CH2·NH·CH(CH3)
		Nitrogen
	Nuclear Quadrupole Coupling Constants
	in 2-Methylaziridine (Propyleneimine)
	The microwave spectra of cis-2-methylaziridine was observed and assigned by Li and Durig [1], and by Schmidt and Beeson [2]. 14N  nuclear quadrupole coupling constants were determined.
	Here, for both cis and trans conformers - shown below, calculation of the nitrogen nqcc tensor was made on molecular structures given by MP2/6-311+G(d,p) and MP2/6-311+G(3df,3pd) optimization.  These calculated nqcc's are compaed with experimental values [1] in Tables 1 and 2.  Structure parameters are given in Z-Matrix format in Table 3, rotational constants and dipole moments in Table 4, quartic centrifugal distortion constants in Table 5.
	cis-2-Methylaziridine					trans-2-Methylaziridine
				At the
				MP2/6-311+G(3df,3pd)
				level of theory,
				Etrans < Ecis
				by 2.1 kJ/mol
	In Tables 1 and 2, 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 = (Xxx - Xyy)/Xzz.  Ø (degrees) is the angle between its subscripted parameters.
	RMS is the root mean square difference between calculated and experimental nqcc's.  RSD is the calibration residual standard deviation of the B3PW91/6-311+G(df,pd) model for calculation of the nitrogen efg's/nqcc's.
	Table 1.  14N nqcc tensor in cis-2-Methylaziridine (MHz).  Calculation was made on  molecular structures given by (1) MP2/6-311+G(d,p) and (2) MP2/6-311+G(3df,3pd)  optimization.     Calc (1) Calc (2) Expt [1]     Xaa - 1.167 - 1.192 - 1.16(2) Xbb 1.778 1.800 1.80(2) Xcc - 0.611 - 0.608 - 0.64(2) Xab 0.676 0.698 Xac 1.999 1.999 Xbc - 2.106 - 2.115   RMS 0.021 (1.8 %) 0.026 (2.2 %) RSD 0.030 (1.3 %) 0.030 (1.3 %)   Xxx 0.551 0.552 Xyy 3.058 3.077 Xzz - 3.609 3.629 ETA 0.694 0.696 Øz,NH 132.1 131.8
	Table 2.  14N nqcc tensor in trans-2-Methylaziridine (MHz).  Calculation was made on  molecular structures given by (1) MP2/6-311+G(d,p) and (2) MP2/6-311+G(3df,3pd)  optimization.     Calc (1) Calc (2) Expt     Xaa 0.813 0.798 Xbb 2.063 2.071 Xcc - 2.876 - 2.869 Xab - 1.391 - 1.406 Xac - 0.944 - 0.963 Xbc - 1.244 - 1.243   RSD 0.030 (1.3 %) 0.030 (1.3 %)   Xxx 0.526 0.519 Xyy 3.018 3.031 Xzz - 3.543 - 3.550 ETA 0.703 0.707 Øz,NH 132.4 132.3
	Table 3.  2-Methylaziridine:  MP2/6-311+G(d,p) and MP2/6-311+G(3df,3pd) optimized structure parameters (Å and degrees). cis-2-Methylaziridine trans-2-Methylaziridine            N            C,1,B1            C,1,B2,2,A1            H,1,B3,2,A2,3,D1,0            H,3,B4,1,A3,2,D2,0            H,2,B5,1,A4,3,D3,0            H,2,B6,1,A5,3,D4,0            C,3,B7,1,A6,2,D5,0            H,8,B8,3,A7,1,D6,0            H,8,B9,3,A8,1,D7,0            H,8,B10,3,A9,1,D8,0 ____________________ MP2/6-311+G(d,p)____________________     cis    trans  B1=1.48455468  B2=1.47718299  B3=1.01960358  B4=1.0869794  B5=1.08404927  B6=1.08672656  B7=1.50764998  B8=1.09465623  B9=1.09467929  B10=1.09562601  A1=60.10403013  A2=108.43032232  A3=112.34906577  A4=114.49349698  A5=118.02587932  A6=119.84653164  A7=110.94814244  A8=110.88386996  A9=110.29693244  D1=101.04559283  D2=-109.62506439  D3=112.1129528  D4=-106.65790104  D5=109.84068261  D6=77.21044473  D7=-162.43218221  D8=-42.82151946  B1=1.4833335  B2=1.47743414  B3=1.01805204  B4=1.08877059  B5=1.08582525  B6=1.08496902  B7=1.50522401  B8=1.0944112  B9=1.0947942  B10=1.09321847  A1=60.18368895  A2=108.93428396  A3=116.28779387  A4=118.24642232  A5=114.20776719  A6=115.78471968  A7=110.73809611  A8=110.84591935  A9=109.5315166  D1=-102.23126317  D2=-105.94736  D3=108.08212475  D4=-110.7183989  D5=112.85626432  D6=81.42600796  D7=-157.95978902  D8=-37.83352299 ____________________ MP2/6-311+G(3df,3pd)____________________    cis    trans  B1=1.47903111  B2=1.47057676  B3=1.01571814  B4=1.08280119  B5=1.07978458  B6=1.0819464  B7=1.50131819  B8=1.0898696  B9=1.0897449  B10=1.09076623  A1=60.09632531  A2=108.67131248  A3=112.33603282  A4=114.30819877  A5=117.87752209  A6=119.47904473  A7=110.96781997  A8=110.998557  A9=110.34458921  D1=101.08504192  D2=-109.60061196  D3=112.20234954  D4=-106.71903851  D5=109.96800372  D6=76.89032242  D7=-162.87302226  D8=-43.11520196  B1=1.47784688  B2=1.47215681  B3=1.01424742  B4=1.08387826  B5=1.08094524  B6=1.08065069  B7=1.4996737  B8=1.08918986  B9=1.08974834  B10=1.08840126  A1=60.11424879  A2=109.07451674  A3=116.32943696  A4=118.17126295  A5=114.06672114  A6=115.47405408  A7=110.76970213  A8=110.94088848  A9=109.63441925  D1=-102.37611586  D2=-106.06808881  D3=108.31965798  D4=-110.63752867  D5=112.79938152  D6=81.33047717  D7=-158.08515319  D8=-37.89761827
	Table 4.  2-Methylaziridine:  Rotational Constants (MHz) and Dipole Moments (D).  Calc (1)  =  MP2/6-311+G(d,p) and Calc (2) = MP2/6-311+G(3df,3pd) optimization. __________cis-2-Methylaziridine__________ Calc (1) Calc (2)  Expt [1] A 16689 16813 B   6561   6624 C   5818   5875 |µa|   1.41   1.40 |µb|   1.10   1.10 |µc|   0.87   0.87 __________trans-2-Methylaziridine__________ Calc (1) Calc (2)  Expt [1] A 16928 17044 B   6535   6596 C   5765   5821 |µa|   0.11   0.12 |µb|   0.88   0.88 |µc|   1.54   1.54
	Table 5.  2-Methylaziridine:  Quartic Centrifugal Distortion Constants (kHz).  Calc = B3LYP/cc-pVTZ ____cis-2-Methylaziridine____ ___trans-2-Methylaziridine___ Calc Expt Calc Expt Delta_J 2.73 2.72 Delta_JK 4.21 3.21 Delta_K 12.8 15.5 delta_J 0.188 0.241 delta_K 3.25 3.48 D_J 2.68 2.66 D_JK 4.55 3.57 D_K 12.5 15.2 d_1 - 0.188 - 0.241 d_2 - 0.0281 - 00303
	[1] Y.S.Li and J.R.Durig, J. Mol. Spectrosc. 47,179(1973).
	[2] R.Schmidt and E.L.Beeson Jr., J.Chem.Phys. 59,3070(1973):  Xaa, Xbb, Xcc = -1.14(6), 2.01(5), -0.88(7) MHz.
	Aziridine		2-Cyanoaziridine		1-Aziridineethanol
	Table of Contents
	Molecules/Nitrogen
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						Last Modified 30 Jan 2014