|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
(CH3)2-CH-CH2Br
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Bromine
|
|
|
Nuclear
Quadrupole Coupling Constants |
|
|
|
in gauche Isobutyl Bromide |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Calculation of the
iodine nqcc tensor in gauche isobutyl bromide was
made on a molecular structure obtained by MP2/6-311+G(2d,p)
optimization, and on this same structure but with empirically
corrected C-C, CH (approximate re), and CBr (see 2-bromoethanol). These calculated nqcc's are compared with
the experimental values of Niide and Ohkoshi [1] in Tables 1 and 2. Structure
parameters are given in Table 3,
rotational constants in Table 4. |
|
|
|
|
|
|
|
|
|
|
|
|
In Tables 1 and 2, 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. Øz,CBr (degrees)
is the angle the z-principal axis makes with the CBr bond axis. ETA = (Xxx
- Xyy)/Xzz. |
|
|
RMS is the root mean square
difference between calculated and experimental diagonal nqcc's (percent of the
average of the magnitudes of the experimental nqcc's). RSD is the residual standard deviation
of calibration of the B1LYP/TZV(3df,3p) model for calculation of
the nqcc's.
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
|
|
|
|
|
|
|
|
|
Table
1. 79Br nqcc's in g-(CH3)2-CH-CH2Br
(MHz). |
|
|
|
|
|
|
|
|
|
|
|
Calculation was made on the following structures: |
|
|
ropt (1) = MP2/6-311+G(2d,p) optimization, and |
|
|
ropt (2) = MP2/6-311+G(2d,p) optimization with empirically corrected C-C, CH, and CBr bond lengths. |
|
| |
|
|
|
|
|
|
|
|
|
|
|
Calc. (1)
|
|
Calc. (2) |
|
Expt. [1] |
|
| |
|
|
|
|
|
|
|
|
|
Xaa |
|
399.13 |
|
396.42 |
|
380.0(22) |
|
|
Xbb |
-
|
165.90 |
-
|
164.52 |
-
|
144.8(41) |
|
|
Xcc |
-
|
233.22 |
-
|
231.90 |
-
|
235.2(46) |
|
|
|Xab| |
|
270.49 *
|
|
270.03 *
|
|
282.5(17) |
|
|
|Xac| |
|
158.97 |
|
158.64 |
|
|
|
|
|Xbc| |
|
69.06
|
|
69.21
|
|
|
|
|
|
|
|
|
|
|
|
|
|
RMS |
|
16.5 (6.5 %)
|
14.9 (5.9 %)
|
|
|
|
RSD |
|
1.58 (0.39 %)
|
1.58 (0.39 %) |
|
|
|
|
|
|
|
|
|
|
|
|
|
Xxx |
-
|
268.19 |
-
|
266.96 |
|
|
|
|
Xyy |
-
|
278.06 |
-
|
276.91 |
|
|
|
|
Xzz |
|
546.25 |
|
543.87 |
|
|
|
|
ETA |
|
0.0181 |
|
0.0183 |
|
|
|
|
Øz,CBr |
|
0.55
|
|
0.56
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
* The algebraic sign of the product XabXacXbc is positive. |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
|
|
|
|
|
|
|
|
|
Table 2. 81Br nqcc's in g-(CH3)2-CH-CH2Br
(MHz). |
|
|
|
|
|
|
|
|
|
|
|
Calculation was made on the following structures: |
|
|
ropt (1) = MP2/6-311+G(2d,p) optimization, and |
|
|
ropt (2) = MP2/6-311+G(2d,p) optimization with empirically corrected C-C, CH, and CBr bond lengths. |
|
| |
|
|
|
|
|
|
|
|
|
|
|
Calc. (1)
|
|
Calc. (2) |
|
Expt. [1] |
|
| |
|
|
|
|
|
|
|
|
|
Xaa |
|
333.52 |
|
331.26 |
|
302.5(20) |
|
|
Xbb |
-
|
138.60 |
-
|
137.45 |
-
|
110.4(33) |
|
|
Xcc |
-
|
194.92 |
-
|
193.81 |
-
|
192.1(38) |
|
|
|Xab| |
|
226.01 *
|
|
225.62 *
|
|
236.4(20) |
|
|
|Xac| |
|
132.69 |
|
132.41 |
|
|
|
|
|Xbc| |
|
57.64
|
|
57.77
|
|
|
|
|
|
|
|
|
|
|
|
|
|
RMS |
|
24.2 (12.0 %)
|
22.8 (11.3 %)
|
|
|
|
RSD |
|
1.38 (0.40 %)
|
1.38 (0.40 %) |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
* The algebraic sign of the product XabXacXbc is positive. |
|
|
|
|
|
|
|
|
|
|
|
|
| |
|
|
|
| Table 3. g-(CH3)2-CH-CH2Br. Heavy atom structure parameters
(Å and degrees). Complete structures are given here in Z-matrix format. |
| |
|
|
|
| ropt(1) = MP2/6-311+G(2d,p) optimization. |
| ropt(2) = MP2/6-311+G(2d,p)
optimization with empirically corrected C-C, CH, and CBr bond lengths. |
| |
|
|
|
 |
|
ropt(1) |
ropt(2) |
|
|
|
| C(3)Br |
1.9560 |
1.9455 |
| C(2)C(3) |
1.5178 |
1.5161 |
| C(2)C(4) |
1.5302 |
1.5247 |
| C(2)C(5) |
1.5247 |
1.5197 |
| C(2)C(3)Br |
113.22 |
113.22 |
| C(3)C(2)C(4) |
108.02
|
108.02 |
| Click on image to enlarge. |
C(3)C(2)C(5) |
112.17
|
112.17 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| Table 3. g-(CH3)2-CH-CH279Br. Rotational Constants (MHz). |
| |
|
|
|
|
|
|
ropt(1) |
ropt(2) |
Expt. [1] |
| |
|
|
|
|
|
A |
7543.3 |
7583.5 |
7483.20(28) |
|
B |
1409.8 |
1420.1 |
1411.1193(57) |
|
C |
1250.6 |
1259.6 |
1250.5110(56) |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
[1] Y.Niide and I.Ohkoshi, J.Mol.Spectrosc. 142,227(1990). |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Isobutyl Chloride |
Isobutyl Iodide |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Table of Contents |
|
|
|
|
|
Molecules/Bromine |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
gCH32CHCH2Br.html |
|
|
|
|
|
|
Last
Modified 5 May 2013 |
|
|
|
|
|
|
|
|
|
|