Computer simulation study of the intermolecular structure in phosphoric acidN, N-dimethylformamide mixtures

Irina V. Fedorova, Liubov P. Safonova, Michael G. Kiselev

G. A. Krestov Institute of Solution Chemistry of Russian Academy of Sciences, 1 Akademicheskaya Street, Ivanovo 153045, Russia

SUPPLEMENTARY MATERIALS

Tables S1 and S2 show the bond lengths and angles for the optimized structure of phosphoric acid and DMF calculated with different basis sets. Corresponding experimental values are provided for comparison in the last row.

Table S1. Bond lengths and angles of the H3PO4 molecule.

Optimization method/basis set / Bond lengths, Å / Angles, º
P=O / P-O / H-O / O-P-O / O=P-O / P-O-H
HF / 6-311G(d,p)
6-31++G(d,p)
cc-pVTZ / gas phase / 1.445
1.452
1.444 / 1.570
1.575
1.566 / 0.943
0.951
0.939 / 102.9
102.9
102.8 / 115.4
115.5
115.5 / 114.5
114.2
113.9
6-311G(d,p)
6-31++G(d,p)
cc-pVTZ / DMF / 1.451
1.459
1.450 / 1.568
1.573
1.563 / 0.946
0.949
0.945 / 102.7
102.7
102.8 / 115.6
115.7
115.5 / 115.9
115.6
115.4
MP2 / 6-311G(d,p)
6-31++G(d,p)
cc-pVTZ / gas phase / 1.471
1.487
1.473 / 1.599
1.611
1.596 / 0.962
0.968
0.962 / 102.0
101.7
101.8 / 116.2
116.5
116.4 / 110.4
111.6
110.3
6-311G(d,p)
6-31++G(d,p)
cc-pVTZ / DMF / 1.475
1.491
1.477 / 1.596
1.608
1.592 / 0.964
0.971
0.966 / 101.8
101.6
101.8 / 116.3
116.5
116.4 / 112.0
113.1
111.9
B3LYP / 6-311G(d,p)
6-31++G(d,p)
cc-pVTZ / gas phase / 1.474
1.482
1.472 / 1.604
1.610
1.600 / 0.964
0.968
0.966 / 101.9
101.9
101.9 / 116.2
116.3
116.3 / 112.0
112.1
112.1
6-311G(d,p)
6-31++G(d,p)
cc-pVTZ / DMF / 1.479
1.487
1.476 / 1.601
1.607
1.596 / 0.966
0.971
0.966 / 101.8
101.9
101.9 / 116.3
116.3
116.3 / 113.6
113.6
113.3
Souhassou et al. [22] (crystal) / 1.493 / 1.550-1.554 / 0.933-0.982 / 104.7-107.2 / 112.3-113.3 / 113.7-118.0

All bond lengths of the H3PO4 molecule at the HF level are smaller than the corresponding values at all levels of calculation. This is due to the fact that the SCF calculation neglects the electron correlation which is essential for accurate description of the molecular structure. The structural parameters for acid at B3LYP and MP2 levels of theory are very close. The structure of the H3PO4 molecule has been determined in the crystalline state by X-ray diffraction [22].

The results from the B3LYP calculations for the DMF molecule are closer to the MP2 rather than to the HF results, however the differences are comparable. The theoretically predicted IR spectrum of the DMF molecule at B3LYP/6-31++G(d,p) level of theory is quite close to the experimental spectrum (http:webbook.nist.gov/chemistry) (see Figure S1).

Table S2. Bond lengths and angles of the DMF molecule.

Optimization method/basis set / Bond lengths, Å / Angles, º
C=O / C(O)-N / C(H3)-N / C-H / C(H3)-N-C(H) / N-C-O / N-C(H)-H
HF / 6-311G(d,p)
6-31++G(d,p)
cc-pVTZ / gasphase / 1.191
1.200
1.192 / 1.348
1.344
1.342 / 1.447
1.453
1.449 / 1.093
1.086
1.084 / 118.6
118.2
118.2 / 126.0
125.0
125.1 / 112.4
113.4
113.1
6-311G(d,p)
6-31++G(d,p)
cc-pVTZ / DMF / 1.204
1.215
1.205 / 1.333
1.329
1.328 / 1.458
1.460
1.452 / 1.090
1.088
1.088 / 119.7
119.0
119.6 / 125.3
120.9
125.3 / 113.4
113.9
113.5
MP2 / 6-311G(d,p)
6-31++G(d,p)
cc-pVTZ / gasphase / 1.218
1.236
1.222 / 1.367
1.358
1.353 / 1.449
1.459
1.452 / 1.107
1.091
1.089 / 120.2
120.2
120.3 / 125.7
124.5
124.5 / 111.3
113.1
112.6
6-311G(d,p)
6-31++G(d,p)
cc-pVTZ / DMF / 1.230
1.249
1.232 / 1.349
1.344
1.342 / 1.461
1.466
1.458 / 1.104
1.098
1.098 / 120.2
119.8
120.0 / 124.7
124.7
124.7 / 112.7
113.6
112.9
B3LYP / 6-311G(d,p)
6-31++G(d,p)
cc-pVTZ / gasphase / 1.214
1.226
1.216 / 1.364
1.359
1.355 / 1.454
1.463
1.457 / 1.107
1.096
1.092 / 120.1
120.2
120.3 / 125.8
124.8
124.8 / 111.7
113.0
112.6
6-311G(d,p)
6-31++G(d,p)
cc-pVTZ / DMF / 1.227
1.240
1.228 / 1.348
1.345
1.342 / 1.463
1.465
1.460 / 1.104
1.103
1.101 / 120.1
119.9
120.0 / 125.0
125.0
125.0 / 112.8
113.5
112.9
Schultz et al.[21] (gaseous) / 1.224 (0.003) / 1.391 (0.007) / 1.453 (0.003) / 1.112 (0.003) / 120.8 (0.3) / 123.5 (0.6) / 117.0 (2.8)

Figure S1. Calculated (dashed line) and observed (full line) IR spectra of DMF molecule.