Pyridine Research Articles

Synthesis, characterization and supra-molecular analysis for (E)-3-(pyridin-4-yl)acrylic acid.

The title compound, C8H7NO2, crystallizes as prismatic colourless crystals in space group P , with one mol-ecule in the asymmetric unit. The pyridine ring is fused to acrylic acid, forming an almost planar structure with an E-configuration about the double bond with a torsion angle of -6.1 (2)°. In the crystal, strong O-H⋯N inter-actions link the mol-ecules, forming chains along the [101] direction. Weak C-H⋯O inter-actions link adjacent chains along the [100] direction, generating an R 2 2(14) homosynthon. Finally, π-π stacking inter-actions lead to the formation of the three-dimensional structure. The supra-molecular analysis was supported by Hirshfeld surface and two-dimensional fingerprint plot analysis, indicating that the most abundant contacts are associated with H⋯H, O⋯H/H⋯O, N⋯H/H⋯N and C⋯H/H⋯C inter-actions.

Tunable Gas Admission via a "Molecular Trapdoor" Mechanism in a Flexible Cationic Metal-Organic Framework Featuring 1D Channels.

Achieving high gas selectivity is challenging when dealing with gas pairs of similar size and physiochemical properties. The "molecular trapdoor" mechanism discovered in zeolites holds promise for highly selective gas adsorption separation but faces limitations like constrained pore volume and slow adsorption kinetics. To address these challenges, for the first time, a flexible metal-organic framework (MOF) featuring 1D channels and functioning as a "molecular trapdoor" material is intoduced. Extra-framework anions act as "gate-keeping" groups at the narrowest points of channels, permitting gas admissions via gate opening induced by thermal/pressure stimuli and guest interactions. Different guest molecules induce varied energy barriers for anion movement, enabling gas separation based on distinct threshold temperatures for gas admission. The flexible framework of Pytpy MOFs, featuring swelling structure with rotatable pyridine rings, facilitates faster gas adsorption than zeolite. Analyzing anion properties of Pytpy MOFs reveals a guiding principle for selecting anions to tailor threshold gas admission. This study not only overcomes the kinetic limitations related to gas admission in the "molecular trapdoor" zeolites but also underscores the potential of developing MOFs as molecular trapdoor adsorbents, providing valuable insights for designing ionic MOFs tailored to diverse gas separation applications.

A Z-scheme heterojunction ZIF67/N, P-WO3 nanocomposite for photocatalytic degradation of levofloxacin

In this work, a ZIF67/N, P-WO3 (ZNPW) Z-scheme heterojunction was constructed by N, P-codoped WO3 (NPW), and ZIF67 and developed as a highly efficient photocatalyst for Levofloxacin (LFX) removal. A series of characterization measurements including FTIR, XRD, SEM, DRS, PL, and XPS are conducted to confirm the formation of the ZNPW. After optimization on the composition of WO3, NPW and ZIF67, the optimal ZNPW shows superior photocatalytic activity, yielding a higher removal efficiency of LFX ∼91.2% in 100 min than those of pure WO3 (9.4%), NPW (47.8%) and ZIF67 (14.3 %). Additionally, ZNPW exhibits remarkable stability and reusability for up to five consecutive runs. Reactive species scavenging experiments and ESR have revealed that the degradation of LFX is primarily facilitated by the generation of holes (h+) and hydroxyl radicals (·OH). Moreover, the degradation process of LFX was identified through an integrated LC-MS analysis and density functional theory computation of the Fukui indices. This process consists of three pathways: the opening of the piperazinyl ring, separation of piperazinyl and quinoline moieties, and cleavage of the pyridine ring on the quinoline moieties. The superior photocatalytic properties can be attributed to the N, P co-doping in the WO3 structure and the simultaneous coupling with ZIF67, leading to the formation of a heterojunction with a reduced band gap, efficient charge separation and transport, and a new N 2p and P 2p energy level. In conclusion, this study provides novel insights into designing high-efficiency antibiotics degradation using WO3-based Z-scheme heterojunction photocatalysts.

Molecular crystals of 2-methyl-1H-benzo[d]imidazole and pyridine-2,6-dimethanol with chloranilic, trimesic and gallic acid

Crystallization experiments of 2-methyl-1H-benzo[d]imidazole (MBI) and pyridine-2,6- dimethanol (PDM) with chloranilic (CLA), trimesic (TMA) and gallic acid (GA) yielded a total of ten multicomponent molecular crystals in salt form, i.e., MBI:CLA (1), 2MBI:CLA:2H2O (2), 2MBI:CLA:3H2O (3A), 2MBI:CLA:3H2O (3B), 2MBI:CLA:4H2O (4), MBI:TMA (5), MBI:GA:3.4H2O (6), PDM:CLA (7), PDM:CLA:H2O (8), and 2PDM:CLA (9), of which compounds 3A and 3B are polymorphs. Characteristic for the crystal structures of all compounds except for 7 is the presence of heterosynthons formed between the molecular components by charge-assisted NHMBI/PDM⋯OCLA/TMA/GA hydrogen bonds, which are mostly bifurcated. In compound 7, the positively charged NH groups are involved in the formation of PDM-PDM homodimers interacting through NHPDM⋯OPDM hydrogen bonds. The series of compounds having 2:1 MBI/PDM:CLA ratio (2, 3A, 3B, 4 and 9) comprise trimeric molecular units of the composition MBI-CLA-MBI or PDM-CLA-PDM, respectively, based on charge-assisted bifurcated NH⋯O hydrogen bonds. Despite the directionality of these interactions, the units have certain flexibility consisting in mutual bending of the aromatic ring planes and are considered interesting building blocks for crystal engineering purposes. Except for compound 9, all crystal structures exhibit π⋯π interactions involving the positively charged benzimidazolium and pyridinium rings of protonated MBI and PDM and/or the π-delocalized sections in the organic anions. The water molecules in hydrates 2, 3A, 3B, 4, 6 and 8 exercise mostly crystal lattice stabilizing functions by interconnecting the synthons established among the organic components. Hirshfeld surface and fingerprint analysis revealed that O⋯H/H⋯O interactions and van der Waals contacts are dominant in conjunct with Cl⋯H/H⋯Cl contacts in the compounds derived from CLA.

Novel secondary pyridinyl amides: Synthesis, in vitro antiproliferative screenings, and molecular docking studies

A novel series of secondary pyridinyl amides, reinforced with the methylsulfonyl pharmacophore unit, was designed and synthesized. Further, we determined the antiproliferative activities of these compounds through experimental assays and analyzed their interactions with Breakpoint Cluster Region/Abelson (bcr/abl), Epidermal Growth Factor Receptor (EGFR), and Human Epidermal Growth Factor Receptor 2 (HER2) tyrosine kinases using molecular autodocking techniques. We grouped these amides into three categories, classified by the type of spacer that binds the pyridine ring to the amide nitrogen atom. Additionally, within each group, we strategically positioned the amide moiety at the ortho, meta, or para position on the pyridyl ring. Among the studied amides, compound 3 exhibited the best overall antiproliferative activity against human immortalized myelogenous leukemia (K562) (IC50 = 26 µM), human leukemia monocytic cell line (THP-1) (IC50 = 81 µM), and human hepatocellular carcinoma (HepG2) (IC50 = 210 µM). Molecular docking studies revealed that compound 3 binds effectively to bcr/abl, EGFR, and HER2 tyrosine kinases, demonstrating strong interactions with crucial active site amino acids, indicative of its targeted antiproliferative mechanism. All investigated compounds showed either very minor or no cytotoxicity against human dermal fibroblast adult cells.

CTAB modification bentonite for enhanced Re adsorption and diffusion suppression

Abstract 99Tc is a crucial high-yield fission product, characterized by its radiotoxicity, extended half-life, high solubility, and significant mobility in the environment. On the other hand, Re is employed as a substitute for Tc due to its analogous properties and non-radioactive nature. Bentonite is commonly used as a backfill material in repositories for high-level radioactive waste storage; however, it exhibits minimal adsorption capacity for Re(Tc). This study aims to enhance the adsorption capability of bentonite for Re(Tc) through modification with Cetyltrimethylammonium Bromide (CTAB). Modified bentonite exhibits excellent adsorption performance under various conditions, primarily driven by the interaction between the ReO4 − anion and the pyridinium ring of the CTA+. Its primary adsorption mechanism involves a chemical precipitation reaction between ReO4 − and CTA+. The adsorption capacity is approximately 30 times that of unmodified bentonite, and the adsorption process is characterized by spontaneous low-temperature chemical monolayer adsorption. Experimental results of the modification indicate that high-temperature and alkaline modification conditions contribute to enhanced adsorption capacity, with an optimal modification time of approximately 30 h and a maximum modifier addition of 250 % of the bentonite’s cation exchange capacity (CEC). Additionally, the incorporation of modified bentonite into natural bentonite significantly inhibits the diffusion behavior of ReO4 −. These findings highlight the substantial improvement in the adsorption capacity of bentonite for Re(Tc) through batch modification, leading to reduced mobility of ReO4 − within backfill materials.

Fabrication of β-cyclodextrin and 2-hydroxypropyl-β-cyclodextrin inclusion complexes of Palbociclib: Physicochemical characterization, solubility enhancement, in -silico studies, in vitro assessment in MDA-MB-231 cell line

Palbociclib (PAL) is an anti-cancer molecule that is highly selective for CDK4/6 inhibition and approved for the management of advanced breast cancer. Due to its down-and-out aqueous solubility and poor oral bioavailability, therapeutic applications have been compromised in the pharmaceutical field. The work aims to explore the physicochemical properties, aqueous solubility, dissolution rate, and in silico analysis of PAL complexed with β-cyclodextrin (β-CD) and 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) and to ascertain the implications of complexation on the in vitro anti-cancer activity of PAL. The two inclusion complexes (ICs) of PAL were prepared by the methodology of freeze-drying and further characterized by FT-IR, DSC, TGA, FESEM, and PXRD. The 1H NMR and 2D NMR revealed that a significant chemical shift was observed for the ICs as well and a correlation was seen between the CH3 of HP-β-CD with protons (ring C & D) of the pyrimidine and pyridine rings respectively. AL type graph was obtained depicting the KS value to be 625.4 M−1 and 3760 M−1 respectively for PAL-β-CD and PAL-HP-β-CD. Also, the aqueous solubility of PAL was improved by 31.05 and 37.99-fold respectively by both the ICs. The stoichiometric ratio of 1:1 was established by Job’s plot. Additionally, the results of in-silico studies were in correlation with the theoretical calculations. Further, it was found that the in vitro cytotoxicity investigation on MDA-MB-231 cells reported IC50 value for PAL-β-CD IC and PAL-HP-β-CD IC a 2.33– and 3.38-fold a lower IC50 value than PAL (IC50 = 9.55 ppm) which indicates higher cellular toxicity for both ICs in comparison to free PAL. Additionally, PAL-β-CD IC (41.99 ± 2.63 %) and PAL-HP-β-CD IC (57.33 ± 1.58 %) showed higher apoptosis than PAL (25.17 ± 1.27 %) also the cellular internalization was seen higher for both the ICs as well as the ROS formation, and MMP depolarization was evidenced.

Metal-Organic Layers with Photosensitizer and Pyridine Pairs Activate Alkyl Halides for Photocatalytic Heck-Type Coupling with Olefins.

Photochemical generation of alkyl radicals from haloalkanes often requires strong energy input from ultraviolet light or a strong photoreductant. Haloalkanes can alternatively be activated with nitrogen-based nucleophiles through a sequential SN2 reaction and single-electron reduction to access alkyl radicals, but these two reaction steps have opposite steric requirements on the nucleophiles. Herein, we report the design of Hf12 metal-organic layers (MOLs) with iridium-based photosensitizer bridging ligands and secondary-building-unit-supported pyridines for photocatalytic alkyl radical generation from haloalkanes. By bringing the photosensitizer and pyridine pairs in proximity, the MOL catalysts allowed facile access to the pyridinium salts from SN2 reactions between haloalkanes and pyridines and at the same time enhanced electron transfer from excited photosensitizers to pyridinium salts to facilitate alkyl radical generation. Consequentially, the MOLs efficiently catalyzed Heck-type cross-coupling reactions between haloalkanes and olefinic substrates to generate functionalized alkenes. The MOLs showed 4.6 times higher catalytic efficiency than the homogeneous counterparts and were recycled and reused without a loss of catalytic activity.

A Partial Metal Coordination Strategy toward High‐Performance and Cost‐Effective Electron Transporting Layer for Organic Solar Cells

Additives are frequently employed in the active layer of organic solar cells (OSCs) to fine‐tune morphology and improve overall device performance. The use of additive in electron transporting layer (ETL) has garnered less attention. In this study, poly(2‐vinyl pyridine) (P2VP) based cost‐effective ETLs are developed for OSCs. Addition of CoCl2 to the P2VP affords ETLs with enhanced conductivity and optimized work function. OSCs employing this ETL demonstrate prolonged carrier lifetime, suppressed charge recombination, and achieve higher power conversion efficiencies (PCEc) than the commonly used ETLs such as PFNBr and Phen‐NaDPO. The cost of the P2VP‐Co is merely one‐twentieth of that associated with Phen‐NaDPO or PFNBr. Mechanism studies and density functional theory (DFT) calculations reveal that the partial metal salt coordination of P2VP leaves free pyridine rings for dipole interactions with the Ag electrode, and provides higher electrostatic potentials and larger dipole moments compared to the polymer alone, thereby increasing conductivity. The polymer and metal salt additive strategy demonstrates its effectiveness in boosting device performance, offering valuable possibility for designing novel electronic materials and expanding the applications of widely available polymers.

Persulfate-Based Advanced Oxidation Process for Chlorpyrifos Degradation: Mechanism, Kinetics, and Toxicity Assessment.

Persulfate-based advanced oxidation process has been proven to be a promising method for the toxic pesticide chlorpyrifos (CPY) degradation in wastewater treatment. However, due to the limitation for the short-lived intermediates detection, a comprehensive understanding for the degradation pathway remains unclear. To address this issue, density functional theory was used to analyze the degradation mechanism of CPY at the M06-2X/6-311++G(3df,3pd)//M06-2X/6-31+G(d,p) level, and computational toxicology methods were employed to explore the toxicity of CPY and its degradation products. Results show that hydroxyl radicals (·OH) and sulfate radicals (SO4•-) initiate the degradation reactions by adding to the P=S bond and abstracting the H atom on the ethyl group, rather than undergoing α-elimination of the pyridine ring in the persulfate oxidation process. Moreover, the addition products were attracted and degraded by breaking the P-O bond, while the abstraction products were degraded through dealkylation reactions. The transformation products, including 3,5,6-trichloro-2-pyridynol, O,O-diethyl phosphorothioate, chlorpyrifos oxon, and acetaldehyde, obtained through theoretical calculations have been detected in previous experimental studies. The reaction rate constants of CPY with ·OH and SO4•- were 6.32 × 108 and 9.14 × 108 M-1·s-1 at room temperature, respectively, which was consistent with the experimental values of 4.42 × 109 and 4.5 × 109 M-1 s-1. Toxicity evaluation results indicated that the acute and chronic toxicity to aquatic organisms gradually decreased during the degradation process. However, some products still possess toxic or highly toxic levels, which may pose risks to human health. These research findings contribute to understanding the transformation behavior and risk assessment of CPY in practical wastewater treatment.

Synthesis and Insecticidal Evaluation of 3,5-Dicyanopyridines Against Cotton Aphids via Microwave-Assisted Multicomponent Reactions.

Certain 2-amino-6-alkoxy-4-arylpyridine-3,5-dicyanide 1a-e were prepared via a straightforward process using microwave technology rather than conventional methods. This involved reaction of arylidenemalononitrile thru propanedinitrile in the occurrence of sodium alkoxide under MW. While, their positional isomer 4-amino-6-alkoxy-2-arylpyridine-3,5-dicyanide 3a-j have been separated from the reaction of aryl aldehydes with 2-aminoprop-1-ene-1,1,3-tricarbonitrile 2 in the presence of sodium alkoxide using microwave technic. Furthermore, the insecticidal properties of all synthesized compounds were observed with respect to Cotton aphid nymphs and adults. Neonicotinoid pesticides are indicated as the most effective pesticides toward aphids and many other pests. Many insecticides are discovered as novelties. As a result, several pyridine compounds were chemical method synthesized to serve as equivalents of neonicotinoids, a broad class of insecticides. With LC50 value of 0.03 mg/L, components 3g exhibit the highest insecticidal bioactivity. This work discusses how to find new chemicals that could be used as insecticidal agents in the future.

Follow-Up Study of Trans-C to Cis-C Thermally or Photochemically Induced Isomerization of Terpyridine Adducts of Cycloruthenated 2-Aryl-2'-pyridine Compounds.

The mechanism of isomerization of the known 2-phenyl,pyridine (phpy) derivatives [Ru(phpy-κC,N) (MeCN-trans-N)(terpy)]PF6, 2, to [Ru(phpy-κC,N)(MeCN-trans-C)(terpy)]PF6 (terpy = 2,2';6',2″-terpyridine), 3, at temperatures >50 °C has been investigated both by 1H NMR spectroscopy and by DFT calculations. The photoisomerization of 2 to 3 by UV light occurred also quantitatively in MeCN after 20 h at room temperature. A similar behavior to that of 2 could be established for the related compound [Ru(3-acridine-2'-C5H4N-κC,N)(MeCN-trans-N)(2,2';6',2″-terpyridine)]PF6, 6 (acridine = dibenzo[b,e]pyridine or 2,3-benzoquinoline), that was obtained from the reaction between [Ru(3-acridine-2'-C5H4N-κC,N) (MeCN)4]PF6, 4, and terpy in MeOH/MeCN at 60 °C for 24 h. Similar to 2, the isomerization of 6 to [Ru(3-acridine-2'-C5H4N-κC,N)(MeCN-trans-C) (terpy)]PF6, 7, could be induced thermally (48 h at 60 °C in pure MeOH) or photochemically under UV radiation in MeCN at room temperature. A compound closely related to 7 but in which MeCN was replaced by H2O was described earlier (Tanaka et al. Inorg. Chem. 2012, 51, 5386-539). The presence of water on this compound had a dramatic effect as far as the coordination of terpy was concerned as its isomerization to a compound related to 6 (in which H2O instead of MeCN is coordinated to Ru) occurred indeed photochemically via irradiation with visible light.

Synthesis, crystal structure investigation and computational studies binding of (7S,8R)-7-acetyl-8-(4-chlorophenyl)-3-(ethylthio)-1,6-dimethyl-7,8-dihydroisoquinoline-4-carbonitrile with monoamine oxidase B

This work reports the preparation of a new dihydroisoquinoline derivative whose structure was characterized by IR, NMR (1H, 13C), MS and verified through single-crystal X-ray analysis. The mean planes of the acetyl and 4-chlorophenyl groups in the title molecule are nearly perpendicular to that of the pyridine ring. In the crystal, π-stacking and C—H···O hydrogen bond interactions involving the pyridine ring and the nitrile group of an adjacent molecule form the full 3-D structure. Hirshfeld surface (HS) analysis shows the topology of the molecules in the crystal packing. Fingerprint (FP) diagrams show the percentage contribution of several intermolecular interactions where H‧‧‧H interactions have a significant contribution (46%). The DFT study reveals a low HOMO-LUMO gap and significant charge transfer is indicated by the natural bonding orbitals (NBO) and frontier molecular orbital (FMO) analyses. Non-covalent interactions and bond characteristics were investigated using the quantum theory of atom in the molecule (QTAIM) and ELF analysis. FMO analysis was used to calculate the HOMO-LUMO energy gap and orbital energies. Using the DFT method, parameters such as global reactivity were calculated. Using the implicit solvent model, properties such as optical and nonlinear optical (NLO) were characterized in the solvent (water) phase and gas phase. The affinity of the title molecule for Monoamine Oxidase B was examined using molecular docking and molecular dynamics studies and these results showed good binding of the target molecule.

Synthesis, Characterization,Computational Studies and Antimicrobial activity evaluation of Mixed ligand‐Metal complexes of selected thiosemicarbazones

AbstractThe current work reports the synthesis of mixed ligand‐metal complexes of (2‐(2‐oxoacenaphthylen‐1 ylidene)hydrazinecarbothioamide) (L1) and carbamothioyl‐2‐chloronicotinohydrazonic acid (L2) and imidazole (im), triphenylphosphine (PPh3) and pyridine (py) ligands with Cu (II), Zn (II), Fe (II) and Co (II) salts.The chacterization was done through FT‐IR, NMR, UV‐visible, and elemental analysis. The X‐ray diffraction (XRD) patterns of [Cu(L1)(im)2(SO4)] demonstrated the crystalline morphology. In the FT‐IR spectra of the ligands, the characteristic frequencies corresponding to ν(C=N) (imine) and ν(C=S) (thiocarbonyl) were observed around 1650 and 1130 cm−1 respectively, which shifted upon complexation. In the 1H NMR spectra, the peak due to the NH proton was observed downfield, whereas that of ‐NH2 was observed comparatively upfield owing to its secondary amine nature. The molecular docking was performed against transforming growth beta (tgf‐β), protease of SARS‐CoV‐2 (Mpro) and aspartate kinase (Asp) kinase.The molecular simulation with the docked complex of [Zn(L2)(py)2(SO4)] and [Zn(L1)(PPh3)2(SO4)] with Asp kinase showed significant stability during the simulation time of 100 ns. The relative free energies of the simulated complexes were calculated with the molecular mechanics Poison‐Boltmann surface area (MM‐PBSA). The complexes were tested against ten bacterial strains and showed enhanced antibacterial activity than the ligands. [Cu(L1)(im)2(SO4)], [Zn(L1)(im)2(SO4)], [Fe(L1)(im)2(SO4)] and [Co(L1)(im)2(Cl2)] were found to be active against E.coli.

Constructing Structural Isomers to Reveal and Enhance Lithium Storage in a Conducting Polymer

AbstractOrganic electrodes have gained great interest for batteries. Conducting polymers have the merits of high conductivity, and hence are attempted as electrode materials in batteries as soon as their discoveries. However, conducting polymers showe poor electrochemical performance and are baring vague charge storage mechanisms. Here, a strategy is reported to reveal the charge storage mechanisms of conducting polymers by constructing isomers and using polypyridines as a proof‐of‐concept. Polypyridines are rarely studied and its redox activity is still not clear. The results indicate that every pyridine ring can accept one electron and the dimer unit with adjacent C═N groups can gain one more electron through chelation effects with Li ions. The electron transferred number and the chelation effects can be quantified by the matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF) mass spectroscopy and verified by density functional theory (DFT) calculations. As a result, one of the polypyridine isomers delivers the highest capacity of 504 mAh g−1 after deducting the contribution of conductive additives. This work provides a universal way to reveal the charge storage mechanism and highlights the significance of adjacent active centers to form chelation with Li ions and hence enhance the performance of organic batteries.

Design, synthesis and mechanistic study of new dual targeting HDAC/tubulin inhibitors.

Aim: The purpose of this work is to create and synthesize a new class of chemicals: 3-cyano-2-substituted pyridine compounds with expected multitarget inhibition of histone deacetylase (HDAC) and tubulin. Materials & methods: The target compounds (3a-c, 4a-c and 5a-c) were synthesized utilizing 6-(4-methoxyphenyl)-2-oxo-4-(3,4,5-trimethoxyphenyl)-3-cyanopyridine, with various linkers and zinc-binding groups (ZBGs). Results: Most of the tested compounds showed promising growth inhibition, and hydroxamic acid-containing hybrids possessed higher HDAC inhibition than other ZBGs. Compound 4b possessed the highest potency;however, it showed the most tubulin polymerization inhibition. Docking studies displayed good binding into HDAC1 and sixpockets and tubulin polymerization protein. Conclusion: Compound 4b could be considered a good antitumor candidate to go further into in vivo and clinical studies.

Two novel Zn(II)-thiazolothiazole extended viologen complexes with photochromism, inkless and erasable printing and photo-modulated luminescence

The insertion of conjugated units between the two pyridine rings of traditional viologens is an effective way to regulate the stimulus response. Herein, the rigid thiazolothiazole extended viologen moiety (TTVP, 2,5-bis (pyridinium-4-yl) thiazolo [5,4-d] thiazole propionate) has been utilized in the preparation of photochromic materials, in which two novel complexes {[Zn (TTVP)0.5 (m-HBTC) (H2O)]·DMF·3H2O}n (1) and [Zn(H2O)6]0.5 (p-BDC)0.5·(TTVP)0.5 (2) (m-H3BTC = 1,2,4-benzenetricarboxylic acid, p-H2BDC = 1,4-benzenedicarboxylic acid), have been synthesized and characterized. Structural analysis exhibits that complex 1 features one-dimensional (1D) chain structure, while complex 2 exists as a discrete monomeric structure. As anticipated, both complexes exhibit reversible photochromic properties under UV irradiation because of electron transfer (ET). More importantly, the photo-controlled luminescent properties and the potential application as inkless and erasable printing media are also explored.

Synthesis and Characterization of Hexathiosianatoiron(II) [Fe(NCS)6] 4- Complex Compound and Tetrapyridindithiosianatoiron(II) [Fe(NCS)2(Py)4] Complex Compound

This research aims to synthesize and characterize the complex compounds Hexathiocyanatoiron(II) [Fe(NCS)6] 4- and Tetrapyridinedithiocyanatoiron(II) [Fe(NCS)2(Py)4]. The synthesis of these complex compounds was conducted in the Chemistry Laboratory, Faculty of Mathematics and Natural Sciences, Medan State University, while magnetic susceptibility measurements were carried out using the Magnetic Susceptibility Balance (MSB) instrument in the Inorganic Chemistry Laboratory, Bandung Institute of Technology. The complex compound synthesis involved the reaction of Iron(II) sulfate heptahydrate with Potassium thiocyanate and Pyridine compound in a 1:2 and 1:2:4 molar ratio. The synthesis process was conducted through a direct reaction method in a polar solvent. The obtained results include Hexathiocyanatoiron(II) complex compound, [Fe(NCS)6] 4-, which is pale yellow crystalline with a yield of 32.76%, and Tetrapyridinedithiocyanatoiron(II) complex compound, [Fe(NCS)2(Py)4] which is dark purple crystalline with a yield of 52.62%. These compounds exhibit a melting point of 219℃. Magnetic susceptibility measurements using the MSB instrument revealed a magnetic susceptibility of 6.69 BM (paramagnetic) for the Hexathiocyanatoiron(II) complex[Fe(NCS)6] 4-, and a magnetic moment of 5.61 BM (diamagnetic) for the Tetrapyridinedithiocyanatoiron(II ) complex [Fe(NCS)2(Py)4].

Crystal structure and synchrotron X-ray powder reference pattern for the porous pillared cyanonickelate, Ni(3-amino-4,4′-bipyridine)[Ni(CN)4

The structure of Ni(3-amino-4,4′-bipyridine)[Ni(CN)4] (or known as Ni-BpyNH2) in powder form was determined using synchrotron X-ray diffraction and refined using the Rietveld refinement technique (R = 8.8%). The orthorhombic (Cmca) cell parameters were determined to be a = 14.7218(3) Å, b = 22.6615(3) Å, c = 12.3833(3) Å, V = 4131.29(9) Å3, and Z = 8. Ni-BpyNH2 forms a 3-D network, with a 2-D Ni(CN)4 net connecting to each other via the BpyNH2 ligands. There are two independent Ni sites on the net. The 2-D nets are connected to each other via the bonding of the pyridine “N” atom to Ni2. The Ni2 site is of six-fold coordination to N with relatively long Ni2–N distances (average of 2.118 Å) as compared to the four-fold coordinated Ni1–C distances (average of 1.850 Å). The Ni(CN)4 net is arranged in a wave-like fashion. The functional group, –NH2, is disordered and was found to be in the m-position relative to the N atom of the pyridine ring. Instead of having a unique position, N has ¼ site occupancy in each of the four m-positions. The powder reference diffraction pattern for Ni-BpyNH2 was prepared and submitted to the Powder Diffraction File (PDF) at the International Centre of Diffraction Data (ICDD).

Synthesis and Photolysis Properties of a New Chloroquine Photoaffinity Probe.

A new chloroquine-derived photoaffinity probe has been prepared by a convergent synthesis from derivative of 4,7-dichloroquinoline and N1,N1-diethyl-N4-methylpentane. The features of this probe are a unique 3-azido photolabel, the pyridine ring of the quinoline, and the presence of a secondary amine at the 4-position of the quinoline. These features, particularly the 4-amino methylation, prevent triazole formation through combination of the 3-azide and the 4-amine. This undergoes facile cleavage with exposure to a medium-pressure mercury lamp with a 254 nm excitation wavelength. Trapping of the nitrene byproduct is accomplished with its reaction with N-phenylmaleimide as its cycloazidation product. The structure of a ring-opened DBU amine has been structurally characterized.