Infrared spectra boron compounds

The compound is soluble in acetone, chloroform, methylene chloride, and nitromethane. It is insoluble in alkanes and cold water and stable toward water in the cold but gives an acidic solution when boiled with water. The infrared spectrum shows a single band at 2510 cm.-1, about 50 cm.-1 higher wave number than in the monobromo compound. The nB spectrum gives a doublet 18.9 p.p.m. upfield from trimethyl borate Jb-h = 155 Hz. The proton spectrum in methylene chloride shows a sharp singlet at 2.91 p.p.m. downfield from external tetramethylsilane and 0.20 p.p.m. farther downfield than the monobromo compound. Boron-attached hydrogens are not detectable. 

The vapor pressure of /i-[(CH3)2N]B2H5 obeys the relationship log P = 2158.56/T + 1.75 log T - 0.008061T + 7.518831 (101 torr at 0°). The gas-phase infrared spectrum has been reported in detail.5 The compound is a useful intermediate in the synthesis of other boron nitrogen compounds, including those containing NBNB6 and PBNB7 chains, and Na[(CH3)2-N(BH3)2].8 The compound can be stored at 25° for months in sealed, evacuated Pyrex tubes. It is soluble in ethers and aromatic hydrocarbons, but is attacked by protic solvents. 

The infrared spectrum of the compound shows the boron-nitrogen ring frequency at 1392 cm.-"1. Its XH n.m.r. spectrum shows a sharp singlet at —3.1 p.p.m. (TMS standard). 

When manganese vapour and a mixture of nitric oxide, trifluorophosphine and boron trifluoride are co-condensed the compound Mn(PF3)(NO)3 is produced [280]. Co-condensation of nickel and carbon dioxide results in the formation of some nickel tetracarbonyl [280]. Burdett and Turner [298] showed that co-condensation of nickel and nitrogen at 20°K resulted in a nickel—nitrogen complex. Moskovits and Ozin [299] have recently repeated the experiment and have shown from the infrared spectrum of the matrix that the major product is NiN2, with the nickel atom bonded to the end of the nitrogen molecule. 

The presence in the molecule of two kinds of boron-hydrogen bond is indicated both by its Raman spectrum and by the chemical evidence that four only of the hydrogen atoms are replaceable by methyl groups. Electron diffraction leads to B-H 1.19 A, B-H, 1.33 A, B-B 1.77 A, ZHBH 121.5° and Z.H, BHjj 100°. Raman and infrared spectra of the tetramethyl compound suggest an absence of terminal hydrogen atoms, and electron diffraction shows the four carbon atoms and two boron atoms to be coplanar. 

Infrared spectroscopy has assisted in the determination of the structure of certain complex inorganic molecules, uch as the metal carbonyls, inter-halogen compounds, boron hydrides, and nitrogen oxides. The practice used has been to compare the observed spectrum with the spectrum expected for an assumed model on the basis... 

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