[M/(_2(/mu/)-OH)${}_2$(DHBQ)${}_3$] (M = Zr, Hf). Two new isostructural coordination polymers based on the unique M${}_2$O${}_{14}$ Inorganic building unit and 2,5-dioxido-p-benzoquinone as linker molecule

Two new isostructural porous coordination polymers (CPs) were obtained under solvothermal reaction conditions using 2,5-dihydroxy-p-benzoquinone (H${}_2$ DHBQ) or 1,2,4,5-tetrahydroxybenzene (H${}_4$ THB) as linker molecule and Zr${}^{4+}$ or Hf${}^{4+}$ salts. Highly crystalline compounds with composition [M/(_2(/mu/)-OH)${}_2$(DHBQ)${}_3$]·xH${}_2$O (M = Zr${}^{4+}$ or Hf${}^{4+}$, x = 0-3.6/3.3) were found in a wide temperature range (120-200 °C) and a reaction time of 70 h. The crystal structures were determined ab initio from powder X-ray diffraction data and the oxidation state of the linker was confirmed spectroscopically. The dinuclear inorganic building unit M${}_2$O${}_{14}$ is new for Zr- and Hf-CPs. For both compounds a full characterization was carried out, i.e. crystal structure determination, spectroscopic measurements, elemental- and thermogravimetric analyses. [M/(_2(/mu/)-OH)${}_2$(DHBQ)${}_3$] (M = Zr${}^{4+}$ or Hf${}^{4+}$) is stable up to 250 and 220 °C, respectively. Water sorption measurements proofed an uptake of 3.6 mol H${}_2$O per mol and 3.3 mol H${}_2$O per mol, respectively. (© 2020 The Authors. Zeitschrift für anorganische und allgemeine Chemie published by Wiley‐VCH GmbH)