Synthesis, structural characterization, and theoretical analysis of novel zinc(ii) schiff base complexes with halogen and hydrogen bonding interactions

In this article, we present the synthesis and characterization of three zinc(ii) complexes, [ZnII(HL1)2] (1), [ZnII(HL2)2]·2H2O (2) and [ZnII(HL3)2] (3), with three tridentate Schiff base ligands, H2L1, H2L2, and H2L3. The structures of the complexes were confirmed by single-crystal X-ray diffraction analysis. DFT calculations were performed to gain insights into the self-assembly of the complexes in their solid-state structures. Complex 1 exhibits dual halogen-bonding interactions (Br⋯Br and Br⋯O) in its solid-state structure, which have been thoroughly investigated through molecular electrostatic potential (MEP) surface calculations, alongside QTAIM and NCIPlot analyses. Furthermore, complex 2 features a fascinating hydrogen-bonding network involving lattice water molecules, which serves to link the [ZnII(HL2)2] units into a one-dimensional supramolecular polymer. This network has been meticulously examined using QTAIM and NCIplot analyses, allowing for an estimation of the hydrogen bond strengths. The significance of H-bonds and CH⋯π interactions in complex 3 was investigated, as these interactions are crucial for the formation of infinite 1D chains in the solid state.

Facile strategy to incorporate amidoxime groups into elastomers toward self-crosslinking and self-reinforcement

Amidoxime modification of NBR and the formation of a multi-crosslinking network structure by self-crosslinking of AO-NBR.

Nickel(ii)-mediated cyanamide–pyrazole coupling highlights distinct reactivity of NCNR2 and NCR nitrile ligands

The nickel(ii) center efficiently promotes the cyanamide–pyrazole coupling to give bis-chelate and tris-chelate products. The formation of the tris-chelate product for dialkylcyanamides is thermodynamically favorable.

Aminonitrones as highly reactive bifunctional synthons. An expedient one-pot route to 5-amino-1,2,4-triazoles and 5-amino-1,2,4-oxadiazoles – potential antimicrobials targeting multi-drug resistant bacteria

A four-component one-pot reaction proceeds very rapidly under mild conditions and gives the heterocyclic systems in good yields.

Tetrachloromethane as halogen bond donor toward metal-bound halides

Two annulated triazapentadiene systems, viz. 1,3,5,7,9-pentaazanona-1,3,6,8-tetraenate chloride complexes of PtII, form CCl4 solvates, containing the Cl3C–Cl···Cl–Pt halogen bonds. These halogen bonds are firstly reported type of Cl3C–Cl···Cl–M contacts. In the X-ray structures of two solvates different non-covalent interactions were detected and studied by DFT calculations and topological analysis of the electron density distribution within the framework of QTAIM method at the M06/DZP-DKH level of theory. Estimated energies of these supramolecular contacts vary from 0.6 to 2.4 kcal/mol.

3-Dialkylamino-1,2,4-triazoles via ZnII-Catalyzed Acyl Hydrazide-Dialkylcyanamide Coupling

Zinc(II)-catalyzed (10 mol % ZnCl₂) coupling of acyl hydrazides and dialkylcyanamides in ethanol leads to 3-dialkylamino-1,2,4-triazoles (76-99%; 17 examples). This reaction represents a novel, straightforward, and high-yielding approach to practically important 3-NR₂-1,2,4-triazoles, which utilizes commercially available and/or easily generated substrates. Seventeen new 3-NR₂-1,2,4-triazoles were characterized by HRESI⁺-MS and IR, ¹H, and ¹³C{¹H} NMR spectroscopies and five species additionally by single-crystal X-ray diffraction (XRD). The Zn^II-catalyzed reaction proceeds via initial generation of the [Zn{RC(=O)NHNH₂}₃](ZnCl₄) complexes (exemplified by isolation of the complex with R = Ph, 76%; characterized by HRESI⁺-MS, IR, CP-MAS TOSS ¹³C{¹H} NMR, and XRD). Electronic effects of substituents at the acyl hydrazide moiety do not significantly affect the reaction rate and the yield of the target triazoles, whereas the steric hindrances reduce the reaction rate without affecting the yield of the heterocycles.

Bromo- and Polybromoantimonates(V): Structural and Theoretical Studies of Hybrid Halogen-Rich Halometalate Frameworks

Cation-dependent reactions "[SbBr₆ ]^3- +Br₂ +HBr+CationBr_x " result in the formation of bromide/polybromide complexes with zero-, one-, two-, or three-dimensional supramolecular frameworks and different Br/Sb ratios (up to 11). Seven new compounds representing six structural types were characterized by XRD and thermogravimetric analysis and DFT calculations enabled estimation of the energies of the Br⋅⋅⋅Br contacts (1.1-4.6 kcal mol^-1 ).

Metal-Involving Synthesis and Reactions of Oximes

This review classifies and summarizes the past 10-15 years of advancements in the field of metal-involving (i.e., metal-mediated and metal-catalyzed) reactions of oximes. These reactions are diverse in nature and have been employed for syntheses of oxime-based metal complexes and cage-compounds, oxime functionalizations, and the preparation of new classes of organic species, in particular, a wide variety of heterocyclic systems spanning small 3-membered ring systems to macroheterocycles. This consideration gives a general outlook of reaction routes, mechanisms, and driving forces and underlines the potential of metal-involving conversions of oxime species for application in various fields of chemistry and draws attention to the emerging putative targets.