N-Acetylethanolamine

(CH₃)C(=O)NH(CH₂CH₂OH)

Nitrogen

Nuclear Quadrupole Coupling Constants

in N-Acetylethanolamine

Molecular conformation and ¹⁴N nuclear quadrupole coupling constants in N-Acetylethanolamine were reported by Bird, et al. [1].

Calculation of the ¹⁴N nuclear quadrupole coupling constants was made here on r_opt molecular structures given by MP2/6-311+G(2d,2p) and MP2/6-311+G(3d,3p) optimization.

Calculated and experimental [1] nqcc's are compared in Table 1. Structure parameters are given in Table 2, rotational constants in Table 3.

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. RMS is the root mean square difference between calculated and experimental diagonal 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's in N-Acetylethanolamine (MHz). Calculation was made on the (1) MP2/6-311+G(2d,2p) and (2) MP2/6-311+G(3d,3p) r_opt structures.

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

X_aa		1.563		1.476		1.56(7)
X_bb		1.659		1.603		1.51(3)
X_cc	-	3.222	-	3.079	-	3.07(9)
X_ab		0.288		0.362
X_ac	-	1.733	-	1.834
X_bc		0.898		1.068

RMS		0.12₃ (6.0 %)		0.07₃ (3.6 %)
RSD		0.030 (1.3 %)		0.030 (1.3 %)

X_xx		1.818		1.832
X_yy		2.124		2.123
X_zz	-	3.942	-	3.955
ETA		0.0777		0.0738


Table 2. N-Acetylethanolamine: Optimized structure parameters (Å and degrees).

	C N,1,B1 C,2,B2,1,A1 O,3,B3,2,A2,1,D1,0 C,3,B4,2,A3,1,D2,0 H,1,B5,2,A4,3,D3,0 H,1,B6,2,A5,3,D4,0 H,2,B7,1,A6,3,D5,0 H,5,B8,3,A7,2,D6,0 H,5,B9,3,A8,2,D7,0 H,5,B10,3,A9,2,D8,0 C,1,B11,2,A10,3,D9,0 H,12,B12,1,A11,2,D10,0 H,12,B13,1,A12,2,D11,0 O,12,B14,1,A13,2,D12,0 H,15,B15,12,A14,1,D13,0

	MP2/6-311+G(2d,2p)	MP2/6-311+G(3d,3p)

	B1=1.46147541 B2=1.35598117 B3=1.23347425 B4=1.50978254 B5=1.08918053 B6=1.087168 B7=1.00285031 B8=1.08590124 B9=1.08621451 B10=1.08506247 B11=1.5255131 B12=1.088038 B13=1.09364398 B14=1.41513884 B15=0.96964116 A1=123.28587684 A2=122.34401216 A3=116.30215106 A4=109.35291971 A5=106.39544661 A6=118.62860763 A7=113.2852725 A8=108.39024982 A9=108.61770385 A10=114.47573834 A11=108.45800418 A12=108.80245422 A13=113.47353629 A14=106.81692856 D1=5.98854118 D2=-173.75514987 D3=52.24783482 D4=169.01296095 D5=-172.84805427 D6=-5.79228988 D7=115.4798549 D8=-127.62596106 D9=-70.09299404 D10=-158.65863791 D11=-41.51761579 D12=83.35732898 D13=-39.65769147	B1=1.46070993 B2=1.35680306 B3=1.23245736 B4=1.51062379 B5=1.09089242 B6=1.08898719 B7=1.00487579 B8=1.08742471 B9=1.08805555 B10=1.08640749 B11=1.52560133 B12=1.09045966 B13=1.09538556 B14=1.41364964 B15=0.9708263 A1=122.99092573 A2=122.15533275 A3=116.26963544 A4=109.14205062 A5=106.64709016 A6=118.60172722 A7=113.28724302 A8=108.33136243 A9=108.54798368 A10=114.21527551 A11=108.43028706 A12=108.72838024 A13=113.44225289 A14=107.34303304 D1=6.275719 D2=-173.25385837 D3=48.69007619 D4=165.62265453 D5=-172.69878633 D6=-8.58615999 D7=112.62612533 D8=-130.45795696 D9=-73.43125049 D10=-160.85572781 D11=-43.77688408 D12=80.75667088 D13=-33.9907241


Table 3. N-Acetylethanolamine: Rotational Constants (MHz). Calc = (1) MP2/6-311+G(2d,2p) and (2) MP2/6-311+G(3d,3p) optimization.

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

	A	5103.	5085.	5072.85(1)
	B	1736.	1735	1728.516(5)
	C	1406.	1413.	1409.371(3)

[1] J.R.Bailey, T.J.McMahon, and R.G.Bird, J.Mol.Spectrosc. 335,33(2017).

J.R.Bailey, T.J.McMahon, R.G.Bird, and D.Pratt, 70th International Symposium on Molecular Spectroscopy, Champaign-Urbana, 2015.

N-Ethylformamide

N,N-Diethylacetamide

N-Methylacetamide

N,N-Dimethylacetamide

see Amides

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Molecules/Nitrogen

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Last Modified 22 Feb 2017