A chiral, low-cytotoxic [Ni15]-wheel complex

The prediction of single-molecule magnet properties via deep learning

This paper uses deep learning to present a proof-of-concept for data-driven chemistry in single-molecule magnets (SMMs). Previous discussions within SMM research have proposed links between molecular structures (crystal structures) and single-molecule magnetic properties; however, these have only interpreted the results. Therefore, this study introduces a data-driven approach to predict the properties of SMM structures using deep learning. The deep-learning model learns the structural features of the SMM molecules by extracting the single-molecule magnetic properties from the 3D coordinates presented in this paper. The model accurately determined whether a molecule was a single-molecule magnet, with an accuracy rate of approximately 70% in predicting the SMM properties. The deep-learning model found SMMs from 20 000 metal complexes extracted from the Cambridge Structural Database. Using deep-learning models for predicting SMM properties and guiding the design of novel molecules is promising.

Ligand-Modulated Nuclearity and Geometry in Nickel(II) Hydrazone Complexes: From Mononuclear Complexes to Acetato- and/or Phenoxido-Bridged Clusters

The propensity of 4-hydroxybenzhydrazone-related ligands derived from 3-methoxysalicylaldehyde (H₂L^3OMe), 4-methoxysalicylaldehyde (H₂L^4OMe), and salicylaldehyde (H₂L^H) to act as chelating and/or bridging ligands in Ni(II) complexes was investigated. Three clusters of different nuclearities, [Ni₃(L^3OMe)₂(OAc)₂(MeOH)₂]∙2MeOH∙MeCN (1∙2MeOH∙MeCN), [Ni₂(HL^4OMe)(L^4OMe)(OAc)(MeOH)₂]∙4.7MeOH (2∙4.7MeOH), and [Ni₄(HL^H)₂(L^H)₂(OAc)₂]∙4MeOH·0.63H₂O·0.5MeCN·HOAc (3∙4MeOH·0.63H₂O·0.5MeCN·HOAc), were prepared from Ni(OAc)₂∙4H₂O and the corresponding ligand in the presence of Et₃N. The hydrazones in these acetato- and phenoxido-bridged clusters acted as singly or doubly deprotonated ligands. When pyridine was used, mononuclear complexes with the square-planar geometry seemed to be favoured, as found for complexes [Ni(L^3OMe)(py)] (4), [Ni(L^4Ome)(py)] (5) and [Ni(L^H)(py)] (6). Ligand substituent effects and the stability of square-planar complexes were investigated and quantified by extensive quantum chemical analysis. Obtained results showed that standard Gibbs energies of binding were lower for square-planar than for octahedral complexes. Starting from [MoO₂(L)(EtOH)] complexes as precursors and applying the metal-exchange procedure, the mononuclear complexes [Ni(HL^3OMe)₂]∙MeOH (7∙MeOH) and [Ni(HL^H)]∙2MeOH (9∙2MeOH) and hybrid organic-inorganic compound [Ni₂(HL^4OMe)₂(CH₃OH)₄][Mo₄O₁₀(OCH₃)₆] (10) were achieved. The octahedral complexes [Ni(HL)₂] (7-9) can also be obtained by the direct synthesis from Ni(Oac)₂∙4H₂O and the appropriate ligand under specific reaction conditions. Crystal and molecular structures of 1∙2MeOH∙MeCN, 2∙4.7MeOH, 3∙4MeOH∙0.63H₂O∙0.5MeCN∙HOAc, 4, 5, 9∙2MeOH, and 10 were determined by the single-crystal X-ray diffraction method.

Synthesis of Novel Tetra(µ3-Methoxo) Bridged with [Cu(II)-O-Cd(II)] Double-Open-Cubane Cluster: XRD/HSA-Interactions, Spectral and Oxidizing Properties

A new double-open-cubane core Cd(II)-O-Cu(II) bimetallic ligand mixed cluster of type [Cl2Cu4Cd2(NNO)6(NN)2(NO3)2].CH3CN was made available in EtOH/CH3CN solution. The 1-hydroxymethyl-3,5-dimethylpyrazole (NNOH) and 3,5-dimethylpyrazole (NNH) act as N,O-polydentate anion ligands in coordinating the Cu(II) and Cd(II) centers. The structure of the cluster in the solid state was proved by XRD study and confirmed in the liquid state by UV-vis analysis. The XRD result supported the construction of two octahedral and one square pyramid geometries types around the four Cu(II) centers and only octahedral geometry around Cd(II) two centers. Interestingly, NNOH ligand acts as a tetra-µ3-oxo and tri-µ2-oxo ligand; meanwhile, the N-N in NNH acts as classical bidentate anion/neutral ligands. The interactions in the lattice were detected experimentally by the XRD-packing result and computed via Hirschfeld surface analysis (HSA). The UV-vis., FT-IR and Energy Dispersive X-ray (EDX), supported the desired double-open cubane cluster composition. The oxidation potential of the desired cluster was evaluated using a 3,5-DTB-catechol 3,5-DTB-quinone as a catecholase model reaction.

A cyanide-bridged wheel featuring a seven-coordinate Mo(iii) center

A new, cyanide-bridged Mo₆Ni₁₂ wheel shows ferromagnetic coupling.

Polynuclear ampyrone based 3d coordination clusters

The use of a monoanionic Schiff base ligand in transition (Co, Ni and Cu) coordination chemistry yields mono-, tetra- and pentanuclear coordination clusters with different structural motifs.

Aggregation of the metallocycles {Cu8} and {Cu20} using [Cu(bp)] units (H2bp = bis(2-hydroxybenzyl)amine): structures and magnetic properties

Two metallocycles, {Cu8(bp)4(OH)4(H2O)4(ClO4)4} (1) and {Cu20(bp)20} (2), were afforded by the reactions of the semi-flexible tridentate ligand bis(2-hydroxybenzyl)amine (H2bp) with Cu(ClO4)2·6H2O and Cu(OAc)2·H2O. Complex 1 has a saddle-shaped cyclic structure and complex 2 has a nanosized wheel-shaped structure. The two compounds consist of [Cu(bp)] units.

Synthesis, crystal structure, DFT/TDDFT calculation, photophysical properties and DNA binding studies of morpholino moiety ligand based two Cu(ii) complexes in combination with carboxylates

Two Cu(II) compounds have been characterized by structure analyses and DFT/TD-DFT calculations. Both the complexes potentially bind with CT-DNA and corresponding binding constants are in the order of 10⁵ M⁻¹.