Vinyl Chloride

CH₂CHCl

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Chlorine

Nuclear Quadrupole Coupling Constants

in Vinyl Chloride

Vinyl chloride has been the subject of several microwave investigations [1-6]. Most recently, Hayashi and Inagusa [4] re-measured the chlorine nqcc's and determined a substitution molecular structure. Merke et al. [5] and Demaison et al. [6] determined several molecular structures.

Chlorine nqcc's calculated on the substitution structure [4] are compared in Tables 1 and 2 with the experimental values [4]. Results of calculations on the structures of Merke et al. are shown in Table 3, and those on the structures of Demaison et al. in Table 4. Substitution [4] and equilibrium [6] structure parameters are compared in Table 5.

In Tables 1 and 2, RMS is the root mean square difference between calculated and experimental diagonal nqcc's (percentage of the average of the magnitudes of the experimental nqcc's). RSD is the computational model residual standard deviation. 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. Ø (degrees) is the angle between its subscripted parameters.


Table 1. ³⁵Cl nqcc's in CH₂CHCl (MHz). Calculation was made on the substitution structure of Hayashi and Inagusa [4].

			Calc.		Expt. [4]

³⁵Cl	X_aa	-	57.03	-	57.21(13)
	X_bb		26.07		25.47
	X_cc		30.96		31.74
	\|X_ab\|		36.10

	RMS		0.58 (1.5 %)
	RSD		0.49 (1.1 %)

	X_xx		39.56		39.01 *
	X_yy		30.96		31.74
	X_zz	-	70.52	-	70.75
	ETA	-	0.122	-	0.103
	Ø_z,a		20.49		20.56
	Ø_a,CCl		20.1		20.1
	Ø_z,CCl		0.4		0.5

* Calculated here from the experimental diagonal nqcc's and the calculated off-diagonal nqcc.


Table 2. ³⁷Cl nqcc's in CH₂CHCl (MHz). Calculation was made on the substitution structure of Hayashi and Inagusa [4].

			Calc.		Expt. [4]

³⁷Cl	X_aa	-	45.06	-	45.13(11)
	X_bb		20.66		20.25
	X_cc		24.40		24.88
	\|X_ab\|		28.32

	RMS		0.37 (1.2 %)
	RSD		0.44 (1.1 %)

	X_xx		31.18		30.81 *
	X_yy		24.40		24.88
	X_zz	-	55.58	-	55.69
	ETA	-	0.122	-	0.106
	Ø_z,a		20.38		20.45
	Ø_a,CCl		20.0		20.0
	Ø_z,CCl		0.4		0.5

* Calculated here from the experimental diagonal nqcc's and the calculated off-diagonal nqcc.


Table 3. ³⁵Cl nqcc's in CH₂CHCl (MHz). The structures on which calculation was made are those according to Merke et al. [5]. RMS is the root mean square difference between calculated and experimental nqcc's [4].

Structure	X_aa	X_bb	X_cc	RMS

r_o	-57.32	26.22	31.11	0.58
r_epislon^I	-57.27	26.26	31.02	0.62
r_m^rho (a/b)	-57.15	26.32	30.84	0.72
r_m^rho (b/c)	-56.97	26.09	30.88	0.62
r_m^rho (a/b/c)	-57.03	26.14	30.88	0.64
near r_e	-57.28	26.52	30.76	0.83
expt. nqcc's	-57.21(13)	25.47	31.74


Table 4. ³⁵Cl nqcc's in CH₂CHCl (MHz). The structures on which calculation was made are those according to Demaison et al. [6]. RMS is the root mean square difference between calculated and experimental nqcc's [4].

Structure	X_aa	X_bb	X_cc	RMS

r_o	-57.35	26.20	31.15	0.55
r_m⁽¹⁾	-57.10	26.18	30.92	0.63
r_m⁽²⁾ mod	-57.20	26.26	30.93	0.66
r_m^(1L)	-57.07	26.19	30.89	0.65
r_s-fit	-57.18	26.15	31.02	0.57
r_e	-57.09	26.30	30.79	0.73
expt. nqcc's	-57.21(13)	25.47	31.74


Table 5. Molecular structure parameters (Å and degrees).

		r_s [4]	r_e [6]

	C(1)Cl	1.726	1.7263
	C=C	1.333	1.3262
	CCCl	122.7	122.77
	C(1)H	1.080	1.0784
	CCH	123.1	123.86
	CH_t	1.079	1.0797
	CH_c	1.086	1.0795
	CCH_t	119.6	119.29
	CCH_c	121.1	121.80

[1] J.H.Goldstein and J.K.Bragg, Phys.Rev. 75, 1453(1949).

[2] D.Kivelson, E.B.Wilson Jr., and D.R.Lide Jr., J.Chem.Phys. 32,205 (1960).

[3] M.C.L.Gerry, Canad.J.Chem. 49,255(1971).

[4] M.Hayashi and T.Inagusa, J.Mol.Struct. 220,103(1990).

[5] I.Merke, L.Poteau, G.Wlodarczak, A.Bouddou, and J.Demaison, J.Mol.Spectrosc. 177,232(1996).

[6] J.Demaison, H.Møllendal, A.Perrin, J.Orphal, F.Kwabia Tchana, H.D.Rudolph, and F.Willaert, J.Mol.Spectrosc. 232,174(2005).

CH₂CHBr

CH₂CCl₂

c-ClHCCHCl

CH₃CH₂Cl

CH₂CHCN

CH₃Cl

CH₂CClCN

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Molecules/Chlorine

CH2CHCl.html

Last Modified 4 July 2005