A trigonal dodecahedral cadmium(II) complex with zinc(II)–salen type metalloligand: Synthesis, structure, self-assembly and application in the detection of various nitroaromatics via turn-off fluorescence response

Experimental and Theoretical Survey of Intramolecular Spodium Bonds/σ/π-Holes and Noncovalent Interactions in Trinuclear Zn(II)-Salen Type Complex with OCN- Ions: A Holistic View in Crystal Engineering

In this work, one new centrosymmetric trinuclear Zn(II) complex 1, [{(OCN)Zn(L)}2Zn], using a salen-type ligand (H2L) in the presence of OCN- was synthesized and characterized via elemental, spectral, SEM-EDX, and single-crystal X-ray diffraction (SCXRD) study. In 1, SCXRD reveals two different stereochemical environments of zinc metal ions; one terminal Zn(II) center adopts square pyramidal geometries with the Addison parameter (τ) 0.095, and the central Zn(II) is tetracoordinated tetrahedral geometry. This article provides evidence of the significance and presence of spodium bonds (SpBs) in solid-state crystal structures involving a pseudotetrahedral environment of the central Zn-atom. X-ray structures reveal intramolecular Zn···O SpBs caused by the methoxy (-OCH3) substituent O-atom adjacent to the coordinated phenoxy O-atom. These noncovalent interactions have been thoroughly studied using density functional theory calculations at the RI-BP86[2]-D3[3]/def2-TZVP level of theory that characterizes the nature of SpBs, including the Baders quantum theory of atoms-in-molecules "QTAIM", molecular electrostatic potential (MEP) surface, and noncovalent index plot (NCI). In addition, a unique complex-isomer-based theoretical model has been vividly employed to estimate the SpBs energy in the complex. Natural bond orbital (NBO) analysis also tries to establish the differentiation between σ-hole and π-hole SpBs' natures more authentically. The complex energy frameworks were used to investigate noncovalent interactions. To better understand the different intermolecular interactions, we conducted a Hirshfeld surface, which revealed N···H (15.4%) and O···H (9.1%) contacts and Zn···O (5.1%) (SpBs).

Synthesis and characterization of a mononuclear zinc(ii) Schiff base complex: on the importance of C-H⋯π interactions

A zinc(ii) complex, [ZnL(H₂O)]·H₂O {H₂L = 2,2′-[(2,2-dimethyl-1,3-propanediyl)bis(nitrilomethylidyne)]bis[6-ethoxyphenol]} has been synthesized and characterized by UV-vis and IR spectroscopy. The structure of the complex has been confirmed by X-ray crystallography and the noncovalent interactions characterized using Hirshfeld surface analysis. In addition to the conventional H-bonds involving the Zn-coordinated and non-coordinated water molecules, interesting C–H⋯π interactions between the H-atoms belonging to aliphatic part of the ligand (2,2-dimethyl-1,3-propanediyl) and the Zn-coordinated aromatic rings are established. These interactions have been studied using DFT calculations (PBE0-D3/def2-TZVP) and characterized using molecular electrostatic potential (MEP) surfaces and the noncovalent interaction (NCI) plot index analyses.

The strength of the C–H⋯π interaction in the solid state of [ZnL(H₂O)]·H₂O has been evaluated using DFT calculations and also analysed using the MEP surface and NCI plot index computational tool.

On the importance of RH3C⋯N tetrel bonding interactions in the solid state of a dinuclear zinc complex with a tetradentate Schiff base ligand

The tetrel bonding and π-stacking interactions in a new dinuclear zinc complex using a tetradentate N₂O₂ donor Schiff base have been analysed energetically using DFT calculations and several computational tools.

Methylene spacer regulated variation in supramolecular assembly of zinc(ii) dicyanamide complexes with reduced Schiff base ligands: synthesis, structure and DFT study

Three tetranuclear zinc dicyanamide complexes with three potential hexadentate reduced Schiff base ligands have been synthesized and characterized. The DFT study is devoted to the analysis of the competition between C–H⋯π and π⋯π interactions.

A series of trinuclear zinc(ii) complexes with reduced Schiff base ligands: turn-off fluorescent chemosensors with high selectivity for nitroaromatics

A series of trinuclear zinc(ii) complexes have been synthesized and characterized by X-ray crystallography. The ability of the complexes to act as sensors for the detection of nitroaromatics in DMF has been assessed.

Phosphatase-mimicking activity of a unique penta-nuclear zinc(ii) complex with a reduced Schiff base ligand: assessment of its ability to sense nitroaromatics

A penta-nuclear zinc(ii) complex has been synthesized and characterized. The complex has shown good phosphatase-mimicking activity, which has been evaluated spectrophotometrically. The complex also behaves as a sensor for the detection of nitroaromatics via turn-off fluorescence response.