Synthesis and crystal structures of 5,5'-(propane-2,2-di-yl)bis-(2-hy-droxy-benzaldehyde) and 5,5'-(propane-2,2-di-yl)bis-(2-hy-droxy-isophthalaldehyde).

The title compounds 5,5'-(propane-2,2-di-yl)bis-(2-hy-droxy-benzaldehyde), CHO, (), and 5,5'-(propane-2,2-di-yl)bis-(2-hy-droxy-isophthalaldehyde), CHO, (), crystallize with one mol-ecule in the asymmetric unit. In mol-ecule (), a >C(CH) group bridges two nearly planar salicyl-aldehyde groups [r.m.

Synthesis and crystal structures of (2)-1,4-bis-(4-chloro-phen-yl)but-2-ene-1,4-dione and (2)-1,4-bis-(4-bromo-phen-yl)but-2-ene-1,4-dione.

The mol-ecular structure of (2)-1,4-bis-(4-chloro-phen-yl)but-2-ene-1,4-dione [CHClO, ()] is composed of two -chlorophenyl rings, each bonded on opposite ends to a near planar 1,4- enedione moiety [-C(=O)-CH=CH-(C=O)-] [r.m.s.

A Ring-Opening Metathesis Polymerization Catalyst That Exhibits Redox-Switchable Monomer Selectivities.

A ring-opening metathesis polymerization catalyst supported by a redox-active N-heterocyclic carbene was synthesized and found to undergo reversible reduction. In its neutral form, the catalyst polymerized 1,5-cis,cis-cyclooctadiene at a higher rate than that of a norbornene derivative; however, upon reduction, the selectivity was found to reverse. Utilizing this oxidation state dependent selectivity, a series of copolymers with controlled compositions, microstructures, and physical properties were prepared by redox-switching the catalyst over the course of a series of polymerization reactions.

Halides with Fifteen Aliphatic C-H···Anion Interaction Sites.

Since the aliphatic C-H···anion interaction is relatively weak, anion binding using hydrophobic aliphatic C-H (Cali-H) groups has generally been considered not possible without the presence of additional binding sites that contain stronger interactions to the anion. Herein, we report X-ray structures of organic crystals that feature a chloride anion bound exclusively by hydrophobic Cali-H groups. An X-ray structure of imidazolium-based scaffolds using Cali-H···A(-) interactions (A(-) = anion) shows that a halide anion is directly interacting with fifteen Cali-H groups (involving eleven hydrogen bonds, two bidentate hydrogen-bond-type binding interactions and two weakly hydrogen-bonding-like binding interactions).

A cyclic (alkyl)(amido)carbene: synthesis, study and utility as a desulfurization reagent.

The synthesis and study of a cyclic (alkyl)(amido)carbene is described. The carbene was found to undergo C-H insertion at low temperatures, formed cyclopropenes upon exposure to alkynes, and facilitated desulfurization reactions. Spectroscopic studies revealed that the carbene is strongly π-accepting but retains a complimentary degree of σ-donating properties.