Synthesis and structure of the pyrazolate-bridged cobalt(II) benzoate Co2(μ-dmpz)2(Hdmpz)2(OOCPh)2

Article abstract of DOI:10.1134/S003602361009010X

The reaction between Co(Hdmpz)₂(OOCPh)₂ and cobalt acetate hydrate leads to the deprotonation of coordinated pyrazole and formation of pyrazolate-bridged Co₂(μ-dmpz)₂(Hdmpz) ₂(OOCPh)₂ binuc

Full text of DOI:10.1134/S003602361009010X

ISSN 0036ꢀ0236, Russian Journal of Inorganic Chemistry, 2010, Vol. 55, No. 9, pp. 1398–1401. © Pleiades Publishing, Ltd., 2010.
Original Russian Text © M.A. Yakovleva, A.A. Andreeva, S.E. Nefedov, 2010, published in Zhurnal Neorganicheskoi Khimii, 2010, Vol. 55, No. 9, pp. 1482–1485.
COORDINATION COMPOUNDS
Synthesis and Structure of the PyrazolateꢀBridged Cobalt(II)
Benzoate Co2( ꢀdmpz)2(Hdmpz)2(OOCPh)2
µ
M. A. Yakovleva, A. A. Andreeva, and S. E. Nefedov
Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences,
Leninskii pr. 31, Moscow, 119991 Russia
eꢀmail: snef@igic.ras.ru
Received January 14, 2010
Abstract—The reaction between Co(Hdmpz)2(OOCPh)2 and cobalt acetate hydrate leads to the deprotonaꢀ
tion of coordinated pyrazole and formation of pyrazolateꢀbridged Co2( ꢀdmpz)2(Hdmpz)2(OOCPh)2 binuꢀ
μ
clear complex. The structure of the complex was determined by Xꢀray crystallography.
DOI: 10.1134/S003602361009010X
The composition and structure of the products of
IR spectra were recorded as KBr pellets on a
reactions between transitionꢀmetal carboxylates NexusꢀNicolet spectrophotometer in the range of
M2(μ
ꢀOOCR)4L2 or M3(
ꢀOOCR)6L2 (M = Zn, Cu, 400–4000 cm–1.
μ
Ni, Co; R = But, Me, Ph; L = NEt3, OC(R')OHNEt3
(R' = Me, Ph)) and 3,5ꢀdimethylpyrazole (Hdmpz),
including the reactions that lead to the formation of
pyrazolateꢀbridged complexes as a result of deprotoꢀ
nation, depend on the transitionꢀmetal nature, reacꢀ
tion conditions, and also on the donor ability of the R
substituent in the carboxylate anion [1–8].
Synthesis of Co2(μꢀdmpz)2(Hdmpz)2(OOCPh)2 (1)
solution of 0.1 (0.2 mmol) of
Co(Hdmpz)2(OOCPh)2 in 10 mL of ꢀxylene, cobalt
.
To
a
g
о
acetate hydrate (0.05 g, 0.2 mmol) was added. The
mixture was stirred at 140°C for 3 h. The resulting
solution was separated from the precipitate by filtraꢀ
tion and kept at +5 С for several days. The violet crysꢀ
°
For example, the reaction between cobalt(II)
μ
tals formed were isolated from the mother liquor by
decantation, washed with hexane, and dried in an
argon flow. Yield, 0.018 g (12%).
pivalate Co3(
ꢀOOCBut)6(NEt3)2 containing donor
tertꢀbutyl substituents in the carboxylate anion and
Hdmpz at room temperature under mild conditions
was shown to lead to deprotonation of pyrazole and
For Co2C34H40N8O4 anal. calcd (%): C, 54.97; H,
5.43; N, 15.09.
formation of a pyrazolateꢀbridged dimer Co2( ꢀ
μ
dmpz)2(Hdmpz)2(OOCBut)2 [1, 2]. After substituꢀ
tion of less donor methyl substituents for tertꢀbutyl
in the initial carboxylate, the analogous reaction
Found (%): C, 54.89; H, 4.97; N, 15.13.
IR (KBr, ν, cm–1): 3700 w, 2924 w, 2852 w, 2368 w,
2336 m, 1664 w, 1604 m, 1552 s, 1524 m, 1448 w, 1388 s,
1296 m, 1184 w, 1048 s, 1016 w, 968 w, 832 w, 792 w,
720 s, 676 m, 620 w, 448 m, 352 w, 392 w, 320 w.
yields
dmpz)4(Hdmpz)2(OOCMe)2 [6, 7]. Lastly, the same
reaction of Co3( ꢀOOCPh)6[OC(Ph)OHNEt3]2 with
the
trinuclear
complex
Co3(
μ
ꢀ
μ
the acceptor phenyl substituent occurs without deproꢀ
tonation of pyrazole, and the monomer
Co(Hdmpz)2(OOCPh)2 is formed [8].
Xꢀray diffraction studies were performed by a stanꢀ
dard procedure on an automated Bruker SMART
Apex II diffractometer equipped with a CCD detector
In this work, we report on the synthesis of binuclear
(
λ
Mo, graphite monochromator,
ω
scan). The strucꢀ
pyrazolateꢀbridged cobalt(II) benzoate structurally tures were solved with the use of SHELXTL PLUS
similar to M2( ꢀdmpz)2(Hdmpz)2(OOCR)2 (M = Zn; (PC version) and refined with SHELXTLꢀ97 [9, 10].
μ
R = But, Me, Ph; M = Co; R = But) complexes.
Crystal data obtained for
742.60) were as follows: space group
8.198(4) = 16.118(9) = 14.108(7)
105.174(19)°, Z = 2,
= 1799.2(15) Å3 (at 296(2) K),
1
(
C34H40Co2N8O4, FW =
P
2(1)/c, a =
Å
,
b
Å
,
c
Å
,
β
=
EXPERIMENTAL
V
All procedures relating to the synthesis and isolaꢀ a total of 14468 reflections, 3532 independent reflecꢀ
tion of complexes were carried out in a pure argon tions with F 2 > 2 ρcalcd = 1.371 g/cm3,
atmosphere with the use of dry solvents. 1 = 0.0798, wR2 = 0.1364.
0.970 cm–1,
σ
(
I
)
,
μ
=
R
1398

SYNTHESIS AND STRUCTURE
1399
2
3
Table 1. Atomic coordinates (×104) and equivalent isotropic parameters (
Å
×
10 ) for complex 1
Atom
x
y
z
Ueq
Atom
C(6)
x
y
z
Ueq
4610(14)
851(6)
1333(7)
78(3)
Co(1)
N(1)
N(2)
N(3)
N(4)
O(1)
O(2)
C(1)
C(2)
C(3)
C(4)
C(5)
840(2)
116(8)
1027(1)
222(4)
361(1)
1233(6)
–928(6)
972(5)
60(1)
60(2)
60(2)
65(2)
71(2)
75(2)
91(2)
62(2)
92(3)
103(4)
68(3)
75(3)
C(7)
C(8)
4515(14)
5943(14)
5400(14)
6222(13)
–292(14)
–72(6)
1353(8)
2155(8)
2981(7)
2766(6)
1266(9)
1779(9)
1701(8)
2046(7)
165(7)
122(4)
101(4)
85(3)
111(4)
67(3)
57(2)
74(3)
87(3)
100(4)
91(3)
80(3)
601(8)
549(4)
3248(9)
3768(10)
–581(7)
1121(8)
186(11)
840(12)
1696(14)
871(12)
405(12)
1325(4)
2112(5)
1997(4)
3104(4)
318(6)
C(9)
1225(5)
208(4)
C(10)
C(11)
410(5)
C(12) –1819(12) 3309(5)
C(13) –1630(13) 4139(5)
C(14) –3034(16) 4638(6)
C(15) –4608(16) 4310(7)
C(16) –4814(13) 3487(7)
C(17) –3407(14) 2980(6)
–197(6)
–336(7)
–667(7)
–865(8)
–710(8)
–384(7)
2179(8)
2697(7)
1109(6)
1742(5) –1679(7)
912(6) –1739(8)
379(7) –2516(7)
RESULTS AND DISCUSSION
The reaction of cobalt acetate hydrate with mononuꢀ
clear pyrazole benzoate Сo(Hdmpz)2(OOCPh)2 in boiling dimer Co2(μꢀdmpz)2(Hdmpz)2(OOCPh)2(
о
ꢀxylene was found to result in deprotonation of coordiꢀ
nated pyrazole and formation of a pyrazolateꢀbridged
). Yield, 52%.
1
Ph
C
Me
Ph
C
Me
Me
Me
Co
Me
N N
O
N
O
Me
O
H
O
H
H
Co(OOCMe)
⋅
4H O
2
2
Xylene 145
N
N N
N N
Co
°
С
H
Co
O
N N
O
N
C
Ph
O
Me
O
N
Et N
3
Me
C
Me
Me
Me
MeCN,
90
Me
Ph
°
С
Noteworthy, cobalt acetate hydrate acts as a deproꢀ nitrogen atom of the terminal pyrazole molecule (Co–N,
tonating agent in this case, whereas the reaction does 1.995(7) Å) and oxygen atom of the terminal benzoate
not occur in the presence of a strong base (triethyꢀ anion (Co–O, 1.928(6) Å). As a result, the binuclear
lamine) in boiling acetonitrile [8].
complex is formed, where each cobalt(II) atom is
electron deficient (15 electrons) and has a distorted
tetrahedral environment.
According to the Xꢀray diffraction data, two cobalt
atoms in
1 (figure; Tables 1, 2), which are at a nonꢀ
bonding Co···Co distance of 3.6283(9) Å, are linked
only by nitrogen atoms of two bridging pyrazolate try of the binuclear pyrazolateꢀbridged pivalate Co2(
ligands (Co(1)–N(1), 1.983(8) Å; Co(1)–N(2), dmpz)2(Hdmpz)2(OOCBut)2
has shown that
A comparison of the geometry of 1 with the geomeꢀ
μ
ꢀ
(2)
1.938(7) Å) formed as a result of deprotonation of 3,5ꢀ replacement of the acceptor phenyl substituent by the
dimethylpyrazole. Each metal atom is bound to a donor tertꢀbutyl that virtually does not influence the
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 55 No. 9 2010

1400
YAKOVLEVA et al.
C(15)
C(12)
C(5)
C(14)
C(13)
C(3)
C(2A)
C(4)
C(16)
C(11)
C(1A)
C(17)
O(1)
C(7A)
N(1A)
C(8A)
C(6A)
N(2)
C(10A)
C(9A)
O(2)
N(3A)
Co(1A)
Co(1)
N(4A)
H(4A)
N(4)
H(4AA)
N(3)
C(6)
O(1A)
C(17A)
N(2A)
O(2A)
C(11A)
C(9)
C(10)
C(7)
N(1)
C(1)
C(8)
C(13A)
C(16A)
C(15A)
C(14A)
C(4A)
C(2)
C(3A)
C(5A)
Structure of complex I.
metal–metal distance, however the distances metal–
nitrogen in become nonequivalent and shorter than
the equalized distances in (Co–N, 1.999(2) and
1.996(1) Å). The bond lengths of the terminal pyrazole
molecules and benzoate anions are somewhat lengthꢀ
As distinct from the electronꢀdeficient cobalt(II)
atom, in structurally similar pyrazolateꢀbridged comꢀ
plexes of tetrahedral electronꢀsaturated zinc (18 elecꢀ
1
2
trons) Zn2( ,
ꢀdmpz)2(Hdmpz)2(OOCR)2 (R = But
μ
Me, Ph), no definite dependence on the nature of the
substituent of the carboxylate anion is observed,
though the metal–metal distances are considerably
ened (in 2, Co–N is 2.015(2) Å and Co–O is 1.942(1) Å).
shortened compared with those in 1 and 2:
Table 2. Selected bond lengths (d) and bond angles (ω) for
complex 1
R
source
t
M···M,
Å
M–μꢀN,
Å
M–NHdmpz,M–OOOCR,
Å
Å
Bond
d
, Å
Bond
d, Å
Bu [2] 3.5821(6) 1.981(2)–1.988(2) 2.030(2) 1.940(1)
Me [7] 3.593(1) 1.976(7)–1.985(6) 2.023(6) 1.949(5)
Ph [7] 3.5827(8) 1.960(4)–1.971(3) 2.008(3) 1.944(2)
Co(1)–O(1)
Co(1)–N(1)
N(1)–C(1)
N(2)–C(4)
N(3)–C(6)
N(4)–C(9)
O(2)–C(11)
1.928(6) Co(1)–N(2)
1.983(8) Co(1)–N(3)
1.938(7)
1.995(7)
1.329(10) N(1)–N(2)#1 1.394(8)
1.354(10) N(2)–N(1)#1 1.393(8)
Therefore, our studies have shown that cobalt aceꢀ
tate hydrate can be a deprotonating agent for the
Hdmpz molecules coordinated in the cobalt pyrazole
benzoate, which leads to formation of pyrazolateꢀ
bridged binuclear cobalt benzoate.
1.339(11) N(3)–N(4)
1.333(10) O(1)–C(11)
1.244(10)
1.355(8)
1.266(10)
Angle
ω
,
deg
Angle
ω
,deg
ACKNOWLEDGMENTS
O(1)Co(1)N(2)
N(2)Co(1)N(1)
N(2)Co(1)N(3)
107.9(3) O(1)Co(1)N(1) 109.3(3)
110.4(3) O(1)Co(1)N(3) 110.7(3)
110.3(3) N(1)Co(1)N(3) 108.2(3)
This work was supported by the Russian Foundaꢀ
tion for Basic Research (project nos. 08ꢀ03ꢀ01063, 08ꢀ
03ꢀ90455), the Council for Grants of the President of
the Russian Federation (the Program for Support of
Leading Scientific Schools of Russia; grant no. NShꢀ
1764.2003.03), and the Presidium and the Division of
Chemistry and Materials Science of the Russian
Academy of Sciences (programs “Theoretical and
Experimental Investigations of the Nature of the
Chemical Bond and the Mechanisms of Important
C(1)N(1)N(2)#1 108.5(7) C(1)N(1)Co(1) 127.3(6)
N(2)#1N(1)Co(1) 124.2(6) C(4)N(2)Co(1) 128.5(6)
N(1)#1N(2)Co(1) 125.1(6) C(6)N(3)Co(1) 131.2(7)
N(4)N(3)Co(1)
123.2(6) C(11)O(1)Co(1) 133.2(7)
Symmetry code: #1 – x, –y, –z.
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 55 No. 9 2010

SYNTHESIS AND STRUCTURE
1401
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