ISSN 1070-3284, Russian Journal of Coordination Chemistry, 2017, Vol. 43, No. 8, pp. 535–539. © Pleiades Publishing, Ltd., 2017.
Copper(II) Complexes of Mono-Condensed N,O-Donor Schiff Base
Ligands: Synthesis, Crystal Structures, and Antibacterial Activity
L. F. Cai*
Key Laboratory of Surface and Interface Science of Henan, School of Material and Chemical Engineering,
Zhengzhou University of Light Industry, Zhengzhou, 450002 P.R. China
Received August 21, 2016
Abstract⎯Two new copper(II) complexes, [Cu(L
] (I) and [Cu(L
] (II), where L
6-(isopropyliminomethyl)phenolate and L
late, have been prepared and structurally characterized by X-ray crystallography (CIF files CCDC
nos. 1445936 (I) and 1445935 (II)). In both complexes, the Cu atoms are coordinated by two phenolate oxy-
gen and two imino nitrogen, giving square planar geometry. The complexes have been tested on various
strains of bacteria to study their antibacterial effects.
Keywords: Cu(II) complexes, N,O-donor bidentate Schiff base, X-ray structure, antibacterial activity
Schiff bases are a kind of biological active com-
pounds, which are reported to show a variety of interest-
ing biological actions, including antibacterial [1–3],
antifungal [4, 5], anticancer [6–8], etc. Schiff bases
derived from salicylaldehyde and its derivatives usually
possess two or more donor atoms, which can chelate to
transition metal atoms, to form a variety of complexes
[9–12]. Metal complexes with Schiff base ligands have
attracted much attention in the fields of magnetic, cata-
lytic, as well as biological materials [13–19]. Thus, in this
paper, we report the synthesis, characterization, and
antibacterial activities of two new copper(II) complexes
derived from Schiff bases 2-bromo-4-chloro-6-(isopro-
) and 2-bromo-4-chloro-
Materials and physical measurements. All chemi-
cals were of reagent grade, purchased from commer-
cial sources, and used without further purification.
Elemental analysis (carbon, hydrogen, and nitrogen)
was performed using a Perkin-Elmer 240C elemental
analyzer. IR spectra in KBr (4000–400 cm
recorded using a Perkin-Elmer RXI FT-IR spectro-
photometer. Electronic spectra in acetonitrile were
recorded in a Lambda 35 spectrophotometer.
Syntheses of the Schiff bases HL
ried out in a similar way by refluxing 3-bromo-5-chlo-
rosalicylaldehyde (1.0 mmol, 235.5 mg) with isopro-
pylamine (1.0 mmol, 59.1 mg) and 2-aminoethanol
(1.0 mmol, 61.1 mg), respectively, in methanol
(20 mL) for 1 h. The Schiff bases were not isolated.
The methanolic solutions were used for the syntheses
of the complexes.
Synthesis of complexes I and II. A methanol solu-
tion (10 mL) of copper(II) chloride dihydrate
(1.0 mmol, 17.0 mg) was added to the methanol solu-
tion (10 mL) of HL
(1.0 mmol, 27.6 mg) and HL
(1.0 mmol, 27.8 mg), respectively, and refluxed for
1 h. Single crystals suitable for X-ray diffraction were
obtained from the filtrate by slow evaporation in a
Complex I: yield, 175 mg (57%). λ
, nm (ε
)) (acetonitrile) 272 (17210),
295 (10365), 375 (10230), 763 (210). IR data (KBr;
): 1624 m (CH=N), 1450 s, 1353 m, 1162 s,
1072 s, 949 s, 860 s, 743 w, 545 m, 521 m, 465 w.
Complex II: yield, 132 mg, 43%. λ
, nm (ε
)) (acetonitrile) 275 (16380), 292 (9878),
367 (8560), 750 (273). IR data (KBr; ν, cm
): 3325 w,
The article is published in the original.
anal. calcd., %: C, 39.08; H, 3.28; N, 4.56.
Found, %: C, 39.21; H, 3.37; N, 4.45.