Cyclopropyl Cyanosilane

C₃H₅SiH₂CN

Nitrogen

Nuclear Quadrupole Coupling Constants

in Cyclopropyl Cyanosilane

Nitrogen nqcc's in the following cis and gauche conformers of cyclopropyl cyanosilane were determined by Seifert et al. [1].

cis (C_s)

gauche (C₁)

Calculation of the nitrogen nqcc tensors in each conformer was made here on molecular r_opt structures given by B3P86/6-31G(3d,3p) and mPW1PW91/6-31G(3d,3p) optimization. Calculated and experimental nqcc's are compared in Tables 1and 2. Structure parameters are given in Z-matrix format 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. 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 cis Cyclopropyl Cyanosilane (MHz). Calculation was made on molecular structures given by (1) B3P86/6-31G(3d,3p) and (2) mPW1PW91/6-31G(3d,3p) optimization.

		Calc (1)		Calc (2)		Expt. [1] *

X_aa	-	0.103	-	0.117	-	0.1177(59)
X_bb	-	2.363	-	2.354	-	2.3345(53)
X_cc		2.466		2.471		2.4523(53)
X_ab		3.677		3.690

RMS		0.020 (1.2 %)		0.016 (0.97 %)
RSD		0.030 (1.3 %)		0.030 (1.3 %)

X_xx		2.614		2.620
X_yy		2.466		2.471
X_zz	-	5.080	-	5.091
ETA	-	0.0291	-	0.0292
Ø_z,a		53.54		53.43
Ø_a,CN		53.88		53.78
Ø_z,CN		0.34		0.35

* Calculated here from 1.5(X_aa) = -0.1766(88) and 0.25(X_bb - X_cc) = -1.1967(22) MHz.


Table 2. ¹⁴N nqcc's in gauche Cyclopropyl Cyanosilane (MHz). Calculation was made on molecular structures given by (1) B3P86/6-31G(3d,3p) and (2) mPW1PW91/6-31G(3d,3p) optimization.

		Calc (1)		Calc (2)		Expt. [1] *

X_aa	-	2.778	-	2.788	-	2.701(9)
X_bb		0.271		0.275		0.211(11)
X_cc		2.507		2.513		2.490(11)
X_ab		3.461	-	3.467
X_ac		0.436		0.436
X_bc	-	0.235		0.235

RMS		0.057 (3.2 %)		0.064 (3.5 %)
RSD		0.030 (1.3 %)		0.030 (1.3 %)

X_xx		2.575		2.581
X_yy		2.493		2.499
X_zz	-	5.068	-	5.080
ETA		0.0162		0.0161
Ø_z,CN		0.12		0.11

* Calculated here from 1.5(X_aa) = -4.052(14) and 0.25(X_bb - X_cc) = -0.5698(49) MHz.


Table 3. Cyclopropyl Cyanosilane. B3P86/6-31G(3d,3p) and mPW1PW91/6-31G(3d,3p) optimized structure parameters (Å and degrees).

	cis Cyclopropyl Cyanosilane

			C C,1,B1 C,2,B2,1,A1 H,1,B3,2,A2,3,D1,0 H,2,B4,1,A3,3,D2,0 H,2,B5,1,A4,3,D3,0 H,3,B6,2,A5,1,D4,0 H,3,B7,2,A6,1,D5,0 Si,1,B8,2,A7,3,D6,0 H,9,B9,1,A8,2,D7,0 H,9,B10,1,A9,2,D8,0 C,9,B11,1,A10,2,D9,0 N,12,B12,9,A11,1,D10,0

		B3P86		mPW1PW91

		B1=1.51434544 B2=1.49039794 B3=1.08773916 B4=1.0835398 B5=1.08472477 B6=1.08472477 B7=1.0835398 B8=1.84229726 B9=1.47816639 B10=1.47816639 B11=1.85166783 B12=1.15863092 A1=60.52175075 A2=114.91007488 A3=117.06383777 A4=118.32616304 A5=117.71852488 A6=118.50968256 A7=121.39922998 A8=113.36320678 A9=113.36320678 A10=107.10486114 A11=177.4074877 D1=105.21912214 D2=-109.08028992 D3=107.59431447 D4=108.5843395 D5=-106.72181861 D6=-110.18380538 D7=-81.91725313 D8=152.32954589 D9=35.20614638 D10=0.		B1=1.51357344 B2=1.48974208 B3=1.08705639 B4=1.0829037 B5=1.08402418 B6=1.08402418 B7=1.0829037 B8=1.84355909 B9=1.47913251 B10=1.47913251 B11=1.85368019 B12=1.15696855 A1=60.51949114 A2=114.92923994 A3=117.02116153 A4=118.34669295 A5=117.74285526 A6=118.47763125 A7=121.4305515 A8=113.34336879 A9=113.34336879 A10=107.20887021 A11=177.42628096 D1=105.23420962 D2=-109.05906622 D3=107.61426609 D4=108.59804886 D5=-106.68274794 D6=-110.21164949 D7=-81.91453071 D8=152.35946954 D9=35.22246941 D10=0.


	gauche Cyclopropyl Cyanosilane

			C C,1,B1 C,2,B2,1,A1 H,1,B3,2,A2,3,D1,0 H,2,B4,1,A3,3,D2,0 H,2,B5,1,A4,3,D3,0 H,3,B6,2,A5,1,D4,0 H,3,B7,2,A6,1,D5,0 Si,1,B8,2,A7,3,D6,0 H,9,B9,1,A8,2,D7,0 H,9,B10,1,A9,2,D8,0 C,9,B11,1,A10,2,D9,0 N,12,B12,1,A11,9,D10,0

		B3P86		mPW1PW91

		B1=1.51338575 B2=1.48993982 B3=1.08657386 B4=1.08341275 B5=1.08472588 B6=1.08498375 B7=1.08343902 B8=1.83931679 B9=1.477847 B10=1.47938242 B11=1.85113806 B12=1.15847136 A1=60.67019268 A2=115.16291264 A3=116.98178696 A4=118.42355626 A5=118.12862134 A6=118.52059465 A7=120.37025103 A8=113.4310095 A9=110.17629106 A10=110.27751387 A11=144.34788552 D1=105.25087772 D2=-109.05863285 D3=108.21014283 D4=108.57495764 D5=-106.64598969 D6=-108.05454463 D7=158.50281202 D8=34.19464919 D9=-83.0734243 D10=179.52741074		B1=1.51277557 B2=1.48927353 B3=1.08587952 B4=1.08273138 B5=1.08402543 B6=1.08427856 B7=1.08276785 B8=1.84057018 B9=1.47864022 B10=1.4801979 B11=1.85279531 B12=1.15682708 A1=60.664694 A2=115.16704634 A3=116.96539204 A4=118.41443378 A5=118.12242264 A6=118.49611676 A7=120.35134591 A8=113.40098323 A9=110.24473908 A10=110.28767458 A11=144.39698396 D1=105.28299302 D2=-109.03255348 D3=108.201219 D4=108.57846189 D5=-106.62393831 D6=-108.06910021 D7=158.48475601 D8=34.18938953 D9=-83.11769605 D10=179.53508545


Table 4. Cyclopropyl Cyanosilane. Rotational Constants (MHz). Calc = (1) B3P86/6-31G(3d,3p) and (2) mPW1PW91/6-31G(3d,3p) optimized molecular structures.

		Calc (1)	Calc (2)	Expt. [1]

cis	A	4433.	4439.	4387.40278(84)
	B	2161.	2156.	2196.50693(68)
	C	1670.	1667.	1684.73866(60)

gauche	A	7150.	7161.	7029.7244(45)
	B	1545.	1543.	1567.1001(48)
	C	1365.	1364.	1377.7489(45)

[1] N.A.Seifert, S.Lobsiger, B.H.Pate, G.A.Guirgis, J.S.Overby, J.R.Durig, and P.Groner, 69th International Symposium on Molecular Spectroscopy, Champaign-Urbana, Ill. 2014.

J.R.Durig, G.A.Guirgis, D.K.Sawant, N.A.Seifert, B.S.Deodhar, B.H.Pate, S.S.Panikar, P.Groner, J.S.Overby, S.M.Askarian, Chem.Phys. 445,68(2014).

SiH₃CN

SiF₃CN

Table of Contents

Molecules/Nitrogen

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Last Modified 4 Feb 2016