pH effect on the assembly of metal–organic architectures

Abstract

Crystal engineering is the rational design and assembly of solid-state structures with desired properties via the manipulation of intermolecular interactions, hydrogen bonding and metalligand complexation in particular. The heart of crystal engineering is to control the ordering of the building blocks, be they molecular or ionic, toward a specific disposition in the solid state. The relatively weak strength of intermolecular forces with respect to chemical bonding renders the assembly of supramolecular constructs sensitive to external physical and chemical stimuli, with pH condition of the reaction mixture being arguably the most prominent and extensively observed. Using selected examples of constructing metal-organic architectures from recent literature, the influences of pH on the specific ligand forms, the generation and metal coordination of hydroxo ligands, ligand transformation promoted by pH condition changes, pH-dependent kinetics of crystallization of a number of metal-organic architectures are discussed. Current status of this particular areas of research in supramolecular chemistry and materials are assessed and personal perspectives as to toward what directions should this chemistry head are elaborated.

Solvothermal synthesis, structures, and magnetic properties of NiII compounds directed by N,N′-bridging auxiliary ligands

“…However, it remains a long-term challenge. Any changes in ligand geometry, in ligand substituents or synthetic conditions may impose a strong influence on the final structures [16,17]. To get designed and predictable frameworks and properties, researchers are being focused on constructing novel coordination polymers by choosing versatile organic ligands and functional metal ions.…”

Crystal structure of a diaqua-bis(3,5-di(1H-imidazol-1-yl)pyridine-κN)-bis(2-(4-carboxy-phenyl)acetato-κO]manganese(II), C40H36MnN10O10

“…Effective synthetic strategies of MOCPs with expected structures and properties should take many factors into account, such as the properties of the metal ions, organic ligands, solvent, temperature, pH value and the crystallization procedure [6,7]. And for this purpose, numerous multi-functional carboxylate ligands have been designed, [8][9][10].…”

Group IIB metal complexes with a multidentate N-donor tecton 3,4-bis(2-pyridyl)-5-(3-pyridyl)-1,2,4-triazole: Metal-directed assemblies, crystal structures and properties

“…It has been well known that such coordination assemblies are basically dominated by organic ligands and metal ions [5], and significantly, may also be controlled by other reaction parameters such as pH value [6], solvent [7] and counterion [8]. In this context, large numbers of group IIB metal complexes have been prepared and explored, because of not only their diverse structures but also their particular properties [9].…”