Zhen-Ping Ji

Synthesis, spectra and X-ray crystal structure of a new type of macrocyclic hexanuclear iron(III) cluster

A macrocyclic iron(III) 18-azametallacrown-6 compound, [Fe6(5-Brashz)6(H2O)6] · 20H2O(5-Brashz = N-acetyl-(5-bromosalicylhydrazide)), where the pentadentate ligands bridge the metal ions, was synthesized and characterized. Due to the meridional coordination of the ligand to the metal ion, the ligand is not only bridging the ring metal ions using a hydrazide N–N group, but also enforcing the stereochemistry of the metal ions as a propeller shape with alternating Λ/Δ configuration. The disc-shaped hexanuclear cluster is about 14.5 Å in diameter, 16.8 Å in thickness and has a vacant cavity in the center of the cluster.

Bent and linear trinuclear nickel complexes with ligands derived from N -acylsalicylhydrazide ligands: structural characterization and bioactivity

Two trinuclear Ni(II) complexes Ni3(L1)2(py)2(DMF)(H2O) (1) and Ni3(L2)2(py)2(DMF)2 (2) with two new trianionic pentadentate ligands N-(3,5-dimethylbenzoyl)-salicylhydrazide (H3L1) and N-(phenylacetyl)-5-nitrosalicylhydrazide (H3L2) have been synthesized and characterized by X-ray crystallography. Nickel ions in the two complexes have square-planar/octahedral/square-planar coordination. Central metal ion and two terminal metal ions in the two complexes are combined by two bridging deprotonated ligands, forming a trinuclear structural unit with an M–N–N–M–N–N–M core. Studies on the trinuclear Ni(II) complexes show that the β-branched N-acylsalicylhydrazide ligands with sterically flexible Cα methylene groups yield linear trinuclear Ni(II) complexes, while α-branched N-acylsalicylhydrazide ligands tend to form bent trinuclear Ni(II) complexes. Antibacterial screening data in a previous study indicates that bent trinuclear Ni(II) compound 1 is more active than linear compound 2 and less active than a tetranuclear nickel compound.

Role Of Solvent In Slurry Phase Reactions

There exists an optimal amount of solvent (generally water) that can be added to the slurry phase reaction between solid reactants; the reactivity and efficiency of such reactions are different from those without solvent or those with large amount of solvent. Obviously, the solvent plays a crucial role in the process of the reaction, and it is the key to the understanding of unique reactivity and high efficiency of such slurry phase reactions. The water molecule absorbed on the surface of solid reactants, which is called bound water, has uniquely different properties compared with bulk water. Surface hydroxylation resulting from bound water greatly influences the chemical activity of the surface, which could be playing a role as catalyst or as the initialization point for further reactions, so that the reactants can react easily and fast under a simple reaction condition.