The doping of [Al(OH)L]n [L = 1,4‐benzenedicarboxylate (bdc) or 1,4‐naphthalenedicarboxylate (ndc)] with vanadium ions yields crystalline porous mixed‐metal solid‐solution metal–organic frameworks (MOFs) of general formula [(AlOH)1–x(VO)xL]n (x can be varied in the whole range from 0 to 1). Several characterization methods, including powder X‐ray diffraction (PXRD), electron paramagnetic resonance (EPR), solid‐state NMR and FTIR spectroscopy, strongly support the effective incorporation of vanadium cations. The Al/V‐doped MOFs are isostructural to the parent monometallic MOFs and show a characteristic uniform dependence of the cell parameters on the metal ratios. Detailed spectroscopic investigation provided evidence that the introduced species are fairly well ordered. Interestingly, for low amounts of doped vanadium for both activated and as‐synthesized Al/V phases, the EPR results revealed the presence of vanadyl units as local defects in pseudo‐octahedral or square‐pyramidal environments, which are different from those in the parent MIL‐47(V). This observation matches the nonlinear response of the adsorption properties on variation of the composition. Remarkably, the presence of such mixed Al/V chains strongly affects the breathing behaviour of the materials. Both CO2 sorption and in situ PXRD studies validated a gradual change from highly flexible (with easily induced phase transitions) to totally rigid structures upon increasing vanadium content.

Spectroscopic techniques are a powerful tool for structure determination, especially if single-crystal material is unavailable. (113)Cd solid-state NMR is easy to measure and is a highly sensitive probe because the coordination number, the nature of coordinating groups, and the geometry around the metal ion is reflected by the isotropic chemical shift and the chemical-shift anisotropy. Here, a detailed investigation of a series of 27 cadmium coordination polymers by (113)Cd solid-state NMR is reported. The results obtained demonstrate that (113)Cd NMR is a very sensitive tool to characterize the cadmium environment, also in non-single-crystal materials. Furthermore, this method allows the observation of guest-induced phase transitions supporting understanding of the structural flexibility of coordination frameworks.

The newly synthesized Zn(4)O-based MOF (3)(∞)[Zn(4)(μ(4)-O){(Metrz-pba)(2)mPh}(3)]·8 DMF (1·8 DMF) of rare tungsten carbide (acs) topology exhibits a porosity of 43% and remarkably high thermal stability up to 430 °C. Single crystal X-ray structure analyses could be performed using as-synthesized as well as desolvated crystals. Besides the solvothermal synthesis of single crystals a scalable synthesis of microcrystalline material of the MOF is reported. Combined TG-MS and solid state NMR measurements reveal the presence of mobile DMF molecules in the pore system of the framework. Adsorption measurements confirm that the pore structure is fully accessible for nitrogen molecules at 77 K. The adsorptive pore volume of 0.41 cm(3) g(-1) correlates well with the pore volume of 0.43 cm(3) g(-1) estimated from the single crystal structure.

Synthesis and solid-state NMR characterization of two isomorphous series of zinc and cobalt coordination networks with 1,2,4-triazolyl benzoate ligands are reported. Both series * To whom correspondence should be addressed † Universität Leipzig, Fakultät für Physik und Geowissenschaften, Linnéstr.

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