Growing ZIF-8 Seeds on Charged COF Substrates toward Efficient Propylene-Propane Separation Membranes.

We report a covalent organic framework (COF) induced seeding strategy to fabricate metal-organic framework (MOF) membranes. Contrary to graphene oxide nuclei-depositing substrate, COF substrate has uniform pore size, high microporosity and abundant functional groups. We designed a series of charged COF nanosheets to induce the formation of ZIF-8@COF nanosheet seeds with high aspect ratio over 150, which were readily processed into a compact and uniform seed layer. The resulting ZIF-8 membranes with thickness down to 100 nm exhibit an ultrahigh C3 H6 /C3 H8 separation performance and superior long-term stability. Our strategy is also validated by fabricating ultrathin ZIF-67 and UiO-66 membranes.

Synthesis and structural characterization of 1,2,4-diazaphospholide complexes of titanium(IV) and titanium(III).

Two 1,2,4-diazaphospholide complexes of [Ti(η(2)-3,5-Ph(2)dp)(4)] and paramagnetic [Ti(η(2)-3,5-tBu(2)dp)(3)] were prepared by the reaction of tetrakis(dimethylamido)titanium(IV) with 3,5-diphenyl-1,2,4-diazaphophole, H[3,5-Ph(2)dp], or by the treatment of 3,5-tert-butyl-1,2,4-diazaphopholide potassium, K[3,5-tBu(2)dp], with titanium trichloride. Complexes can be viewed as the core of P(σ(2)λ(3))-functionalized metallodendrimers, in which the metal atoms are exclusively η(2)(N,N) bonding to the 1,2,4-diazaphospholides while P atoms (σ(2)λ(3)) with electron lone pairs are located on the periphery of the molecules.