13 research outputs found
N-functionalised heterocyclic carbene complexes and their catalytic properties
Son yirmi yılda N-heterosiklik karben (NHC) ligandları hem organometalik kimyada hem de homojen katalizde oldukça popüler hale gelmiştir. Ligand olarak kullanılan NHC'lerin çoğu imidazol çekirdeği temelli iken; kaynaşmış altı- ve yedi-üyeli kiral bisiklik iskeletli analogları, daha büyük sterik engel ve özellikle artan bazikliğe/nükleofilliğe bağlı olarak beş-üyeli türevlerden çok farklı özellikler gösterdiklerinden dolayı oldukça ilgi çekmektedirler. Sodyum azid ile kamforik asidin Schmidt Reaksiyonu yoluyla oluşturduğu (1R,3S)-diamino-1,2,2-trimetilsiklopentan'dan türeyen (1, R,S-tmcp) NHC öncüllerinin sentezi için iki yöntem vardır. İlk yöntem, başlangıçta azot atomlarının alkillenmesi ile gerçekleşen diaminin modifikasyonu ve sonrasında halka kapanmasını içerir. İkinci yöntem ise başlangıçta halka kapanması ve ardından azot atomlarının alkilasyonunu içerir. Son olarak yeni PEPPSI-tip kiral paladyum kompleksleri (9a-f), öncül kiral azolyum tuzlarının piridin varlığında, PdCl2 ve K2CO3 ile ısıtılmasıyla hazırlanmış ve 9a bileşiğinin Asimetrik Suzuki-Miyaura Çapraz-Eşleşme reaksiyonu ve Asimetrik Allilik Alkilasyon reaksiyonundaki katalitik aktivitesi incelenmiştir. Sentezlenen yeni bileşiklerin yapıları spektroskopik yöntemlerle aydınlatılmış, ayrıca 7, 9a, 9b, 9d ve 9e'nin kristal yapıları X-ışını kırınımı yöntemi ile de belirlenmiştir.
N-heterocyclic carbene (NHC) ligands become increasingly popular in both organometallic chemistry and homogeneous catalysis over the past 20 years. While the majority of NHCs employed as ligands are based on an imidazole core, analogues with fused six- and seven-membered a chiral bicyclic skeleton has attracted attention, as it has been established that they possess quite different properties from the five-membered derivatives, most notably an enhanced basicity/nucleophilicity and greater steric demand. There are two main synthetic routes to bicyclic NHC precursors, which are derived from camphoric acid via a Schmidt reaction with sodium azide yielding (1R,2S)-diamino-1,2,2-trimethylcyclopentane (1, R,S-tmcp). The first route involves the initial modification of the diamine through alkylation of the nitrogen proceeded by ring closure. The second involves an initial ring closure and subsequent introduction of the exo N-alkylation. Finally, the novel PEPPSI-type chiral palladium complexes (9a-f) have been prepared by heating their precursor chiral azolium salts with PdCl2 and K2CO3 in neat pyridine and examined complex of 9a catalytic activity in the Asymmetric Suzuki-Miyaura cross-coupling reaction and Asymmetric Allylic Alkylation reaction. The structure of synthesized the novel compounds were characterized using spectroscopic techniques; also the single crystal structures of 7, 9a, 9b, 9d and 9e were determined by X-ray analysis
Synthesis, Experimental and Theoretical Characterization of (μ4-oxo)hexakis(μ2-chloro)-tetrakis[1-(allyl)-1H-imidazole]tetracopper(II)
A new [Cu4OCl6L4] cluster [L = 1-(allyl)-1H-imidazole] has been isolated and its crystal structure and spectroscopic properties determined. The compound crystallizes as a yellow solid in the monoclinic system, space group P21, with cell constants a = 10.6937(7) Å, b = 13.1004(7) Å, c = 13.2452(9) Å, β = 93.537(6)°, and two formula units per cell. The title tetranuclear complex has a central µ4-oxide ion surrounded tetrahedrally by four CuII atoms. Each Cu atom is connected to three others via bridging Cl atoms. The fifth coordination position, located on the central Cu─O axis on the outside of the cluster, is occupied by an N atom of the monodentate imidazole ligand. The resulting coordination geometry of the metal ion is a slightly distorted trigonal bipyramid with the O and N atoms in the axial positions. The molecular structure and spectroscopic data were obtained using density functional theory (DFT/HSEH1PBE) method with the cc-pVDZ basis set for C, H, N, O and Cl atoms, and the LANL2DZ basis set for the Cu atoms, and compared with the experimental data. Consequently, the experimental data well coherences with the theoretical ones
Unsymmetrically substituted imidazolium salts: synthesis, characterization and antimicrobial activity
Unsymmetrically substituted imidazolium salts were synthesized and characterized using 1H-NMR and 13C-NMR. The antimicrobial activities of the salts were evaluated using the agar-well diffusion method against 14 bacteria and five yeasts. The minimal inhibitory concentrations (MIC) against seven bacteria and one yeast were also determined. Among the test compounds applied, 1, 2, 3, 6 and 11 showed activities against Micrococcus luteus ATCC 9341, Staphylococcus aureus ATCC 25923, Staphylococcus epidermidis ATCC 12228, Bacilllus cereus ATCC 11778, Bacillus subtilis ATCC 6633, Bacillus thuringiensis, Listeria monocytogenes ATCC 19112 and Candida trophicalis. However, compounds 1, 2 and 3 showed the highest antimicrobial activities against Micrococcus luteus ATCC 9341, Stapylococcus aureus ATCC 25923, Staphylococcus epidermidis ATCC 12228, Bacilllus cereus ATCC 11778 and Bacillus subtilis ATCC 6633 with inhibition zones of 14-20 mm. In addition, compound 6 have only demonstrated activities against Candida trophicalis while compounds 4, 5, 7, 8, 9, 10, 12, 13 and 14 had no effect on test microorganisms
Application of enaminone ruthenium(II) complexes as catalysts in the transfer hydrogenation of ketones
This study reported the synthesis of two new ligands (1,2) and their Ru(II)-enaminone complexes (3,4). The Ru(II) complexes were obtained from the reaction of the [RuCl2(p-cymene)]2 dimers with the new enaminone derivative ligands (1,2). The use of standard spectroscopy techniques entirely characterized the compounds. Single crystal studies investigated the crystal structure of ligand (1) and complexes (3,4). X-ray diffraction data analysis was used to confirm the enaminone form of 1. Also, 3 and 4 exhibited the classical three-legged piano stool structure with Ru(II) coordinated by the nitrogen and oxygen atoms of 1 and a chloride ligand as the legs and the η6-π-bound p-cymene ligand occupies the seat of the piano stool. The Ru(II) complexes have been studied as catalysts in the transfer hydrogenation of acetophenone and other various ketones in the presence of KOtBu. The catalytic conditions were optimized using different substrate/catalyst and base/catalyst ratios. We found that the complexes show good activities and up to 100 % selectivity. The best turnover frequency (1667 h−1) was found for 3 when using acetophenone as the substrate
Palladium(II) complexes of amino acid derived ONO-tridentate enamine ligand for Suzuki-Miyaura cross-coupling reaction
Synthesis and characterization of Zn(II) complexes derived from thiobarbiturate ligand: Investigation of antibacterial and anticancer activities
We have reported the synthesis of the new thiobarbiturate derivative ligand (1) and its three Zn(II) complexes (2–4). The ligand and complexes were structurally characterized by various techniques such as ATR-FTIR, 1H NMR, 13C NMR, and elemental analysis. The molecular structure of 3 was determined by the single-crystal X-ray diffraction analysis study. The study revealed that it consists of a zig-zag one-dimensional polymeric chain, in which the Zn(II) ion is five coordinated by three oxygen atoms from the ligand, one nitrogen atom from the ligand, and one nitrogen atom from the ancillary ligand (1-methyimidazole). Also, Addison's five-coordinated index of 3 (τ5 = 0.45) showed that Zn(II) ion has a distorted square pyramidal geometry. Ligand (1) and Zn(II) complexes (2–4) were tested using the MTT cell viability assay on two types of cancer cell lines from human prostate cancer (PC-3), colon cancer (HT-29) and a normal cell line of the bronchial epithelium (BEAS-2B). 1 acted as a potent growth inhibitor on HT-29 cells, while 4 showed cytotoxic effects against PC-3 cells. Their antibacterial activity was determined by the agar well diffusion method. Depending on the 2 and 4 doses, it showed activity against both gram (+) and gram (−) bacteria. In terms of anti and anticancer effects, 4 seems to be a biologically highly active complex and promising biomedically
Synthesis, characterization and antimicrobial activity of metal complexes with N,O-bidentate ligand derived from dimedone
One N,O-bidentate dimedone derivatives ligand (1) and its Ni(II), Pd(II), and Cu(II) complexes (2,3,4) have been prepared and structurally characterized by the spectroscopic methods such as T-IR, NMR, and X-Ray. 1,3, and 4 crystallize in the triclinic crystal system in the space group P-1, 2 crystallizes in the monoclinic crystal system in the space group C2/c. X-Ray diffraction studies showed 1 exists in enamine form, 2–4 have a square planar geometry around metal atoms which are surrounded by two nitrogen and two oxygen atoms from two ligands. Antibacterial properties of 1–4 have been examined against selected bacteria and yeast strains. Also, the minimum inhibitory concentration of 1–4 against these pathogens was compared with the selected antibiotic drugs. The result revealed that all compounds have good activity.</p
Cu(II) and Ni(II) metallacycles derived from barbituric acids: Synthesis with solvent/agent effects in crystallization and structural characterization with non-covalent interaction analysis
It is well known that solvent molecules and additional agents significantly impact crystal structures. In relation to this, the barbituric acid-based 1,3-dimethyl-2,4,6-trioxo-hexahydro-pyrimidine-5-(2,6-dimethylphenylamino)methylene (HL1) as ligand and three novel copper(II) complexes, 2[Cu(L1)2] (1), 2[Cu(L1)2(4,4′bpy)] (2), Cu(L1)2(CH3)2SO (3), (where H is the deprotonatable hydrogen) were synthesized and characterized by elemental analysis, FT-IR spectroscopy. As a comparison, a potentially tridentate barbituric acid-based ligand, 1,3-dimethyl-2,4,6-trioxo-hexahydro-pyrimidine-5-(8-quinolylamino)methylene (HL2), and its three new copper(II) and nickel(II) complexes, Cu(L2)2 (4), Cu(L2)2 (5) and Ni(L2)2 (6), were also synthesized and characterized by elemental analysis, FT-IR spectroscopy. The crystal structures of the ligands and their complexes were determined based on an X-ray diffraction study. X-ray diffraction studies have shown that the ligands HL1 and HL2 exist in keto-enamine form. The crystal structure of complexes of HL1 revealed that Cu center is distorted square-planar in 2[Cu(L1)2] (1), while it is found in distorted square-pyramidal in relation to additional agent (4,4′ bpyridine) and solvent (DMSO) conditions in 2[Cu(L1)2(4,4′bpy)] (2) and Cu(L1)2(CH3)2SO (3), respectively. In the crystal structure, [M(L2)2] (M = Cu (4 and 5), Ni (6)), metal ions possess a distorted octahedral environment, and the HL2 ligands coordinate with a meridional geometry. Structures of all complexes reveal a tendency to form C–H···O, C–H···π and π···π interactions, except for molecule Cu(L1)2(CH3)2SO (3) in terms of C–H···O bonds which was not observed. Exploring noncovalent interactions indicates similar molecular structures in [M(L2)2] (M = Cu (4 and 5), Ni (6)) suggesting the difference in packing due to the solvent of crystallization (CH2Cl2) in the lattice of Cu(L2)2 (5) and the different metal ion in the molecular structure of Ni(L2)2 (6). The packing in the structures of HL1 complexes is found to be strongly dependent on the additional agent (4,4′ bpyridine) and solvent (DMSO) fused in molecular structure with different supramolecular assemblies such as 1D chains, π···π dimers, 2D sheets, etc. In addition, Hirshfeld surface analysis and 2D fingerprint plots were employed to verify intermolecular interactions in both ligands and their complexes
Structural Analysis and Biological Activity Predictions of Some Organometallic Compounds
Barbituricacid derivatives and their organometallic compounds have long been recognizedfor their pharmacological potential [1-2]. There exist numerous molecularcompounds in our surroundings that significantly influence human health,ranging from pharmaceuticals to environmental pollutants [3-4]. Understandingthe absorption, distribution, metabolism, excretion, and toxicity (ADMET)properties of these compounds is crucial for assessing their effects on thehuman body. In the pursuit of developing new drugs, accurate knowledge of molecularstructure is essential, achieved by X-ray diffraction techniques. In thisstudy, two barbituric acid-based ligands, namely1,3-dimethyl-2,4,6-trioxo-hexahydro-pyrimidine-5-(2,6-dimethylphenylamino)methylene(HL1) and1,3-dimethyl-2,4,6-trioxo-hexahydro-pyrimidine-5-(8-quinolylamino)methylene(HL2), along with their correspond-ing organometallic compounds, were investigated.The molecular and crystal structures of these compounds were determined usingX-ray diffraction techniques. The X-ray diffraction studies revealed variouscoordination geometries around the metal center, ranging from distortedsquare-planar to distorted octahedral. Additionally, non-covalent interactionswere examined in detail. Furthermore, predictive biological activity studiesusing PASS online software suggested promising activities for these compounds,including CYP2H substrate, cell adhesion molecule inhibitor, and nicotinicreceptor antagonist. This comprehensive investigation sheds light on thepotential pharmacological applications of barbituric acid derivatives and theirorganometallic complexes, offering insights for further drug developmentendeavors. </p
Enamines of 1,3-dimethylbarbiturates and their symmetrical palladium(II) complexes: synthesis, characterization and biological activity
Three 1,3-dimethylbarbiturate-enamine derivatives and their symmetrical palladium(II) complexes were prepared and characterized by spectroscopic methods. In addition, the structures of the complexes were determined by single-crystal X-ray diffraction. The X-ray diffraction studies revealed the geometry around the Pd(II) atom in each complex is almost perfectly square-planar. Also, the ligands and their palladium(II) complexes were tested for antifungal and antibacterial activity against various clinical and food-borne microorganisms, revealing promising biological activities