Scandium Metal–Organic Frameworks Containing Tetracarboxylate Linker Molecules: Synthesis, Structural Relationships, and Properties

Abstract

Three structurally related metal–organic frameworks (MOFs) of composition [Sc2(OH)2(L)] denoted Sc-CAU-9-PTCDA, Sc-CAU-9-TCPB, and Sc-CAU-9-H2TCPP containing the tetratopic linker molecules L1 4– = PTCDA4– (perylene-3,4,9,10-tetracarboxylate), L2 4– = TCPB4– (1,2,4,5-tetrakis­(4-carboxylatophenyl)-benzene), or L3 4– = H2TCPP4– (meso-tetra­(4-carboxylatophenyl)-porphyrin), have been obtained from solvothermal syntheses. The crystal structures were determined from powder X-ray diffraction data. The title compounds contain chains of trans corner-sharing [ScO6] octahedra, connected by the linker molecules to form three-dimensional networks. Depending on the shape of the respective linker the compounds crystallize in a frz or fry topology and with increasing size of the linker, an expansion of the framework and the formation of accessible channels are observed. The compounds were thoroughly characterized and exhibit high thermal stabilities up to 500 °C. Sc-CAU-9-TCPB and Sc-CAU-9-H2TCPP possess permanent porosity toward nitrogen with specific surface areas of asBET = 1350 m2/g and 650 m2/g, respectively. Luminescence measurements revealed a ligand-based emission in the blue spectral region for Sc-CAU-9-TCPB.

Metal–organic frameworks based on infinite secondary building units: recent progress and future outlooks

“…Besides, ISBU MOFs based on transition metals(III) have also been prevailingly studied. 21,31,[97][98][99][100] The recently emerged CAU-50 (ref. 99) [Sc 2 (FcDC) 3 ] was a 1D Sc-MOF constructed by reacting Sc(NO 3 ) 3 $5H 2 O with H 2 FcDC in a mixture of water and DMF at 95 C. CAU-50 crystallized in the orthorhombic crystal system and the Pnna space group, where the Sc 3+ center was attached by six carboxylate oxygens from different linkers (Fig.…”

Sc(iii)-Based metal–organic frameworks

“…The emission in the blue spectral region is due to the π* → π transition, a characteristic of organic molecules with a π-conjugated system. 72…”

Isoreticular chemistry of scandium analogues of the multicomponent metal–organic framework MIL-142

“…The surface area of MIL-142(Sc)-TATB is close to that of Sc-BTB (1865 m 2 g -1 and 0.70 cm 3 g -1 ) and relatively high when compared to known Sc MOFs. [52][53][54][55] Similarly, MIL-142(Sc)-TATB-NH 2 and MIL-142(Sc)-TATB-NO 2 showed BET surface areas and pore volumes of 1497 m 2 g -1 and 1468 m 2 g -1 and 0.57 cm 3 g -1 and 0.56 cm 3 g -1 , respectively (Figure 7B). The pore volumes of the parent and the functionalised MOFs are in fair agreement with the theoretical values (Table ST7).…”