John Ada K. Cha

Microporous chiral metal coordination polymers: hydrothermal synthesis, channel engineering and stability of lanthanide tartrates

L-Tartrate ions can endure hydrothermal conditions up to 160 degrees C to form the robust, enantiopure open-framework coordination polymers [Ln2(L-TAR)3(H2O)2]3H2O, 1; the addition of succinate results in formation of the related [Ln2(L-TAR)2(SUC)(H2O)2]5.5H2O, with larger channels than , whereas racemic D/L-tartrate gives the more condensed [Ln2(D/L-TAR)3(H2O)2], . TAR = [C4H4O6]2-.

Nanostructured magnetoceramics from hyperbranched polymer precursors

Abstract Controlled pyrolysis of a hyperbranched polysilyne, poly[1,1′-ferrocenylene(methyl)silyne] (1), at high temperature in inert atmosphere produces nonostructured ceramics (2) in ∼48–62% yields. The ceramic products 2 are characterized by SEM, XPS, EDX, XRD, and SQUID. It is found that the ceramics are electrically conductive and possess a mesoporous architecture. The iron contents of 2 estimated by EDX are 36–43%. The nanocrystals formed in the ceramics produced under nitrogen 2N are mainly α-Fe2O3 whereas those in the ceramics produced under argon 2A are mainly Fe3Si. When magnetized by an external field at room temperature, 2A exhibits a high saturation magnetization (Ms∼49 emu/g) and near-zero remanence and coercivity.

Construction strategies for new generation micro-porous solids

Approaches to the formation of three new types of micro-porous materials that complement zeolites will be discussed. In each case, whether metal coordination polymers, metal-linked ceramic oxide clusters, or new hybrids containing both coordination and ceramic components, engineering of the Secondary Building Unit (SBU) is of critical importance. Successful examples of these approaches include the first thermally stable 3-D micro-porous coordination polymer with chemical functionalizability [cu3(TMA)2(H2O)3]n, as well as a 3-D micro-porous cluster based material [V12B18O60H8Cd(en)(H2O)3]n.