Schiff Base Research Articles

Investigation of MXene@APP/FDS/AgNPs@EG system for preparing multifunctional thermoplastic polyurethane composites with flame retardancy and electromagnetic shielding performance

In order to comply with the requirement of flame retardancy and electromagnetic interference (EMI) shielding for encapsulant applied to electronic devices, multifunctional thermoplastic polyurethane (TPU) composites are prepared with the construction of an intumescent flame retardant (IFR) system comprising internal conductive network. In this work, ammonium polyphosphate wrapped with MXene (MXene@APP) is attained by microencapsulation, and expandible graphite decorated with Ag nanoparticles (AgNPs@EG) is prepared by the reducibility of silk sericin. The IFR system with conductivity is established by the introduction of MXene@APP, AgNPs@EG and furfural-derived Schiff base (FDS). The as-prepared TPU/MXene@APP/FDS/AgNPs@EG composites are able to attain significant elevation in flame retardancy, exhibiting V-0 rating and a LOI value of 33.1 %. Furthermore, TPU composites are integrated with warp-knitted metal mesh (WMM) to fabricate TPU@WMM coated fabric, displaying strengthened electromagnetic interference (EMI) shielding effectiveness (SE) of 37.53 dB within X band. This work provides a potential method for application in encapsulant with flame retardancy and electromagnetic protection.

Spectroscopic, anti-cancer, anti-bacterial and theoretical studies of new bivalent Schiff base complexes derived from 4-bromo-2,6-dichloroaniline

Spectroscopic, anti-cancer, anti-bacterial and theoretical studies of new bivalent Schiff base complexes derived from 4-bromo-2,6-dichloroaniline

Interaction between peptide and solid lignin suggest mechanisms of abiotic covalent bond formation

The mechanisms behind the formation of soil organic matter (SOM) and associated nitrogen immobilization remain partially elusive, while ongoing research continues to shed light on carbon and nitrogen sequestration in the environment. Studies show that quinone-like structures within alkali-soluble humic extracts of SOM can bond covalently with nitrogen-containing molecules derived from proteinaceous organic matter. However, direct molecular evidence for this chemical bonding with lignin in the solid form and non-solvent-extracted SOM is lacking. Using gel-state 1H-15N heteronuclear single quantum coherence (HSQC) high-resolution magic angle spinning (HRMAS) nuclear magnetic resonance (NMR) spectroscopy, we demonstrate that a 15N-labeled peptide (glycine-glycine-glycine-arginine, GGGR), can covalently bind to solid, untreated, brown rotted wood as well as 1,2-naphthoquinone, a quinone-model molecule typically found in degraded lignin. The new peaks in both reactions represent a change in the environment surrounding the N-functional groups. Interaction of the 15N-labeled peptide with the model quinone produced NMR cross peaks that are similar to those of the solid lignin. This suggests that the quinone-like structures are the most likely functional groups to form covalent bonds with peptides in the degraded lignin. Both Michael addition and Schiff base formation is proposed when the peptide GGGR interacts with white oak lignin and 1,2-naphthoquinone. These processes are of considerable importance to N incorporation into SOM and offer insights into how proteinaceous molecules could potentially be preserved and sequestered through covalent bond formation.

Pharmacologically significant penta, hexa, and heptacoordinate mono organosilicon (IV) Schiff base complexes derived from phenyl alanine: Synthesis, spectral characterization, antimicrobial, antioxidant, anti-inflammatory, and anti-diabetic studies

Mono organosiliocn (IV) Schiff base complexes 1a-2c derived from phenyl alanine were prepared and characterized. Six new complexes were evaluated in vitro against different bacteria; besides their antioxidant, anti-inflammatory and antidiabetic properties were also tested. Combination of infrared and multinuclear NMR (1H NMR, 13C NMR and 29Si NMR) techniques evidenced the formation of penta, hexa, and heptacoordinated species. The in-vitro antileishmanial study for complexes 1a and 2b against the amastigote stage of the parasite, a mouse macrophage cell line infected with promastigotes expressing luciferase, the IC50 for all tested complexes was lower than that of the miltefosine (standard drug). In antibacterial activity, with the increase in the concentration the zone of inhibition increased. 2c showed the maximum percent inhibition for most number of bacteria which are E. coli (87.50 ± 4.17 %), S. typhi (85.96 ± 3.04 %), S. aureus (70.71 ± 1.75 %), K. pneumonia (7.97 ± 1.26 %) and while 2a and 2b only showed maximum percent inhibition of 77.78 ± 1.92 % and 66.67 ± 2.31 for the bacterium B. subtilis and S. abony respectively at a concentration of 10 mg/ml. Also the methyl silicon (IV) Schiff base complexes showed less antibacterial activity than the ethyl silicon (IV) Schiff base complexes. Pharmacological activities of mono organosilicon (IV) complexes increase with an increase in the number of organo group as well as ligands. 2c possessed the best antioxidant, anti-inflammatory, and anti-diabetic activities.

Pancreatic lipase immobilization on cellulose filter paper for inhibitors screening and network pharmacology study of anti-obesity mechanism

The discovery of pancreatic lipase (PL) inhibitors is an essential route to develop new anti-obesity drugs. In this experiment, chitosan was used to add amino groups to cellulose filter paper (CFP) and then glutaraldehyde was used to covalently combine PL with amino-modified CFP through the Schiff base reaction. Under optimal immobilization conditions, CFP immobilized PL has a wide range of pH and temperature tolerance, as well as excellent reproducibility, reusability and storage stability. Subsequently, 26 natural products (NPs) were screened by immobilized PL with black tea extract having the highest inhibition rate. Three compounds with binding effects on PL (epigallocatechin gallate, theaflavin-3-gallate and theaflavin-3,3'-digallate) were captured. Molecular docking proved that these three compounds have a strong binding affinity for PL. Fluorescence spectra further revealed that theaflavin-3,3’-digallate could statically quench the intrinsic fluorescence of pancreatic lipase. The molecular docking and thermodynamic parameters indicated that electrostatic interaction was considered as the main interaction force between PL and theaflavin-3,3'-digallate. Finally, the potential anti-obesity targets and pathways of the three compounds were discussed through network pharmacology. This study not only proposes a simple and efficient method for screening PL inhibitors, but also sheds light on the anti-obesity mechanism of active compounds in black tea.

Construction of a 12-metal Zn(II)-Nd(III) nanocluster for ratiometric fluorescence detection of inflammatory marker neopterin

A 12-metal Zn(II)-Nd(III) cluster 1 (sizes: 1.8 nm × 2.0 nm × 2.0 nm) was synthesized from a long-chain type Schiff base ligand. It displays ratiometric fluorescence response to neopterin (Neo) with high selectivity and sensitivity, which can be expressed by the equation I545 nm /I1060 nm = A·[Neo]2 + B·[Neo] + C. 1 is used to quantitatively test Neo concentrations in fetal calf serum (FCS) and urine, and the recovery ranges are 98.57%–103.82% and 99.25%–103.50%, respectively, while the relative standard deviations (RSDs) are 7.89%–9.46% and 1.85%–4.16%, respectively. The limits of detection of 1 to Neo in FCS and urine are 0.034 and 0.021 μmol/L, respectively.

Enhancing Long-Segmental Tracheal Restoration: A Self-Repairing Hydrogel Loaded with Chondrocytokines for Sutureless Anastomosis and Cartilage Regeneration

Artificial tracheal substitutes encounter significant challenges during long-segmental tracheal defects (LSTD) reconstruction, notably early postoperative anastomotic stenosis and tracheal chondromalacia. Mitigating early anastomotic stenosis by creating a compliant sutureless substitute is pivotal. Enhancing its chondrogenic capacity is equally critical for sustained healthy tracheal cartilage regeneration. This study proposes a self-healing hydrogel for sutureless tracheal anastomosis to mitigate anastomotic stenosis, enriched with kartogenin (KGN) and transforming growth factor-β1 (TGFβ1) to bolster chondrogenic properties. Initially, two precursor solutions were prepared: 1) aldehyde-modified hyaluronic acid with sulfonation and β-cyclodextrin-CHO loaded with KGN; 2) hydrazide-grafted gelatin loaded with TGFβ1. Coextrusion of these solutions resulted in a gelated G+TGFβ1/sH-CD+KGN hydrogel, characterized by a robust covalent bonding network of acylhydrazones between hydrazide and aldehyde groups, imparting excellent self-healing properties. The G+TGFβ1/sH-CD+KGN hydrogels, showcasing favorable cytocompatibility, excellent injectability, and rapid gelation, were loaded with bone marrow stem cells. These were customized into O-shaped rings and assembled into a malleable tracheal substitute using our established ring-to-tube method. This resultant compliant substitute facilitated sutureless anastomosis of LSTD in a rabbit model, attributed to the Schiff base reaction between the hydrogel's carbonyl group and the tissue's amino group. Notably, the tracheal substitute reduced early postoperative anastomotic stenosis, maintained tracheal patency, alleviated sputum blockage, promoted reepithelization, and increased the survival rate of the experimental rabbits. The sustained release of chondrocytokines resulted in excellent tracheal cartilage regeneration. Employing chondrocytokines-loaded hydrogels with self-healing properties represents a significant advancement in sutureless tracheal anastomosis and tracheal cartilage regeneration, holding promising potential in inhibiting early postoperative anastomotic stenosis and tracheal chondromalacia when treating LSTD.

Synergetic effects of S, N co-doping and surface concave-pores rich in lotus-leaf-like carbon nanosheets enabled threefold lithium storage mechanisms

Carbon-based materials based on structural and dimensional optimization are appealing as anode materials in lithium-ion batteries (LIBs). However rational design of high-efficiency low-dimensional carbon-based electrodes is still challenging. Therefore, a synthesis strategy based on Schiff base reaction has been devised for S, N co-doped and surface-enriched concave pores coupled with two-dimensional lotus-leaf-like carbon nanosheets (S, N-SCP/LCN). Experimental and theoretical results disclose that the synergetic effect of S, N co-doping and surface concave pores synergistically contribute to the improved lithium storage efficiency. The numerous concave pores within the defective carbon substrates significantly enhance the specific surface area and boost the quantity of active sites. Furthermore, S, N co-doping induces additional surface and structural defects and widens the crystallographic spacing. Herein, the formed threefold lithium storage mechanisms work synergistically to increase the active lithium storage sites and ion diffusion channels, promoting ion diffusion and charge transfer during lithium storage. As expected, the S, N-SCP/LCN exhibits remarkably high lithium storage capacity (1250 mAh/g at 0.1 A/g) and exceptional rate performance (445.65 mAh/g at a high rate of 10 A/g).

Oligolysine-based hydrogel dressing with antibacterial, anti-inflammatory, and tissue-adhesion activities for infected wound treatment

Fabricating injectable hydrogel with multiple functions and effective promotion of wound repair has a great prospect in treatment of bacterial infected wounds. Herein, a pH/reactive oxygen species (ROS) dual responsive injectable hydrogel (PVBDL-gel) was constructed, the PVBDL-gel was cross-linked by dynamic Schiff base bonds and borate ester bonds between poly(vanillin acrylate-co-3 acrylamide phenylboronic acid-co-N,N-dimethylacrylamide) (P(VA-co-AAPBA-co-DMA)), oligolysines and polyvinyl alcohol (PVA). The anti-inflammatory drug, dexamethasone sodium phosphate (DEX), was encapsulated in this hydrogel. The hydrogel exhibited excellent degradability, stable rheology and suitable tissue adhesion, more importantly, which showing pH/ROS responsive ability and controllable releasing of DEX. In vitro and in vivo experiment results showed that the PVBDL-gel with good biocompatibility and efficient anti-infection ability can effectively eradicate 99.9 % of pathogenic bacteria within 3 h and promote the repair and regeneration of bacterial infection wounds. This novel multifunctional injectable hydrogel has great application in the field of bacterial infection wound repair.

Synthesis of stimuli-responsive copolymeric hydrogels for temperature, reduction and pH-controlled drug delivery

Stimuli-responsive copolymeric hydrogels (CH) are synthesized for controlled drug delivery. Oxidized glycyrrhizic acid is connected to acrylamide through Schiff base reaction, which is then copolymerized with N,N-bis (acryloyl) cystamine and N-isopropylacrylamide by free-radical polymerization for the loading of 5-fluorouracil with a loading efficiency of 96.7 %. The lower critical solution temperature of the CH is 39.14 °C. The N-isopropylacrylamide unit in the CH is sensitive to temperature, endowing the CH with temperature sensitivity. The carboxyl groups of oxidized glycyrrhizic acid can be deprotonated in alkaline solutions, and the electrostatic repulsions between the resultant carboxylate can cause swelling of the CH. The disulfide bond (S–S) of the N,N-bis (acryloyl) cystamine unit can be reduced to sulfhydryl (–SH) by glutathione, and thus the CH is also reduction-sensitive. Therefore, temperature, reduction and pH-controlled delivery of 5-fluorouracil from the CH is achieved. Cytotoxicity assay reveals that the drug-free hydrogels have good biocompatibility while the CH shows high cytotoxicity against human hepatoma SMMC-7721 cells, and the cell viability is only 25 % at the CH concentration of 1 mg mL−1.

A Novel Class of thiazole based thiadiazole hybrids: The privileged Scaffolds of potent anti-Alzheimer's activity along with molecular docking and ADME analysis

A novel series of thiazole-thiadiazole based schiff base derivatives (1-16) were synthesized and examined for their inhibitory profile against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). All the compounds exhibited excellent inhibitory activity ranging from IC50= 1.87 ± 1.47 to 27.4 ± 2.45 µM for AChE and 1.72 ± 1.43 to 29.4 ± 1.87 µM for BuChE when compared with the standard drug donepezil (IC50= 3.87 ± 1.14 µM and 3.56 ± 2.52 µM for AChE and BuChE, respectively). Among the members of the whole series, compounds-6 (IC50 = 3.49 ± 1.20 µM, 3.18 ± 0.27 µM), 7 (IC50 = 3.20 ± 1.14 µM, 3.21 ± 0.49 µM), 8 (IC50 =1.87 ± 1.47 µM, IC50 = 1.72 ± 1.43) and 9 (IC50 = 2.18 ± 1.02 µM, IC50 = 2.02 ± 0.49 µM), showed remarkable potency against AChE and BuChE and emerged as anti-alzheimer's agents. Molecular docking study revealed the excellent binding interactions of ligands with different amino acids of the target enzymes. Structure activity relationship (SAR) study was also conducted to evaluate inhibitory potency of all the derivatives that depends on the position, number and nature of the substituents. Furthermore, ADME outcomes authenticate the drug likeness of the potent analogs. Structural confirmation of the derivatives was achieved through different spectroscopic techniques, including 13C-NMR, 1H-NMR and HREI-MS.

Silica supported Schiff-based palladium nanocatalyst for n-alkylation at room temperature

This works documents a new silica gel-supported nanocatalyst (Si@NSBPdNPs 3) with low Pd loadings for n-alkylation reactions at room temperature. Post synthesis characterisation using SEM-EDX and ICP techniques provided a quantitative assessment of palladium species. Additionally, TEM analysis unveiled an average palladium nanoparticle size of 5.87 ± 0.2 nm. In-depth X-ray Photoelectron Spectroscopy (XPS) analysis revealed its predominant composition as Pd(0) complexed to a Schiff base ligand on low cost silica matrix. The nanocatalyst exhibited high efficacy in the catalysis of n-alkylation (Michael addition) reactions with various α,β-unsaturated Michael acceptors, yielding the corresponding n-alkyl products at room temperature with exceptional yields. Notably, the catalyst exhibited good stability and could be easily separated from the reaction mixture. Moreover, the catalyst displayed recyclability potential, maintaining its original catalytic efficacy for up to seven cycles without any discernible loss.

VALD-2 mitigates cisplatin-induced acute kidney injury: Mechanistic insights into oxidative stress modulation and inflammation suppression.

This study explores the compelling antitumor properties of VALD-2, a synthetic Schiff base ligand known for its low toxicity. The focus is on investigating VALD-2's protective role against cisplatin-induced acute kidney injury (AKI) in mice, with a specific emphasis on mitigating oxidative stress and inflammation. The study involves daily intraperitoneal injections of amifostine or VALD-2 over 7 days to establish an AKI model. Subsequently, mice were assigned to normal control, cisplatin group, cisplatin + amifostine group, and cisplatin + VALD-2 10 mg/kg group, cisplatin + VALD-2 20 mg/kg, and cisplatin + VALD-2 40 mg/kg. Kidney injury is assessed through serum blood urea nitrogen (BUN) and creatinine (Cr) activity assays. Levels of inflammatory factors,tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), in kidney tissue of mice were assessed through enzyme-linked immunosorbent assay (ELISA). The protective effect of VALD-2 is further examined through HE staining to observe pathological changes in kidney injury. The ultrastructural changes of renal cells and tubular epithelial cells were observed by electron microscopy under experimental conditions, indicating the effect of VALD-2 on reversing cisplatin-induced renal injury. The study delves into VALD-2's protective mechanisms against cisplatin-induced kidney injury by using western blot analysis to assess the expression levels of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA) in kidney tissues. VALD-2 demonstrates significant improvement in cisplatin-induced AKI, as evidenced by increased BUN and Cr levels. It effectively protects kidney tissue from oxidative damage, enhancing SOD and GSH-Px activities while reducing MDA levels. The study also reveals a decrease in TNF-α and IL-6 levels, supported by ELISA results, and histological findings confirm anti-nephrotoxic effects. Western blot analysis shows an upregulation of antioxidant enzymes (SOD, GSH-Px) and a reduction in MDA production. VALD-2 emerges as a promising mitigator of cisplatin-induced AKI, showcasing its ability to enhance oxidative stress-related protein expression. The findings suggest VALD-2 as a potential therapeutic agent for protecting against cisplatin-induced kidney injury.

Ti4+ functionalized zirconium metal-organic frameworks with polymer brushes for specific identification of phosphopeptides in human serum and skimmed milk.

In the present study, click chemistry and Schiff base reactions were simultaneously applied to prepare polymer brush (PEG)-functionalized MOF materials (UiO-66-NH2) and immobilized with Ti4+ (MOF-Brush-THBA-Ti4+) for phosphopeptide analysis. The material has a detection limit of 0.5 fmol, a selectivity of 2000:1, and a loading capacity of 133 mg/g for phosphopeptides. It also demonstrated great repeatability (10 cycles) and recovery rate (96.7 ± 1.4%). During the analysis of bio-samples, 4 specific phosphopeptides were identified in endogenous breast cancer serum, while 11 phosphopeptides were identified in skimmed milk. Moreover, 47 phosphopeptides correlated with 29 phosphorylated proteins were selectively identified from normal control serum, and 66 phosphopeptides correlated with 26 phosphorylated proteins were identified from breast cancer serum. Further analysis of gene ontology (GO) revealed that the detected phosphorylated proteins associated with breast cancer included positive regulation of receptor-mediated endocytosis, proteolysis, extracellular exosome, heparin binding, and chaperone binding. These findings suggest that these associated pathways might contribute to the etiology of breast cancer. Overall, this application exhibits enormous potential in the identification of phosphorylated peptides within bio-samples.

Dual COF functionalized magnetic MXene composite for enhancing magnetic solid phase extraction of thiophene compounds from oilfield produced waters prior to GC-MS/MS analysis

In this study, a novel COFTABT@COFTATp modified magnetic MXene composite (CoFe2O4@Ti3C2@COFTABT@COFTATp) was synthesized by Schiff base reaction and irre-versible enol-keto tautomerization, and employed to establish a sensitive monitoring method for six thiophene compounds in oilfield produced water samples based on magnetic solid-phase extraction (MSPE) prior to gas chromatography coupled with a triple quadruple mass spectrometer (GC-MS/MS). The designed magnetic materials exhibited unexpected enrichment ability to target thiophene compounds and achieved good extraction efficiencies ranging from 83% to 98%. The developed MSPE/GC-MS/MS method exhibited good linearity in the range of 0.001-100 μg L-1, and obtained lower limits of detection ranging from 0.39 to 1.9ngL-1. The spiked recoveries of thiophene compounds obtained in three oilfield produced water samples were over the range of 96.26%-99.54% with relative standard deviations (RSDs) less than 3.7%. Notably, benzothiophene, 4-methyldibenzothiophene and 4,6-dimethyldibenzothiophene were detected in three oilfield-produced water samples. Furthermore, the material still kept favorable stability after six recycling experiments. The adsorption kinetics, adsorption isotherms as well as adsorption thermodynamics of thiophene compounds were investigated in detail to provide insight into the mechanisms. Overall, the present work contributed a promising strategy for designing and synthesizing new functionalized materials for the enrichment and detection of typical pollutants in the environment.

Cross-linking impacts the physical properties of mycelium leather alternatives by targeting hydroxyl groups of polysaccharides and amino groups of proteins

Cross-linking, also called tanning, improves mechanical properties of leather and also increases its enzymatic and thermal stability. As a final product, leather has an ultimate tensile strength (σ) of 8–25 MPa and an elongation at break (ε) of >30 %. Mycelium-based materials are a sustainable alternative to leather. Here, the effect of cross-linkers was assessed on mechanical properties of Schizophyllum commune mycelium sheets. To this end, glutaraldehyde and N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide (EDC) were used as well as extracts of Ligustrum vulgare leaves, and bark of Acacia mearnsii and Caesalpinia spinosa. Untanned sheets had a σ of 7.8 MPa and an ε of 15.2 %, while the best overall combination of strength and elasticity was obtained with 0.1 % glutaraldehyde with a σ of 11.1 MPa and an ε of 14.6 %. Cross-linking also increased enzymatic stability and reduced mycelial water absorption but did not result in increased thermal stability. Fourier transform infrared spectroscopy (FTIR), 1D nuclear magnetic resonance spectroscopy (NMR), and amino acid analysis showed that glutaraldehyde bound both protein amino groups and polysaccharide hydroxyl groups by forming Schiff bases and acetals, respectively. Together, synthetic and vegetable cross-linkers can be used to obtain mycelium materials with leather-like tensile strength.

Facile synthesis of imidazolidinyl phenolate supported Dicopper(II/II) Complexes: Activation and fixation of atmospheric CO2 as MeOCO2− showing exogenous bridge modulating magnetic exchange coupling

Two imidazolidine grafted Schiff bases H3L2 and H3L3 have been utilized to fasten the Cu2 core in four new complexes [Cu2(μ-L2)(μ-O2CMe)]·H2O (1·H2O), [Cu2(μ-L2)(μ-O2COMe)]·H2O (2·H2O), [Cu2(μ-L2)(μ-NO3)]·H2O (3·H2O) and [Cu2L3(μ-OAc)]·5H2O (4·5H2O). Room temperature solution reaction of H3L2 with Cu2(OAc)4·2H2O provided 1·H2O in good yield. Follow-up reaction of 1·H2O with Et4NOH in air replaces μ-O2CMe (acetato) bridge by MeOCO2− (monomethyl carbonato) linker in 2·H2O. Single crystal X-ray structure established the individual complexes and confirmed the fixation of atmospheric CO2. Variable temperature (2 to 300 K) magnetic susceptibility measurements recognized the antiferromagnetic exchange interactions between the adjacent copper(II) centers in complexes 2 and 3. The amount of spin–spin interactions are found to be higher for ancillary NO3− bridge (−284 cm−1) compared to the in situ transformed MeOCO2− bridged (−1.64 cm−1).

Exploration of iron(III) complexes with bidentate N, O-donor Schiff base ligands through synthesis, characterization, DFT, and antibacterial studies

Iron(III) complexes [Fe(SBn)2(H2O)2]NO3 (1, 2) (n=1 or 2) were synthesized via a reaction of Fe(NO3)3.9H2O with N, O-donor Schiff-base ligands (HSBn) in a ratio of 1:2 in terms of moles. Schiff-base ligands (HSBn) were synthesized when a solution of salicylaldehyde in methanol underwent reflux with aniline (HSB1) or 4-chloroaniline (HSB2) in methanol respectively. These aquated iron(III) complexes, 1 & 2 were further reacted with nitrogen-containing molecules as neutral donors (L) (such as pyridine, imidazole, and benzimidazole) in a ratio of 1 part to 2 parts by moles, yielding mixed-ligand complexes [Fe(SBn)2(L)2]NO3(3-8). The synthesized complexes were characterized by elemental analyses, mass spectrometry, and spectroscopic studies (electronic, infrared & NMR spectra), as well as measurements of magnetic susceptibility and conductance. Infrared spectra revealed that Schiff bases coordinated with iron(III) centers in bidentate and chelating mode, primarily through phenolic –O and azomethine–N groups. Electronic spectra confirmed the existence of octahedral iron(III) in a high-spin state within these complexes, consistent with assessments of magnetic susceptibility. DFT-based parameters were determined for ligands HSB1, & HSB2, and complexes 1, 2, & 8 using Gaussian 09 at the B3LYP level. Structural analysis showed slightly distorted octahedral geometry with high spin (d5) and sextet multiplicity in all complexes. The global hardness exhibited an increasing trend: HSB2 < 8 < 2 < 1 < HSB1, while chemical reactivity showed the opposite trend: HSB2 > 8 > 2 > 1 > HSB1. The antibacterial activity of ligands, HSB1 and HSB2, along with complexes 1 and 2, was evaluated against various bacterial strains. Schiff bases, HSB1 and HSB2 inhibited several strains, with complexes 1 and 2 demonstrating improved efficacy, possibly due to altered chemical properties from the complex formation. Despite lower potency than Ciprofloxacin, they offer therapeutic alternatives.

All-visible-light-driven salicylidene schiff-base-functionalized artificial molecular motors

Light-driven rotary molecular motors are among the most promising classes of responsive molecular machines and take advantage of their intrinsic chirality which governs unidirectional rotation. As a consequence of their dynamic function, they receive considerable interest in the areas of supramolecular chemistry, asymmetric catalysis and responsive materials. Among the emerging classes of responsive photochromic molecules, multistate first-generation molecular motors driven by benign visible light remain unexplored, which limits the exploitation of the full potential of these mechanical light-powered systems. Herein, we describe a series of all-visible-light-driven first-generation molecular motors based on the salicylidene Schiff base functionality. Remarkable redshifts up to 100 nm in absorption are achieved compared to conventional first-generation motor structures. Taking advantage of all-visible-light-driven multistate motor scaffolds, adaptive behaviour is found as well, and potential application in multistate photoluminescence is demonstrated. These functional visible-light-responsive motors will likely stimulate the design and synthesis of more sophisticated nanomachinery with a myriad of future applications in powering dynamic systems.

Investigation of the anticancer of photodynamic therapy effects by using the novel Schiff base ligand palladium complexes on human breast cancer cell line

Investigation of the anticancer of photodynamic therapy effects by using the novel Schiff base ligand palladium complexes on human breast cancer cell line