Definitions Cytosine Thiocytosine
Cyt Cyt+ Cyt- TCyt TCyt+ TCyt-
Cal Exp [6] Cal Cal Exp [7] Cal
r (N1-C2) 1.428 1.356 1.425 1.423 1.407 1.367 1.366 1.394
r (C2-N3) 1.369 1.372 1.345 1.354 1.354 1.343 1.306 1.325
r (N3-C4) 1.317 1.354 1.345 1.352 1.323 1.345 1.351 1.383
r (C4-C5) 1.440 1.413 1.435 1.407 1.437 1.426 1.432 1.380
r (C5-C6) 1.356 1.345 1.387 1.377 1.358 1.354 1.356 1.405
r (C5-H10) 1.080 0.950 1.082 1.085 1.081 0.940 1.081 1.085
 r (N1-C6) 1.354 1.361 1.330 1.384 1.353 1.355 1.370 1.411
r (C6-H11) 1.083 1.020 1.084 1.082 1.083 0.960 1.082 1.081
r (N1-H7) 1.010 0.850 1.018 1.008 1.011 0.860 1.013 1.010
r (C2-O8/S8) 1.216 1.226 1.233 1.236 1.672 1.702 1.743 1.727
r (C4-N9) 1.360 1.312 1.331 1.397 1.355 1.332 1.329 1.421
r (N9-H12) 1.008 0.900 1.012 1.015 1.008 0.960 1.011 1.014
r (N9-H13) 1.005 0.800 1.009 1.018 1.005 0.900 1.009 1.014
a (C6-N1-C2) 123.3 122.6 121.5 122.9 123.2 122.0 119.8 123.0
a (C6-N1-H7) 121.4   122.2 120.8 121.4   119.7 120.9
a (N1-C6-H11) 116.9   118.1 117.8 116.7   116.3 117.1
a (N1-C6-C5) 120.0 121.4 119.5 117.6 120.1 120.1 120.1 115.5
a (C6-C5-H10) 121.5   119.7 120.9 121.5   120.7 120.2
a (C6-C5-C4) 116.1 118.1 118.4 117.3 115.8 116.7 117.4 118.5
a (C5-C4-N9) 119.0 123.5 121.9 120.5 119.8 119.2 122.2 122.5
a (C5-C4-N3) 124.0 118.0 120.8 124.3 123.4 122.3 120.7 124.1
a (C4-N9-H12) 117.6 116.0 118.9 111.5 118.1   119.3 108.5
a (C4-N9-H13) 121.4 124.0 122.7 115.2 122.2   122.1 113.0
a (C4-N3-C2) 120.5 124.3 120.2 119.2 120.7 119.3 119.6 118.4
a (N1-C2-N3) 116.1 115.5 119.6 117.3 116.8 119.6 122.4 119.9
a (N1-C2-O8/S8) 118.3 123.4 116.4 117.2 118.3 117.6 120.8 116.0
d(C2-N1-C6-H11) 180.0   180.0 -168.6 180.0   180.0 172.0
d(C2-N1-C6-C5) 0.0   0.0 13.2 0.0   0.0 10.0
d(H7-N1-C6-H11) 0.0   0.0 -4.1 0.0   0.0 -23.3
d(H7-N1-C6-C5) -180.0   180.0 177.7 180.0   180.0 174.7
d(C6-N1-C2-N3) 0.2   0.0 -11.8 0.0   0 -7.6
d(C6-N1-C2-O8/S8) 180.0   180.0 169.1 180.0   180.0 172.7
d(H7-N1-C2-N3) -179.8   180.0 -177.1 -180.0   180.0 -173.3
d(H7-N1-C2-O8/S8) 0.0   0.0 3.8 0.0   -0.1 7.0
d(N1-C6-C5-H10) 179.6   180.0 179.1 180.0   180.0 174.3
d(N1-C6-C5-C4) 0.0   0.0 -4.5 0.0   0.0 -6.4
d(H11-C6-C5-H10) -0.4   0.0 1.0 -0.1   0.0 13.8
d(H11-C6-C5-C4) -180.0   180.0 177.4 -180.0   180.0 -167.0
d(C6-C5-C4-N9) 179.0   180.0 176.4 -180.0   180.0 -179.4
d(C6-C5-C4-N3) -0.2   0.0 -5.5 -0.1   -0.1 1.0
d(H10-C5-C4-N9) -0.7   0.0 -7.2 -0.2   -0.1 -0.1
d(H10-C5-C4-N3) -179.8   180.0 171.0 -180.0   180.0 -179.8
d(C5-C4-N9-H12) 174.3   180.0 156.4 178.5   180.0 164.0
d(C5-C4-N9-H13) 10.6   0.0 26.7 3.0   0.1 41.4
d(N3-C4-N9-H12) -6.6   0.0 -21.8 -1.8   -0.1 -16.4
d(N3-C4-N9-H13) -170.3   180.0 -151.5 -177.4   180.0 -139.0
d(C5-C4-N3-C2) 0.4   0.0 7.0 0.1   0.1 1.8
d(N9-C4-N3-C2) -178.8   180.0 -175.0 -180.0   180.0 -178.0
d(C4-N3-C2-N1) -0.3   0.0 1.6 -0.1   0.0 -178.8
d(C4-N3-C2-O8/S8) 180.0   180.0 -179.5 180.0   180.0 1.5
*r: bond lengths (Å); a: bond angles (°); d: dihedral angle (°)
Table 1: Experimental and Calculated Structural Parameters* of Cyt, TCyt and their cations and anions.