Synthesis of tervalent phosphorus esters in biphasic system using potassium phosphate as unique solid base

The synthesis of tervalent phosphorus esters continues to be a significant area of interest, much of it again directed toward the synthesis of phosphite ligands for metal‐catalyzed reactions. Typically, they were obtained through esterification of the corresponding phosphorus chlorides with the appropriate alcohols in the presence of an amine. In this paper, we present a new method for the synthesis of tervalent phosphorus esters, not yet mentioned in the literature, when potassium phosphate, as a unique base, is used in liquid–solid system. Symmetrical and unsymmetrical phosphites were obtained with good yields (65%–80%) using this method. The compounds were characterized by ³¹P NMR spectroscopy. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:360–364, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20438     

Structural Diversity in the Solid-State Structures of the Rubidium and Cesium Salts of 2,6-Dimesitylphenylphosphane

A coordination environment reminiscent of a paddle-wheel is exhibited by aryl groups about one of the two cesium ions in CsP(H)Dmp (Dmp=2,6-dimesitylphenyl; structure depicted on the right), which has now been synthesized and is found to exhibit Cs⁺{Cs₂[P(H)Dmp]₃}⁻ contact ion pairs in the solid state. In contrast, the analogous rubidium compound displays a Rb₄P₄ cube as the central structural motif.     

A 1,2,4‐diazaphospholane complex of rhodium

The crystal structure of a prospective olefin catalyst, namely {2‐[1‐acetyl‐5‐(2‐hydroxy­phenyl)‐4‐phenyl‐1,2,4‐di­aza­phospholan‐3‐yl]­phenyl acetate‐κP}chloro­(η⁴‐cyclo­octa‐1,5‐diene)rhodium(I) di­chloro­methane solvate, [RhCl(C₈H₁₂)(C₂₄H₂₃N₂O₄P)]·CH₂Cl₂, has been determined at 173 K. The five‐membered heterocycle of the phosphine ligand is in a slightly distorted twist conformation. An intramolecular N1—H1⃛Cl1 hydrogen bond contributes to the adopted conformation and may additionally participate in secondary interactions with substrates during catalysis.     

Artificial Cytoskeleton Assembly for Synthetic Cell Motility

Imitation of cellular processes in cell-like compartments is a current research focus in synthetic biology. Here, a method is introduced for assembling an artificial cytoskeleton in a synthetic cell model system based on a poly(N-isopropyl acrylamide) (PNIPAM) composite material. Toward this end, a PNIPAM-based composite material inside water-in-oil droplets that are stabilized with PNIPAM-functionalized and commercial fluorosurfactants is introduced. The temperature-mediated contraction/release behavior of the PNIPAM-based cytoskeleton is investigated. The reversibility of the PNIPAM transition is further examined in bulk and in droplets and it could be shown that hydrogel induced deformation could be used to controllably manipulate droplet-based synthetic cell motility upon temperature changes. It is envisioned that a combination of the presented artificial cytoskeleton with naturally occurring components might expand the bandwidth of the bottom-up synthetic biology.     

Heterogenization of metalorganic catalysts of olefin polymerization and evaluation of active site non-uniformity

Heterogenized activators - “support-H₂O/AlR₃” (where R=Me, iBu, support=montmorillonite, zeolite), synthesized directly on the support, form with metallocenes metal alkyl complexes highly active in olefin polymerization without the use of commercial methylaluminoxane (MAO). It was shown by the method of temperature programmed desorption with the application of mass-spectrometry (TPD-MS) that the aluminumorganic compound in support-H₂O/AlR₃ is in general similar to the structure of commercial MAO. The heterogenization of Zr-cenes on support-H₂O/AlR₃ is accompanied by the appearance of the energy non-uniformity of active sites. The activation energy of thermal destruction of active Zr-C bonds in the active sites of prepared catalysts changes in the range from 25 to 32 kcal/mol.