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A. Višnjevac et al. / Polyhedron 28 (2009) 3101–3109
and with cone and desolvation gas flows of 5–10 and 500 L/h,
respectively (details and spectra Figs. S2–S12 in Supplementary
material).
Cl]+ (C33H33N9O9S3CuCl): calc. 893.0548, found: 893.0547
(0.1 ppm).
2.3.2. Cd(1-TsC-N3)2Cl2 (4)
2.2. Preparation of the ligands
Starting materials: solutions of 1-(p-toluenesulfonyl)cytosine
(1) (133 mg, 0.5 mmol) in methanol (23 mL), 2 M aqueous solution
of CdCl2 (0.125 mL, 0.25 mmol). The colorless solution was stirred
overnight and was then left to evaporate at room temperature. After
4 days, colorless prisms were obtained. One transparent colorless
crystal was picked for the X-ray diffraction study, and the remaining
crystals were filtered off and dried in vacuum to give 131 mg (77%)
of white powder 4: 1H NMR (DMSO-d6) d/ppm: 8.75 (brs, 1H, NH),
8.26 (brs, 1H, NH), 8.22 (d, 1H, J6,5 = 8.0 Hz, H-6), 7.88 (d, 2H,
Jb,c = 8.3 Hz, Ph-b), 7.48 (d, 2H, Jc,b = 8.1 Hz, Ph-c), 6.06 (d, 1H,
J5,6 = 8.0 Hz, H-5), 2.41 (s, 3H, CH3); 1H NMR (CD3CN) d/ppm: 8.19
(brd, 1H, H-6), 8.08 (brs, 1H, NH), 7.90 (brd, 2H, Ph-b), 7.43 (brd,
2H, Ph-c), 7.39 (brs, 1H, NH), 6.10 (brd, 1H, H-5), 2.45 (brs, 3H,
CH3); 13C NMR (DMSO-d6) d/ppm: 163.35 (s, C-4), 148.38 (s, C-2),
146.02 (s, Ph-d), 140.38 (d, C-6), 133.29 (s, Ph-a), 129.71 (d, Ph-c),
129.01 (d, Ph-b), 97.13 (d, C-5), 21.17 (q, CH3). ESI-HRMS (m/z):
[MÀTsCÀCl]+ (C11H11N3O3SCdCl): calc. 413.9243, found: 413.9225
(4.3 ppm); [MÀCl]+ (C22H22N6O6S2CdCl): calc. 678.9764, found:
678.9730 (5.0 ppm); [M+TsCÀCl]+ (C33H33N9O9S3CdCl): calc.
944.0286, found: 944.0291 (0.5 ppm).
A mixture of cytosine (1 mmol) and N,O-bis(trimethylsilyl)acet-
amide (BSA) (3 mmol) was heated under reflux in dry acetonitrile
(3.3 mL) for 1 h. The solution was cooled to 0 °C and sulfonyl chlo-
ride (1.2 mmol) was added. The reaction mixture was heated for
16 h at 80 °C, cooled and treated with a small amount of methanol.
The resulting solid was filtered off and recrystallized.
2.2.1. 1-(p-Toluenesulfonyl)cytosine (1)
Synthesis of ligand 1 was performed according to the procedure
reported by Kašnar-Šamprec et al. [7]. [1H NMR (DMSO-d6) d/ppm:
8.14 (d, 1H, J6,5 = 7.8 Hz, H-6), 7.95 (brd, 2H, NH2), 7.87 (d, 2H,
Jb,c = 8.1 Hz, Ph-b), 7.46 (d, 2H, Jc,b = 8.1 Hz, Ph-c), 5.98 (d, 1H,
J5,6 = 7.8 Hz, H-5), 2.42 (s, 3H, CH3); 13C NMR (DMSO-d6) d/ppm:
166.27 (s, C-4), 151.22 (s, C-2), 145.61 (s, Ph-d), 139.73 (d, C-6),
134.47 (s, Ph-a), 129.80 (d, Ph-c), 129.02 (d, Ph-b), 97.50 (d, C-5),
21.20 (q, CH3)]. Anal. Calc. for C11H11N3O3S (Mr = 265.30): C,
49.80; H, 4.18; N, 15.84. Found: C, 50.09; H, 4.02; N, 15.89%.
Additional data for 1-(p-toluenesulfonyl)cytosine (1): 1H NMR
(CD3CN) d/ppm: 8.13 (d, 1H, J6,5 = 7.9 Hz, H-6), 7.92 (brd, 2H,
Jb,c = 8.4 Hz, Ph-b), 7.46 (d, 2H, Jc,b = 8.0 Hz, Ph-c), 6.42 (brd 2H,
NH2), 5.98 (d, 1H, J5,6 = 7.8 Hz, H-5), 2.49 (s, 3H, CH3).
2.3.3. Co(1-TsC-N3)2Cl2 (5)
Starting materials: solutions of 1-(p-toluenesulfonyl)cytosine
(1) (130 mg, 0.5 mmol) in methanol (40 mL), CoCl2 Â 6H2O
(60 mg, 0.25 mmol) in methanol (4 mL). The resulting dark violet
solution was left to slowly evaporate at room temperature yielding
112 mg of blue powder 5: 1H NMR (DMSO-d6) d/ppm: 8.10 (d, 1H,
J6,5 = 8 Hz, H-6), 7.90 (brd, 2H, NH2), 7.84 (d, 2H, Jb,c = 8.4 Hz, Ph-
b), 7.44 (d, 2H, Jc,b = 8.4 Hz, Ph-c), 5.93 (d, 1H, J5,6 = 7.9 Hz, H-5),
2.40 (s, 3H, CH3); 1H NMR (CD3CN) d/ppm: 8.05 (brd, 1H, H-6),
7.85 (brd, 2H, Ph-b), 7.40 (brd, 2H, Ph-c), 6.33 (brs, 2H, NH2), 2.42
(brs, 3H, CH3). ESI-HRMS (m/z): [MÀCl]+ (C22H22N6O6S2CoCl): calc.
624.0063, found: 624.0041 (3.5 ppm); [M+TsCÀCl]+ (C33H33N9O9-
S3CoCl): calc. 889.0584, found: 889.0582 (0.2 ppm).
2.2.2. 1-Methanesulfonylcytosine (6)
1-Methanesulfonylcytosine (6) was prepared according to the
literature method [8]. [1H NMR (DMSO-d6) d/ppm: 8.21 (brs, 1H,
NH), 8.05 (brs, 1H, NH), 7.87 (d, 1H, J6,5 = 7.8 Hz, H-6), 5.96 (d,
1H, J5,6 = 7.9 Hz, H-5), 3.63 (s, 3H, CH3); 13C NMR (DMSO-d6) d/
ppm: 165.44 (s, C-4), 151.42 (s, C-2), 139.45 (d, C-6), 96.64 (d,
C-5), 41.13 (q, CH3)]. Anal. Calc. for C5H7N3O3S (Mr = 189.20): C,
31.74; H, 3.73; N, 22.21. Found: C, 31.92; H, 4.01; N, 22.02%.
2.3. Preparation of the complexes
To a water or methanol solution of MCl2 Â nH2O (1 equiv.), the
1-sulfonylcytosine ligand (2 equiv.) in methanol was added and
the reaction mixture was left stirring. The solid product obtained
by evaporation was filtered off, washed with methanol and dried.
2.3.4. Cu(1-MsC-N3)2Cl2 (7)
Starting materials: solutions of 1-methanesulfonylcytosine (6)
(113 mg, 0.6 mmol) in methanol (40 mL), CuCl2 Â 2H2O (51 mg,
0.3 mmol) in methanol (2 mL). The resulting turquoise solution
was left to slowly evaporate at room temperature in order to ob-
tain high quality single crystals. After 5 days, dark green prisms
were obtained, one of which was picked for X-ray diffraction mea-
surements, while the others were filtered off, yielding 137 mg
(89%) of dark green powder 7: 1H NMR (DMSO-d6) d/ppm: 7.97
(brs, 2H, NH2), 7.32 (brs, 1H, H-6), 3.67 (s, 3H, CH3); 13C NMR
(DMSO-d6) d/ppm: 136.06 (d, C-6), 39.01 (q, CH3). ESI-HRMS (m/
z): [MÀCl]+ (C10H14N6O6S2CuCl): calc. 475.9401, found: 475.9388
(2.7 ppm).
2.3.1. Cu(1-TsC-N3)2Cl2 (2)
Starting materials: solutions of 1-(p-toluenesulfonyl)cytosine
(1) (133 mg, 0.5 mmol) in methanol (23 mL), CuCl2 Â 2H2O
(43 mg, 0.25 mmol) in methanol (5 mL). The resulting dark green
solution was left to slowly evaporate at room temperature in order
to obtain high quality single crystals. After 7 days, two types of sin-
gle crystals were present in the crystallization vessel – deep blue
prisms (X-ray structure 2) and turquoise plates [methanol solvate
of 2, X-ray structure 3 (2 Â 2CH3OH)]. After selection of single
crystals suitable for X-ray diffraction experiments, the remaining
crystals were filtered off and dried in vacuum to remove the
methanol yielding 110 mg (66%) of the blue-green complex 2: 1H
NMR (DMSO-d6) d/ppm: 8.25 (brs, 1H, H-6), 7.89 (brs, 2.5H,
Ph-b + part of NH2), 7.42 (brs, 3.5H, Ph-c + part of NH2), 2.34 (brs,
3H, CH3); 1H NMR (CD3CN) d/ppm: 9.48 (brs, 1H), 8.71 (brs, 2H),
7.79 (brs, 2H), 2.59 (brs, 3H, CH3); 13C NMR (DMSO-d6) d/ppm:
143.22 (s, Ph-d), 132.13 (s, Ph-a), 127.58 (d, Ph-c), 126.75 (d,
Ph-b), 19.27 (q, CH3). Anal. Calc. for C22H22Cl2CuN6O6S2 Â 2H2O
(Mr = 701.06): C, 37.69; H, 3.74; N, 11.99. Found: C, 37.29; H,
4.10; N, 11.74%. ESI-HRMS (m/z): [MÀTsCÀCl]+ (C11H11N3O3SCuCl):
calc. 362.9506, found: 362.9494 (3.3 ppm); [MÀCl]+ (C22H22N6-
O6S2CuCl): calc. 628.0027, found: 627.9995 (5.1 ppm); [M+TsC –
2.3.5. Cd(1-MsC-N3)2Cl2 (8)
Starting materials: solutions of 1-methanesulfonylcytosine (6)
(113 mg, 0.6 mmol) in methanol (40 mL), 2 M aqueous solution
of CdCl2 (0.15 mL, 0.3 mmol). After 1 h, a white precipitate was
formed. It was filtered off and dried in vacuum to give 131 mg
(77%) of snow-white powder 8. The mother liquor was left to crys-
tallize, but the colorless prisms formed after four days turned out
to be single crystals of ligand 6. Complex 8: 1H NMR (DMSO-d6)
d/ppm: 7.92 (brs, 1H, NH), 7.89 (brs, 1H, NH), 7.84 (d, 1H,
J6,5 = 7.8 Hz, H-6), 5.90 (d, 1H, J5,6 = 7.8 Hz, H-5), 3.62 (s, 3H,
CH3); 13C NMR (DMSO-d6) d/ppm: 166.06 (s, C-4), 152.08 (s, C-2),
139.08 (d, C-6), 96.68 (d, C-5), 41.05 (q, CH3). ESI-HRMS (m/z):
[MÀClÀHCl]+ (C10H13N6O6S2Cd): calc. 490.9372, found: 490.9345