1,2-Dicyanoethane

CH₂CN-CH₂CN

Nitrogen

Nuclear Quadrupole Coupling Constants

in 1,2-Dicyanoethane (Succinonitrile)

Calculation of the ¹⁴N nqcc's succinonitrile was made here on an r_s molecular structure derived by Jahn et al. [1].

Calculated and experimental nqcc's [1] are compared in Table 1. Structure parameters are given in Z-matrix format in Table 2. In Table 1, subscripts a,b,c refer to the principal axes of the inertia tensor; x,y,z to the principal axes of the nqcc tensor. ETA = (X_xx - X_yy)/X_zz. Ø (degrees) is the angle between its subscripted parameters. RMS is the root measn square difference between calculated and experimental diagonal nqcc's. 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.


Table 1. ¹⁴N nqcc's in Succinonitrile (MHz). Calculation was made on r_s structure.

			Calc		Expt. [1]

¹⁴N	X_aa	-	0.063	-	0.068726(673)
	X_bb	-	1.697	-	1.72773(65) *
	X_cc		1.756		1.79645(65) *
	X_ab	+/-	2.939		2.907(102) **
	X_ac	+	0.962		0.963(239) **
	X_bc	-/+	1.058		-------

	RMS		0.031 (2.6 %)
	RSD		0.030 (1.3 %)

	X_xx		2.004
	X_yy		2.261
	X_zz	-	4.265
	ETA		0.060
	Ø_z,CN		0.52

* Derived here from X_aa and (X_bb - X_cc) = -3.52418(111) MHz [1]. ** Absolute value.


Table 2. Succinonitrile, r_s structure parameters [1] (Å and degrees).

	C C 1 R1 C 2 R2 1 A1 C 3 R3 2 A2 1 D1 N 1 R4 2 A3 3 D2 N 4 R5 3 A4 2 D3 H 2 R6 3 A5 4 D4 H 2 R7 3 A6 4 D5 H 3 R8 2 A7 1 D6 H 3 R9 2 A8 1 D7

	R1 1.4558 R2 1.5297 R3 1.4558 R4 1.1627 R5 1.1627 R6 1.1227 R7 1.1111 R8 1.1111 R9 1.1227 A1 112.65 A2 112.65 A3 178.8 A4 178.8 A5 110.10 A6 108.37 A7 108.37 A8 110.10 D1 65.94 D2 59.41884 D3 59.41884 D4 -53.19001 D5 -172.38254 D6 -172.38254 D7 -53.19001

[1] M.K.Jahn, J.-U.Grabow, P.D.Godfrey, and D.McNaughton, Phys.Chem.Chem.Phys. 16,2100(2014).

Methyl cyanide

Ethyl cyanide

t-Butyl cyanide

Benzonitrile

Dicyanomethane

t-1-Cyanopropane

Table of Contents

Molecules/Nitrogen

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Last Modified 10 June 2016