Iodine cyanide basicity

Iodoacetylenes as well as iodine cyanide are soft Lewis acids (Laurence etal. 1981), which interact with basic solvents yielding characteristic wavenumber shifts Av (C-I) (e g., for ICN relative to the wavenumber in CCI4 solutions). These shifts differ for soft solvents, with sulfur or selenium donor atoms or n systems, and hard solvents, with oxygen or nitrogen donor atoms. However, these authors have not converted this observation and their data to a solvent softness scale. In fact, if prorated values of A v (O-H), for phenol, relative to CCI4 solutions, see B0 H above, representing the hard basicity of the solvents, are subtracted, the remainder measures the solvent softness. Quantitatively,... 

Studies of the X—Y stretching vibration in complexes of XY with different Lewis bases reveal a characteristic decrease in frequency as the strength of the base increases [35, 36]. Hence spectroscopic scales of halogen-bond basicity can be built [37] in the manner described in Chapter 4 for the O—H stretching vibration in hydrogen-bonded complexes. Spectroscopic scales based on the shifts of the v(I—I) band of diiodine at 211 cm , the u(I—Cl) band of iodine monochloride at 376 cm and the v(I—CN) band of iodine cyanide at 485 cm will be presented and compared with thermodynamic basicity and/or affinity scales. 

This chapter is intended to provide detailed examples of the spectroscopic and thermodynamic determination of most Lewis basicity scales presented in the previous chapters, namely the BF3 affinity scale, 4-fluorophenol basicity and affinity scales, the methanol infrared (IR) shift scale, the 4-nitrophenol solvatochromic shift scale, diiodine basicity and affinity scales, the iodine cyanide IR shift scale, the diiodine blue shift scale and the lithium cation basicity scale. With these examples, it is hoped that professional chemists, and also students of physicochemical sciences, will be able to supplement the scales for the molecules in which they are interested. 

Hydrazine is typically oxidized with oxygen, air, or hydrogen peroxide in basic media with or without a catalytic amount of copper(II) ions [23 to 28]. Other oxidants used are mercuric oxide [24], iron(lll) cyanide [24, 29], iodine [30], iodate [26], dichromate [26], or selenium [31]. 

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