MICROWAVE SPECTRA, DIPOLE MOMENTS AND EQUILIBRIUM STRUCTURES OF (Z)-PENT-2-ENE-4-YNENITRILE AND MALEONITRILE

Author Institution: University Of Michigan; Department Of Chemistry, University Of Michigan; Department Of Chemistry, University Of Wisconsin; Department Of Chemistry, University Of Wisconsin; Department Of Chemistry, University Of Texas At AustinThe rotational spectra of 10 isotopomers of (Z)-pent-2-ene-4-ynenitrile and 6 isotopomers of maleonitrile were measured using pulsed supersonic nozzle, Fourier-transform microwave spectroscopy. The ground state rotational constants in each case were adjusted for vibration-rotation interaction effects using ab initio force field calculations. The resulting equilibrium rotational constants were in very good agreement with those from high level ab initio calculations. Stark effect measurements allowed dipole moments of 3.53(3) D and 5.32(6) D, respectively to be determined for the two molecules. The equilibrium structural parameters and comparisons with calculated values will be presented

Characterization of fulvic acid fractions of dissolved organic matter during ice-out in a hyper-eutrophic, coastal pond in Antarctica

Dissolved humic material (HDOM) is ubiquitous to all natural waters and its source material influences its chemical structure, reactivity, and bioavailability. While terrestrially derived HDOM reference materials distributed by the International Humic Substances Society (IHSS) have been readily available to engineering and scientific communities, a microbially derived reference HDOM was not, despite the well-characterized differences in the chemistry and reactivity of HDOM derived from terrestrial versus microbial sources. To address this gap, we collected a microbial reference fulvic acid from Pony Lake (PLFA) for distribution through the IHSS. Pony Lake is a saline coastal pond on Ross Island, Antarctica, where the landscape is devoid of terrestrial plants. Sample collection occurred over a 17-day period in the summer season at Pony Lake. During this time, the dissolved organic carbon (DOC) concentrations increased nearly two-fold, and the fulvic acid fraction (collected using the XAD-8 method) accounted for 14.6% of the DOC. During the re-concentration and desalting procedures we isolated two other chemically distinct fulvic acid fractions: (1) PLFA-2, which was high in carbohydrates and (2) PLFA-CER, which was high in nitrogen. The chemical characteristics (elemental analysis, optical characterization with UV-vis and fluorescence spectroscopy, and C-13 NMR spectroscopy) of the three fulvic acid fractions helped to explain their behavior during isolation