Oximato Ligands Research Articles

Study of the anticancer properties of optically active titanocene oximato compounds

New water soluble and optically active cyclopentadienyl titanium derivatives [(η5-C5H5)2Ti{(1R,4S)-ĸON,(R)NH}Cl] (R = Bn (Benzyl) 1a’, 2-pic (2-picolylamine) 1b’) have been synthesized. The novel compounds along with those previously described [(η5-C5H5)2Ti{(1S,4R)-ĸON,(R)NH}Cl] (R = Bn 1a, 2-pic 1b) were evaluated by polarimetry, ultra-violet and circular dichroism spectroscopy. The structure of 1b was determined by single crystal X-ray crystallography and showed a unique terminal monohapto TiO disposition of the oximato ligand. All enantiomers have been tested against several cancer cell lines in vitro: prostate PC-3 and DU-145, lung A-549, pancreas MiaPaca-2, colorectal HCT-116, leukemia Jurkat and cervical HeLa. In addition, 1a, 1b and 1b’ were tested against non-tumorigenic prostate RWPE-1 cell line. After 24 h of incubation, 1b and 1b’ were moderately active against Jurkat and A-549 cells. The anti-proliferative effect of titanium compounds on prostate PC-3, DU-145 and RWPE-1 cell lines was also assessed after 72 h of drug exposure. The cytotoxic profile of the enantiomers was similar, exception made for the PC-3 cells, with S,R-isomers exhibiting cytotoxicities 2 to 3 times higher than R,S-compounds. Under these conditions, derivative 1b showed calculated IC50 values better than those of Tacke's Titanocene-Y (bis-[(p-methoxybenzyl)cyclopentadienyl]titanium(IV) dichloride) on both the prostate PC-3 and DU-145 cells. 1a and 1b cytotoxic behaviour shows certain selectiveness, with activities 2–4 times lower on normal prostate RWPE-1 than on cancer PC-3 cells. Furthermore, 1b produces higher cytotoxicity on prostate PC-3, DU-145 and RWPE-1 cells than the additive dose of titanocene dichloride and pro-ligand b·HCl. Additionally, compound-DNA interactions have been investigated by equilibrium dialysis, Fluorescence Resonance Energy Transfer (FRET) melting assays and viscometric titrations, which suggest that these metal complexes and/or their hydrolysis products bind DNA either in the minor groove or externally.

Electrical properties of solution processed multilayer high-k ZrO2 capacitors in inert atmosphere

The solution deposition of ZrO2 thin films from a single-source precursor with oximato ligands allowed the deposition of very uniform and homogenous films. Variation of the film thickness by either employing higher precursor concentrations or the succeeding deposition of multiple layers did not lead to any observable changes in the film morphology. Measurements were carried out using scanning electron microscopy as well as white light interferometry. Detailed investigations of the electrical properties by impedance spectroscopy of capacitors revealed that the relative permittivity is not affected by the processing procedure. No influence of the particular thickness and the number of the individual layers in a stack could be determined. In all cases, the dielectric constant of the amorphous ZrO2 had a value ~14.8, as extracted from the impedance at 10kHz. The method seems attractive for the application in printed electronics as it is robust against changes in the deposition conditions.

Synthesis and characterization of some acetoxime-modified hetero-metal alkoxide precursors of zinc(II) and aluminum(III) for sol–gel transformation to nano-sized ZnAl2O4

Reactions of [ZnAl2(OPri)8] [A] with acetoxime in different molar ratios in refluxing anhydrous benzene, yield complexes of the type [ZnAl2(OPri)8−n{(CH3)2CNO}n] {where, n = 1–4}. All the complexes are transparent viscous/foamy solids. They were characterized by elemental analyses, FT-IR and NMR (1H, 13C {1H}) spectral studies. 27Al NMR spectrum of [ZnAl2(OPri)4{(CH3)2CNO}4] [4] in CDCl3 suggests presence of four coordination around both the aluminum atoms. IR spectra suggest that the oximato ligands bind the aluminum atoms in a side on manner in all the complexes. The ESI-mass spectrum of the representative derivative [4] suggests its monomeric nature while the thermo-gravimetric curve shows its low thermal stability. Sol–gel transformations of the precursors (A), (1), and (4) yielded nano-sized ZnAl2O4 samples (a), (b) and (c) at ~500 °C, respectively. The XRD patterns of (a), (b) and (c) indicate formation of cubic phase nano-sized zinc aluminate in all the samples. Surface morphologies of these samples were investigated by SEM images. IR spectra as well as EDX analyses indicate formation of pure zinc aluminate in all the cases. TEM image of sample (c) shows spherical (~5–8 nm) morphology.

Unusual Seven Coordination of Oxovanadium(V) Oximato Complex: Synthesis and X-Ray Crystal Structure

The new oxovanadium(V) complex, [VO(acac)(dametsc)] (1) (acac = acetylacetonate (-1), H2dametsc = diacetylmonoxime-4-ethylthiosemicarbazone), has been prepared and characterized by studying its physicochemical properties. The X-ray crystal structure of the complex (1) has been determined and showed the presence of vanadium(V) atom in a unique heptacoordination state with distorted pentagonal bipyramidal geometry. The oximato ligand in the pentagonal plane is bonded to the central vanadium atom in dihapto (η2= N,O) manner with the formation of three membered ring, while the other three coordination sites in the plane are occupied by hydrazinic imine nitrogen, thiolate sulfur, and one of the acac oxygen atoms. The axial position sites are defined by the other acac oxygen and the trans oxo-atom. The supramolecular structure of the complex is exclusively constructed by intermolecular interactions, N–H⋯O and C–H⋯O.

Syntheses and characterization of a new class of vanadia precursors of oxime-modified oxovanadium(V) isopropoxide, crystal and molecular structure of [VO{ONC10H16}3

Modification of [VO(OPri)3] with oximes in different molar ratios, yielded new class of vanadia precursors, [VO{OPri}3−n{L}n] {where, n = 1–3 and LH = C9H16C=NOH (1–3) and (CH3)2C=NOH (4–6)}.All the products are yellow in colour. (1) and (2) are liquid/viscous liquid, while others are solids. Molecular weight measurements of all these derivatives and the ESI-mass spectral studies of (1), (2), (3) and (5) indicate their monomeric nature. 1H and 13C{1H} NMR spectra suggest that the oximato moieties are monodentate in solution which was further confirmed by the 51V NMR signals, appeared in the region expected for tetra-coordinated oxo-vanadium atoms. On ageing, a disproportionation reaction occurs in (1) and some crystals appeared. Single crystal X-ray diffraction analyses of the crystals obtained from (1) as well as from (3) were found to be the same and indicate the presence of side-on {dihapto η2-(N, O)} binding modes of the oximato ligands, leading to the formation of seven coordination environment around the vanadium atom. Thermogravimetric curve of (1) exhibits multi-step decomposition with the formation of V2O5 as the final product at ~850 °C. Sol–gel transformation of (3) yielded (a) VO2 sintered at 300 °C and (b) V2O5 at 600 °C. Similarly, sol–gel transformations of (1) and (2) yielded V2O5 (c) and (d) at 600 °C, respectively. Formation of monoclinic phase in (a) and orthorhombic phase in (b), (c) and (d) were confirmed by powder XRD patterns.

Syntheses and characterization of a new class of zirconia precursors of oxime-modified zirconium(IV) isopropoxide

Some oxime modified complexes of the type [Zr{OPri}4−n{L}n] {where, n = 1–4 and LH=(CH3)2C=NOH (1–4) and C9H16C=NOH (5–8)} have been synthesized by the reaction of [Zr(OPri)4·PriOH] with oximes, in anhydrous refluxing benzene. These synthesized complexes were characterized by elemental analyses, molecular weight measurements, ESI-mass, FT-IR and NMR (1H and 13C{1H}) spectral studies. The ESI-mass spectral studies indicate dimeric nature for [Zr{OPri}2{ONC(CH3)2}2] (2), [Zr{OPri}3{ONC10H16}] (5) and [Zr{OPri}{ONC10H16}3] (7) and monomeric nature for [Zr{ONC10H16}4] (8). Oximato ligands appear to bind the zirconium in side on manner in all the complexes. Thermogravimetric curves of (2) and (8) exhibit multi-step decomposition with the formation of ZrO2, under nitrogen atmosphere. Sol–gel transformations of precursors (5), (6), (7) and (8) in organic medium, yielded nano-sized tetragonal phase of zirconia samples (a), (b), (c) and (d), respectively, on sintering at ~600 °C. All these samples were characterized by Powder XRD patterns and EDX analyses. Surface morphologies of these samples were investigated by SEM images.

Novel Tin Complexes Containing an Oximato Ligand: Synthesis, Characterization, and Computational Investigation

AbstractOrganotin complexes 1–6 of the general formula [SnR2L] and [(SnR3)2L] (L=phenanthrenequinone dioximato – a bidentate ligand, R=Me, Bu, and Ph) were synthesized by the reaction of the sodium salt of the ligand H2L (prepared in situ with MeONa) and SnR2Cl2/SnR3Cl in 1 : 1 and 1 : 2 molar ratios. The physical and spectral properties of the newly synthesized complexes 1–6 are described. DFT and HF Calculations were performed to confirm the proposed structures.

Microwave synthesis and field effect transistor performance of stable colloidal indium-zinc-oxide nanoparticles

Indium zinc oxide nanoparticles were prepared by microwave-assisted decomposition employing solutions of molecular air stable In and Zn precursors of Schiff base type. Stable colloidal ready to use dispersions with shelf-lives of several months were obtained at comparably low temperature of 140 °C by heating mixtures of indium and zinc complexes with Schiff base oximato ligands in 2-ethoxyethanol. IZO particles prepared therefrom with an In : Zn ratio of 60 : 40 display an average diameter of about 5 nm and appeared amorphous in nature. Thin films of the colloidal particles with a uniform surface coverage and low roughness could be obtained by spin-coating on silicon dioxide substrates. X-ray photoelectron spectroscopy showed that oxide formation had occurred after the microwave reaction, but could be improved further by annealing the films at elevated temperatures. The removal of adherent organic and hydroxy moieties at 450 °C thus led to an excellent semiconducting behaviour of the finally resulting IZO films. Obtained thin film transistors exhibited a n-type enhancement mode performance, with a mobility of 8.7 cm2 V−1 s−1, an Ion/off ratio of 2.8 × 105 and a threshold voltage Vth of +3.3 V.

A new linear trinuclear cobalt complex bearing oximato and azido ligands: synthesis, structure, and magnetic characterization

The reaction of CoCl2 · 6H2O, mpkoH (methyl 2-pyridyl ketone oxime), NEt3, and NaN3 in a 1 : 1 : 2 : 1 molar ratio affords a linear trinuclear complex, [CoII(mpko)4(N3)4(H2O)2] (1). Complex 1 has been characterized by single-crystal X-ray diffraction, elemental analysis, and infrared spectrum. Three cobalt ions are in the center of distorted octahedra, which are connected by two μ-1,1 azides and two oxime oxygen atoms to form a linear trinuclear structure. Discrete units of 1 are connected to form a stable 3-D supramolecular network by C–H···O and C–H···N weak interactions. Variable temperature magnetic susceptibility measurements reveal that 1 exhibits antiferromagnetic behavior.

A oximato-bridged linear trinuclear [MnIVMnIIIMnIV] single-molecule magnet

The reaction of Mn(HCOO)(2)·2H(2)O, (t)BuSaoH(2) (3,5-di-tert-butyl-salicylaldoxime) and sodium azide in isopropanol leads to [NaMn(3)((t)BuSao)(6)] (1). Its structure can be described as a linear trinuclear cluster bridged by oximato ligands. Magnetic investigation revealed that the ferromagnetic coupling interaction is dominant in 1 leading to a ground-state spin S(T) = 5. 1 shows single-molecule magnet behaviour under zero or 1 kOe dc field with energy barrier U(eff) ~ 10 K.

A new tetranuclear copper(II) complex with oximate bridges: Structure, magnetic properties and DFT study

A new tetranuclear complex, [Cu 4L 4](ClO 4) 4·2H 2O ( 1), has been synthesized from the self-assembly of copper(II) perchlorate and the tridentate Schiff base ligand (2 E,3 E)-3-(2-aminopropylimino) butan-2-one oxime (HL). Single-crystal X-ray diffraction studies reveal that complex 1 consists of a Cu 4(NO) 4 core where the four copper(II) centers having square pyramidal environment are arranged in a distorted tetrahedral geometry. They are linked together by a rare bridging mode (μ 3-η 1,η 2,η 1) of oximato ligands. Analysis of magnetic susceptibility data indicates moderate antiferromagnetic ( J 1 = −48 cm −1, J 2 = −40 cm −1 and J 3 = −52 cm −1) exchange interaction through σ-superexchange pathways (in-plane bridging) of the oxime group. Theoretical calculations based on DFT technique have been used to obtain the energy states of different spin configurations and estimate the coupling constants and to understand the exact magnetic exchange pathways.

Zirconia and hafnia films from single source molecular precursor compounds: Synthesis, characterization and insulating properties of potential high k-dielectrics

Abstract Novel hafnium and zirconium complexes with oximato ligands are used for chemical solution deposition of zirconia and hafnia thin films. X-ray diffraction and high resolution transmission electron microscopy reveal an amorphous microstructure. Scanning electron as well as atomic force microscopy show uniform and smooth films of both oxides. Electrical breakdown measurements are carried out in order to evaluate the application potential of the hafnia and zirconia thin films as dielectric layers in thin film transistors.

Synthesis and characterization of some bis(cyclopentadienyl)titanium(IV) complexes with internally functionalized oximes(LH): sol–gel transformations of Cp2TiCl2, Cp2TiClL and Cp2TiL2 to nano‐sized anatase titania

AbstractSome bis(cyclopentadienyl)titanium(IV) complexes of the type [Cp2TiCl2−n{L}n] {where, n = 1 or 2; L = ONC(R)Ar; R = H or CH3 and Ar = C5H4N‐2, C4H3O‐2 or C4H3S‐2} have been synthesized by the metathetical reactions of Cp2TiCl2 with the sodium salt of internally functionalized oximes in 1:1 and 1:2 stoichiometry in anhydrous THF. All these red to brown colored solid derivatives have been characterized by elemental analyses, FT‐IR and NMR (1H and 13C{1H}) spectral studies. The FAB mass spectra of some representative derivatives indicate their monomeric nature. Oximato ligands in all the complexes appear to bind the titanium via N and O in a dihapto (${\bf \eta}^{2}$‐N, O) manner in the solid state. Thermogravimetric curves of [Cp2TiCl{ONC(CH3)C5H4N‐2}] and [Cp2Ti{ONC(CH3)C5H4N‐2}2] suggest the formation of hybrid materials CpTiO(Cl) and Cp2TiO, respectively, as the final products at 900 °C under nitrogen atmosphere. Sol–gel transformations of Cp2TiCl2, [Cp2TiCl{ONC(CH3)C5H4N‐2}] and [Cp2Ti{ONC(CH3)C5H4N‐2}2] yielded titania a–c, respectively, at low sintering temperature (600 °C). The powder XRD patterns, IR as well as Raman spectra of all these oxides indicate the formation of nano‐sized anatase phase. The SEM images of titania a–c indicate agglomers like surface morphologies. The absorption spectra of a–c exhibit an energy band gap in the range of 3.47–3.71 eV. Copyright © 2011 John Wiley & Sons, Ltd.

Chemically modified oximato complexes of titanium(IV) isopropoxide as new precursors for the sol–gel preparation of nano-sized titania: Crystal and molecular structure of [Ti{ONC10H16}4·2CH2Cl2

Abstract Reactions of [Ti(OPri)4] with various oximes, in anhydrous refluxing benzene yielded complexes of the type [Ti{OPri}4−n{L}n], where, n = 1–4 and LH = (CH3)2C NOH (1–4), C9H16C NOH (5–8) and C9H18C NOH (9–12). The compounds were characterized by elemental analyses, molecular weight measurements, FAB-mass, FT-IR and NMR (1H, 13C{1H}) spectral studies. The FAB-mass spectra of mono- (1), and di- (2), (6), (10) substituted products indicate their dimeric nature and that of tri- (3) and tetra- (4), (8) substituted derivatives suggest their monomeric nature. Crystal and molecular structure of [Ti{ONC10H16}4·2CH2Cl2] (8A) suggests that the oximato ligands bind the metal in a dihapto η2-(N, O) manner, leading to the formation of an eight coordinated species. Thermogravimetric curves of (3), (6) and (10) exhibit multi-step decomposition with the formation of TiO2 as the final product in each case, at 900 °C. Low temperature (∼600 °C) sol–gel transformations of (2), (3), (4), (6), (7) and (8) yielded nano-sized titania (a), (b), (c), (d), (e) and (f), respectively. Formation of anatase phase in all the titania samples was confirmed by powder XRD patterns, FT-IR and Raman spectroscopy. SEM images of (a), (b), (c), (d), (e) and (f) exhibit formation of nano-grains with agglomer like surface morphologies. Compositions of all the titania samples were investigated by EDX analyses. The absorption spectra of the two representative samples, (a) and (f) indicate an energy band gap of 3.17 eV and 3.75 eV, respectively.

The use of methylsalicyloxime in manganese chemistry: A [formula omitted] triangle and its oxidation to a [formula omitted] rod

The preparation, crystal structure and reactivity of a trimetallic Mn III carboxylate cluster containing the dianion of methylsalicyloxime (Me-saoH 2), is reported. The reaction between Mn(OAc) 2 · 4H 2O and Me-saoH 2 in pyridine (py) produces the complex [ Mn 3 III O ( OAc ) ( Me-sao ) 3 ( py ) 4 ] · 2 py ( 1 · 2py ) in very good yields. The neutral complex consists of a central triangular { Mn 3 III O } unit assembled together by three η 1:η 1:η 1:μ 2-oximato(−2) and one bridging AcO − ligands. Oxidation of 1 · 2 py in MeCN in the presence of (NH 4) 2[Ce IV(NO 3) 6] leads to the formation of complex [ Mn 4 IV Ce 2 III O 2 ( Me-sao ) 6 ( NO 3 ) 4 ( OAc ) 2 ( H 2 O ) 2 ] · 6 MeCN ( 2 · 6MeCN ) . Its centrosymmetric structure may be described as two { Mn 2 IV Ce III O } triangles linked through two η 2:η 2:η 1:μ 4 oximato(−2) ligands. Each { Mn 2 IV Ce III O } unit is held together via one η 2:η 1:η 1:μ 3 and one η 1:η 1:η 1:μ 2-Me-sao 2− ligand, and one bridging acetate. Dc magnetic susceptibility studies reveal the presence of dominant antiferromagnetic interactions in both complexes.

Synthesis and characterization of some oxovanadium(V) complexes with internally functionallized oximes. Crystal and molecular structure of heptacoordinated [VOCl{ON=C(CH3) (C4H3S-2)}2] · CH3OH

New heteroleptic oxovanadium(V) chloro oximato complexes of the type [VO{Cl}3-n{ON=C(CH3)(Ar)}n] (where Ar = C4H3O-2, C4H3S-2, C5H4N-2 and n = 1 or 2) have been synthesized in excellent yields by the reaction of VOCl3 with the sodium salts of corresponding internally functionallized oximes in refluxing anhydrous benzene. The complexes are characterized by elemental analyses and spectroscopic techniques (FT-IR, 1H-, 13C{1H}- and 51V-NMR). FAB mass spectral analysis of one of the derivatives, [VOCl{ON=C(CH3)C4H3S}2] indicates the monomeric nature of the complex. 51V-NMR spectral studies of these complexes suggest tetra-coordination around the vanadium atom in solution. However, the single crystal X-ray diffraction study of a redistribution product [VOCl{ON=C(CH3)(C4H3S-2)}2] · CH3OH obtained on recrystallization of [VOCl2{ON=C(CH3)(C4H3S-2)}] from a methanol-hexane mixture shows the vanadium(V) atom is hepta-coordinated with distorted pentagonal bipyramidal geometry. The oxo-atom occupies the axial position while the weakly coordinated CH3OH group is trans to the V=O atom. The two oximato ligands in the approximate pentagonal plane are bonded to the central vanadium atom in dihapto (η2-N, O) manner with the formation of three-membered rings. The V–Cl bond occupies the fifth position in the approximate plane.

Synthesis, Structure, and Reactivity of Mononuclear Re(I) Oximato Complexes

Complexes [Re(ONCMe2)(CO)3(bipy)] (1) and [Re(ONCMe2)(CO)3(phen)] (2), synthesized by reaction of the respective triflato precursors [Re(OTf)(CO)3(N-N)] (N-N = bipy, phen) with KONCMe2, feature O-bonded monodentate oximato ligands. Compound [Re(CO)3(phen)(HONCMe2)]BAr'4 (3), with a monodentate N-bonded oxime ligand, was prepared by reaction of [Re(OTf)(CO)3(phen)], HONCMe2, and NaBAr'4. Deprotonation of 3 afforded 2. The oximato complexes reacted with p-tolylisocyanate, p-tolylisothiocyanate, maleic anhydride, and tetracyanoethylene, affording the products of the insertion of the electrophile into the Re-O bond, compounds 4-7. One representative of each type of compound was fully characterized, including single-crystal X-ray diffraction. The reactions of 1 and 2 with dimethylacetylenedicarboxylate were found to involve first an insertion as the ones mentioned above but followed by incorporation of water, loss of acetone, and formation of the charge-separated neutral amido complexes 9 and 10. The structure of 9 and 10 was determined by X-ray diffraction, and key features of their electronic distribution were studied using a topological analysis of the electron density as obtained from the Fourier map.

Synthesis and characterization of some oxovanadium(V) complexes with internally functionalized oximes: Crystal and molecular structures of heptacoordinated [VO{ON [dbnd]C(CH 3)(C 4H 3O-2)} 3] and [VO{ON [dbnd]C(CH 3)(C 4H 3S-2)} 3] · 0.5C 6H 6

New oxovanadium(V) complexes with internally functionalized oximes of the type VO{OPr i } 3− n {ON C(CH 3)(Ar)} n ] (where Ar = C 4H 3O-2, C 4H 3S-2 and C 5H 4N-2 and n = 1–3) have been prepared in quantitative yields by the reaction of VO(OPr i ) 3 with the corresponding oximes in various stoichiometric ratios in refluxing anhydrous benzene. The products have been characterized by elemental analyses and spectroscopic (FT IR, 1H, 13C{ 1H} and 51V NMR) studies. FAB mass spectral analysis of [VO{OPr i }{ON C(CH 3)C 4H 3S} 2] indicates the monomeric nature of the complex. 51V NMR values for these complexes suggest the formation of tetra-coordinate species in solution. However, the single crystal X-ray diffraction studies of [VO{ON C(CH 3)(C 4H 3O-2)} 3] and [VO{ON C(CH 3)(C 4H 3S-2)} 3] · 0.5C 6H 6 exhibit the presence of vanadium(V) atoms in a unique hepta-coordination state with distorted pentagonal bipyramidal geometry in the solid state. The oxo- atom occupies the axial position while the oximato ligands are bonded in a dihapto (η 2-N,O) manner with the formation of three membered rings.

A rare all-Mn 2+ decametallic cage from distorted face-sharing cubes

The preparation and crystal structure of a decametallic Mn II carboxylate cluster containing neutral 2-pyridinealdoxime, (py)C(H)NOH, and its anion, (py)C(H)NO −, is reported. The reaction between Mn(O 2CPh) 2 · 2H 2O and (py)C(H)NOH in CH 2Cl 2, in the presence of NH 4PF 6, produces the complex [Mn 10(O 2CPh) 12{(py)C(H)CNO} 6{(py)C(H)NOH} 2](PF 6) 2 · 2.6CH 2Cl 2 · 1.3H 2O ( 1 · 2.6CH 2Cl 2 · 1.3H 2O) in good yield. The cationic complex consists of ten Mn II ions assembled together by four η 1:η 1:η 3:μ 4 and two η 1:η 1:η 2:μ 3 oximato(−1) ligands, and four η 1:η 2:μ 3 PhCO 2 - ligands to form an unprecedented { Mn II 10 ( μ -OR ) 4 ( μ - OR ′ ) 2 ( μ 3 - OR ′ ) 4 } 10 + core, where R = PhCO and R′ = (py)C(H)N. Peripheral ligation is provided by a combination of bridging benzoates and chelating (py)C(H)NOH ligands. Dc magnetic susceptibility studies reveal the presence of dominant antiferromagnetic interactions leading to a spin ground-state of S T = 0. A survey of the ternary Mn II / RCO 2 - / ( py ) C ( H ) NOH reaction system is attempted with comparisons to previously reported complexes.

Trans-Bis{2-[1-(hydroxyimino)ethyl]phenolato}cobalt(II)

In the title compound, [Co(C8H8NO2)2], the Co atom has a distorted square-planar coordination involving two N atoms and two O atoms from two ethanone 1-(2-hydroxyphenyl)oximato ligands. The molecular structure and packing are stabilized by intramolecular O—H...O hydrogen bonds and C—H...π intermolecular interaction.