
CF3CN |
CH3CN |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Table of Contents |
|
|
|
|
|
Molecules/Nitrogen |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
CH2FCN.html |
|
|
|
|
|
|
Last
Modified 19 Oct 2003 |
|
|
|
|
|
|
|
|
|
|