still of jmol image
Aniline, C6H5NH2
Models were made using the best ab initio level of theory, which was 6311-G.  This is the best level because it is the biggest basis set for the molecule.  Click below for aniline bond lengths.

aniline picture
Figure 1: C6H5NH2: (1)C, (2)C, (3)C, (4)C, (5)C, (6)C, (7)H, (8)H, (9)H, (10)H, (11)H, (12)N, (13)H, (14)H.

Bond lengths for atoms (1)C, (2)C, (3)C, (4)C, (5)C, (6)C, (7)H, (8)H, (9)H, (10)H, (11)H, (12)N, (13)H, (14)H in angstroms, , at the different levels of theory.
The experimental values were C-H 1.084 , C-C 1.392 , and C-N 1.431 .1
Atoms  PM3  AM1  321-G  631-G  6311-G
1-2  1.402123  1.414806  1.395290 1.397001  1.396503
1-6  1.402087  1.414810  1.395298  1.396984  1.396505
1-12  1.429962  1.399938  1.376384  1.380452  1.381926
2-3  1.388584  1.390066  1.380267  1.384708  1.384094
2-11  1.096318  1.099924  1.072553  1.074170  1.071858
3-4  1.390950  1.394044  1.384180  1.387937  1.387465
3-10  1.094956  1.100514  1.072639  1.073712  1.071441
4-5  1.390967  1.394053  1.384201  1.387926  1.387465
4-9  1.094357  1.098574  1.071023  1.072262  1.069927
5-6  1.388581  1.390077  1.380268  1.384710 1.384097
5-8  1.094954  1.100513  1.072642  1.073710  1.071438
6-7  1.096331  1.099924  1.072618  1.074192  1.071858
12-13  0.995849  0.995952  0.994508  0.988952  0.986486
12-14 0.995849  0.995913  0.994526  0.988954  0.986498




Click below for Aniline angles, C-C-H and C-N-H.

Click below for Aniline Angles, C-C-C.

Bond angles between atoms (1)C, (2)C, (3)C, (4)C, (5)C, (6)C, (7)H, (8)H, (9)H, (10)H, (11)H, (12)N, (13)H, (14)H in degrees, , at the different levels of theory.  The experiemental values are H-N-H 113.9,  H-N-C 114.92. 1

Atoms  PM3  AM1  321-G  631-G  6311-G
1-12-13  111.58  114.18  120.95  121.07  121.02
1-12-14  111.58  114.19  120.95  121.07  121.02
14-12-13  111.05  113.08  118.10  117.86  117.97
12-1-6  120.05  120.71  120.95  120.69  120.71
12-1-2  120.02  120.72  120.95  120.69  120.71
1-2-3  119.73  120.29  120.69  120.40  120.43
2-3-4  120.46  120.74  120.95  120.91  120.93
3-4-5  119.85  119.48  118.62  118.76  118.71
4-5-6  120.45  120.74  120.94  120.90  120.93
5-6-1  119.77  120.29  120.70  120.41  120.43
6-1-2  119.74  118.46  118.10  118.62  118.57
1-6-7  120.65  120.14  119.38  119.55  119.53
1-2-11  120.66  120.13  119.38  119.54  119.53
11-2-3  119.61  119.57  119.94  120.06  120.04
2-3-10  119.67  119.40  119.11  119.16  119.14
10-3-4  119.87  119.86  119.93  119.94  119.92
3-4-9  120.08  120.26  120.70  120.61  120.65
9-4-5  120.07  120.26  120.68  120.63  120.65
4-5-8  119.88  119.85  119.93  119.93  119.92
8-5-6  119.67  119.41  119.13  119.17  119.14
5-6-7  119.61  119.57  119.93  120.05  120.04



Click below to view the Aniline HOMO orbital.  The HOMO orbital is the highest energy molecular orbital occupied by electrons.   From the model, it can be predicted how a molecule will react.    

Vibrational Frequencies
The next two frequencies contribute to the ~3400 cm-1 peak in the IR spectrum. 2 Click below to see the motion of the molecule at frequency 3993 cm-1
Click below to see the motion of the molecule at frequency 3851 cm-1.  


The next five frequencies contribute to the ~3000 cm-1 peak in the IR spectrum. 2 Click below to see the motion of the molecule at frequency 3380 cm-1
Click below to see the motion of the molecule at frequency 3354 cm-1.  
Click below to see the motion of the molecule at frequency 3333 cm-1.  
Click below to see the motion of the molecule at frequency 3329 cm-1.  
Click below to see the motion of the molecule at frequency 3305 cm-1.  

Click below to see the motion of the molecule at frequency 1839 cm-1. This contributes to ~1600 cm-1 peak in the IR spectrum. 2

Click below to see the motion of the molecule at frequency 1785 cm-1. This contributes to the motion of the ring.  

Click below to see the motion of the molecule at frequency 1216 cm-1. This is a different motion that also contributes to the ring.


Dipole moments at each level of theory for aniline. The experimental value is 1.13 D.3  
Theory Level  Dipole (D)
PM3  1.541795
AM1  1.296054
321-G  1.627040
631-G  1.455966
6311-G  1.530404

UV/Vis
Transition energies were found in the 321-G and 631-G ab initio levels.  Transition energies (nm) were compared to the experimental values, by viewing the UV/Vis spectrum.  For the highest oscillator strength, which is the greatest intensity, the transition energy in 321-G is 145.63 nm, and in 631-G the transition energy is 148.066 nm. These values do not correspond to experimental values.4  

References:
(1)  http://cccbdb.nist.gov/ .  Geometries. Experimental geometry data for a given species.  aniline.
(2) http://webbook.nist.gov/. IR spectrum of aniline.
(3) Lide, D. R. CRC Handbook of Chemistry and    Physics; CRC Press: Boca Raton, 1992.
(4) http://webbook.nist.gov/. UV/Vis spectrum of aniline.


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