Bifunctional Role of Methyl Viologen in UV and X-ray Sensitive Switchable Organophosphonate Single Crystal

Abstract

Finding X-ray and UV responsive hybrid single crystals including their versatile properties is highly desirable though the fabrication of such material is a very challenging task to researchers. Herein, a methyl viologen assisted hybrid nickel organophosphonate structure (i.e., NIT1) is demonstrated by adapting an in situ solvothermal strategy to investigate the X-ray effect and photochromic behaviors. The bifunctional coordinated and templated roles of monocationic and bicationic methyl viologen units present in the hybrid structure are noteworthy and can manifest prominent structural enhancement and reversible photochromism behaviors.

Intrinsic Specific Activity Enhancement for Bifunctional Electrocatalytic Activity toward Oxygen and Hydrogen Evolution Reactions via Structural Modification of Nickel Organophosphonates

“…The B-level alerts in both the compounds are observed due to the close proximity of phosphonate hydrogens as well as lattice water molecules. The hydrogen atoms of the disordered water molecules are displaced from their original positions due to the thermal vibration, as observed in our earlier report also. ,,, …”

“…In this respect, Wang et al communicated a large number of amine-directed metal phosphonate frameworks as well as many hybrid photochromic materials. Among them, TPT (2,4,6-tri­(4-pyridyl)-1,3,5-triazine) ligand-supported lanthanide­(III) and zinc diphosphonate materials are very promising for photochromic and photomagnetic behaviors. − , Concurrently, our continuous attempts on hybrid frameworks successfully yielded few aromatic (4,4′-bipyridine) and cyclic aliphatic amine (piperazine and their derivatives)-directed silver and zinc diphosphonate frameworks which are new examples for the exhibition of exciting electronic and catalytic behaviors in the metal phosphonate family. ,,− With this connection, our recent effort explored amine-templated one-dimensional transition-metal phosphonate materials introduced as efficient bifunctional electrocatalysts . Furthermore, Demadis and co-workers currently investigated proton conductivity as well as the trifunctional electrocatalytic activities of the produced metal phosphonate framework materials .…”

“…If the amine molecules are modified from aliphatic to aromatic amines, the nitrogen atoms intend to bind with the metal centers to improve the dimensionality . Dipyridine- and tripyridine-based aromatic ligands are the commonly investigated amines for their unusual structural orientation and photochromic behaviors. ,, However, single aromatic ring-based amines are rarely investigated for the formation of metal–phosphonate compounds. Yin et al utilized pyrazine as a structure-building agent for Co–phosphonate, while pyrazine was not observed in the framework as found in our compound I .…”

“…Among the inorganic–organic hybrid family, metal organophosphonate has emerged as a flourishing class of hybrid framework with organic and inorganic moieties altogether. − Remarkably, organophosphonic acid plays an important role to form highly stable hybrid materials as it can possess the promising capability to bind various metal centers due to a plenty of flexible coordinating oxygen sites. ,,, Organophosphonate ligand is also capable to show different valence states from monovalent to pentavalent at different pH which can make a broad range of coordination networks at different pH. − A great diversity of metal phosphonates can also be obtained by using variable inorganic and organic moieties as secondary ligands. − Hence, the dimensionality as well as porosity can be enhanced by making amendments to the reaction conditions such as pH, reaction time, solvent, structure directing agent, and supportive ligands.…”

“…In today’s scenario, dual-ligand approach has been taken into consideration for the synthesis of novel hybrid frameworks. − In general, metal phosphonates incorporated with different types of auxiliary ligands have given rise to distinct novel architectures of the hybrid frameworks. − Earlier, various N-containing aliphatic or aromatic ligands were utilized to form metal phosphonate hybrid structures. Such auxiliary ligands in hybrid framework structures can act as templates or structure-directing agents, and they can also coordinate with different metal centers to generate various molecular structures to 3D hybrid metal phosphonate frameworks. − ,− Among various N-containing auxiliary ligands, pyrazine-based metal phosphonate hybrid structures are very less explored until date. − The diverse alignment of the pyrazine ligand, which often binds with different metal centers, as well as the flexible coordination of phosphonate moieties not only provides new metal phosphonate architectures but also offers a versatile platform for designing active electrocatalysts to promote water-splitting reactions.…”