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5‐Coordinated methoxybenzylidene complexes M(=NAr)(=CH−C6H4−o‐OMe)(OtBuF3)2 (Ar=2,6‐iPr2C6H3; tBuF3=CMe2(CF3)) of Mo (1mMo) and W (1mW) were synthesized by cross‐metathesis from the corresponding neophylidene/neopentylidene precursors and o‐methoxystyrene. 1mMo and 1mW were grafted onto the surface of silica partially dehydroxylated at 700 °C to give well‐defined silica‐supported alkylidenes (≡SiO)M(=NAr)(=CH−C6H4−o‐OMe)(OtBuF3) (M=Mo (1Mo), W (1W)). Supported methoxybenzylidene complexes were tested in metathesis of cis‐4‐nonene, 1‐nonene, and ethyl oleate, and compared to their molecular precursors and supported classical analogs (≡SiO)M(=NAr)(=CHCMe2R)(OtBuF3) (M=Mo, R=Ph (2Mo), M=W, R=Me (2W)). Both grafted complexes 1Mo and 1W show significantly better performance as compared to their molecular precursors 1mMo and 1mW but are less efficient than the classical 4‐coordinated alkylidenes 2Mo and 2W. Noteworthy, both 1Mo and 1W can reach equilibrium conversion in metathesis of cis‐4‐nonene at catalyst loadings as low as 50 ppm. [ABSTRACT FROM AUTHOR]

Glass‐ceramics are multi‐phase materials that are comprised of one amorphous phase and at least one crystalline phase. Their versatile performance and properties can be engineered by alterations of the three fundamental steps – formulation and production of the amorphous base glass, nucleation, and crystallization. Efforts have been made on syntheses of glass‐ceramics with different components, yet little is known about the details of nucleation and crystallization processes that are essential for tailoring glass‐ceramic properties. Herein, we investigate the nucleation and crystallization mechanisms of a multi‐component, that is SiO2‐Al2O3‐CaO‐Li2O‐K2O‐P2O5‐F, glass‐ceramic system by a combined use of powder X‐ray diffraction (pXRD), solid‐state nuclear magnetic resonance (NMR), and electron microscopic (EM) techniques. The role of P2O5 in the nucleation and crystallization processes is particularly studied. We show that the formation of lithium silicate crystals being independent of the P2O5‐associated crystals, and the separation of P2O5 phases into individual growth domains of lithium orthophosphate and fluorapatite. We also observe the non‐uniform distribution of fluorapatite particles that explains the opalescence effect of this glass‐ceramic. [ABSTRACT FROM AUTHOR]