598
Bohm, Ruppertova, Havlicek, Kuthan:
Benzene–Water Cluster of 2,4,6-Triphenylpyridinium-1-(2-benzimidazolate) (1a)
A solution of perchlorate 2a (ref.3; 1 g, 2 mmol) in chloroform (5 ml) was chromatographed on a
column of alumina (100 g, II-neutral according to Brockmann) in the same solvent. Red fractions were
collected and evaporated in vacuo. The residue (0.8 g, 81%) was crystallized from a benzene–heptane
mixture and gave a ternary addition compound (orange crystals) of m.p. 265–267 °C. References2,4
give m.p. 255–257 °C and 265–268 °C for compound 1a. For C30H21N3 . C6H6 . H2O (519.6) calculated:
83.21% C, 5.62% H, 8.09% N; found: 83.17% C, 5.69% H, 8.16% N. HR MS for [C30H21N3–H]+
calculated: 422.1657, measured: 422.1660. 1H NMR spectrum: 6.95–6.99 m, 2 H (H-4a and H-7a);
7.18–7.29 m, 6 H (m,p-Ph and m,p-Ph6); 7.40–7.44 m, 2 H (H-5a and H-6a); 7.49–7.54 m, 4 H (o-Ph2
and o-Ph6); 7.60–7.67 m, 3 H (m,p-Ph4); 7.85–7.89 m, 2 H (o-Ph4); 8.06 s, 2 H (H-3 and H-5). 13C NMR
spectrum: 118.09 CH, 119.81 CH, 125.05 CH, 128.52 CH, 128.98 CH, 129.53 CH, 130.63 CH,
131.04 CH, 132.96 CH, 133.74 C, 134.98 C, 151.84 C, 156.67 C, 158.65 C.
Chloroform–Water Cluster of 4-(4-Nitrophenyl)-2,6-diphenyl-1-(2-benzimidazolate) (1b)
A mixture 4-(4-nitrophenyl)-2,6-diphenylpyrylium perchlorate5 (1 g, 2.2 mmol) and 2-aminobenzi-
midazole (0.31 g, 2.3 mmol) and ethanol (10 ml) was stirred and refluxed for 3 h. Yellow pyridinium
salt 2b crystallized from the reaction mixture after cooling, yield 0.9 g (72%), m.p. 172–174 °C. In
1
the HR MS for [C30H21ClN4O6 – HClO4]+ calculated: 468.1586, found: 468.1558. H NMR spectrum:
7.02–7.06 m, 2 H (H-4a and H-7a); 7.22–7.36 m, 6 H (m,p-Ph2 and m,p-Ph6); 7.40–7.44 m, 2 H
(H-5a and H-6a); 7.57–7.62 m, 4 H (o-Ph2 and o-Ph6); 8.05–8.09 m, 2 H (m-Ph4); 8.12 s, 2 H, (H-3
and H-5); 8.46–8.50 m, 2 H (o-Ph4). 13C NMR spectrum: 117.98 CH, 121.04 CH, 125.61 CH, 126.07 CH,
129.24 CH, 129.67 CH, 129.93 CH, 131.56 CH, 133.56 C, 141.07 C, 143.81 C, 150.51 C, 154.84 C,
159.43 C. Work-up as decribed in the case of betaine 1a provided 0.7 g (70%) of a red product of
m.p. 228–231 °C after crystallization from chloroform. For C30H20N4O2 . CHCl3 . 1/2 H2O (596.9)
calculated: 62.37% C, 3.72% H, 9.39% N; found: 62.49% C, 3.65% H, 9.01% N. In the HR MS for
[C30H20N4O2]+• calculated: 468.1586, found: 468.1550. 1H NMR spectrum: 7.18–7.22 m, 2 H (H-4a
and H-7a); 7.24–7.39 m, 8 H (H-5a, H-6a, m,p-Ph2, m,p-Ph6); 8.09–8.13 m, 2 H (m-Ph4); 8.22 s, 2 H
(H-3 and H-5); 8.39–8.43 m, 2 H (o-Ph4). 13C NMR spectrum: 116.90 CH, 125.09 CH, 125.50 CH,
127.29 CH, 129.47 CH, 129.98 CH, 130.44 CH, 131.58 C, 132.19 CH, 140.81 C, 141.08 C, 150.64 C,
157.85 C, 159.27 C.
Toluene–Water Cluster of 4-(4-Dimethylaminophenyl)-2,6-diphenylpyridinium-1-(2-benzimidazolate) (2c)
4-(4-Dimethylaminophenyl)-2,6-diphenylpyrylium perchlorate6 was converted to corresponding py-
ridinium salt 2c in the same way as in the case of 2b. Yield 72% of perchlorate 2c, m.p. 163–165
°C. In the HR MS for [C32H27N4ClO4 – HClO4]+ calculated: 466.2157, found: 466.2130. 1H NMR
spectrum: 6.77–6.82 m, 2 H (m-Ph4); 6.92–6.96 m, 2 H (H-4′ and H-7′); 7.15–7.28 m, 6 H (m,p-Ph2
and m,p-Ph6); 7.38–7.42 m, 2 H (H-5′ and H-6′); 7.48–7.53 m, 4 H (o-PH2 and o-Ph6); 7.79–7.84 m, 2
H (o-Ph4); 7.90 s, 2 H (H-3 and H-5). 13C NMR spectrum: 40.73 CH3, 113.03 CH, 117.94 CH, 119.43 CH,
120.31 C, 121.78 CH, 128.76 CH, 129.47 CH, 130.05 CH, 130.54 CH, 134.41 C, 145.57 C, 152.20 C,
153.92 C, 155.27 C, 157.37 C.
Salt 2c (0.6 g) was chromatographed on alumina (80 g) in the same way as in the case of 2a but
using a chloroform–toluene (1 : 1) mixture as eluent. Yield 0.35 g (64%) orange crystals of inner salt
1c melting in the region of 188–208 °C (after crystallization from a chloroform–toluene mixture). For
C32H26N4 . 1/3 C7H8 . 5/3 H2O (527.3) calculated: 78.20% C, 6.11% H, 10.62% N; found: 78.26% C,
5.77% H, 10.48% N. In the HR MS for [C32H26N4]+• calculated: 466.2157, measured: 466.2130.
1H NMR spectrum: 6.47–6.79 m, 2 H (m-Ph4); 7.10–7.14 m, 2 H (H-4a and H-7a); 7.19–7.28 m,
Collect. Czech. Chem. Commun. (Vol. 61) (1996)