Aroylthiourea Ligands Research Articles

Synthesis, characterization and biological applications of bismuth(III) complexes with aroylthiourea ligands

This work describes the synthesis, structural characterization and biological applications of three new bismuth(III) complexes with aroylthiourea-based ligands: [Bi(La)3(HLa)] (1), [Bi2(Lb)4(μ-Lb)2]⋅2(C3H6O) (2), and [Bi6(μ-Lc)6(μ3-NO3)2(μ6-NO3)](NO3)3⋅4H2O (3), where HLa = N-benzoyl(N′,N′-diethylthiourea), HLb = N-benzoyl(morpholinylthiourea), and H2Lc = N2,N6-bis(diethylcarbamothioyl)pyridine-2,6-dicarboxamide. The ligands HLa and HLb were considered as monopodal, while H2Lc as bipodal. All compounds were characterized by melting point determination, Fourier-transform infrared spectroscopy (FTIR), proton proton and carbon-13 nuclear magnetic resonance spectroscopy (NMR), mass spectrometry (MS), elemental analysis (EA) and single-crystal X-ray diffraction (SC-XRD). Structural analysis showed that compound 1 was a mononuclear heptacoordinate complex, while compound 2 presented a dinuclear structure and compound 3 was built up by a hexanuclear framework. The proligands, the new complexes, and Bi(NO3)3⋅5H2O had their antibacterial activities evaluated against E. coli (ATCC 25922), S. aureus (ATCC 25923), and P. aeruginosa (ATCC 27853). The in vitro disk-diffusion (DD) method showed the ability of compound 2 to inhibit two types of bacteria (P. aeruginosa and S. aureus). In the results of minimum inhibitory concentration (MIC), all complexes showed significant activity against the tested microorganisms except for compound 1. The inorganic salt used for comparison showed antibacterial activity only against P. aeruginosa and the ligands showed no apparent activity. Compound 2 presented the best antibacterial activity among the tested substances, and its performance was remarkable even when compared to other similar compounds found in the literature, attesting the importance of targeting bismuth(III) aroylthioureas for further research on new drugs development.

Highly active copper(i) complexes of aroylthiourea ligands against cancer cells – synthetic and biological studies

Copper(i) complexes containing sulfur donor monodentate aroylthiourea ligands have been synthesized and evaluated for their biological applications.

Water soluble Ru (II)–p‐cymene complexes of chiral aroylthiourea ligands derived from unprotected D/L‐alanine as proficient catalysts for asymmetric transfer hydrogenation of ketones

The newfangled chiral aroylthiourea ligands (L1‐L6) were produced from unprotected D/L‐alanine and their water soluble Ru (II) organometallic catalysts (1–6) were designed from their reaction with [RuCl2(η6‐p‐cymene)]2. The analytical and spectral methods were used to confirm the structure of the ligands and complexes. The solid state structure of L1, 5 and 6 was confirmed by single crystal XRD. The organometallic compounds (1–6) catalyzed the asymmetric transfer hydrogenation of aromatic, heteroaromatic and bulky ketones to yield respective enantiopure secondary alcohols with admirable conversions (up to 99%) and attractive enantiomeric excesses (ee up to 98%), in presence of formic acid and triethylamine in water medium under non‐inert atmospheric conditions.

Synthesis, characterization and chemosensitivity studies of half-sandwich ruthenium, rhodium and iridium complexes containing к1(S) and к2(N,S) aroylthiourea ligands

The reaction of [(p-cymene)RuCl2]2 and [Cp*MCl2]2 (M = Rh/Ir) metal precursors with aroylthiourea ligands (L1-L3) yielded a series of neutral mono-dentate complexes 1–9. The neutral mono-dentate coordination of aroylthiourea with metals via S atom was confirmed by single crystal X-ray diffraction study. Further reaction of mono-dentate complexes 1–9 with excess NaN3 in polar solvent resulted in the formation of highly strained four member ring к2(N,S) azido complexes 10–18. Further these complexes were treated with activated alkynes to isolate triazole complexes, but unfortunately the reaction was unsuccessful. All these complexes were fully characterized by various spectroscopic techniques. The molecular structures of the representative complexes have been determined by single crystal X-ray diffraction studies. The molecular structures of the complexes revealed typical piano stool geometry around the metal center. The chemosensitivity activities of the complexes 1–9 evaluated against the cancer cell line HCT-116 (human colorectal carcinoma) and ARPE-19 (human retinal epithelial cells) cell line. Of these, complex 3 was the most potent and whilst its potency was less than cisplatin, its selectivity for cancer as opposed to non-cancer cell lines in vitro was comparable to cisplatin.

Piano-stool Ru(II)-benzene complexes bearing D/L-alanine derived chiral aroylthiourea ligands for asymmetric transfer hydrogenation of ketones in water

The new water soluble chiral Ru(II)-benzene complexes of the type [ $$\hbox {RuCl}_{2}(\eta ^{6}\hbox {-C}_{6}\hbox {H}_{6})\hbox {L}$$ ] were obtained from the reactions between $$[\hbox {RuCl}_{2}(\eta ^{6}\hbox {-C}_{6}\hbox {H}_{6})]_{2 }$$ and the chiral aroylthiourea ligands (L) derived from unprotected D/L-alanine and characterized. The solid-state structure of representative complexes was confirmed by single crystal X-ray diffraction technique. The Ru(II)-benzene complexes catalyzed the asymmetric transfer hydrogenation (ATH) of aromatic ketones to their enantiopure secondary alcohols. The reactions were carried out in the presence of formic acid–triethylamine mixture in water, and the product alcohols were obtained with excellent conversions (up to 99%) and enantiomeric excesses (up to 99%). The scope of the catalytic system was extended to various aromatic ketones. The catalytic activity of the present water-soluble Ru-benzene complexes toward enantioselective reduction of ketones was considerably higher than that of p-cymene analogues in water. The water-soluble chiral Ru(II)-benzene complexes were produced from the reactions between $$[\hbox {RuCl}_{2}(\eta ^{6}\hbox {-C}_{6}\hbox {H}_{6})]_{2 }$$ and the chiral aroylthiourea ligands derived from unprotected D/L-alanine. The catalytic activity of the Ru(II)-benzene complexes toward enantioselective reduction of ketones was found to be good in water medium.

Synthesis, Structure and Spectroscopic Properties of Oxovanadium Tris(3,5-dimethylpyrazolyl)borate Aroylthiourea Complexes

Aroylthiourea ligands, 1-aroyl-3-cyclohexyl-3-methylthiourea (HL1), 1-(2-chloroaroyl)-3-cyclohexyl-3-methylthiourea (HL2), 1-(3-chloroaroyl)-3-cyclohexyl-3-methylthiourea (HL3) and 1-(4-chloroaroyl)-3-cyclohexyl-3-methylthiourea (HL4) were synthesized through a condensation reaction of methylcyclohexylamine and aroylisothiocyanate with a general formula (X-Ph)(CO)NH(CS)N(C6H5)(CH3) where X = H, o-Cl, m-Cl and p-Cl, fully characterized by CHNS micro elemental analysis, infrared spectroscopy, UV-visible, nuclear magnetic resonance (1H, 13C) and X-ray crystallography. 1-(3-chloroaroyl)-3-cyclohexyl-3-methylthiourea (HL3) crystallized in the monoclinic system, a=14.504(3), b=4.9599(11), c=22.325(5) A, β=98.461(7)°, Z= 4 and V=1588.5(6) A with space group P21/c. The IR spectra of the ligands exhibits the characteristic v(CO) and v(N-H) at range 1701-1640 cm-1 and 3317-3144 cm-1, respectively. Whereas the 1H and 13C NMR spectra shows the resonances for N-H and -CO groups at range 8.3-8.5 and 160-163 ppm, respectively. A one-pot reaction involving the aroylthiourea ligand, oxovanadium(IV) ion and potassium hydrotris(3,5-dimethylpyrazolyl)borate (KTp*) complex gave the desired [oxovanadium(IV)(tris(pyrazolyl)borate)(aroylthiourea)] complexes namely Tp*VOL1, Tp*VOL2, Tp*VOL3 and Tp*VOL4 and all complexes were characterized accordingly. X-ray study showed that Tp*VOL1 adopted a monoclinic crystal, a=3.415(2), b=19.463(3), c=14.22(3) A, β=107.411(4)°, Z= 4 and V=3542.7(11) A with P21/c space group. The VO2+ center adopted a pseudo-octahedral geometry O2N3S, with the oxovanadium(IV) coordinated to the bidentate ligand (X-Ph)(CO)NH(CS)N(C6H5)(CH3) and tridentate Tp* ligands. The results showed that aroylthiourea ligands behave as bidentate chelate through O and S atom and the Tp* C3v symmetry adds stabilization to the VO2+ through its protective tripodal geometry.

Synthesis of Ru(ii)–benzene complexes containing aroylthiourea ligands, and their binding with biomolecules and in vitro cytotoxicity through apoptosis

Ru(ii)(η6-benzene) complexes containing sulfur donor monodentate aroylthiourea ligands have been synthesized and evaluated for their biological applications.

Asymmetric hydrogenation of pro-chiral ketones catalyzed by chiral Ru(II)-benzene organometallic compounds containing amino acid based aroylthiourea ligands

A series of Ru(II)-benzene organometallic compounds (1–6) constructed from [RuCl2(η6-benzene)]2 and chiral aroylthiourea ligands (L1-L6) obtained from D/L-phenylalanine, was fully characterized. The chiral complexes along with 2-propanol and NaOH effected the asymmetric hydrogenation of aromatic ketones at 82 °C within 8–10 h. The reduction reactions proceeded with excellent conversions and enantiomeric excesses (up to 99%).

Half-sandwich RuCl2(η(6)-p-cymene) core complexes containing sulfur donor aroylthiourea ligands: DNA and protein binding, DNA cleavage and cytotoxic studies.

A series of Ru(ii)(η(6)-p-cymene) complexes (1-4) bearing the general formula [RuCl2(η(6)-p-cymene)L] (L = monodentate aroylthiourea ligand) has been synthesized and characterized by analytical and various spectroscopic techniques. The neutral monodentate coordination of aroylthiourea with Ru via an S atom was confirmed by single crystal X-ray diffraction study. The complexes were tested for their ability to interact with DNA and protein. The complexes bound with calf thymus DNA (CT DNA) with the intrinsic binding constant value in the order of 10(4) M(-1). The intercalative mode of binding was confirmed by the ethidium bromide (EB) displacement study. The interaction of the complexes with CT DNA was further supported by viscosity measurements and circular dichroic (CD) spectra. The Ru(ii) complexes cleaved the supercoiled DNA without the need of any external agent. The spectroscopic evidence showed good binding efficacy of the complexes with BSA (Bovine Serum Albumin). The alterations in the secondary structure of BSA by the Ru(ii) complexes were confirmed by synchronous fluorescence spectra. Cytotoxicity examination by MTT assay was carried out in two cancer cell lines (MCF7 and A549) and one non-cancerous cell line (L929). Complex 4 showed significant activity [IC50 = 52.3 (MCF7) and 54.6 (A549) μM] which was comparable with that of similar known complexes. The morphological changes assessed by Hoechst staining revealed that the cell death occurred by apoptosis.

Structural diversity in aroylthiourea copper complexes – formation and biological evaluation of [Cu(i)(μ-S)SCl]2, cis-Cu(ii)S2O2, trans-Cu(ii)S2O2and Cu(i)S3cores

Four different copper complexes containing aroylthiourea ligands displayed good interaction with CT DNA and BSA and cytotoxicity.

Ru(ii)-p-cymene complexes containing esters of chiral d/l-phenylalanine derived aroylthiourea ligands for enantioselective reduction of pro-chiral ketones

The chiral Ru(ii)-p-cymene complexes are efficient catalysts for the enantioselective reduction of ketones to chiral alcohols.