Showing papers on "Tetrahedral molecular geometry published in 2017"
TL;DR: The in vitro antibacterial activity of all the compounds, at their two different concentrations, was screened against four bacterial pathogens, and showed better activity compared to parent drug and control drug.
Abstract: A novel Schiff base ligand of type HL was prepared by the condensation of amoxicillin trihydrate and nicotinaldehyde. The metal complexes of Co+2, Ni+2, Cu+2, and Zn+2 were characterized and investigated by physical and spectral techniques, namely, elemental analysis, melting point, conductivity, 1H NMR, IR, UV-Vis spectra, ESR, SEM, and mass spectrometry measurements. They were further analyzed by thermal technique (TGA/DTA) to gain better insight about the thermal stability and kinetic properties of the complexes. Thermal data revealed high thermal stability and nonspontaneous nature of the decomposition steps. The Coats-Redfern method was applied to extract thermodynamic parameters to explain the kinetic behavior. The molar conductance values were relatively low, showing their nonelectrolytic nature. The powder XRD pattern revealed amorphous nature except copper complex (1c) that crystallized in the triclinic crystal system. The EPR study strongly recommends the tetrahedral geometry of 1c. The structure optimization by MM force field calculation through ArgusLab 4.0.1 software program supports the concerned geometry of the complexes. The in vitro antibacterial activity of all the compounds, at their two different concentrations, was screened against four bacterial pathogens, namely, E. coli, P. vulgaris, K. pneumoniae, and S. aureus, and showed better activity compared to parent drug and control drug.
46 citations
TL;DR: Those compounds with greater distortion from the ideal tetrahedral geometry showed a larger-magnitude axial magnetic anisotropy (D) together with a high rhombicity factor (E/D), and thus, slow magnetic relaxation effects also appear.
Abstract: A family of tetrahedral mononuclear CoII complexes with the cytosine nucleobase ligand is used as the playground for an in-depth study of the effects that the nature of the ligand, as well as their noninnocent distortions on the Co(II) environment, may have on the slow magnetic relaxation effects. Hence, those compounds with greater distortion from the ideal tetrahedral geometry showed a larger-magnitude axial magnetic anisotropy (D) together with a high rhombicity factor (E/D), and thus, slow magnetic relaxation effects also appear. In turn, the more symmetric compound possesses a much smaller value of the D parameter and, consequently, lacks single-ion magnet behavior.
32 citations
TL;DR: The synthesis of a rare terminal Fe(IV) nitride complex is reported, and Fukui analysis shows electrophilic character at the nitride functionality.
Abstract: Utilizing the bulky guanidinate ligand [LAr*]− (LAr* = (Ar*N)2C-(R), Ar* = 2,6-bis-(diphenylmethyl)-4-tert-butylphenyl, R = NCtBu2) for kinetic stabilization, the synthesis of a rare terminal Fe-(IV) nitride complex is reported. UV irradiation of a pyridine solution of the Fe-(II) azide [LAr*]-Fe-(N-(py) (3-py) at 0 °C cleanly generates the Fe-(IV) nitride [LAr*]-FeN-(py) (1). The 15N NMR spectrum of the 115N (50% Fe≡15N) isotopomer shows a resonance at 1016 ppm (vs externally referenced CH3NO2 at 380 ppm), comparable to that known for other terminal iron nitrides. Notably, the computed structure of 1 reveals an iron center with distorted tetrahedral geometry, τ4 = 0.72, featuring a short Fe≡N bond (1.52 A). Inspection of the frontier orbital ordering of 1 shows a relatively small HOMO/LUMO gap with the LUMO comprised by Fe-(dxz,yz)-N-(px,y) π*-orbitals, a splitting that is manifested in the electronic absorption spectrum of 1 (λ = 610 nm, e = 1375 L·mol–1·cm–1; λ = 613 nm (calcd)). Complex 1 persists in ...
29 citations
TL;DR: The structure contains rare Mn2+-4N tetrahedral geometry and has larger cell parameters, resulting in 20% larger amounts of gas uptake compared with [Zn(2-methylimidazolate)2]; a kinetically favored reaction using a reactive metal borohydride precursor is key for the construction of new metal-organic framework systems.
Abstract: Cubic and highly porous [Mn(2-methylimidazolate)2] (Mn-ZIF-8) was synthesized from [Mn(BH4)2·3THF]·NaBH4 under an Ar atmosphere. The structure contains rare Mn2+-4N tetrahedral geometry and has larger cell parameters, resulting in 20% larger amounts of gas uptake compared with [Zn(2-methylimidazolate)2]. A kinetically favored reaction using a reactive metal borohydride precursor is key for the construction of new metal–organic framework systems.
27 citations
TL;DR: A new tridentate N3 ligand consisting of cis,cis-1,3,5-triaminocyclohexane (tach) and three N,N,N',N'-tetramethylguanidino (TMG) groups has been developed to prepare copper complexes with a tetrahedral geometry and a labile coordination site.
Abstract: A new tridentate N3 ligand (TMG3tach) consisting of cis,cis-1,3,5-triaminocyclohexane (tach) and three N,N,N′,N′-tetramethylguanidino (TMG) groups has been developed to prepare copper complexes with a tetrahedral geometry and a labile coordination site. Treatment of the ligand with CuIIX2 (X = Cl and Br) gave copper(II)-halide complexes, [CuII(TMG3tach)Cl]+ (2Cl) and [CuII(TMG3tach)Br]+ (2Br), the structures of which have been determined by X-ray crystallographic analysis. The complexes exhibit a four-coordinate structure with C3v symmetry, where the labile halide ligand (X) occupies a position on the trigonal axis. 2Br was converted to a methoxido-copper(II) complex [CuII(TMG3tach)(OMe)](OTf) (2OMe), also having a similar four-coordinate geometry, by treating it with an equimolar amount of tetrabutylammonium hydroxide in methanol. The methoxido-complex 2OMe was further converted to the corresponding phenolato-copper(II) (2OAr) and thiophenolato-copper(II) (2SAr) complexes by ligand exchange reactions wit...
26 citations
TL;DR: The carboxamides; N,N′-bis(thiophene-2-carboxamido)-1,3-diaminopropanol (L1 ) and N, N′−bis(furan)-2-Carboxamidis)-1-3-dimitriropropanol(L2 ) were synthesized and characterized using 1 H NMR, 13 C NMR and FT-IR spectrum, thermogravimetric analysis (TGA/DTA curves), magnetic moments and molar conductivities as discussed by the authors.
26 citations
TL;DR: In this paper, the authors describe synthesis of new chloride and alkoxo-titanium (IV) complexes 3-7 with diol O,O-type ligands from readily available and scalable precursors.
23 citations
TL;DR: New copper(ii) complexes were synthesized and characterized as catalysts for selective fixation of atmospheric CO2 and regenerated catalysts were active enough to fix CO2 in eight repeating cycles without any change in efficiency.
Abstract: New copper(II) complexes, [Cu(L1)2(H2O)](ClO4)2, 1 [L1 = 2-pyridin-2-yl-quinoline], [Cu(L2)2(H2O)](ClO4)2, 2 [L2 = 2-pyridin-2-yl-quinoxaline], [Cu(L3)2(H2O)](ClO4)2, 3 [L3 = 6,7-dimethyl-2-pyridin-2-yl-quinoxaline], [Cu(L4)2(H2O)](ClO4)2, 4 [L4 = 4-phenyl-2-pyridin-2-yl-quinoline] and [Cu(L5)2(H2O)](ClO4)2, 5 [L5 = 4-phenyl-2-pyridin-2-yl-quinazoline], were synthesized and characterized as catalysts for selective fixation of atmospheric CO2. The molecular structure of 2 was determined by single-crystal X-ray studies and shown to have an unusual trigonal bipyramid geometry (τ, 0.936) around the copper(II) center, with the coordination of two ligand units and a water molecule. The Cu–Nquin (2.040, 2.048 A) bonds are slightly longer than the Cu–Npyr (1.987 A) bonds but shorter than the Cu–Owater bond (2.117 A). Well-defined Cu(II)/Cu(I) redox potentials of around 0.352 to 0.401 V were observed for 1–5 in acetonitrile. The electronic absorption spectra of 1–5 showed ligand-based transitions at around 208–286 nm with a visible shoulder at around 342–370 nm. The d–d transitions appeared at around 750–800 and 930–955 nm in acetonitrile. The rhombic EPR spectra of 1–5 exhibited three different g values gx, 2.27–2.34; gy, 2.06–2.09; and gz, 1.95–1.98 at 70 K. Atmospheric CO2 was successfully fixed by 1–5 using Et3N as a sacrificial reducing agent, resulting in CO32−-bound complexes of type [Cu(L)CO3(H2O)] that display an absorption band at around 614–673 nm and a νst at 1647 cm−1. This CO32−-bound complex of 1 was crystallized from the reaction mixture and it displayed a distorted square pyramidal geometry (τ, 0.369) around the copper(II) center via the coordination of only one ligand unit, a carbonate group, and water molecules. Furthermore, treatment of the carbonate-bound Cu(II) complexes with one equivalent of H+ under N2 atmosphere resulted in the liberation of bicarbonate (HCO3−) and regenerated the parent complexes. These regenerated catalysts were active enough to fix CO2 in eight repeating cycles without any change in efficiency. The fixation of CO2 possibly occurs via the formation of Cu(I)-species, which is accompanied by the formation of an MLCT band at around 450–500 nm. The rates of Cu(I)-species formation, kobs, were determined and found to be 5.41–10.31 × 10−3 s−1 in the presence of Et3N in acetonitrile at 25 °C. Interestingly, the copper(I)-species of 3 has been successfully crystallized and displayed a distorted tetrahedral geometry through the coordination of two units of ligand L3.
22 citations
TL;DR: In this paper, a four-coordinated tetrahedral copper(I) complexes of the type [CuCl(HL)(PPh3)2] (1, 2, 3, 3-dialkyl/aryl-1-(2,4-dichlorobenzoyl)thiourea derivatives] were found to be active catalysts for the oxidation of primary and secondary alcohols.
20 citations
TL;DR: In this paper, the authors have synthesized the novel Cu(II) and Zn-II complexes (CDM) for ring-opening polymerization (ROP) of rac-lactide (rac-LA) with narrow polydispersity indexes.
20 citations
TL;DR: In the presence of BnOH, complexes Al1–Al5 efficiently initiated the ring-opening homopolymerization of ε-caprolactone (ε-CL) and rac-lactide (rac-LA), respectively, in a living/controlled manner.
Abstract: The stoichiometric reactions of 8-(2,6-R1-4-R2-anilide)-5,6,7-trihydroquinoline (LH) with AlR3 (R = Me or Et) afforded the aluminum complexes LAlR2 (Al1–Al5,Al1: R1 = iPr, R2 = H, R = Me; Al2: R1 = Me, R2 = H, R = Me; Al3: R1 = H, R2 = H, R = Me; Al4: R1 = Me, R2 = Me, R = Me; Al5: R1 = Me, R2 = Me, R = Et) in high yields. All aluminum complexes were characterized by NMR spectroscopy and elemental analysis. The molecular structures of complexes Al4 and Al5 were determined by single-crystal X-ray diffractions and revealed a distorted tetrahedral geometry at aluminum. In the presence of BnOH, complexes Al1–Al5 efficiently initiated the ring-opening homopolymerization of e-caprolactone (e-CL) and rac-lactide (rac-LA), respectively, in a living/controlled manner.
TL;DR: In this paper, a novel 7-hydroxy-4-methyl-8-(p-tolylazo)-2H-1-benzopyran-2-one (coumarin) and their metal complexes with Mn(II, Co(II), Ni(II) Cu(II and Zn(II)) were prepared and characterized by elemental analysis, infrared (IR), proton nuclear magnetic resonance (1H NMR) and mass spectra.
TL;DR: In this article, a homoleptic zinc(II) dithiocarbamates was synthesized and characterized by elemental analyses and spectroscopy (IR, UV-vis, 1H and 13C{1H} NMR).
Abstract: New homoleptic zinc(II) dithiocarbamates, [Zn(L)2] (L = N-ferrocenyl-N-methyl dithiocarbamate (L1) 1, (N-(benzo[d][1,3]dioxol-5-ylmethyl)-N-furfuryl) dithiocarbamate (L2) 2, N-(benzo[d][1,3]dioxol-5-ylmethyl)-(N-benzyl) dithiocarbamate (L3) 3, N-(benzo[d][1,3]dioxol-5-ylmethyl)-(N-methyl) dithiocarbamate (L4) 4, N-ethylmorpholine-(N-4-methoxyphenylmethyl) dithiocarbamate (L5) 5 and N-(benzo[d][1,4]dioxol-6-ylmethyl)-(N-benzylmethyl) dithiocarbamate (L6) 6, have been synthesized and characterized by elemental analyses and spectroscopy (IR, UV-vis, 1H and 13C{1H} NMR). X-ray crystallography revealed different dimeric structures for (1 and 2) and (3, 4, and 5) adopting distorted tetrahedral and TBP/SP coordination geometries, respectively, in which the dithiocarbamate ligands are bonded to the metal centers both in terminal S,S-chelating and μ2,κ2S,S-bridging and μ2,κ2-S,S-chelating–bridging arrangements. 6 is a mononuclear complex showing a distorted tetrahedral geometry. The supramolecular frameworks in these complexes have been sustained by C–H⋯S, C–H⋯O, C–H⋯π, π⋯π, C–H⋯π (ZnCS2, chelate) and H⋯H interactions. The anti-leishmanial activities of the complexes have been screened; 4 and 6 showed potential anti-promastigote and anti-amastigote activities with IC50 values of 0.66 ± 0.22, 1.48 ± 0.10 μg mL−1 and IC50 2.98 ± 0.30, 2.51 ± 0.10 μg mL−1, respectively. Cytotoxicity assays on both complexes showed toxicity on promastigotes but lower toxicity against the RAW 264.7 cell line at different concentrations. All the complexes show luminescence characteristics in CH2Cl2 solution at room temperature arising from the metal perturbed intra-ligand charge transfer (ILCT) states. Their TG analyses show single step decomposition with formation of binary ZnS and ternary FeZn2S3 materials which have been examined by PXRD, SEM and EDAX.
TL;DR: In this article, the synthesis, thermal analysis, crystal structure and magnetic properties of (2-aminobenzothiazolium)2CuCl4, organic-inorganic hybrid compound, have been described.
TL;DR: In this paper, a Schiff base, (E)-N′-((1H-indol-3-yl)methylene)-2-aminobenzohydrazide (Iabh) and its Mn(II, Co(II), Ni(II ), Cu(II) and Zn(II)) complexes have been synthesized.
TL;DR: In this paper, two new compounds, [Cu(SCN)(µ-L)] n ( 1 ) and [Ag (µ 2 -L)](ClO 4 )} n ( 2 ) have been synthesized at room temperature by one-pot reactions between the 1,1-(1,4-butanediyl)bis(1,3-dihydro-3-methyl-1H-imidazole- 2-thione) (L) and appropriate copper(I) and silver(I)) salts.
TL;DR: The present work brings out the role of the distorted tetrahedral coordination geometry of transition-metal ions and ligand-metal charge transfer (which is manifested as narrowing of the band gap) in producing brilliantly colored garnet-based materials.
Abstract: We explored garnet-structured oxide materials containing 3d transition-metal ions (e.g., Co2+ , Ni2+ , Cu2+ , and Fe3+ ) for the development of new inorganic colored materials. For this purpose, we synthesized new garnets, Ca3 Sb2 Ga2 ZnO12 (I) and Ca3 Sb2 Fe2 ZnO12 (II), that were isostructural with Ca3 Te2 Zn3 O12 . Substitution of Co2+ , Ni2+ , and Cu2+ at the tetrahedral Zn2+ sites in I and II gave rise to brilliantly colored materials (different shades of blue, green, turquoise, and red). The materials were characterized by optical absorption spectroscopy and CIE chromaticity diagrams. The Fe3+ -containing oxides showed band-gap narrowing (owing to strong sp-d exchange interactions between Zn2+ and the transition-metal ion), and this tuned the color of these materials uniquely. We also characterized the color and optical absorption properties of Ca3 Te2 Zn3-x Cox O12 (0
TL;DR: In this paper, the atomic charges and second-order interaction energies between orbitals were calculated with natural bond orbital (NBO) analysis, while the calculated ΔE values for neutral organic ligands were about twice smaller.
TL;DR: In this article, a new organic-inorganic hybrid compound (4APH)(4APH 2)[AsO4]·H2 O) was synthesized at room temperature by slow evaporation method and characterized by X-ray diffraction at 150 K.
Abstract: Single crystals of a new organic–inorganic hybrid compound, with the formula (4-APH)(4-APH 2)[AsO4]·H2 O, was synthesized at room temperature by slow evaporation method and characterized by X-ray diffraction at 150 K, DSC–TG measurements, FT-IR and Raman spectroscopies . The title salt, (C 5H7N2)(C5H8N2)[AsO4]·H2 O, contains mono and diprotonated 4-aminopyridine cations, an arsenate trianion and one water molecule. The diprotonated 4-ammoniumpyridinium dication [C 5H8N2]2+ is disordered over two positions with refined site occupancies of 0.73 and 0.27 however the monoprotonated 4-aminopyridinium cation [C5H7N2]+ is ordered. The 4-aminopyridinium rings are essentially planar and occur in stacks along b axis. In the crystal, the AsIII atom is coordinated by four O atoms in a slightly distorted tetrahedral geometry. The arsenate O atoms link the 4-aminopyridinium cations and water molecules into a three-dimensional network via intermolecular O–H···O and N–H···O hydrogen bonds . Additionally, in this structure, the different types and the nature of aromatic–aromatic interactions can distinguish between a stacked arrangement are parallel displaced and T-shaped conformation. Furthermore, the room temperature IR and Raman spectra of the title compound were recorded and analyzed. On the basis of detailed vibrational studies, the detailed assignment confirms the presence of the organic groups and the anionic entities. Besides, the thermal analysis studies have been performed, but no phase transition was found in the temperature range 298–625 K. Results from X-ray crystallography , Raman, IR spectroscopy and thermal analysis are combined to provide a description of the new organic arsenate monohydrate, (C 5H7N2)(C5H8N2)[AsO4]·H2O.
TL;DR: In this paper, the synthesis and photophysical study of novel fluorescent boron-aminotroponimine complexes are described, and the chemical structure of one of these complexes is confirmed by single crystal X-ray analysis.
TL;DR: In this paper, a series of metal coordination polymers of Mn(II), Fe, Co, Ni, Cu, and Zn(II) have been investigated by the reaction of metal acetate with newly synthesized adipoyl bis(isonicotinoylhydrazone) (ADBI).
TL;DR: Temperature-dependent magnetic susceptibility measurements for 2-4 reveal predominant antiferromagnetic interactions between the paramagnetic metal(ii) ions.
Abstract: A series of zinc(II), cobalt(II) and manganese(II) coordination networks with phosphoserine ligand (H3PSer) are synthesized and characterized. Whereas in compounds 1 and 2 with the general formula [M(HPser)]n [M = Zn (1) and Co (2)], the metal(II) ion presents a tetrahedral geometry, in [Co(HPSer)(H2O)2]n (3) and [Mn(HPSer)(H2O)]n (4), the metal(II) ions are in a distorted octahedral geometry. The 3D frameworks are formed by inorganic layers built up from MO4 or MO6 polyhedra and phosphate groups. These layers are linked by the carboxylate groups of the phosphoserine ligand. The presence of extended hydrogen bonding stabilizes the 3D network and favours the proton transfer leading to moderate proton conductors. The highest proton conductivity, 2.70 × 10−5 S cm−1 (at 80 °C and 95% RH), is obtained for compound 3. Temperature-dependent magnetic susceptibility measurements for 2–4 reveal predominant antiferromagnetic interactions between the paramagnetic metal(II) ions.
TL;DR: In this article, the same authors obtained new Schiff bases in the reaction of 2-thiopheneethylamine with 3-methyl-2thiophencarboxaldehyde (3-methca), L1) or 5-bromo-2-thio-2.5-branched carbone derivatives (5-Brthca, L2) and characterized 1H, 13C and 15N NMR spectra and a 1H differential Nuclear Overhauser Effect diff.
TL;DR: In this paper, the Na salt of heteroleptic molybdenum complex with nitrilotris(methylenephosphonic) acid (NTP), hydroxylamine, and nitrogen(II) oxide Na3[Mo(NO)(NH2O){N(CH2PO3)3H}]· 8H2O was synthesized, isolated, and studied.
Abstract: The sodium salt of heteroleptic molybdenum complex with nitrilotris(methylenephosphonic) acid (NTP), hydroxylamine, and nitrogen(II) oxide Na3[Mo(NO)(NH2O){N(CH2PO3)3H}]· 8H2O was synthesized, isolated, and studied (space group P21/c, Z = 4, a = 9.7385(2), b = 10.2542(2), c =21.6517(3) A, β = 93.7060(10)°). The nitrilotris(methylenephosphonate) ion is monoprotonated at the PO3 group. The nitrogen atom is deprotonated and coordinates the Mo atom; the NTP denticity is 4. Hydroxylamine is ionized according to the acid type and is bidentate. The Mo–NO group is almost linear (176.31(19)° angle; Mo–N, 1.7599(13) A; ν(N–O), 1756 cm–1), the electron density distribution attests to the formation of an Mo–N π-bond. The Mo coordination polyhedron is a distorted pentagonal bipyramid. Two Na ions are coordinated at the vertices of a distorted octahedron and the third one forms a distorted tetrahedral geometry. (CIF file CCDC no. 1543700.)
TL;DR: The structures of 5, 7, 8, and 10' were determined by X-ray diffraction, and the Ru4 core structure and the coordination mode of hydrido ligands were discussed based on density functional theory (DFT) calculations for model compounds where the methyl groups of Cp* ligand were replaced with hydrogen atoms.
Abstract: Dicationic tetranuclear ruthenium octahydride [(Cp*Ru)4H8]2+ (5) with tetrahedral geometry was obtained by reaction of dinuclear ruthenium tetrahydride (Cp*Ru)2(μ-H)4 (1) with an excess of Bronsted acids, such as HBF4·OEt2, in toluene. Monocationic tetraruthenium heptahydride [(Cp*Ru)4H7]+ (7) was obtained by dropwise addition of a diluted acid to a rigorously stirred solution of 1 at ambient temperature. Dication 5 was converted into monocationic heptahydrido complex 7 in high yield by treatment with sodium methoxide or sodium hydride. The direct conversion of 5 into neutral hexahydrido complex (Cp*Ru)4H6 (8) was achieved in a highly efficient manner by treating 5 with LiAlH4 in tetrahydrofuran (THF). The conversion of 5 into 8 was reversible, and the addition of a Bronsted acid to 8 gave 5via the formation of 7 as an intermediate. Tetranuclear complex 8 was directly obtained from 1 by heating it in THF at 70 °C. Complex 8′ and tetraruthenium tetrahydride (CpEtRu)4H4 (10′), where 8′ and 10′ possessed η5-C5EtMe4 ligands instead of Cp* ligands, were mutually related by the elimination/addition of dihydrogen. The structures of 5, 7, 8, and 10′ were determined by X-ray diffraction, and the Ru4 core structure and the coordination mode of hydrido ligands were discussed based on density functional theory (DFT) calculations for model compounds where the methyl groups of Cp* ligands were replaced with hydrogen atoms.
TL;DR: In this article, six Nalkylpyridinium salts [CnPy]2[MCl4] (n = 4 or 12 and M = Co, Cu, Zn) were synthesized and their structure and thermal properties were studied.
Abstract: Six N-alkylpyridinium salts [CnPy]2[MCl4] (n = 4 or 12 and M = Co, Cu, Zn) were synthesized and their structure and thermal properties were studied. In the solid state, the [C4Py]2[MCl4] compounds are monoclinic and crystallize in the space group P21/n. The crystals of the longer chain analogues [C12Py]2[MCl4] are triclinic and crystallize in the space group P1 . Only the derivatives with the longer C12 chain exhibit liquid crystalline phases. The shorter chain compounds only show a melting transition. Consistent with single crystal analysis, electron paramagnetic resonance spectroscopy suggests that the [CuCl4]2- ions in the Cu-based ionic liquids have a distorted tetrahedral geometry.
TL;DR: In this paper, the geometric and electronic structure of transition metal complexes of ethylvanillin [Mn(L)2(H2O)2] (1), [Co(L), 2, 3, and 4 has been solved by X-ray diffraction analysis and EPR spectroscopy.
TL;DR: In this article, the properties of thiamine metal complexes were characterized by elemental analysis, IR, electronic spectra, magnetic susceptibility, ESR spectra of Cu(II) complex and EDX for structural investigation of the complexes.
TL;DR: In this paper, the emission energy of cubane cluster-based coordination polymers with strong yellow emission has been investigated and shown to occur in the mid-range of the Cu⋅Ⓟ⒵�⓵ distances and tetrahedral geometry index values.
TL;DR: In this paper, a Schiff base was synthesized by condensation of 2-acetyl thiophene with methionine in a mole ratio of 1:1 and characterized with 1H-13C NMR, UV-Vis, FT-IR and MS methods.
Abstract: New Schiff base; (S)-4-(methylthio)-2-((1-(thiophen-2-yl)ethylidene)amino) butanoic acid (LH); was synthesized by condensation of 2-acetyl thiophene with methionine in a mole ratio of 1:1 and characterized with1H-13C NMR, UV–Vis, FT-IR and MS methods. The metal complexes of manganese(II), cobalt(II), nickel(II), copper(II), and zinc(II) were prepared by direct reaction of the ligand (LH) and the metal chlorides which structurally characterized with spectroscopic methods, magnetic, and conductivity measurements. The data showed that the Schiff base LH ligand behaves as a bidentate via nitrogen atom of imine group and oxygen atom of carboxylic methionine moiety. The results obtained from magnetic moments, electronic spectra, mass spectra and elemental analyses confirmed the tetrahedral geometry around the central metal ions. The optimization of geometry, vibrational band assignments, frontier molecular orbitals, and absorption spectrum of the compounds were investigated by DFT/B3LYP/6–31 + G(d,p) methods. Natural bond orbital analysis was carried out for the investigation of major stabilizing orbital interactions.