Pyrazole-type complexes with Ni(II) and Cu(II) Jaćimović, Željko K.; Giester, Gerald; Kosović, Milica ...
Journal of thermal analysis and calorimetry,
02/2017, Volume:
127, Issue:
2
Journal Article
Peer reviewed
New nickel(II) and copper(II) coordination compounds were synthesized by the reaction of
N
-(benzyloxycarbonyl)-1
H
-pyrazole-1-carboxamidine ligand (HL) with Ni(II) and Cu(II) acetate in methanolic ...solution. The crystal and molecular structures of the complexes as well as those of the ligand were determined by single-crystal X-ray structure analysis. The octahedral surrounding around the metal centers in the isostructural complexes ML
2
(MeOH)
2
, M = Ni(II), Cu(II), MeOH = methanol, is established by the bidentate coordination of two ligand molecules through the pyrazole nitrogen and the deprotonated nitrogen atom of the carboxamidine group along with the oxygen atoms from two MeOH molecules. Despite that the molecular structure of the complexes was determined by X-ray structure analysis, in the FT-IR spectra of the compounds the characteristic bands for MeOH were missing. By coupled TG–MS measurements, it was found that compounds during the transport and storage exchanged MeOH by water molecules. The amount of the water was calculated on the basis of thermogravimetric data. The antifungal activity of the compounds was tested against fungi
Ph. viticola
and
B. dothidea
and compared to that of a commercial fungicide. Depending on the fungi and on the structure, the compounds showed different, but somewhat lower activity than the commercial fungicide.
In the reaction of 1,3-dimethylpyrazole-5-carboxylic acid (HL) with M(OAc)2·4H2O, (M = Cu or Co), two novel complexes were prepared, the square-planar CuL2(H2O)2 and the octahedral CoL2(MeOH)4. The ...crystal structures were determined by single-crystal X-ray diffraction. In both complexes, the deprotonated acid displays monodentate coordination to the metal ions. According to the results of a CSD survey, this is the first structural report on the metal complexes with an N1-substituted pyrazole-5-carboxylic ligand.
Abstract
C
5
H
12
N
6
O
4
, monoclinic,
P
2
1
/
n
(no. 14),
a
= 4.3368(6) Å,
b
= 15.483(2) Å,
c
= 13.8852(19) Å,
β
= 97.714(3)°,
V
= 923.9(2) Å
3
,
Z
= 4,
R
gt
(
F
) = 0.0411,
wR
ref
(
F
2
) = ...0.1109,
T
= 200(2) K.
Abstract
C
13
H
10
F
3
N
3
O
4
, triclinic,
P
1̅ (no. 2),
a
= 7.0524(14) Å,
b
= 7.8044(16) Å,
c
= 12.954(3) Å,
α
= 97.93(3)°,
β
= 96.29(3)°,
γ
= 100.11(3)°,
V
= 688.6(3) Å
3
,
Z
= 2,
R
gt
(
F
) = ...0.0478,
wR
ref
(
F
2
) = 0.1140,
T
= 200 K.
Abstract
C
9
H
7
BrN
2
O, triclinic,
C
2/
c
(no. 15),
a
= 16.255(3) Å,
b
= 4.4119(9) Å,
c
= 25.923(5) Å,
β
= 107.99(3)°,
V
= 1768.2(7) Å
3
,
Z
= 8,
R
gt
(
F
) = 0.0450,
wR
ref
(
F
2
) = 0.0960, T = ...150 K.
In the reaction of acetone solutions of CoX2?nH2O (X = Cl, Br) with methyl pyruvate semi/thiosemicarbazone (Hmps, Hmpt) the first Co(II) complexes with these ligands, i.e., Co(Hmps)(H2O)X2 (X = Cl ...(1), Br (2)), Co(Hmpt)2CoCl4?2H2? (3) and Co(Hmpt)2Br2?Me2CO (4) were obtained. Complexes 1 and 2 represent the first examples of metal complexes of Hmps. All the obtained compounds were characterized by elemental analysis, conductometry, magnetic measurements, and IR spectra, and for complexes 2?4, single crystal X-ray diffraction analysis was also performed. The effective magnetic moments were close to the upper limit (5 ?B) for complexes 1 and 2, and close to the lower limit (4.4 ?B) for complexes 3 and 4, and as such are characteristic for high-spin Co(II) complexes. Structural analysis showed that both ligands coordinate in a neutral form in a tridentate manner, via the ester oxygen, imine nitrogen and the oxygen atom of the ureido (Hmps), or the sulfur atom of the thioureido group (Hmpt). The central metal atoms are situated in a deformed octahedral coordination environment. Complex 2 has cis-Br configuration, while complexes 3 and 4 have mer-configuration.
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