A highly connected (5,5,18)-c trinodal MOF with a 3D diamondoid inorganic connectivity: tunable luminescence and white-light emission

A new heterometallic MOF, namely [Cd2K4(2,3-PDC)(4)] (1) (2,3-H2PDC - 2,3-pyridine dicarboxylic acid), has been successfully synthesized from Cd2+ and K+ salts with 2,3-H2PDC under the solvothermal conditions. Single crystal X-ray diffraction studies reveal that 1 is a three-dimensional, highly connected trinodal (5,5,18)-c net. Compound 1 features a rare 3D diamondoid Cd(II)-K(I) inorganic connectivity constructed by a {Cd2K4} cluster. The K+ ion in the structure functions not only as a charge balancer but also as a connector in the construction of MOF. Tunable blue-green to white luminescence of 1 was achieved by variation of the excitation wavelength and the inclusion amount of Eu3+ ions in the host framework of 1.