Isolation of ethynyltriethylammonium bromide and chloride was achieved in the reaction between triethylamine and the respective monohaloacetylenes (1) in dry ether. The kinetics of the same reaction was studied in dimethylformamide (DMF). Because of the ready decomposition of 1 in air, a conductometric method of following the formation of 2 in a closed, oxygen-free system was devised. This conductance method could be used for kinetics in the range [HC=CBr]" = 0.002-0.004 M and gave consistent rates for [(C2H5)3N]o < 0AM.

The enhanced bathochromic shifts attributable to type B hydrogen bonding by 4-nitroaniline (1) to HBA (hydrogen bond acceptor) solvents are more than twice as large as comparable solvatochromic displacements for N-methyl-, -ethyl-, and JV-isopropyl-4-nitroaniline (2a-c). Solvatochromic dilution experiments show the VF50 values in Me2SO/CCl4 (volume fractions of HBA solvent at which the hydrogen bonded complex is half dissociated) to be 0.0057 for 2b and 0.0063 for 1. It is concluded that the ratio of the spectral effects of the first and second hydrogen bonds of 1 is l/(0.93 ± 0.13), whereas hydrogen bond strengths are in a ratio of about 1.5:1.

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Enhanced red shifts ( -AAvmux) of the [ +R2N==Cr-*-C4=NC>2-] band in the ultraviolet spectrum for 4-nitroaniline relative to A,V-diethyl-4-nitroaniline on going from cyclohexane to oxygen-base solvents are attributable primarily to the bathochromic influence of hydrogen bonding by 4-nitroaniline to these solvents and are considered to be measures of relative solvent-proton affinity. Such AA¡/max values show good correlation with * values of R in a series of ROH solvents which includes water. Good correlations between -AAvmax and * values are also obtained from the following pairs: Ar-ethyl-4-nitroaniline/iV,Ar-diethyl-4-nitroaniline and 4-nitrophenol/4nitroanisole. These probes of relative solvent-proton affinity do not, however, show ethers to be better hydrogen-bond acceptors than alcohols, probably because of steric factors.

From the relative absorption intensities of two characteristic bands in the ultraviolet spectra of 2.4.6-trinitroaniline and its derivatives, it is possible to estimate angles of twist from planarity of the 2-, 4-, and 6-nitro-substituents.