Synthesis, Characterization and Crystal Structure of Samarium(III)- (E)-1-phenyl-N-(4H-1,2,4-triazol-4-yl)methanimine Complex
- Research Summary
Samarium-benzylidene Schiff base adduct with the formula [Sm(NO3)3(H2O)3].2L (L= (E)-1-phenyl-N-(4H-1,2,4-triazol-4-yl) methanimine) (1) has been prepared, with two water molecules bonded to the samarium center form hydrogen bond with three molecules of title Schiff base through nitrogen atoms of the triazole rings. The chemical structure was confirmed by means of single-crystal X-ray diffraction (scXRD), FT-IR, electrical conductivity, thermogravimetric analysis (TGA), mass spectrometry and elemental analysis. The title complex 1 crystallizes in the triclinic P-1 space group. The unit cell parameters are a = 10.4045(1) Å, b = 12.5403(1) Å, c = 12.5477(2) Å, a = 96.668(1)o, b = 110.810(1)o, g = 111.567(1)o, V = 1.788 Å3, Z = 2, Rgt(F) = 0.0223, wRref(F2) = 0.0576. The samarium ion is in a distorted capped square antiprism environment, coordinated by three bidentate nitrates and three coordination water molecules. The [Sm(H2O)3(NO3)3] complex and the (E)-1-phenyl-N-(4H-1,2,4-triazol-4-yl)methanimine) moiety (L) are held together via hydrogen interactions to form a 2-D supramolecular framework. It is a non-electrolyte as indicated by its molar conductivity (ΛM= 10.1 S cm2 mol-1) in MeOH at 1.0 mM. The mass spectral results confirm the suggested structure of the investigated adduct.
- Research link
- key words
Samarium complex, Synthesis, Spectroscopy, Triazole, Schiff base, Crystal structure.
SYNTHESIS AND CHARACTERIZATION OF BENZOCAINE SCHIFF BASE AND ITS COBALT COMPLEX
- Research Summary
Ethyl4-(2-hydroxy-benzylideneamino) benzoate Schiff base (C16H15NO3), were synthesized and the structure was studied against the bases of X-ray, UV, visible, elemental analysis, 1HNMR, IR and Mass spectroscopy. The crystal structure of the nickel complex has been determined by single crystal X-ray conformed the molecule, which indicate the compound is crystalline in the monoclinic C2 / c with a = 16.0916 (5) Å, b = 6.0315 (2) Å, c =29.0072 (10) Å, α = 90.00°, β= 101.856 (2)°, γ = 90.00°, V= 2755.3 (2) Å3 and Z = 8. Because of intra-molecular hydrogen bond involving the O atom of hydroxy group and N atom of azomethine group; the two benzene rings and azomethine group are practically coplanar. The Cobalt complex was prepared; the structure was characterized in the bases of IR spectra, elemental analysis, UV - visible, and conductance measurements. Also, the biological activity of both Schiff base and its Cobalt complex show that they are biologically active.
- Research link
- key words
Spectroscopic, Benzocaine, Schiff base, X-ray single crystal, Biological activities and Cobalt complex
The crystal structure of ethyl 4-((2-hydroxybenzyl)amino)benzoate, a Schiff base, C16H17NO3
- Research Summary
C16H17NO3, triclinic, P1̅ (no. 2), a = 7.5445(7) Å, b = 8.3326(9) Å, c = 12.4291(10) Å, α = 94.468(8)°, β = 91.063(7)°, γ = 116.644(10)°, V = 695.01(13) Å3, Z = 2, Rgt(F) = 0.0461, wRref(F2) = 0.1240, T = 291 K. The asymmetric unit of the title crystal structure is shown in the figure. Tables 1 and 2 contain details of the measurement method and a list of the atoms including atomic coordinates and displacement parameters.
- Research link
- key words
Crystal structure , Schiff base
Synthesis of 2-{(Z)-[(4-methylphenyl)imino]methyl}phenol Schiff base
- Research Summary
2-{(Z)-[(4-methylphenyl)imino]methyl}phenol Schiff base (C14H13NO),were synthesized and the structure was
elucidated in the bases of 1HNMR and X-ray. The X-ray establish the conformation of the molecule, which indicate
the compound is crystalline in the monoclinic P 21/c with a = 19.3092(19) Å, b = 4.7611(4) Å, c = 12.2222(11) Å a
= 90°, b = 102.087(10)°, g = 90°and Z = 4. Two benzene rings and azomethine group are practically coplanar, as
a result of intramolecular hydrogen bond involving the O atom of hydroxyl group and N atom of azomethine group.
- Research link
- key words
Salicylaldehyde, p-Toluidine, Schiff base and x-ray
Synthesis and Spectroscopic Characterization of
Tris(hydroxymethyl)aminomethane Proton Transfer Complexes
with Acidic π-Acceptors
- Research Summary
Two charge transfer complexes based on an organic basic donor, tris(hydroxymethyl)-
aminomethane (Tris), and two π-acceptors having acidic protons, picric acid (PA) and
chloroanilic acid (CA), were synthesized for the first time. Some physicochemical analyses
including UV-Vis, FT-IR and 1H-NMR were employed to investigate and confirm the proposed
chemical structures of the prepared complexes. It was found that the donor–acceptor molar ratio
is 1:1 for Tris:PA and 1:2 for Tris:CA charge transfer complexes. The formed charge transfer
complexes have –NH3
+
and –OH2
+ ions as a result of proton transfer from acidic to basic
centers. The formation constant (KCT) and molar absorptivity coefficient (CT) were calculated
from the experimental spectroscopic data. Thermodynamic studies for both charge transfer
complexes showed the favorability of the complex formation.
- Research link
- key words
Charge transfer complexes, π-acceptors; Tris(hydroxymethyl)aminomethane; Picric acid and Chloroanilic acid.
Reduced Schiff base zinc complexes as proposed models of the active
site of the dinuclear zinc enzyme A. Aminopeptidase
- Research Summary
Complexes of zinc with ligands prepared through the reduction of Schiff bases derived from salicylaldehyde and the
primary aliphatic amines 1,4-diaminobutane (H2Salbn), 1,6-diaminohexane (H2Salhx), and tris(hydroxymethyl)
aminomethane (H2Saltris) have been prepared and proposed as models of the active site of the zinc enzyme
Aeromonas Proteolytica aminopeptidase. The complexes were characterized by 1H-NMR, FT-IR spectroscopy, and
mass spectrometry. In complexes of both H2Salbn and H2Salhx, the 5-ccordinate zinc atoms are present in a N,O
environment with bridging carboxylate ligands thus providing close analogues to the enzyme's active site. On the
other hand, the complex of H2Saltris contains one zinc atom with an all-oxygen environment and one zinc atom
bound to one N and five O atoms.
- Research link
- key words
dinuclear zinc complexes, Reduced Schiff bases, models of enzymes, amino alcohol complexes,
Aeromonas aminopeptidase.
Synthesis and Characterization of β-Diketimine Schiff Base Complexes with Ni(II) and Zn(II) Ions: Experimental and Theoretical Study
- Research Summary
Schiff base diethyl 4,4-(pentane-2,4-diylidenebis(azanylylidene))benzoate (1) as a new ligand (L) was prepared by the reaction of acetylacetone with benzocaine in the ratio of 1 :1. Two transition-metal complexes, [Ni(II)(LCl(HOEt))] (2) and [Zn(II)(LCl(HOEt))] (3), have been synthesized from metal salts with didentate Schiff base ligand (L) and characterized by elemental analyses, FT-IR, 1H NMR, 13C NMR UV-Vis spectroscopy, and magnetic susceptibility. +e biological activity of the complexes was studied. In addition, the M06-2x density function theory method and the 6-31G(d) basic set were applied to determine the optimized structures of 1–3 and to determine their IR and 1 H NMR, 13C NMR spectra theoretically. +e data are in good agreement with the experimental results. +e geometries of complexes 2 and 3 were determined to be square-planar for 2 and tetrahedral for 3
- Research link
- key words
Schiff base. acetylacetone, Nickle complex
SYNTHESIS, CHARACTERIZATION, CRYSTAL STRUCTURE AND
FLUORESCENCEOFANEWSAMARIUMSCHIFF-BASECOMPLEX
- Research Summary
A new samarium Schiff base complex with the formula [SmIII(NO3)3(H2O)L2]⋅EtOH, where L = {(E)-2-
(((4-(ethoxycarbonyl)phenyl)iminio)-methyl)phenolate}, is synthesized. Its molecular structure is
determined by means of single crystal X-ray diffraction (XRD). The complex crystallizes in the
orthorhombic space group Pbca with the following unit cell dimensions: a = 14.1304(19) Å,
b = 18.0218(13) Å, and c = 31.246(2) Å. Photoluminescence characteristics of the complex are investigated
experimentally in the solid state and obtained theoretically using the Sparkle/PM7 modeling. Moreover,
several methods such as powder XRD, FT-IR and UV-Visible spectroscopy are utilized to confirm the
structure of the complex
- Research link
- key words
samarium, Schiff base, fluorescence, crystal structure, Sparkle/PM7
Proton transfer complexes based on some π-acceptors having acidic protons
with tyramine donor: Synthesis and spectroscopic characterizations
- Research Summary
Charge transfer complexes based on tyramine (Ty) (4-(2-aminoethyl) phenol) organic basic donor and π -acceptors
having acidic protons such as picric acid (PA), and chloroanilic acid (CA) with the compositions, [(Ty)(CA)2] and
[(Ty)(PA)2] have been synthesized and the chemical structures were confirmed by thermal analysis and
physicochemical studies such as UV visible, FT-IR and 1H-NMR spectral studies. Spectroscopy measurements show
that the donor–acceptor molar ratio was found to be 1: 2 for both (Ty): (PA) and (Ty): (CA) charge transfer
complexes, in addition to that the ArNH+
3 ammonium ion and OH2+ were formed under the acid–base theory
through proton transfer from an acidic to basic centers in charge transfer complexes, as well as the spectroscopic
data were discussed in terms of formation constant (KCT) and molar extinction coefficient (εCT). Thermal behavior of
both charge transfer complexes showed that the complexes were more stable than their parents.
- Research link
- key words
Charge transfer complexes, Tyramine, picric acid and chloroanilic acid.
_________________________________________________________________
Synthesis, Characterization and Biological Activities of New
Schiff Base Compound and Its Lanthanide Complexes
- Research Summary
The thermal condensation of 3-(2-Furyl)acrolein with 2-Amino-6-ethoxybenzothiazole generated
a new Schiff base, (1E,2E)-N-(6-ethoxybenzo[d]thiazol-2-yl)-3-(furan-2-yl)prop-2-en-1-imine
(L), with general formula of C16H14N2O2S. Also, a series of lanthanide complexes of gadolinium,
samarium, and neodymium (La–Lc) were synthesized utilizing acetonitrile as the solvent and triethylamine
as a buffer and catalyst. Based on elemental analysis, mass spectroscopy, and FTIR
analysis, all of the Bis-(1E,2E)-N-(6-ethoxybenzo[d]thiazol-2-yl)-3-(furan-2-yl)prop-2-en-1-iminetrinitratolanthanide(
III) complexes with the general formula [LnL2(NO3)3]H2O are solids with a 2:1
molar ratio (ligand: metal). Based on conductivity estimates, they are nonelectrolytes and monoatomic
paramagnetic according to the magnetic moment measurements, and one mole of lattice water was
found after thermal gravimetric measurements and FTIR analysis. Therefore, the lanthanide complexes
show a ten-coordination structure with a deformed bicapped square antiprismatic. The Schiff
base and its complexes were screened for their antimicrobial, antifungal, antioxidant, and antitumor
properties. Their antimicrobial and antifungal activities were strong, and they also produced good
antioxidant and antitumor effects.
- Research link
- key words
synthesis; spectroscopic; 2-Amino-6-ethoxybenzothiazole; 3-(2-Furyl)acrolein; lanthanide
complexes; antimicrobial; antitumor; antioxidant
Synthesis, characterization and crystal structure of LnIII - (1E,2E)-3-(furan-2-yl)-N-(4H-1,2,4-triazol-4-yl)prop-2-en-1-imine.
- Research Summary
New neodymium (1a) and samarium (1 b) complexes with the general formula [LnIII(NO3)3(H2O)3L]·L (1) were synthesized based on the previously reported ligand L (L = (1E,2E)-3-(furan-2-yl)-N-(4H-1,2,4-triazol-4-yl)prop-2-en-1-imine) which were investigated by X-ray analysis. Through X-ray studies, it was shown that the Schiff base L coordinates to LnIII via κN-bonding of one of the triazole ring nitrogen atoms as a monodentate ligand, three κ2OO′-bonded nitrate ions and three κO-bonded water molecules completing the coordination sphere around the LnIII ion, resulting in a tenfold-coordinated LnNO9 unit in a distorted bicapped square antiprismatic geometry. The mononuclear complex units [Ln(NO3)3(H2O)3·L] are linked to the L molecule through intermolecular hydrogen-bonding interactions to form a 2 D polymeric supramolecular architecture. The complexes are neutral and paramagnetic mononuclear complexes, as determined by conductivity and magnetic investigations at room temperature, as well as findings from FT-IR and UV–vis spectroscopy. Finally, thermogravimetric measurements confirm the presence of three water molecules in the coordination sphere. In the visible region, the spectrum of the complex shows typical parity forbidden narrow 4f–4f absorptions originating from the 4I9/2 ground state to the various excited states of NdIII.
- Research link
- key words
Synthesis, spectroscopy, crystal structure, lanthanide complexes, triazol Schiff base ligand.
Synthesis, chemical and physical properties of lanthanide(III) (Nd, Gd, Tb)
complexes derived from (E)-ethyl 4-(2-hydroxybenzylideneamino)benzoate
- Research Summary
The 1:2 reaction between Ln(NO3)3⋅6H2O (1) (Ln = Nd (a), Gd (b) or Tb (c)) and ((E)-ethyl 4-((2-hydroxybenzylidene)
amino)benzoate) (LN,OH) in ethanol has provided access to the complexes [LnIII(LNH,O)2(NO3)3(H2O)]
(2a–c) in good yield. The isomorphous structures of 2a–c have been determined by single-crystal X-ray crystallography.
The LnIII ions in 2a–c are coordinated by 9 oxygen atoms: two from the phenolate oxygen atoms of the
Schiff bases, six from three chelating nitrato groups and one aqua ligand. The ligands LN,OH behave as monodentate
phenolate O–donors, whereby an additional hydrogen atom is bonded to the imino nitrogen atom, resulting in a
formally neutral ligand that adopts an exceptionally unusual coordination mode engaging in the zwitterionic form.
The nine donor atoms that define the coordination polyhedra surrounding the LnIII ion are best described as capped
square antiprisms. The crystal structures are based on a variety of intermolecular interactions. Hirshfeld surface
analysis was used to assess the degree of interactions between the molecules. Susceptibility measurements on 2a–2c
confirm the occurrence of the free ion ground 2S+1LJ state at room temperature. However, the magnetization
measurements at 2 K revealed a lack of saturation at the highest applied field of 70,000 Oe for both 2a and 2c,
indicating the presence of substantial magnetic anisotropy in these compounds. On the other hand, 2b exhibits
perfect paramagnetic behavior with magnetic saturation at high fields, indicating the absence of significant magnetic
anisotropy in this compound. Solid-state IR and UV/VIS data are discussed in terms of the structural features.
Solid 2a–c emit in the visible region upon UV-Excitation with the emission exhibiting dopant characteristics.
- Research link
- key words
Lanthanides
X-ray structure analysis
Hirshfeld surface analysis
Magnetic studies
Photoluminescence properties
Triply Bridged Binuclear lanthanides- Zwitterion complexes: Synthesis and characterization of (Gd(III), Nd(III), Sm(III)) complexes
- Research Summary
2,2'-((1E,1'E)-(butane-1,4-diylbis (azanylylidene))bis (methanylylidene)) diphenol Zwitterion (L) (4`) was prepared by treatment of two equiv. of (3-(2-Furyl)acrolein) (1) with one equiv. of ,4-Butanediamine (2) in refluxing ethanol, through intramolecular Diels-Alder reaction. Three new lanthanide compounds based on (4`), [Ln2(NO3)4(H2O)2L3].2NO3 (5) (a, Ln = Gd; b, Ln = Nd; c, Ln = Sm) have been obtained and further characterized by elemental analysis, conductivity, magnetic measurements, FT-IR, powder x-ray and thermogravimetric analysis. Compounds 5ac exhibits a discrete dinuclear structure constructed by three ligands coordinating two Ln3+ ions. The oxygen atoms of the diphenol are involved in the coordination of compound 5, while the nitrogen at of the imine are not involved. A hypersensitive transition could be observed at 877, 807 753, 588, 522 nm in the UV-visible absorption spectrum of the neodymium complex 5b which corresponding to 4I9/24F3/2 (877 nm); 4I9/24F5/2, 2H9/2 (807 nm); 4I9/24S3/2, 4F7/2 (753 nm); 4I9/22G7/2, 4G5/2 (588 nm); 4I9/2 4G9/2 4G7/2, and 2K13/2 (522 nm), respectively, could be observed. Emission spectra of the ligand and its samarium complex 5c revealed characteristic luminescence within the visible region with the emission of the Samarium complex being relatively red shifted.
- Research link
- key words
Lanthanide’s complexes; synthesis; characterization; Schiff base, Zwitterion
Crystal structure, spectroscopic studies, DFT calculations, and biological activity of 5-bromosalicylaldehyde–based Schiffbases
- Research Summary
A single-crystal X-ray diffraction investigation verified the chemical structure of (E)-ethyl-4-(5–bromo-2- hydroxybenzylidene amino)benzoate ( 1 ). Schiffbase 1 crystallizes in the triclinic space group P ¯1 with unit cell dimensions of a = 5.961(2), b = 7.499(3), c = 17.112(6) ˚A and unit cell angles of α= 95.565(12), β= 94.192 (13), γ= 104.689(13) °. Density functional theory (DFT) calculations utilizing the B3LYP level of theory and the 6–31 + G (d,p) basis set have validated the reported experimental geometries and spectroscopic data (UV–vis, FT-IR, 1 H NMR) for 1 and 2-((E)-(4H-1,2,4-triazole-4-ylimino)methyl)-4- bromophenol ( 2 ), whereby Schiffbase 2 corresponds to a literature known compound. The optimized ge- ometry generated from DFT simulations was used to compute the molecules’ vibrational frequencies. The experimentally observed frequencies are compared to the DFT calculated ones. TD-DFT simulations were also used to study the compounds’ molecular electronic structures. The results of UV–vis spectroscopy, both experimental and computed, support the synthesis of the target compounds. The calculations of the molecular electrostatic potential surfaces of compounds 1 and 2 were performed. According to the calculated molecular electrostatic potential results, the reactive sites of 1 and 2 were determined. The compounds showed bactericidal activity against selective Gram-positive and Gram-negative bacte- ria except for 2 with no candidacidal activity compared to 1 . In vitro cytotoxicity of 1 and 2 was screened for MCF-7 and fibroblasts cell lines by MTT assay. Results showed that 1 is more cytotoxic than 2 on MCF-7 but nontoxic on fibroblasts indicating that 1 has potential for further development in the search of safe and potent anticancer agent.
- Research link
- key words
Schiffbase Single crystal X-Ray diffraction DFT calculations MCF7 Antimicrobial
Preparation, spectroscopic investigation, biological activity and magnetic properties of three inner transition metal complexes based on (2-((p-tolylimino)methyl)phenol) Schiffbase
- Research Summary
(2-(( p -tolylimino)methyl) phenol ) Schiffbase as ligand ( L ) reacts with Ln(NO 3 ) 3 6H 2 O; Ln = with 1:3 molar ratio Three neutral lanthanides Schiffbase coordination complexes L a , L b and L c had a general formula [Ln III ( L O ’ ) 3 (NO 3 ) 3 ]; Ln = Nd ( a ), Tb ( b ) and Dy ( c ). Through the reaction, ligand ( L) was converted into 2-((p-tolyliminium)methyl)phenolato) ( L’ ) zwitterionic tautomer, three units of L’ whose phenolato oxy- gen donor atoms are kO -bonded to Ln(III), whereas the coordination sphere of Ln(III) is surrounded by three k 2 OO ’-bonded nitrate ions produce nine-coordinated LnO 9 unit exhibits a distorted tricapped trigo- nal prismatic structure. In vitro antimicrobial activity showed effectiveness of Lc by a comparative study of MIC values against Candida albicans and Staphylooccus aureus ATCC 29213 which was identified to exhibit higher antimicro- bial activity than the free ligand. The magnetic properties of L a , L b and L c have been investigated using SQUID (Superconducting Quan- tum Interference Device) magnetic susceptibility measurements.
- Research link
- key words
Lanthanides Schiff base physical studies antimicrobial studies zwitterionic tautomer
Development and method validation for detection the concentration of Benzocaine Schiff base by high performance liquid chromatography
- Research Summary
A reversed-phase high performance liquid chromatographic method (HPLC) with UV detection has been developed and validated for the qualification and quantization of synthesized (E)-ethyl 4-(2-hydroxybenzylidene amino) benzoate Schiff base which has an absorption maximum wavelength (λmax) at 280 nm using a UV detector. The HPLC method employs a C18 5µm particle size analytical column (250 mm x 4.6 mm), column temperature-controlled at 40⁰C, detection at 280 nm and 15-µL injection volume with isocratic elution mode of a methanol/water (50:50, v/v) mobile phase at a flow rate of 1.0 mL/min.
The statistical validation parameters such as linearity (Range), accuracy (recovery), precision (repeatability and Intermediate Precision (Ruggedness), System Suitability and Robustness were checked, the benzoate Schiff base concentrations were found to be 0.02 mg/ml, relative concentration 2%, recovery and assay studies of benzoate Schiff base were within (98-102) %. The retention time is about 6.4 min which is within the precision of 10 %. The standard deviations of relative peak areas were within 2% indicating the suitability of the system which support a suitable suggested method for the synthesized title.
- Research link
- key words
RP-HPLC, Validation by USP guideline, UV detection, Schiff base and Benzocaine