Magnetic effects of lanthanide bonding Lanthanide coordination compounds have attracted attention for their persistent magnetic properties near liquid nitrogen temperature, well above alternative molecular magnets. Gould et al . report that introducing metal-metal bonding can enhance coercivity. Reduction of iodide-bridged terbium or dysprosium dimers resulted in a single electron bond between the metals, which enforced alignment of the other valence electrons. The resultant coercive fields exceeded 14 tesla below 50 and 60 kelvin for the terbium and dysprosium compounds, respectively. —JSY

Synthesis of 1−3, IR spectroscopy, UV−vis spectroscopy, crystallographic data, magnetic characterization, and DFT calculations (PDF) Data for C 40 H 70 Tb, BC 24 F 20 (CIF) Data for C 40 H 70 Dy (CIF) Data for C 40 H 70 Tb (CIF) ■ AUTHOR INFORMATION

Subtle changes in ligand substitution result in substantial changes in molecular structure and magnetic properties in a series of dysprosium(iii) metallocenium salts.

High-density fuel candidates have been synthesized in up to 90% yield from β-pinene, a renewable strained bicyclic compound derived from wood and plant sources. The process is based on the heterogeneous acidic catalysts Montmorillonite-K10 and Nafion, which promote selective isomerization and dimerization of pinenes under moderate conditions (100°C and atmospheric pressure). Montmorillonite-K10 was shown to be a highly active catalyst for dimerization but was also active in the ring opening of β-pinene followed by dehydrogenation to produce p-cymene, which limited the yield of the dimer to ca. 75%. Nafion was capable of producing dimers in up to 90% yield primarily through isomerization followed by dimerization. Amberlyst-15, a common industrial catalyst had very poor activity and conversion even at 150°C. The dimer mixtures were upgraded through hydrogenation over PtO 2 and fractional distillation. The synthesized fuels have a density of 0.94 g/cm 3 and a net volumetric heating value of 39.5 MJ/L (141 745 BTU/gallon). These values are nearly identical to those for the widely used tactical fuel JP-10 (primarily composed of exotetrahydrodicyclopentadiene), suggesting that these renewable fuels may have applications for rocket propulsion.

OVERVIEW: The development of innovative methods to efficiently convert biomass to fuels and industrial chemicals is one of the grand challenges of the current age. n-Butanol is a versatile and sustainable platform chemical that can be produced from a variety of waste biomass sources. The emergence of new technologies for the production of fuels and chemicals from butanol will allow it to be a significant component of a necessarily dynamic and multifaceted solution to the current global energy crisis.IMPACT: The production of butanol from biomass and its utilization as a precursor to a diverse set of fuel products has the potential to reduce petroleum use worldwide. In concert with other emerging renewable technologies, significant reductions in greenhouse gas emissions may be realized. The rapid incorporation of renewables into the world fuel supply may also help to offset predicted increases in transportation fuel prices as the supply of oil declines. APPLICATIONS: Recent work has shown that butanol is a potential gasoline replacement that can also be blended in significant quantities with conventional diesel fuel. These efforts have transitioned to research focused on the development of viable methods for the production of an array of oxygenated and fully saturated jet and diesel fuels from butanol. The technologies discussed in this paper will help drive the commercialization and utilization of a spectrum of butanol based sustainable fuels that can supplement and partially displace conventional petroleum derived fuels. Published

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Two cyanate ester resins and a polycarbonate thermoplastic have been synthesized from vanillin. The bisphenol precursors were prepared by both an electrochemical route as well as by a McMurry coupling reaction. 1,2-bis(4-cyanato-3-methoxyphenyl)ethene (6) had a high melting point of 237 °C and did not cure completely under a standard cure protocol. In contrast, the reduced version, 1,2-bis(4-cyanato-3-methoxyphenyl)ethane (7) melted at 190 °C and underwent complete cure to form a thermoset material with T g = 202 °C. 7 showed thermal stability up to 335 °C and decomposed via formation of phenolics and isocyanic acid. A polycarbonate was then synthesized from the reduced bisphenol by a transesterification reaction with diphenylcarbonate. The polymer had M n = 3588, M w /M n = 1.9, and a T g of 86 °C. TGA/FTIR data suggested that the polycarbonate decomposed via formation of benzodioxolanes with concomitant elimination of methane. The results show that vanillin is a useful precursor to both thermosetting resins and thermoplastics without significant modification.

A series of renewable bis(cyanate) esters have been prepared from bisphenols synthesized by condensation of 2-methoxy-4-methylphenol (creosol) with formaldehyde, acetaldehyde, and propionaldehyde. The cyanate esters have been fully characterized by infrared spectroscopy, (1)H and (13)C NMR spectroscopy, and single crystal X-ray diffraction. These compounds melt from 88 to 143 °C, while cured resins have glass transition temperatures from 219 to 248 °C, water uptake (96 h, 85 °C immersion) in the range of 2.05-3.21%, and wet glass transition temperatures from 174 to 193 °C. These properties suggest that creosol-derived cyanate esters may be useful for a wide variety of military and commercial applications. The cure chemistry of the cyanate esters has been studied with FTIR spectroscopy and differential scanning calorimetry. The results show that cyanate esters with more sterically demanding bridging groups cure more slowly, but also more completely than those with a bridging methylene group. In addition to the structural differences, the purity of the cyanate esters has a significant effect on both the cure chemistry and final Tg of the materials. In some cases, post-cure of the resins at 350 °C resulted in significant decomposition and off-gassing, but cure protocols that terminated at 250-300 °C generated void-free resin pucks without degradation. Thermogravimetric analysis revealed that cured resins were stable up to 400 °C and then rapidly degraded. TGA/FTIR and mass spectrometry results showed that the resins decomposed to phenols, isocyanic acid, and secondary decomposition products, including CO2. Char yields of cured resins under N2 ranged from 27 to 35%, while char yields in air ranged from 8 to 11%. These data suggest that resins of this type may potentially be recycled to parent phenols, creosol, and other alkylated creosols by pyrolysis in the presence of excess water vapor. The ability to synthesize these high temperature resins from a phenol (creosol) that can be derived from lignin, coupled with the potential to recycle the composites, provides a possible route to the production of sustainable, high-performance, thermosetting resins with reduced environmental impact.