STA-27, a porous Lewis acidic scandium MOF with an unexpected topology type prepared with 2,3,5,6-tetrakis(4-carboxyphenyl)pyrazine (dataset)

A porous scandium MOF denoted STA-27 (St Andrews Porous Material-27) has been synthesized solvothermally using 2,3,5,6-tetrakis(4-carboxyphenyl)pyrazine (TCPP) as the tetratopic carboxylate linker. STA-27 possesses a unique scandium based 1D rod secondary building unit (SBU) comprising corner-sharing scandium dimers connected via carboxylate groups from the TCPP. Under similar synthesis conditions the smaller Al3+ and Ga3+ cations give a predictable MOF topology type based on chains of corner-sharing MO4(OH)2 octahedra. After activation under mild conditions STA-27 is an active Lewis acidic catalyst, while heating at elevated temperatures results in rupturing of the Sc-O-Sc linkages and a phase transition to a different topological type.