Probing the origin and stability of bivalency in copper based porous coordination network and its application for H2S gas capture

Preparative and Catalytic Properties of MoVI Mononuclear and Metallosupramolecular Coordination Assemblies Bearing Hydrazonato Ligands

A series of polynuclear, dinuclear, and mononuclear Mo(VI) complexes were synthesized with the hydrazonato ligands derived from 5-methoxysalicylaldehyde and the corresponding hydrazides (isonicotinic hydrazide (H2L1), nicotinic hydrazide (H2L2), 2-aminobenzhydrazide (H2L3), or 4-aminobenzhydrazide (H2L4)). The metallosupramolecular compounds obtained from non-coordinating solvents, [MoO2(L1,2)]n (1 and 2) and [MoO2(L3,4)]2 (3 and 4), formed infinite structures and metallacycles, respectively. By blocking two coordination sites with cis-dioxo ligands, the molybdenum centers have three coordination sites occupied by the ONO donor atoms from the rigid hydrazone ligands and one by the N atom of pyridyl or amine-functionalized ligand subcomponents from the neighboring Mo building units. The reaction in methanol afforded the mononuclear analogs [MoO2(L1-4)(MeOH)] (1a-4a) with additional monodentate MeOH ligands. All isolated complexes were tested as catalysts for cyclooctene epoxidation using tert-butyl hydroperoxide (TBHP) as an oxidant in water. The impact of the structure and ligand lability on the catalytic efficiency in homogeneous cyclooctene epoxidation was elucidated based on theoretical considerations. Thus, dinuclear assemblies exhibited better catalytic activity than mononuclear or polynuclear complexes.

Development of new magnetic nanocomposite designed by reduced graphene oxide aerogel and HKUST-1, and its catalytic application in the synthesis of polyhydroquinoline and 1,8-dioxo-decahydroacridine derivatives

In this study, new magnetic reduced graphene oxide aerogel/HKUST-1 nanocomposite was designed and synthesized given the transformation of graphene oxide sheets to three-dimensional reduced graphene oxide aerogel, the in-situ magnetization of aerogel substrate, and the in-situ formation of HKUST-1 particles. Apart from characterizing the chemistry and structure of the designed magnetic nanocomposite (FT-IR, EDX, ICP, FE-SEM, DLS, XRD, VSM, and TG analyses), its catalytic performance was evaluated in the one-pot synthesis of biologically active 1,8-dioxo-decahydroacridine and polyhydroquinoline derivatives. The combination of magnetized reduced graphene oxide aerogel and HKUST-1 in the form of a new heterogeneous magnetic nanocatalyst was accompanied by a high synergetic catalytic effect in the symmetric and unsymmetrical Hantzsch condensation reactions. Compared to previous research studies, the pharmaceutical 1,8-dioxo-decahydroacridine and polyhydroquinoline derivatives can be synthesized using a partial amount of this nanocatalyst with a high percentage of yields in a short reaction time.