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A weak absorption in this region has been reported by Andrews and Ozin for matrix-isolated Cr2.& Hot bands arising from ( v ,~ = 0) -(uh = n, n = 1-3) transitions to this excited state, shown at X5 magnification in Figure 1, yield we = 470 f 25 cm-I and w,x, = 20 f IO cm-' for the Cr2-anion.The X20 inset to Figure 1 displays an expansion of the spectrum near the ground-state transition. As shown on the right side of the inset, vibrational states of neutral Cr2 from v = 2 to v = 6 are observed 875, 1275, 1650, 1995, and 2305 cm-' (f15 cm-') above the 0-0 transition. These features are far more intense than would be expected on the basis of Franck-Condon factors for a direct photodetachment process. With the u = 1 level constrained to its literature value: the observed energies can be fit to within our experimental uncertainty to a Morse potential with we = 479 f 2 cm-l and w x = 13.5 f 1 .O cm-I. This anharmonicity constant is unusually large: w,x, values for all other neutral homonuclear first-row transition-metal dimers measured to date3 fall in the range 1-4 cm-I. Interestingly, the excellent Morse potential fit to vibrational levels up to v = 6 (0.3 eV above the zero-point level) extrapolates to a dissociation asymptote of only 0.5 eV, far below the true4 Cr2 bond energy (0,) of 1.44 f 0.05 eV. Thus, it is clear that the Cr2 ground-state potential energy curve strongly diverges from a Morse potential at higher energies.A weak vibrational progression of the neutral molecule comprising more than a dozen peaks is observed from 5100 to 6700 cm-l above the 0-0 transition, as shown on the left side of the X20 inset to Figure 1. Surprisingly, the peak spacings are only 130 f IO cm-I, and they exhibit no detectable anharmonicity. This

The environmentally friendly vegetable-oil-based waterborne polyurethane dispersions with very promising properties have been successfully synthesized without difficulty from a series of methoxylated soybean oil polyols (MSOLs) with different hydroxyl functionalities ranging from 2.4 to as high as 4.0. The resulting soybean-oil-based waterborne polyurethane (SPU) dispersions exhibit a uniform particle size, which increases from about 12 to 130 nm diameter with an increase in the OH functionality of the MSOL from 2.4 to 4.0 and decreases with increasing content of the hard segments. The structure and thermophysical and mechanical properties of the resulting SPU films, which contain 50-60 wt % MSOL as renewable resources, have been studied by Fourier transform infrared spectroscopy, differential scanning calorimetry, dynamic mechanical analysis, thermogravimetric analysis, transmission electron microscopy, and mechanical testing. The experimental results reveal that the functionality of the MSOLs and the hard segment content play a key role in controlling the structure and the thermophysical and mechanical properties of the SPU films. These novel films exhibit tensile stress-strain behavior ranging from elastomeric polymers to rigid plastics and possess Young's moduli ranging from 8 to 720 MPa, ultimate tensile strengths ranging from 4.2 to 21.5 MPa, and percent elongation at break values ranging from 16 to 280%. This work has addressed concerns regarding gelation and higher cross-linking caused by the high functionality of vegetable-oil-based polyols. This article reports novel environmentally friendly biobased SPU materials with promising applications as decorative and protective coatings.

The palladium-catalyzed coupling of 2-iodoaniline and the corresponding N-methyl, -acetyl, and -tosyl derivatives with a wide variety of internal alkynes provides 2,3-disubstituted indoles in good-to-excellent yields. The best results are obtained by employing an excess of the alkyne and a sodium or potassium acetate or carbonate base plus 1 equiv of either LiCl or n-Bu4NCl, occasionally adding 5 mol % PPh3. The yields with LiCl appear to be higher and more reproducible than those obtained with n-Bu4NCl. The process is quite general as far as the types of substituents which can be accommodated on the nitrogen of the aniline and the two ends of the alkyne triple bond. The reaction is quite regioselective, placing the aryl group of the aniline on the less sterically hindered end of the triple bond and the nitrogen moiety on the more sterically hindered end. This methodology readily affords 2-silylindoles, which can be easily protodesilylated, halogenated, or reacted with alkenes and Pd(OAc)2 to produce 3-substituted indoles, 2-haloindoles, or 2-(1-alkenyl)indoles, respectively. The presence of alcohol groups in the alkyne seems to have a particularly strong directing effect, perhaps due to coordination with palladium. This catalytic process apparently involves arylpalladium formation, regioselective addition to the C−C triple bond of the alkyne, and subsequent intramolecular palladium displacement.

Polyurethanes are among the most versatile polymers because of the wide range of monomers, particularly diols or polyols, that can be utilized in their synthesis. This Review focuses on the most recent advances made in the production of polyurethane materials from vegetable oils. Over the past several years, increasing attention has been given to the use of vegetable oils as feedstocks for polymeric materials, because they tend to be very inexpensive and available in large quantities. Using various procedures, a very broad range of polyols or diols and in some cases, poly- or diisocyanates, can be obtained from vegetable oils. The wide range of vegetable oil-based monomers leads to a wide variety of polyurethane materials, from flexible foams to ductile and rigid plastics. The thermal and mechanical properties of these vegetable oil-based polyurethanes are often comparable to or even better than those prepared from petroleum and are suitable for applications in various industries.