Three novel 3D (3,8)-connected metal–organic frameworks constructed from flexible-rigid mixed ligands

Three novel 3D (3,8)-connected networks, namely [Cd2(L1)2(1,3-bdc)] 1, [Cd2(L2)2(1,4-bdc)]·3H2O 2 and [Cd3(L3)2(1,3-bdc)2] 3, where L1 = 3,5-bis(pyridin-4-ylmethoxy)benzoic acid, L2 = 3,4-bis(pyridin-4-ylmethoxy)benzoic acid, L3 = 3,5-bis(pyridin-3-ylmethoxy)benzoic acid, bdc = benzenedicarboxylate, have been synthesized hydrothermally and characterized. Complex 1 exhibits a twofold interpenetrating network constructed from Cd2-based secondary building units (SBUs) [Cd2(CO2)2O2N4] with (42·6)2(44·622·82) topology. Complex 2 is constructed from Cd2-based SBUs [Cd2(CO2)4N4] with (43)2(46·618·84) topology. The structure of 3 is based on linear Cd3-based SBUs [Cd3(CO2)6N2] with a Schläfli symbol (42·5)2(44·56·610·75·82·9). In addition, X-ray powder diffraction (XRPD) and luminescent properties of 1–3 were also investigated in detail.