Some Aromatic Schiff Bases and Their Metal Complexes

Schiff bases represent a widely studied group of compounds, interesting from the synthetic and structural, but also applicational point of view. Among these, aromatic Schiff bases stand out due to their stability and possible application as safer therapeutic agents. Since the presence of the phenolic group and the heteroatom in the benzene ring seems to be of interest for the biological activity of Schiff bases, imine derivatives of some dihydroxybenzaldehydes, 2-acetylpyridine, and 2,6-diacetylpyridine are chosen to be described here. The syntheses, structural features, as well as investigations of possible application of Schiff bases themselves, but also their metal complexes are described. The Cambridge Structural Database has been searched to obtain a better knowledge of the structures of these Schiff bases and their metal complexes, structural changes upon coordination, and the most common and interesting modes of coordination. The main accent is given to those compounds that are promising candidates for medicinal and pharmaceutical use, but some of the described complexes are good as catalysts, optical materials, sensors, analytical reagents, etc

1D and 2D Silver-Based Coordination Polymers with Thiomorpholine-4-carbonitrile and Aromatic Polyoxoacids as Coligands: Structure, Photocatalysis, Photoluminescence, and TD-DFT Study

Four silver-based coordination polymers, {[Ag(L)2](BF4)}∞ (1), {[Ag(H2BTC)(L)]·(H3BTC)}∞ (2), {[Ag2(H2BTEC)(L)2]·3.33H2O}∞ (3), and [Ag(H25SSA)(L)]∞ (4), were synthesized using thiomorpholine-4-carbonitrile (L) as the primary ligand and three aromatic polyoxoacids as coligands: trimesic (H3BTC), pyromellitic (H4BTEC), and 5-sulfosalicylic acid (H35SSA). Compounds 1 and 3 are two-dimensional, while 2 and 4 are one-dimensional. L acts as a bis-monodentate ligand, while the Ag(I) ion is three-coordinated in 2 and four-coordinated in all of the other compounds. The tetrahedral coordination of Ag(I) in 3 leads to an almost complete absence of intermolecular interactions with the metal center. All compounds show reasonable photocatalytic activity for photocatalytic degradation of mordant blue 9 dye, with reaction rates in the 0.036–0.056 min–1 range. Changes in the reaction rates can be correlated with the type and coordination of the coligand. Complex 3 exhibits photoluminescence at 77 K, while 4 exhibits photoluminescence at both room temperature and 77 K. Luminescence lifetimes indicate electronic transitions of singlet parentage, where transitions are allowed. A TD-DFT study determined the contributions of individual singlet–singlet electronic excitations to the fluorescence, indicating that metal– intraligand transitions are responsible for luminescence in both complexes.This is the peer-reviewed version of the article: Ristić, P., Todorović, T.R., Blagojević, V., Klisurić, O.R., Marjanović, I., Holló, B.B., Vulić, P., Gulea, M., Donnard, M., Monge, M., Rodríguez-Castillo, M., López-de-Luzuriaga, J.M., Filipović, N.R., 2020. 1D and 2D Silver-Based Coordination Polymers with Thiomorpholine-4-carbonitrile and Aromatic Polyoxoacids as Coligands: Structure, Photocatalysis, Photoluminescence, and TD-DFT Study. Crystal Growth & Design 20, 4461–4478. [https://doi.org/10.1021/acs.cgd.0c00287]Supplementary material: [https://hdl.handle.net/21.15107/rcub_dais_9452

Supplementary data for the article: Ristić, P.; Todorović, T. R.; Blagojević, V.; Klisurić, O. R.; Marjanović, I.; Holló, B. B.; Vulić, P.; Gulea, M.; Donnard, M.; Monge, M.; Rodríguez-Castillo, M.; López-de-Luzuriaga, J. M.; Filipović, N. R. 1D and 2D Silver-Based Coordination Polymers with Thiomorpholine-4-Carbonitrile and Aromatic Polyoxoacids as Coligands: Structure, Photocatalysis, Photoluminescence, and TD-DFT Study. Crystal Growth & Design 2020, 20 (7), 4461–4478. https://doi.org/10.1021/acs.cgd.0c00287

Supplementary material for: [https://pubs.acs.org/doi/10.1021/acs.cgd.0c00287#]Related to published version: [https://cherry.chem.bg.ac.rs/handle/123456789/4200]Related to accepted version: [https://cherry.chem.bg.ac.rs/handle/123456789/4203

Synthesis, Physicochemical, Thermal and Antioxidative Properties of Zn(II) Coordination Compounds with Pyrazole-Type Ligand

The reactions of pyrazole derivative, i.e., ethyl-5-amino-1-methyl-1H-pyrazole-4-carboxylate (L) with zinc halogenides in methanolic solution and zinc nitrate and zinc acetate in acetonic solution are described. The formulae of synthesized compounds are ZnL2Cl2 (1), [ZnL2Br2] (2), ZnL2I2·0.5MeOH (3), [Zn(L)2(H2O)4](NO3)2 (4), and {ZnL(OAc)2}2 (5). Two complexes are obtained in form of single crystals: [ZnL2Br2] (2) and [Zn(L)2(H2O)4](NO3)2 (4). Their crystal and molecular structure were determined by single-crystal X-ray structure analysis. The FTIR spectra of compounds prove the complex formation with all five zinc salts. The complexes are characterized by conductometric and thermoanalytical measurements, and their antioxidative activity was also tested by the scavenging effect on the DPPH radical. Conductometric results, solvolytic stability, and antioxidative activity of the compounds are in correlation

Correlations between the in vitro antiproliferative activity, structure and thermal stability of some macrocyclic dinuclear Cu(II) complexes

Seven macrocyclic dinuclear Cu(II) complexes with tpmc = N,N',N",N'"-tetrakis(2-pyridylmethyl)-1,4,8,11-tetraazacyclotetradecane of coordination formulae [Cu2tpmc](ClO4)4 (1), [Cu2(X)tpmc](ClO4)3•nH2O, X= F-, n = 0 (2), X = Cl-, n = 1 (3), X = Br-, n = 0 (4), X= I-, n = 1 (5), X = NO2-, n = 0 (6), [Cu2(NCS)2tpmc](ClO4)2 (7) were evaluated for their cytotoxic activity against human cervix adenocarcinoma (HeLa), human melanoma (Fem-x) and human colon carcinoma (LS174) cell lines. The results were compared with the corresponding data for the cis-dichlorido-diammineplatinum(II) (CDDP) as referent cytostatic together with the free ligands and solvent dimethyl sulfoxide (DMSO) as controls. The complexes showed considerable antiproliferative effect, although significantly less than CDDP. The thermal decomposition pattern of the complexes was determined by simultaneous TG/DSC measurements. The thermal stability of the compounds 2-7 followed the trend of their antiproliferative activity against HeLa cell line, as well as their corresponding stability constants. The highest thermal stability and cytotoxicity belonged to complex [Cu2tpmc](ClO4)4, with no anionic co-ligand. Complex [Cu2(NO2)tpmc](ClO4)3 exhibited a selective cytotoxicity against LS174 cells, at the level of the most active [Cu2tpmc](ClO4)4. [Projekat Ministartsva nauke Republike Srbije, br. 172014 i br. 175011