C3N2H3-CH=CH-CO2H














 









Nitrogen


Nuclear Quadrupole Coupling Constants


in trans Urocanic Acid


 


















Calculations of the nitrogen nqcc tensors in Urocanic Acid was made on each conformer shown below, with structures given by B3LYP/cc-pVTZ optimization.   These calculated nqcc's are compared with the experimental results of Walker, et al. [1] in Tables 1 - 3.  Structure parameters are given in Table 4, rotational constants in Table 5.

 








A

 B
C
































 








In Tables 1 - 3, 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 calibration residual standard deviation for the B3PW91/6-311+G(df,pd) model for calculation of the nitrogen  efg's/nqcc's.

 








 








   






Table 1.  Nitrogen nqcc's in the A-Conformer of trans Urocanic Acid (MHz).  Calculation was made on the B3LYP/cc-pVTZ optimized molecular strcuture.  See figure above for atomic numbering.
   









Calc
Expt. I [1]
   






14N(1) Xaa
1.349
1.321(14)


Xbb
1.122
1.36(13) *


Xcc -
 2.471
 -
 2.68(13) *


Xab -
 0.037












RMS
0.183 (10. %)




RSD
0.030 (1.3 %)











14N(3) Xaa -
 0.003
 -
 0.134(33)


Xbb -
 2.190 -
 2.30(18) **


Xcc
2.193
2.43(18) **


Xab
2.766












RMS
0.169 (10. %)




RSD
0.030 (1.3 %)












 








* Calculated here from Xaa and Xbb - Xcc = 4.03(26) MHz

** Calculated here from Xaa and Xbb - Xcc = -4.72(36) MHz

 








 








   






Table 2.  Nitrogen nqcc's in the B-Conformer of trans Urocanic Acid (MHz).  Calculation was made on the B3LYP/cc-pVTZ optimized molecular strcuture.  See figure above for atomic numbering.
   









Calc
Expt. I [1]
   






14N(1) Xaa
1.352
1.316(14)


Xbb
1.124
1.195(11) *


Xcc -
 2.477
 -
 2.511(11) *


Xab -
 0.037












RMS
0.050 (3.0 %)




RSD
0.030 (1.3 %)











14N(3) Xaa
0.078




Xbb - Xcc -
 4.467
 -
 4.275(18)


Xbb -
 2.273




Xcc
2.194




Xab
2.740












RSD
0.030 (1.3 %)












 








* Calculated here from Xaa and Xbb - Xcc = 3.707(18) MHz

 








 







 
   






Table 3.  Nitrogen nqcc's in the C-Conformer of trans Urocanic Acid (MHz).  Calculation was made on the B3LYP/cc-pVTZ optimized molecular strcuture.  See figure above for atomic numbering.
   









Calc
Expt. III [1]
   






14N(1) Xaa
1.250
1.303(36)


Xbb
1.113
1.098(25) *


Xcc -
 2.364
 -
 2.401(25) *


Xab
0.109












RMS
0.027 (1.7 %)




RSD
0.030 (1.3 %)











14N(3) Xaa
1.472
1.341(35)


Xbb -
 3.772 -
 3.671(24) **


Xcc
2.299
2.330(24) **


Xab -
 1.364












RMS
0.097 (4.0 %)




RSD
0.030 (1.3 %)












 








* Calculated here from Xaa and Xbb - Xcc = 3.499(34) MHz

** Calculated here from Xaa and Xbb - Xcc = -6.000(33) MHz

 












Table 4.  Urocanic Acid: B3LYP/cc-pVTZ optimized structure parameters.





 N
 C,1,B1
 N,2,B2,1,A1
 C,3,B3,2,A2,1,D1,0
 C,4,B4,3,A3,2,D2,0
 H,1,B5,2,A4,3,D3,0
 H,2,B6,1,A5,5,D4,0
 H,5,B7,4,A6,3,D5,0
 C,4,B8,3,A7,2,D6,0
 C,9,B9,4,A8,3,D7,0
 H,9,B10,4,A9,3,D8,0
 H,10,B11,9,A10,4,D9,0
 C,10,B12,9,A11,4,D10,0
 O,13,B13,10,A12,9,D11,0
 O,13,B14,10,A13,9,D12,0
 H,15,B15,13,A14,10,D13,0
 Conformer A








 B1=1.36712001
 B2=1.30346416
 B3=1.38361167
 B4=1.37808517
 B5=1.00516349
 B6=1.07753796
 B7=1.07509596
 B8=1.44126525
 B9=1.33911284
 B10=1.08440362
 B11=1.08002779
 B12=1.46792393
 B13=1.21056657
 B14=1.35969503
 B15=0.96786688
 A1=111.71639053
 A2=105.86432695
 A3=109.5700965
 A4=126.55083814
 A5=122.27519923
 A6=131.8234638
  A7=123.65836848
 A8=125.31086135
 A9=116.84629359
 A10=121.42056516
 A11=120.31549462
 A12=126.66567969
 A13=111.48525771
 A14=106.23861945
 D1=0.
 D2=0.
 D3=180.
 D4=180.
 D5=180.
 D6=180.
 D7=0.
 D8=180.
 D9=0.
 D10=180.
 D11=0.
 D12=180.
 D13=180.









 N
 C,1,B1
 N,2,B2,1,A1
 C,3,B3,2,A2,1,D1,0
 C,1,B4,2,A3,3,D2,0
 H,1,B5,2,A4,3,D3,0
 H,2,B6,1,A5,5,D4,0
 H,5,B7,1,A6,2,D5,0
 C,4,B8,3,A7,2,D6,0
 C,9,B9,4,A8,3,D7,0
 H,9,B10,4,A9,3,D8,0
 H,10,B11,9,A10,4,D9,0
 C,10,B12,9,A11,4,D10,0
 O,13,B13,10,A12,9,D11,0
 O,13,B14,10,A13,9,D12,0
 H,15,B15,13,A14,10,D13,0
 Conformer B








 B1=1.36732171
 B2=1.30330029
 B3=1.38332361
 B4=1.36855711
 B5=1.00516544
 B6=1.07752516
 B7=1.07513985
 B8=1.44311659
 B9=1.34013073
 B10=1.08305632
 B11=1.08004551
 B12=1.46427579
 B13=1.20961519
 B14=1.36379324
 B15=0.9672414
 A1=111.70653533
 A2=105.89463576
 A3=107.1817397
 A4=126.53232259
 A5=122.25268894
 A6=122.52706615
  A7=123.58808802
 A8=124.76569374
 A9=116.23580272
 A10=120.95662133
 A11=124.01128287
 A12=124.4590089
 A13=114.0738991
 A14=105.75531372
 D1=0.
 D2=0.
 D3=180.
 D4=180.
 D5=180.
 D6=180.
 D7=0.
 D8=180.
 D9=0.
 D10=180.
 D11=180.
 D12=0.
 D13=180.

 


 


 N
 C,1,B1
 N,2,B2,1,A1
 C,3,B3,2,A2,1,D1,0
 C,1,B4,2,A3,3,D2,0
 H,1,B5,2,A4,3,D3,0
 H,2,B6,1,A5,5,D4,0
 H,5,B7,1,A6,2,D5,0
 C,4,B8,3,A7,2,D6,0
 C,9,B9,4,A8,3,D7,0
 H,9,B10,4,A9,3,D8,0
 H,10,B11,9,A10,4,D9,0
 C,10,B12,9,A11,4,D10,0
 O,13,B13,10,A12,9,D11,0
 O,13,B14,10,A13,9,D12,0
 H,15,B15,13,A14,10,D13,0
Conformer C








 B1=1.36676185
 B2=1.30449759
 B3=1.38357134
 B4=1.3664008
 B5=1.00555512
 B6=1.07719661
 B7=1.07468369
 B8=1.44377141
 B9=1.33984683
 B10=1.08367369
 B11=1.08140122
 B12=1.46792549
 B13=1.20894308
 B14=1.36180567
 B15=0.96784874
 A1=111.41221223
 A2=106.09988868
 A3=107.48151243
 A4=126.46979391
 A5=122.37886731
 A6=122.10469703
  A7=120.37737257
 A8=126.955161
 A9=115.0243855
 A10=122.65593782
 A11=120.6970715
 A12=126.83826982
 A13=111.23388097
 A14=106.1718662
 D1=0.
 D2=0.
 D3=180.
 D4=180.
 D5=180.
 D6=180.
 D7=180.
 D8=0.
 D9=0.
 D10=180.
 D11=0.
 D12=180.
 D13=180.







 













Table 3.  Urocanic Acid:  Rotational Constants (MHz).   ropt = B3LYP/cc-pVTZ

 





   ropt     Expt. [1]






Conformer A
 A   4960.
 4920.844(15)


B    576.
   576.93690(17)


C    516.
   516.64802(18)






Conformer B
 A
   4936.
 4899.5706(52)


B
     581.
   582.26973(17)


C
     520.
   520.69877(14)






Conformer C
 A
   4976. 4932.59263(97)


B
     567.   568.35033(18)


C
     509.   510.02466(13)


 


















[1] G.A.Cooper, C.Medcraft, E.Gougoula, and N.Walker, PCCP, 21,9495(2019).

 








N.Walker, G.A.Cooper, C.Medcraft, and E.Gougoula, Abstract WK10, 73rd ISMS, Champaign-Urbana, Illinois, 2018.

 








 








Table of Contents




Molecules/Nitrogen




 








 













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Last Modified 15 April 2019