For three-dimensional (3D) metal-organic frameworks (MOFs), the presence and nature of structural defects has been recognized as a key factor shaping the material's physical and chemical behavior. In this work, the formation of the "missing linker" defects has been addressed in the model biphenyl-4,4'-dicarboxylate (bpdc)-based Zr MOF, UiO-67. The defect showed strong dependence on the nature of the modulator acid used in the MOF synthesis; the defects, in turn, were found to correlate with the MOF physical and chemical properties. The dynamic nature of the Zr6 (node)-monocarboxylate bond showed promise in defect functionalization and "healing", including the formation of X-ray-quality "defect-free" UiO-67 single crystals. Chemical transformations at defect sites have also been explored. The study was also extended to the isoreticular UiO-66 and UiO-68' systems.

Through the use of cyclic beta-diketones as supporting ligands, the copper-catalyzed coupling of aryl iodides with aliphatic amines occurs at room temperature in as little as 1 h. These high reaction rates allow for the coupling of a wide range of aryl and heteroaryl iodides at room temperature. This method is highly tolerant of a number of reactive functional groups, including -Br and aromatic -NH2 as well as phenolic and aliphatic -OH. The high selectivity of the CuI-beta-diketone catalyst for aliphatic amines represents a useful complement to the palladium-based methods.

ABSTRACT:The use of the hypervalent iodine reagents in oxidative processes has become a staple in modern organic synthesis. Frequently, the reactivity of λ 3 iodanes is further enhanced by acids (Lewis or Brønsted). The origin of such activation, however, has remained elusive. Here, we use the common combination of PhI(OAc)2 with BF3·Et2O as model to fully explore this activation phenomenon. In addition to the spectroscopic assessment of the dynamic acid-base interaction, for the first time the putative PIDA·BF3 complex has been isolated and its structure determined by X-Ray diffraction. Consequences of such activation are discussed from a structural and electronic (DFT) points of views, including the origins of the enhanced reactivity.

Two complementary protocols for copper-catalyzed arylation of aminoalcohols were developed. Selective N-arylation was accomplished at room temperature using 2-isobutyrylcyclohexanone (a β-diketone) as supporting ligand, while selective O-arylation required the use of 3,4,7,8-tetramethylphenanthroline at 80−110 °C. Systematic examination of the reaction scope revealed that high levels of selectivity are achieved for a variety of substrates, provided that nonchelating (or weakly chelating) aminoalcohols are used. The generality of the method was highlighted by the synthesis, in a pairwise fashion, of a number of functionalized N- and O-arylated aminoalcohols.

We report an improved synthesis of 1,1′-diaminoferrocene, employing the reduction of 1,1′diazidoferrocene with H 2 -Pd/C, along with extensive characterization data for both compounds. Diaminoferrocene undergoes a reversible 1eoxidation in CH 3 CN at a potential of -602 mV vs Fc 0/+ , one of the most negative redox potentials for a ferrocene derivative. The chemical reversibility of this process was confirmed by isolation of the stable, 17-electron [Fc(NH 2 ) 2 ] + cation as PF 6 -, OTf -, and TCNEsalts. In the solid state, diaminoferrocene exists in two conformations: one with the NH 2 groups eclipsed, and the other with the NH 2 groups offset by one-fifth turn around the Cp-Fe-Cp axis. Diazidoferrocene, on the other hand, exhibits only the fully eclipsed conformation in the solid state. The Fe-Cp(centroid) vectors in the diazidoferrocene molecules are roughly aligned with the crystallographic c-axis, and the molecules form layers perpendicular to this axis. The compound is thermally unstable at elevated temperatures, and rapid heating above its melting point results in explosion.