Rational synthesis and dimensionality tuning of MOFs from preorganized heterometallic molecular complexes

Abstract

Rational synthesis of a series of new heterometallic MOFs was carried out by the judicious choice of the corresponding pivalate complexes [Li₂M₂(piv)₆(py)₂] (M = Zn²⁺, Co²⁺, piv⁻ = pivalate anion and py = pyridine) as a source of secondary building units, {LiM(O₂CR)₃} and an organic tricarboxylate linker as a node defining the dimensionality of the framework by the orientation of the carboxylic group in or out of the central aromatic ring plane. Thus the trimesate (btc³⁻) linker results in 3D srs topology frameworks with intersecting systems or isolated channels, and 1,3,5-benzenetribenzoate (btb³⁻) results in layered hcb isostructural compounds additionally stabilized with H–π interactions between the layers. The layered compounds demonstrate a permanent porosity with a BET surface area of up to 688 m²·g⁻¹ with the possibility of selective gas adsorption (CO₂ over N₂ and CH₄). Zn-Based coordination polymers show notable color changes and drastic (up to 30 times) quenching of luminescence upon inclusion of different nitroaromatics.