N. Turan, K. Buldurun, R. Adiguzel et al.
Journal of Molecular Structure 1244 (2021) 130989
(ε, L mol−1 cm−1) 220 (486), 236 (596), 364 (688) nm. Color: Yel-
low.
Azo dye ligand (L) (0.5 g 2.16 mmol) was dissolved in ethanol
(15 mL). FeCl2•4H2O, CoCl2•6H2O, ZnCl2 and [RuCl2(p-cymene)]2
(0.43 g; 2.16 mmol, 0.514 g; 2.16 mmol, 0.29 g; 2.16 mmol, 0.66 g;
1.08 mmol, respectively) dissolved in ethanol (10 mL) were added.
The reaction was refluxed for 4 h. The reaction was completed, fol-
lowing the formation of the reaction with TLC. The solvent was re-
moved. The precipitate formed was filtered, washed with diethyl
ether, and dried under vacuum. The product obtained was crystal-
lized in a methanol-dichloromethane (1/2) mixture (Fig. 4).
[FeLCl2(H2O)2]: Yield: 82%. FW: 393.75 g/mol. μeff (B.M.): 4.85.
Anal. Calc. for C11 H17 N5O3FeCl2: C; 33.53, H; 4,32, N; 17.76. Found:
C; 33.91, H; 4.81, N; 17.81. Selected IR data (KBr, cm−1): ν: 3438
(NH), 3321, 3207 (NH2)broad, 3168 (Ar-CH), 2960 (Alip.-CH), 1643
(pyrazole C=C), 1596 (N=N), 1539 (C=N), 1502, 1469, 1429 (Ar-
C=C), 1402, 1245 (C-N), 1029 (=N-NH-) and (δ:NH) band is hid-
den due to broad bands between 815–684 cm−1, 815 (M-OH2),
526 ν(M-N), 484 ν(M-O). UV-Vis. (in EtOH): λ max (ε, L mol−1
cm−1) 209 (952), 213 (190), 227 (572), 236 (571), 243 (952), 255
(1496), 381 (976), 708 (44) nm. MS [ES]: m/z 393.75 (calc.), 393.30
(found) [M]+. Color: Brownish yellow.
Schema 1. . Coupling reaction in the obtaining of the ligand (L).
Schema 2. Ring closure reaction in the obtaining of the ligand (L).
the present study, we synthesized a new series of pyrazole deriva-
tives and evaluated their enzyme inhibitory and antioxidant activ-
ities.
2. Experimental section
[CoLCl2(H2O)2]•1.5H2O: Yield: 80%. FW: 424.14 g/mol. μeff
(B.M.): 3.93. Anal. Calc. for C11 H20N5O4.5CoCl2: C; 31.15, H; 4.75,
N; 16.51. Found: C; 31.28, H; 4.49, N; 16.63. Selected IR data (KBr,
cm−1) ν: 3433 (NH), 3320, 3231 (NH2)broad, 3134, 3096 (Ar-CH),
2963 (Alip.-CH), 1597 (N=N), 1587 (pyrazole C=C), 1539 (C=N),
1500, 1456, 1434 (Ar-C=C), 1403, 1247 (C-N), 1027 (=N-NH-), 815
(M-OH2), 781 (δ: NH), 573, 527 (M-N), 455 (M-O). UV-Vis. (in
EtOH): λ max, nm (ε, L mol−1 cm−1) 220 (100), 243 (190), 262,
289, 296 (4000), 305, 321, 351, 361, 382, 399 (4000), 412 (4000),
429 (3818), 434 (3762), 452 (3761), 615 (76), 678 (117) nm. MS
[ES]: m/z 427.14 (calc.), 427.37 (37Cl isotopic peak) (found) [M+2]+.
Color: Brownish yellow.
2.1. Materials and measurements
All used solvents were of analytical grade and no further purifi-
cations were performed. The metal salts CoCl2•6H2O, FeCl2•4H2O,
ZnCl2, and [RuCl2(p-cymene)]2 and starting materials for the lig-
and were purchased from Merck, Aldrich, and Alfa Aesar. Elemen-
tal analyses were carried out with a Leco CHNS-O model 932
elemental analyzer. FT-IR spectra were recorded with a Perkin
Elmer Precisely Spectrum One spectrometer using KBr discs in the
wavenumber range of 4000–400 cm−1. Electronic spectral stud-
ies were conducted with a Shimadzu model UV-1800 Spectropho-
tometer in the wavelength 1100–200 nm. Magnetic susceptibility
measurements were carried out using the standart Gouy tube tech-
nique to Hg[Co(SCN)4] as a calibrator/calibration. 1H NMR and 13C
NMR data were obtained in DMSO-d6 solvent on a Bruker AVANCE
400 spectrometer at room temperature. The high-resolution mass
spectra (HRMS) were obtained on a Waters LCT Premier XE Mass
Spectrometer also coupled to an EQUITY Ultra Performance Liquid
Chromatography System. Thermogravimetric analysis (TGA) and
differential thermal analysis (DTA) were carried out in a nitrogen
atmosphere with a heating rate of 10 °C/min. using Shimadzu DTG-
60 AH (Shimadzu DSC 60 A) thermal analyzers. A sample size of 5–
10 mg was used and sintered α-alumina was used as the reference
material.
[ZnLCl (H2O)]•Cl•H2O: Yield: 76%. FW: 403.29 g/mol. μeff
(B.M.): Dia. Anal. Calc. for C11 H17 N5O3ZnCl2: C; 32.75, H; 4.25
N; 17.35. Found: C; 32.55, H; 4.45, N; 17.05. 1H NMR (DMSO-
d6, 400 MHz) δ: 11.81 (s, 2H, NH), 7.69–6.96 (m, 4H, Ar-H), 3.81,
3.39 (s, 3H, OCH3), 2.52, 2.38 (s, 3H, CH3). 13C NMR (DMSO-d6,
400 MHz) δ 160.08–147.74 pyrazole ring (C-C=C), 122.81–114.67
(Ar-C), 55.84, 56.48 (OCH3), 11.01 (CH3). Selected IR data (KBr,
cm−1) ν: 3446 (N-N), 3338, 3214 (NH2)broad, 3132, 3067 (Ar-CH),
2998 (Alip.-CH), 1602 (N=N), 1586 (pyrazole C=C), 1500, 1432 (Ar-
C=C), 1551 (C=N), 1406, 1249 (C-N), 1029 (=N-NH-), 817 (M-OH2),
785 (δ:NH), 567, 529 (M-N), 472 (M-O). UV-Vis. (in EtOH): λ max
(ε, L mol−1 cm−1) 209 (952), 227 (572), 243 (952), 255 (1496), 275
(269), 381 (676), 686 (42), 708 (77) nm. Color: Orange.
[RuL(η6-p-cymene)Cl]•Cl•0.5H2O:
Yield:
75%.
FW:
545.97 g/mol. μeff (B.M.): Dia. Anal. Calc. for C21H28N5O1.5 RuCl2:
C; 46.15, H; 5.17, N; 12.82. Found: C; 46.35, H; 5.29, N; 12.90. 1H
NMR (DMSO-d6, 400 MHz) δ (ppm): 11.85 (s, 1H, NH), 7.74–7.01
(m, 4H, Ar-H), 5.83–5.69 (m, 4H, p-cymene ring), 3.81 (s, 3H,
OCH3), 2.86–2.81 (h, 1H, CH(CH3)2), 2.38 (s, 3H, CH3), 1.21–1.18 (d,
6H, HC(CH3)2), 2.52 (s, 3H, CH3). 13C NMR (100 MHz, DMSO-d6)
δ (ppm): 159.82, 147.68, 129.38–122.56, 114.33, 106.55, 100.55,
86.74–85.99, 65.36 (pyrazole ring, benzene ring, p-cymene moiety),
55.85 (OCH3), 40.43 (p-cymene CH3), 30.52 (HC(CH3)2), 24.37,
2.2. Synthesis and characterization of azo dye ligand (L) and its FeII,
CoII, ZnII, and RuII complexes
The azo dye ligand was obtained according to the literature
thesis of an azo dye, the ligand has been occurred by azo coupling
and ring closure reactions.
Characterization of ligand: FW: 231.25 g/mol. Anal. Calcd. for
C11 H13N5O: C; 57.13, H; 5.66, N; 30.27. Found: C; 57.10, H; 5.60,
N; 30.20. 1H NMR (DMSO-d6, 400 MHz) δ 12.00 (s, 1H, NH), 7.10–
6.90 (m, 4H, Ar-H), 6.51 (s, 2H, NH2), 3.83 (s, 3H, OCH3), 2.34 (s,
3H, CH3). 13C NMR (DMSO-d6, 100 MHz) δ 157.01–140.10 (pyra-
zole ring), 130.80–114.10 (Ar-C), 55.60 (OCH3), 10.90 (CH3). IR (KBr,
cm−1) ν: 3468 (NH), 3357 (NH2)broad, 3180 (Ar-CH), 2967 (Alip.-
CH), 1599 (N=N), 1583 (pyrazole C=C) shoulder and overlapped
with N=N band, 1536 (C=N), 1498, 1454, 1428 (Ar-C=C), 1396,
1236 (C-N), 1025 (=N-NH-), 796 (δ: NH). UV-Vis (in EtOH): λ max
21.87, 18.34 (HC(CH3)2), 10.80 (CH3). Selected IR data (KBr, cm−1
)
ν: 3412 (NH), 3280 (NH2)broad, 3059 (Ar-CH), 2961 (Alip.-CH), 1602
(N=N), 1529 (C=N), 1500, 1466, 1428 (Ar-C=C), 1401, 1248 (C-N),
1030 (=N-NH), 788 (δ:NH), 487, 465 (Ru-NH2 and backdonation).
UV-Vis (in EtOH): λ max (ε, L mol−1 cm−1) 207 (2476), 226 (48),
239 (2095), 259 (4000), 276 (2836), 297 (4000), 304, 322, 345,
363, 383, 392 (4000), 408 (4000), 421 (3775), 427 (3844) nm.
Color: Orange.
2