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Chromium(iii) complexes of chelating diphosphines, with PNP or PCNCP backbones, are excellent catalysts for ethylene tetra- and/or trimerisations. A missing link within this ligand series are unsymmetric chelating diphosphines based on a PCNP scaffold. New bidentate PCNP ligands of the type Ph 2 PCH 2 N(R)PPh 2 (R = 1-naphthyl or 5-quinoline groups, 2a-d) have been synthesised and shown to be extremely effective ligands for ethylene tri-/tetramerisations. Three representative tetracarbonyl Cr 0 complexes bearing a single PN(R)P (5), PCN(R)P (6), or PCN(R)CP (7) diphosphine (R = 1-naphthyl) have been prepared from Cr(CO) 4 (η 4 -nbd) (nbd = norbornadiene). Furthermore we report a single crystal X-ray diffraction study of these compounds and discuss their structural parameters.

The diphenyl-phosphine groups in the title compound, C(29)H(31)NP(2), are staggered relative to the PNP backbone. The N atom adopts an almost planar geometry with the two P atoms and the C atom attached to it, in order to accommodate the steric bulk of the phenyl groups and the alkyl group. Three C atoms of the 1,2-dimethylpropylamine group are disordered over two positions in a 9:1 ratio. The mol-ecules pack diagonally in the unit cell across the ac plane in a head-to-tail fashion.

The origin of cancer health disparities and mortality in Arkansas is multifactorial. In response to a cooperative agreement with the National Cancer Institute's Center to Reduce Cancer Health Disparities, the Arkansas Special Populations Access Network (ASPAN) was developed to reduce these disparities. ASPAN's partnership with local primary care physicians of the Arkansas Medical, Dental, and Pharmaceutical Association through the Cancer Education Awareness Program is the focus of this article. A quasi-experimental intervention, the Community Cancer Education Awareness Program, was employed that included 1) physician education to increase awareness of risk factors and cancer screening; and 2) patient education to increase screening, and 3) patient-generated screening questionnaires to prompt discussion of cancer risk and screening recommendations between patients and physicians. Two urban and 2 rural clinics were targeted during a 12-month period with interval intervention assessments. Baseline review of records (n = 200) from patients >/=40 were utilized to assess the rate of breast, prostate, and colorectal screenings among clinics. For the patient education intervention, patients (n = 120) were interviewed via a 34-item assessment. Physician awareness of cancer risk factors and screening recommendations significantly increased. Statistically significant increases were seen for prostate (P = .028), breast (P = .036), and colorectal (P < .001) cancer screening across all 4 clinics. Patients' increased likelihood of cancer screenings was associated with knowledge about consumption of animal fat (P < .001), dietary fiber (P < .013), and mammograms (P < .001). Utilizing the physician as the central change agent, the ASPAN provider network successfully enhanced cancer screening awareness of minority physicians and their patients. Cancer 2006. (c) 2006 American Cancer Society.

The unprecedented selective tetramerisation of ethylene to 1-octene was recently reported. In the present study various mechanistic aspects of this novel transformation were investigated. The unusually high 1-octene selectivity in chromium-catalyzed ethylene tetramerisation reactions is caused by the unique extended metallacyclic mechanism in operation. Both 1-octene and higher 1-alkenes are formed by further ethylene insertion into a metallacycloheptane intermediate, whereas 1-hexene is formed by elimination from this species as in other reported trimerisation reactions. This is supported by deuterium labeling studies, analysis of the molar distribution of 1-alkene products, and identification of secondary co-oligomerization reaction products. In addition, the formation of two C6 cyclic products, methylenecyclopentane and methylcyclopentane, is discussed, and a bimetallic disproportionation mechanism to account for the available data is proposed.

D-Ribofuranose and D-arabinofuranose derivatives were converted in a few steps into their 1,4-diketone derivatives, which were pinacol cyclised under the action of SmI2 to form the corresponding chiral cyclobutanediol products. These products can potentially be applied to the synthesis of anti-viral agents, some of whose structures incorporate chiral cyclobutanediol moieties.

In situ prepared chromium catalysts containing bulky diphosphinoamine (PNP) ligands, upon activation with MAO, are extremely efficient catalysts for the trimerisation of ethylene to 1-hexene.

Chromium-based catalyst systems with polar-substituted diphosphinoamine ligands are selective for either trimerisation or tetramerisation of ethylene, depending on the position of the polar groups on the aryl rings.

Linear alpha-olefins, such as 1-hexene and 1-octene, are important comonomers in the production of linear low-density polyethylene (LLDPE). The conventional method of producing 1-hexene and 1-octene is by oligomerization of ethylene, which yields a wide spectrum of linear alpha-olefins (LAOs). While there exists several processes for producing 1-hexene via ethylene trimerization, a similar route for the selective production of 1-octene has so far been elusive. We now, for the first time, report an unprecedented ethylene tetramerization reaction that produces 1-octene in selectivities exceeding 70%, using an aluminoxane-activated chromium/((R2)2P)2NR1 catalyst system.