Synthesis, mesomorphic and photo-physical properties of few<i>d-</i>and<i>f-</i>block metals coordinated to polar Schiff's bases

Chakraborty, Lopamudra; Chakraborty, N.; Choudhury, Trirup Dutta; Kumar, B. V. N. Phani; Mandal, Asit Baran; Rao, N. V. S.

doi:10.1080/02678292.2012.669854

Cited by 10 publications

(5 citation statements)

References 51 publications

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“…Figure shows a polarizing optical microscopy image of the LC phase of CAGE-oct at 278 K. There appear to be two distinct birefringent areas with larger scale and smaller scale patterning (solid red oval and dashed red oval, respectively). Both of these optical textures are conic fan textures characteristic of a smectic A (SmA) structure − and the apparently distinct patterns are likely to arise from differences in nucleation . In addition, there are regions with no birefringence present between LC domains, indicating isotropic liquid regions.…”

Section: Resultsmentioning

confidence: 99%

MAS NMR Investigation of Molecular Order in an Ionic Liquid Crystal

et al. 2020

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The structure and molecular order in the thermotropic ionic liquid crystal (ILC), [choline][geranate(H)octanoate], an analogue of Choline And GEranate (CAGE), which has potential for use as a broad-spectrum antimicrobial and transdermal and oral delivery agent, were investigated by magic-angle spinning (MAS) nuclear magnetic resonance (NMR), polarizing optical microscopy, small-angle X-ray scattering (SAXS), and mass spectrometry. Mass spectrometry and the 1 H NMR chemical shift reveal that CAGE-oct is a dynamic system, with metathesis (the exchange of interacting ions) and hydrogen exchange occurring between hydrogen-bonded/ionic complexes such as [(choline)(geranate)(H)(octanoate)], [(choline)(octanoate) 2 (H)], and [(choline)-(geranate) 2 (H)]. These clusters, which are shown by mass spectrometry to be significantly more stable than expected for typical electrostatic ion clusters, involve hydrogen bonding between the carboxylic acid, carboxylate, and hydroxyl groups, with rapid hydrogen bond breaking and re-formation observed to average the 1 H chemical shifts. The formation of a partial bilayer liquid crystal (LC) phase was identified by SAXS and polarizing optical microscopy at temperatures below ∼293 K. The occurrence of this transition close to room temperature could be utilized as a potential temperature-induced "switch" of the anisotropic properties for particular applications. The presence of an isotropic component of approximately 23% was observed to coexist with the LC phase, as detected by polarizing optical microscopy and quantified by both 1 H− 13 C dipolar-chemical shift correlation (DIPSHIFT) and 1 H double-quantum (DQ) MAS NMR experiments. At temperatures above the LC-to-isotropic transition, intermediate-range order (clustering of polar and nonpolar domains), a feature of many ILs, persists. Site-specific order parameters for the LC phase of CAGE-oct were obtained from the MAS NMR measurement of the partially averaged 13 C− 1 H dipolar couplings (D CH ) by cross-polarization (CP) build-up curves and DIPSHIFT experiments, and 1 H− 1 H dipolar couplings (D HH ) by double-quantum (DQ) build-up curves. The corresponding order parameters, S CH and S HH , are in the range 0−0.2 and are lower compared to those for smectic (i.e., layered) phases of conventional nonionic liquid crystals, resembling those of lamellar phases formed by lyotropic surfactant−solvent systems.

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Section: Resultsmentioning

confidence: 99%

MAS NMR Investigation of Molecular Order in an Ionic Liquid Crystal

et al. 2020

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“…The peak centered between 3277-3300 cm -1 may be ascribed to -NH stretching vibration while the strong peak appearing between 1696-1712 cm -1 may be assigned to >C=O stretching vibration of urethane groups. 15 The peak lying in between 1541-1536 cm -1 may be due to the N-H out-ofplane bending of urethane. Similarly, the peak observed between 896-916 cm -1 may be due to rocking and wagging vibrations in M-H 2 O, [7] while the new peak appearing in between 752-773 cm -1 in Mn(II), Co(II) and Ni(II), Zn(II) may be due to the presence of coordinated water molecules.…”

Section: Electrical Conductivitymentioning

confidence: 99%

“…PUs generally comprises a linear copolymer having exible components called as soft segments well as relatively polar, a stiff component called a hard segment. The PUs are one of the most versatile classes of polymeric materials as they nd applications in various emerging elds like catalysis [10], drug delivery [11], gas storage, [12] luminescence [13], non-linear optics [14], adsorption [6], photo-physical studies [15], antimicrobial agents [16], material [17], pollutant sequestration [18], and biomedical elds. The chemical and structural properties of PUs can be varied by: (i) Changing the chemical structure of diisocyanate and/or diols [19], (ii) Changing the chemical structure or length of chain extenders having α, -alkane di-ols [20], (iii) Altering the ratio of diisocyanate/diols, (iv) Changing the polymerization procedure and processing conditions.…”

Section: Introductionmentioning

confidence: 99%

Transition Metal-Ions Incorporated PEG300 and TDI Based Hydroxy-Terminated Polyurethanes

Laxmi¹,

Shahzaib²,

Khan³

et al. 2021

Preprint

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Present work reports the synthesis of polyethylene glycol, PEG 300 (soft segment) and toluene 2,4-diisocyanate, TDI (hard segment) based hydroxy-terminated polyurethane ligands (HTPU300) for the first time to the best of our knowledge. The effect of 3d transition metal ions with different 3d electrons within HTPU (M(II)-HTPU300, M= Mn, Co, Ni, and Zn) was evaluated by their physical and antibacterial studies of the final complex polymeric unit. M(II) HTPU300 and was conveniently synthesized in appreciable yields following a facile and one-pot addition polymerization reaction scheme. Foremost the thermal stability of all the M(II)-HTPU300 polymeric materials were evaluated using TGA, DSC, and IPDT calculations. FTIR technique was used to ascertain the structure of M(II)-HTPU300, while SEM/EDX and XRD techniques were used to study their morphology, elemental analysis, and crystalline nature of the material, respectively. Further, the in-vitro antimicrobial activity of the PU was investigated against gram-positive (Staphylococcus aureus, Bacillus subtilis) and gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacterial strains. The comparatively moderate efficacy against bacterial stain supports the possible application of such PU as thermally stable bacterial resistant materials constructed out of degradable PEG.

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“…N-salicylidene anilines can form chelates with certain metal ions such as Ni, Rh, Cu, Pd, Co, and Pt. The geometric structure of the molecules is modified by these complexes, leading to sematic mesomorphism [23][24][25][26]. Through extensive literature research, it has been discovered that there are no reports of work being conducted on the 2-(2-hydroxybenzylidinemine)-aniline (L) Schiff base with the metal ions lanthanum(III), zirconium(IV), yttrium(III), and copper(II), in addition to cobalt (II).…”

Section: Introductionmentioning

confidence: 99%

First Report on Several NO-Donor Sets and Bidentate Schiff Base and Its Metal Complexes: Characterization and Antimicrobial Investigation

et al. 2023

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The condensation product of the reaction between aniline and salicylaldehyde was a 2-(2-hydroxybenzylidinemine)—aniline Schiff base bidentate ligand (L). L was used to generate complexes by interacting with the metal ions lanthanum(III), zirconium(IV), yttrium(III), and copper(II), in addition to cobalt(II). Various physicochemical techniques were utilized to analyze the synthesized L and its metal chelates, including elemental analysis (CHN), conductimetry (Λ), magnetic susceptibility investigations (μeff), Fourier-transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance (1H NMR) spectroscopy, ultraviolet–visible (UV-Vis.) spectrophotometry, and thermal studies (TG/DTG). FT-IR revealed that the L molecule acted as a bidentate ligand by binding to metal ions via both the oxygen atom of the phenolic group in addition to the nitrogen atom of the azomethine group. Additionally, 1H NMR data indicated the formation of complexes via the oxygen atom of the phenolic group. An octahedral geometrical structure for all of the chelates was proposed according to the UV-Vis. spectra and magnetic moment investigations. Thermal analysis provided insight into the pattern of L in addition to its chelates’ breakdown. In addition, the investigation furnished details on the chelates’ potential chemical formulas, the characteristics of adsorbed or lattice H2O molecules, and the water that is coordinated but separated from the structure at temperatures exceeding 120 °C. The thermodynamic parameters utilizing Coats–Redfern in addition to Horowitz–Metzger equations were studied. The antimicrobial effectiveness of L and its chelates against distinct species of bacteria and fungi was studied using the disc diffusion method. Cu(II) and Y(III) chelates had significant antimicrobial activity against Staphylococcus aureus and Micrococcus luteus.

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Synthesis, mesomorphic and photo-physical properties of fewd-andf-block metals coordinated to polar Schiff's bases

Cited by 10 publications

References 51 publications

MAS NMR Investigation of Molecular Order in an Ionic Liquid Crystal

MAS NMR Investigation of Molecular Order in an Ionic Liquid Crystal

Transition Metal-Ions Incorporated PEG300 and TDI Based Hydroxy-Terminated Polyurethanes

First Report on Several NO-Donor Sets and Bidentate Schiff Base and Its Metal Complexes: Characterization and Antimicrobial Investigation

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