Microanalytical data (%), Calculated for [C
1.26; H, 2.97; N, 16.53. Found C, 20.89; H, 2.99; N, 16.93. HCl
gas absorption: A vial containing 25 mg of [CoCl (Hpz) ] (2) was
placed in a sealed jar. This was flushed with dry nitrogen gas to
displace any moisture present and then filled with dry HCl gas.
The pink powder changed to blue after one hour of exposure.
3
H
5
N
2
]
2
[CoCl
4
]: C,
[ZnCl
2
(Hpz)
2
]
(4). Mechanochemical synthesis: 136 mg
2
(2 mmol) of pyrazole and 136 mg (1 mmol) of ZnCl were forcefully
ground in an agate mortar, resulting in the formation of a white
polycrystalline powder. Microanalytical data (%), Calculated for
2
2
2
[(C
H, 3.09; N, 20.97. Mechanochemical elimination (KOH): 70 mg
(0.2 mmol) of [C [ZnCl ] was ground with 22 mg (0.4 mmol)
of KOH in an agate mortar. Microanalytical data (%), Calculated
for [(C ZnCl ] + 2KCl: C, 17.10; H, 1.91; N, 13.29.
Found C, 16.65; H, 1.90; N, 13.33. Mechanochemical elimination
(K CO ): 35 mg (0.1 mmol) of [C [ZnCl ] was ground with
14 mg (0.1 mmol) of K CO in an agate mortar. The reaction
proceeded with no apparent colour change. Microanalytical data
(%), Calculated for [(C ZnCl ] + 2KCl: C, 17.10; H,
.91; N, 13.29. Found C, 17.55; H, 2.09; N, 13.49. Reaction of
pyrazolium chloride with 3Zn(OH) : 500 mg (5 mmol)
·2ZnCO
of pyrazolium chloride was ground with 275 mg (0.5 mmol) of
Zn(OH) . The title compound was formed as a white
·2ZnCO
powder following a mild effervescence. Microanalytical data (%),
Calculated for [(C ZnCl ]: C, 26.45; H, 2.96; N, 20.56.
3
H
4
N
2
)
2
ZnCl
2
]: C, 26.45; H, 2.96; N, 20.56. Found C, 26.92;
Microanalytical data (%) Calculated for [C
1.26; H, 2.97; N, 16.53. Found C, 21.06; H, 2.94; N, 16.23.
Solution synthesis: 136 mg (2 mmol) of pyrazole was dissolved in
conc. HCl (5 ml) and CoCl O (238 mg, 1 mmol) was added.
3
H
5
N
2
]
2
[CoCl
4
]: C,
3
H
5
N
2
]
2
4
2
3
H
4
N
2
)
2
2
2
·6H
2
The solution was allowed to evaporate at room temperature and,
after a few days, blue crystals were obtained. Microanalytical data
2
3
3
H
5
N
2
]
2
4
2
3
(
%) calculated for [C
3
H
5
N
2
]
2
[CoCl ]: C, 21.26; H, 2.97; N, 16.53.
4
Found C, 20.95; H, 3.07; N, 16.12.
3
H
4
N
2
)
2
2
1
[
CoCl (Hpz) (2). Mechanochemical synthesis: 129 mg
2
2
]
2
3
(
1 mmol) of anhydrous CoCl and 136 mg (2 mmol) of pyrazole
2
were forcefully ground in an agate mortar, resulting in the
formation of a pink polycrystalline powder. Microanalytical data
3
2
3
(
%) calculated for [(C
Found C, 24.79; H, 3.20; N, 19.82. Reaction of pyrazolium
chloride with (i) Co(OH) : 209 mg (2 mmol) of pyrazolium
chloride was ground with 93 mg (1 mmol) of Co(OH) forming
{CoCl (Hpz) ] as a pink powder, which was dried in vacuo.
Microanalytical data (%), Calculated for [(C CoCl ]: C,
3.09; H, 3.03; N, 21.06. Found C, 26.83; H, 3.22; N, 20.98. (ii)
3
H
4
N
2
)
2
CoCl
2
]: C, 25.37; H, 3.55; N, 19.73.
3
H
4
N
2
)
2
2
Found C, 26.58; H, 2.97; N, 20.76. Crystal synthesis: A small
amount of the white powder of 4 was dissolved in acetonitrile
and the solution allowed to evaporate slowly at room temperature.
After a few days plate-like colourless crystals of the title compound
were obtained.
2
2
[
2
2 n
}
3
H
4
N
2
)
2
2
1
CoCO
3
: 209 mg (2 mmol) of pyrazolium chloride was forcefully
forming [{CoCl (Hpz)
as a pink powder, which was dried in vacuo. Microanalytical data
%), Calculated for [(C CoCl ]: C, 13.09; H, 3.03; N, 21.06.
[H
(1 mmol) of anhydrous CuCl
chloride were ground in an agate mortar, forming a dark brown
2
pz][CuCl
4
]
(5). Mechanochemical synthesis: 134 mg
ground with 119 mg (1 mmol) of CoCO
3
2
2
}
n
]
2
and 209 mg (2 mmol) of pyrazolium
(
3
H
4
N
2
)
2
2
powder of [C
for [C
3
H
[CuCl
5
N
2
]
2
[CuCl
4
]. Microanalytical data (%), Calculated
Found C, 13.04; H, 3.08; N, 21.30. Mechanochemical elimination
with: (i) KOH: 34 mg (0.1 mmol) of 1 was ground with 11 mg
3
H
5
N
2
]
2
4
]: C, 20.98; H, 2.93; N, 16.31. Found C, 20.89;
H, 2.82; N, 16.33. HCl gas absorption: A vial containing 25 mg of
6 was placed in a jar. This was flushed with dry nitrogen gas to
displace any moisture present and then filled with dry HCl gas. The
green powder changed to brown after a few minutes of exposure.
(
0.2 mmol) of KOH resulting in the formation of a pink powder.
Microanalytical data (%), Calculated for [(C CoCl ] +
KCl: C, 17.36; H, 1.94; N, 13.50. Found C, 17.19; H, 2.12; N,
3.69. (ii) K CO : 34 mg (0.1 mmol) of 1 was ground with 14 mg
CO resulting in the formation of a pink powder.
Microanalytical data (%), Calculated for [(C CoCl ] +
KCl: C, 17.36; H, 1.94; N, 13.50. Found C, 17.67; H, 2.15; N,
3.07. Crystal synthesis: A small amount of the pink powder of 2
3
H
4
N
2
)
2
2
2
1
2
3
Microanalytical data (%) Calculated for [C
3
H
5
N
2
]
2
[CuCl ]: C,
4
(
0.1 mmol) of K
2
3
20.98; H, 2.93; N, 16.31. Found C, 21.31; H, 3.41; N, 16.56.
3
H
4
N
2
)
2
2
[
CuCl (Hpz) (6). Mechanochemical synthesis: 134 mg
1 mmol) of anhydrous CuCl and 136 mg (2 mmol) of pyrazole
were forcefully ground in an agate mortar, resulting in the for-
mation of [{CuCl (H pz) ] 6 as a green polycrystalline powder,
which was dried in vacuo. The same product was obtained when
CuCl O was ground with two molar equivalents of pyrazole.
·2H
Microanalytical data (%), Calculated for [(C CuCl ]: C,
2
2
]
2
1
(
2
was dissolved in acetonitrile and the solution allowed to evaporate
slowly at room temperature. After a few days pink crystals of the
title compound were obtained.
2
2
2 n
}
2
2
[H
2
pz][ZnCl
4
]
(3). Mechanochemical synthesis: 136 mg
and 209 mg (2 mmol) of pyrazolium chloride
3
H
4
N
2
)
2
2
(
1 mmol) of ZnCl
2
26.63; H, 2.98; N, 20.70. Found C, 26.76; H, 3.05; N, 21.02.
Mechanochemical elimination (KOH): 34 mg (0.1 mmol) of 5 were
forcefully ground with 11 mg (0.2 mmol) of KOH causing a colour
change from dark brown to green. Excess water was removed in
were ground in an agate mortar forming 3 as a white crystalline
powder which was then dried in vacuo. Microanalytical data (%),
Calculated for [C
Found C, 21.06; H, 2.96; N, 16.48. HCl gas absorption: A vial
containing 44 mg of [(C ZnCl ] 4 was placed in a sealed
3
H
5
N
2
]
2
[ZnCl ]: C, 20.87; H, 2.92; N, 16.22.
4
vacuo. Microanalytical data (%) for [(C
Calculated: C, 17.17; H, 1.92; N, 13.35. Found C, 17.58; H, 2.32;
N, 13.73. Mechanochemical elimination (K CO ): 34 mg (0.1 mmol)
] was forcefully ground with 14 mg (0.1 mmol)
causing a colour change from dark brown to green.
3
H
4
N
2
)
2
CuCl ] + 2KCl,
2
3
H
4
N
2
)
2
2
jar, which was flushed with nitrogen gas and then filled with
dry HCl gas for 8 h. Microanalytical data (%), Calculated for
2
3
of [C
of K
3
H
CO
5
N
2
]
2
[CuCl
4
[
3
C
3
H
5
N
2
]
2
[ZnCl
.02; N, 15.87. Solution synthesis: 136 mg (2 mmol) of pyrazole
was dissolved in conc. HCl (5 ml) and ZnCl (136 mg, 1 mmol)
4
]: C, 20.87; H, 2.92; N, 16.22. Found C, 20.85; H,
2
3
Excess water was removed in vacuo. Microanalytical data (%) for
[(C CuCl ] + 2KCl, Calculated: C, 17.17; H, 1.92; N, 13.35.
Found C, 17.51; H, 2.25; N, 13.75. Reaction of pyrazolium chloride
with Cu(OH) : 418 mg (4 mmol) of pyrazolium chloride
·CuCO
was ground with 221 mg (1 mmol) of Cu(OH) , forming
·CuCO
a green powder of [{CuCl (H pz) ], which was dried in vacuo.
2
3
H
4
N
2
)
2
2
was added. The solution was allowed to evaporate at room tem-
perature, and after a few days colourless crystals were obtained.
Microanalytical data (%), Calculated for [C
2
3
3
H
5
N
2
]
2
[ZnCl
4
]: C,
2
3
2
0.87; H, 2.92; N, 16.22. Found C, 20.42; H, 2.78; N, 16.03.
2
2
2 n
}
6
982 | Dalton Trans., 2010, 39, 6974–6984
This journal is © The Royal Society of Chemistry 2010