Spectroscopic, analytical and DFT calculation studies of two novel Al3+ complexes derived from 2,4,6-tri-(2-pyridyl)-1,3,5-triazine (TPTZ)

Pathway-directed recyclable chirality inversion of coordinated supramolecular polymers

It remains challenging to elucidate the fundamental mechanisms behind the dynamic chirality inversion of supramolecular assemblies with pathway complexity. Herein, metal coordination driven assembly systems based on pyridyl-conjugated cholesterol (PVPCC) and metal ions (Ag+ or Al3+) are established to demonstrate pathway-directed, recyclable chirality inversion and assembly polymorphism. In the Ag(I)/PVPCC system, a competitive pathway leads Ag-Complex to form either kinetically controlled supramolecular polymer (Ag-SP I) or thermodynamically favored Ag-SP II, accompanied by reversible chiroptical inversion. Conversely, the Al(III)/PVPCC system displays a solvent-assisted consecutive pathway: the Al-Complex initially forms ethanol-containing Al-SP II, and subsequently converts into ethanol-free Al-SP I with opposite chiroptical performance upon thermal treatment. Moreover, stable chirality inversion in the solid state enables potential dynamic circularly polarized luminescence encryption when Ag(I)/PVPCC is co-assembled with thioflavin T. These findings provide the guidance for the dynamic modulation of chirality functionality in supramolecular materials for applications in information processing, data encryption, and chiral spintronics.

FeII/III and MnII complexes based on 2,4,6-tris(2-pyridyl)-triazine: synthesis, structures, magnetic and biological properties

Reaction of the polypyridyl ligand 2,4,6-tris(2-pyridyl)-s-triazine (tpt) with mono- and polynuclear Fe(iii) or Mn(ii) precursors, specifically tri- or hexanuclear Fe(iii) pivalates (piv^-), [Mn₆O₂(piv)₁₀(Hpiv)₄] and Mn(ii) isobutyrate (ib^-), in various solvents and under various reaction conditions showcase the ligand's surprising coordination characteristics. The reactions result in mononuclear [Fe^III(tpt)(tptH)][Fe^IIICl₄]₄·2(thf)·0.23(H₂O) (1), [Fe^III(piv)(tpt)Cl₂] (2), [Fe^II(tpt)Cl₂]·2(H₂O) (3a), dinuclear [Fe^III ₂O(tpt)₂Cl₄] (3), and heptanuclear [Fe^III ₇O₄(piv)₁₂(tpt-O)]·A [A = MeCN (4a) or 4(dioxane) (4b)] and [Fe^III ₇O₄(piv)₁₁(tpt-O)(i-PrO)(i-PrOH)]·0.75(i-PrOH) (5), as well as the mononuclear compounds [Mn^II(tpt)(NO₃)(H₂O)₂](NO₃) (6) and [Mn^II(tpt)(ib)(Cl)(MeOH)]·MeOH (7). Single-crystal X-ray diffraction analyses identify tpt as a tridentate NNN donor ligand that forms two five-membered metallocycles in 1-3, 6 and 7, whereas in 4 and 5 five tpt N atoms form coordinative bonds accompanied by an unusual metal-induced oxidation of one of the carbon atoms of the central triazine core. Magnetic properties of Fe(iii)-tpt (2-5), Fe(ii)-tpt (3a), and Mn(ii)-tpt (7) compounds show dominant antiferromagnetic coupling for polynuclear coordination cluster compounds. The Mn(ii)-tpt complexes 6 and 7 exhibit efficient catalytic properties in the production of enzymes by microorganisms, which concerns the synthesis of exocellular proteases in Fusarium gibbosum CNMN FD 12 or Trichoderma koningii Oudemans CNMN FD 15 fungi strains. Thus, compounds 6 and 7 can be used for producing proteolytic enzymes with wide applications including in the food, detergents and pharmaceutical industries.

A new thiourea derivative [2-(3-ethylthioureido)benzoic acid] for cloud point extraction of some trace metals in water, biological and food samples

2-(3-Ethylthioureido)benzoic acid was prepared and characterized by electronic spectrum, elemental analysis, Fourier transform infrared spectroscopy, ¹H nuclear magnetic resonance spectrum and mass spectrum. The produced ligand was applied for the preconcentrative of Fe³⁺, Co²⁺, Cu²⁺ and Zn²⁺ in aqueous samples by cloud point extraction methodology. Triton X-114 was used as extractant. Experimental parameters that may affect the extraction process were examined and optimized; such as pH, ligand and triton concentrations, type of diluting solvent, extraction temperature and ionic strength. The calibration curves were linear upto 500μgL^-1 for Fe³⁺, Cu²⁺ and Zn²⁺ and upto 200μgL^-1 for Co²⁺. The achieved detection limits were 1.5, 0.23, 0.71 and 0.35μgL^-1 for Fe³⁺, Co²⁺, Cu²⁺ and Zn²⁺ respectively. The accuracy was established by analysis of certified reference materials (Seronorm whole blood L2 and ZCS ZC85006 Tomato). The proposed procedure was used for preconcentration of these metal ions in water, biological and food samples prior to their determination by flame atomic absorption spectrometry.

Design, synthesis, and characterization of 2,2-bis(2,4-dinitrophenyl)-2-(phosphonatomethylamino)acetate as a herbicidal and biological active agent

The present study was designed to synthesize the bioactive molecule 2,2-bis(2,4-dinitrophenyl)-2-(phosphonatomethylamino)acetate (1), having excellent applications in the field of plant protection as a herbicide. Structure of newly synthesized molecule 1 was confirmed by using the elemental analysis, mass spectrometric, NMR, UV-visible, and FTIR spectroscopic techniques. To obtain better structural insights of molecule 1, 3D molecular modeling was performed using the GAMESS programme. Microbial activities of 1 were checked against the pathogenic strains Aspergillus fumigatus (NCIM 902) and Salmonella typhimurium (NCIM 2501). Molecule 1 has shown excellent activities against fungal strain A. fumigates (35 μg/l) and bacterial strain S. typhimurium (25 μg/l). To check the medicinal significance of molecule 1, interactions with bovine serum albumin (BSA) protein were checked. The calculated value of binding constant of molecule 1-BSA complex was 1.4 × 10⁶ M^-1, which were similar to most effective drugs like salicylic acid. More significantly, as compared to herbicide glyphosate, molecule 1 has exhibited excellent herbicidal activities, in pre- and post-experiments on three weeds; barnyard grass (Echinochloa Crus), red spranglitop (Leptochloa filiformis), and yellow nuts (Cyperus Esculenfus). Further, effects of molecule 1 on plant growth-promoting rhizobacterial (PGPR) strains were checked. More interestingly, as compared to glyphosate, molecule 1 has shown least adverse effects on soil PGPR strains including the Rhizobium leguminosarum (NCIM 2749), Pseudomonas fluorescens (NCIM 5096), and Pseudomonas putida (NCIM 2847).

Crystal structure of aquadichlorido(2,4,6-tri-2-pyridyl-1,3,5-triazine-κ3 N,N′,N′′)nickel(II) monohydrate, C18H16Cl2N6NiO2

C18H16Cl2N6NiO2, monoclinic, P21/n (no. 14), a = 8.5737(6) Å, b = 11.4177(9) Å, c = 20.3031(16) Å, β = 99.309(3)°, V = 1961.3(3) Å3, Z = 4, R gt(F) = 0.0479, wR ref(F 2) = 0.0865, T = 293 K.

Interactions of atrazine with transition metal ions in aqueous media: experimental and computational approach

Transition metal ions have their own significances and utility. Externally applied pesticides may alter the bioavailability of these metal ions to plants through the coordinating ability of these pesticides with metal ions. In current study a series of metal complexes containing atrazine (Atr) group(s) attached to metal(II) (M) frame, with the formula; [M(Atr)_n.xH₂O.yCl] (where M = Mn, Fe, Co, Ni, Cu or Zn; n = 1 or 2; x = 1-4; y = 1-2), have been synthesized for the first time to check the interactions of atrazine with transition metal ions. More importantly, all the complexes were synthesized at neutral pH in aqueous medium. The major differences among the FTIR spectra were observed between 3,700-2,800 and 1,800-1,350 cm^-1. On the basis of FTIR, CHN and computational study, it was observed that Mn, Ni and Cu formed complexes in 1:2 and Fe, Co and Zn in 1:1. The obtained results were supported by 3D molecular modeling using GAMESS computations as a package of ChemBio3D Ultra14 program. The FTIR spectral analysis and 3D molecular modeling suggests that the Atr can show coordination through the nitrogen (in between two side chains) of ring as well as nitrogen (non steric amine) of side chain with different metal ions.