Synthesis, Characterization, X-Ray Crystal Structures and Antibacterial Activity of Cobalt(III) Complexes Derived from 5-Bromo-2-((2-(phenylamino) ethylimino)methyl)phenol

Two new and similar cobalt(III) complexes, [CoL2] · NO3 (1) and [CoL2] · Cl (2), where L is 5-bromo-2-((2-(phenylamino) ethylimino)methyl)phenolate, have been synthesized and characterized by IR and UV-Vis spectra. Structures of the complexes were confirmed by single crystal X-ray determination. The Co atoms in the complexes are in octahedral coordination, with the donor atoms come from the two Schiff base ligands, viz. phenolate oxygen, and imino and amino nitrogen. The anions of the cobalt salts crystallized as counteranions in the complexes. The complexes were assayed for antibacterial activities by MTT method.

Bis(ethanol-κO)bis(1-ferrocenyl-4,4,4-trifluorobutane-1,3-dionato-κ2 O,O′)nickel(II)

In the title compound, [NiFe2(C5H5)(C9H5F3O2)2(C2H6O)2], the central NiII ion is observed in an octahedral coordination environment. The chelating β-diketonate ligands are substituted by ferrocene, a lipophilic organometallic moiety. The ferrocene groups have the normal geometry, with eclipsed cyclopentadiene rings. Coordinated ethanol molecules are engaged in intermolecular hydrogen bonds, and the crystal is further stabilized by weak C—H...F and C—H...π contacts.

Synthesis, X-Ray Crystal Structures and Catalytic Epoxidation of Oxidovanadium(V) Complexes with Aroylhydrazone and Ethyl Maltolate Ligands

Two oxidovanadium(V) complexes, [VOL1L] (1) and [VOL2L] (2) (L = ethyl maltolate), derived from the aroylhydrazones 4-bromo-N’-(2-hydroxy-5-methylbenzylidene)benzohydrazide (H2L1) and N’-(3,5-dibromo-2-hydroxybenzylidene)- 4-methoxybenzohydrazide (H2L2), respectively, have been synthesized and characterized by elemental analysis, infrared and electronic spectroscopy. Structures of the complexes were further confirmed by single crystal X-ray determination. The V atoms in the complexes are coordinated by the ONO donor atoms of the aroylhydrazone ligand, OO donor atoms of the ethyl maltolate ligand, and one oxido O atom, forming octahedral coordination. The complexes function as effective olefin

Room-Temperature Structure of Xylitol-Bound Glucose Isomerase by Serial Crystallography: Xylitol Binding in the M1 Site Induces Release of Metal Bound in the M2 Site

Glucose isomerase (GI) is an important enzyme that is widely used in industrial applications, such as in the production of high-fructose corn syrup or bioethanol. Studying inhibitor effects on GI is important to deciphering GI-specific molecular functions, as well as potential industrial applications. Analysis of the existing xylitol-bound GI structure revealed low metal occupancy at the M2 site; however, it remains unknown why this phenomenon occurs. This study reports the room-temperature structures of native and xylitol-bound GI from Streptomyces rubiginosus (SruGI) determined by serial millisecond crystallography. The M1 site of native SruGI exhibits distorted octahedral coordination; however, xylitol binding results in the M1 site exhibit geometrically stable octahedral coordination. This change results in the rearrangement of metal-binding residues for the M1 and M2 sites, the latter of which previously displayed distorted metal coordination, resulting in unstable coordination of Mg2+ at the M2 site and possibly explaining the inducement of low metal-binding affinity. These results enhance the understanding of the configuration of the xylitol-bound state of SruGI and provide insights into its future industrial application.

Synthesis, Crystal Structures, Characterization and Catalytic Property of Copper(II) Complexes Derived from Hydrazone Ligands

A new bromido-coordinated mononuclear copper(II) complex [Cu(HL1)Br2] (1), and a new mononuclear copper(II) complex [CuL2(HL2)]ClO4 · 0.5H2O (2), with the hydrazone ligands 4-tert-butyl-N’-(1-(pyridin-2-yl)ethylidene)benzohydrazide (HL1) and 4-bromo-N’-(pyridin-2-ylmethylene)benzohydrazide (HL2), have been synthesized and structurally characterized by physico-chemical methods and single crystal X-ray determination. X-ray analysis indicates that the Cu atom in complex 1 is in distorted square pyramidal coordination, and that in complex 2 is in octahedral coordination. The catalytic property for epoxidation of styrene by the complexes was evaluated.

Can Serendipity Still Hold Any Surprises in the Coordination Chemistry of Mixed-Donor Macrocyclic Ligands? The Case Study of Pyridine-Containing 12-Membered Macrocycles and Platinum Group Metal Ions PdII, PtII, and RhIII

This study investigates the coordination chemistry of the tetradentate pyridine-containing 12-membered macrocycles L1-L3 towards Platinum Group metal ions PdII, PtII, and RhIII. The reactions between the chloride salts of these metal ions and the three ligands in MeCN/H2O or MeOH/H2O (1:1 v/v) are shown, and the isolated solid compounds are characterized, where possible, by mass spectroscopy and 1H- and 13C-NMR spectroscopic measurements. Structural characterization of the 1:1 metal-to-ligand complexes [Pd(L1)Cl]2[Pd2Cl6], [Pt(L1)Cl](BF4), [Rh(L1)Cl2](PF6), and [Rh(L3)Cl2](BF4)·MeCN shows the coordinated macrocyclic ligands adopting a folded conformation, and occupying four coordination sites of a distorted square-based pyramidal and octahedral coordination environment for the PdII/PtII, and RhIII complexes, respectively. The remaining coordination site(s) are occupied by chlorido ligands. The reaction of L3 with PtCl2 in MeCN/H2O gave by serendipity the complex [Pt(L3)(m-1,3-MeCONH)PtCl(MeCN)](BF4)2·H2O, in which two metal centers are bridged by an amidate ligand at a Pt1-Pt2 distance of 2.5798(3) Å and feature one square-planar and one octahedral coordination environment. Density Functional Theory (DFT) calculations, which utilize the broken symmetry approach (DFT-BS), indicate a singlet d8-d8 PtII-PtII ground-state nature for this compound, rather than the alleged d9-d7 PtI-PtIII mixed-valence character reported for related dinuclear Pt-complexes.