Uncovering the Structural Diversity of Y(III) Naphthalene-2,6-Dicarboxylate MOFs Through Coordination Modulation

Abstract

Metal-organic frameworks (MOFs)—network structures built from metal ions or clusters and connecting organic ligands—are typically synthesized by solvothermal self-assembly. For transition metal based MOFs, structural predictability is facilitated by control over coordination geometries and linker connectivity under the principles of isoreticular synthesis. For rare earth (RE) MOFs, coordination behavior is dominated by steric and electronic factors, leading to unpredictable structures, and poor control over self-assembly. Herein we show that coordination modulation—the addition of competing ligands into MOF syntheses—offers programmable access to six different Y(III) MOFs all connected by the same naphthalene-2,6-dicarboxylate ligand, despite controlled synthesis of multiple phases from the same metal-ligand combination often being challenging for rare earth MOFs. Four of the materials are isolable in bulk phase purity, three are amenable to rapid microwave synthesis, and the fluorescence sensing ability of one example toward metal cations is reported. The results show that a huge variety of structurally versatile MOFs can potentially be prepared from simple systems, and that coordination modulation is a powerful tool for systematic control of phase behavior in rare earth MOFs.

Adsorption Properties of Ce5(BDC)7.5(DMF)4 MOF

“…Ce-based MOFs have recently created interest in the scientific community. General features that can be drawn from looking at the current published literature are the following: (i) both Ce 3+ and Ce 4+ oxidation states can be used in the synthesis of MOFs [5][6][7][8][9]; (ii) synthetic conditions for Ce 3+ -containing MOFs tends to be harsher than Ce 4+ [5,6,10]; (iii) usually, Ce 4+ starting reagents may be reduced to Ce 3+ during the synthesis [11,12]; (iv) Ce 3+ materials more frequently have peculiar structures, while Ce 4+ tends to give rise to MOFs with the same structure as other 4+ cations (e.g., Zr 4+ or Hf 4+ ) [5][6][7]13,14]. Their thermal stability is generally lower than their Zr 4+ counterparts [7,8,14,15].…”

Variability in the Formation and Framework Polymorphism of Metal‐organic Frameworks based on Yttrium(III) and the Bifunctional Organic Linker 2,5‐Dihydroxyterephthalic Acid

“…[ 9i ] Because the hydroxy groups do not participate in metal coordination, other ditopic ligands can form compounds with the same network topology; for instance, it has been reported recently for naphthalene‐2,6‐dicarboxylate. [ 20 ]…”

Metal–Organic Frameworks Based on Group 3 and 4 Metals

“…Taking advantage of unique fluorescence properties of rare earth (RE) elements including yttrium and lanthanides, RE-MOFs have been applied in broad applications, such as light emitting, [72][73][74][75][76][77][78][79][80][81][82][83][84][85][86][87][88] sensing, [89][90][91][92][93][94] catalysis, [95][96][97] and imaging [98][99][100][101][102] (Figure 3).…”