Activation of Methyltrioxorhenium for Olefin Metathesis in a Zirconium-Based Metal–Organic Framework

Abstract

The zirconium nodes of the metal-organic framework (MOF) known as NU-1000 serve as competent supports for the activation of methyltrioxorhenium (MTO) toward olefin metathesis. Itself inactive for olefin metathesis, MTO becomes an active catalyst only when immobilized on the strongly acidic Lewis acid sites of dehydrated NU-1000. Uptake of MTO at the dehydrated secondary building units (SBUs) occurs rapidly and quantitatively to produce a catalyst active in both gas- and liquid-phase processes. These results demonstrate for the first time the utility of MOF SBUs for olefin metathesis, an academically and industrially relevant transformation.

Quo vadis niobium? Divergent coordination behavior of early-transition metals towards MOF-5

“…In the simulated spectrum ( Fig. S5 and S6 †), the hyperne interactions of both isotopes 35 Cl and 37 Cl (both I ¼ 3/2 nuclei) are included, and although they do not affect the alignment of the electron spins, these contribute to inhomogeneous line broadening. Notably, EPR signals obtained for Nb(IV)-MOF-5 and a toluene-MeCN frozen glass of NbCl 4 (-THF) 2 are similar, the aforementioned line broadening in the MOF notwithstanding (Fig.…”

“…In fact, the vast majority of examples that employ decoration of the SBUs with exogenous metals, rather than cation exchange, are reported for Zr-based materials. 16,[32][33][34][35] One recent example with transition metals in MOF-5 involved the installation of Fe(OH) 3 (H 2 O) 2 moieties bridging SBUs on two interpenetrated lattices, 36 with limited additional examples focusing on alkali metal decoration of MOF-5. [37][38][39][40][41][42] These ndings point to a previously unrecognized divergence in the reactivity of early and late transition metals with oxygen-based SBUs: whereas the late transition metals favor cation exchange reactivity (the Zr-based MOFs notwithstanding 43 ), we show here that the high-valent early transition metals prefer to adhere to the SBU rather than exchange within the SBU, presumably because of their extreme oxophilicity.…”

Imaging defects and their evolution in a metal–organic framework at sub-unit-cell resolution

“…Fine-tuning the defects and catalytic activities of UiO-66. The catalytic activity of UiO-66 has been correlated with the concentration of defects 38,39 . However, previous studies did not specify or distinguish the effects from missing-linker defects and missing-cluster defects [38][39][40][41] .…”

“…The catalytic activity of UiO-66 has been correlated with the concentration of defects 38,39 . However, previous studies did not specify or distinguish the effects from missing-linker defects and missing-cluster defects [38][39][40][41] . Here, the 1 day and 3 day UiO-66-D samples (hereafter denoted UiO-66-D(1d) and UiO-66-D(3d)) offer an opportunity to investigate the structure-activity relationships of this catalyst more definitively, because these samples have similar overall defect concentrations as indicated by the content of the defect-terminating formates (3.93 wt% and 3.65 wt%; Fig.…”

Engineering Metal–Organic Framework Catalysts for C−C and C−X Coupling Reactions: Advances in Reticular Approaches from 2014–2018

“…MOFs are generally used as solid supports for the activation of conventionalm etathesis catalysts such as methyltrioxorhenium (MOT) [173] and Hoveyda-Grubbs catalyst. Although Ru-MOFs are known, they have not been actively used as direct metathesis catalysts.…”