Cyanide ion complexes of some aromatic nitro compounds

Abstract

The results are presented of spectral studies which characterize the complexes formed in deutcrochlorofornl solution between cyanide ion and 1,3,5-trinitrobenzene, 2,4,6-trinitrotoluene, and 2,4,6-trinitrobenzaldehyde.Canadian Journal of Chemistry, 46. 2759Chemistry, 46. (1968 The species formed in the interactioi~s of aromatic nitro compounds with anionic and neutral bases have been under study since 1902 (1) but it is only in the last several years that definitive evidence on their structures has become available, chiefly through 'H nuclear magnetic resonance (n.m.r.) studies (2-4).The n.m.r. work has confirmed Meisenheimer's (I) formulation of the structure of the stable adduct formed from 2,4,6-trinitroanisole and methoxide ion as a o-complex (I), but has also revealed that a metastable complex is first formed by addition of methoxide ion at C-3 (4). The structures of amine and acetonate adducts of various nitro compounds have similarly been elucidated (5,6). II H-C CN Ha CN Ha NO2 NO2In contrast, corresponding clarification with cyanide ion has not yet been obtained, even though the structures of cyanide ion complexes of aromatic nitro compounds have long been speculated upon (7). The visible spectrum of the 1,3,5-trinitrobei~zene -cyanide ion system showed changes with time but the initial spectrum was ascribed (8-10) to the o-complex (2). Recently such spectral changes were interpreted in terms of both charge-transfer and o-complex formation (1 l). A red cornplex formed from 1,3-dinitrobenzene and cyanide ion in dimethylformamide was formulated as a o-complex on the basis of its electronic and infrared spectra but no detectable i1.m.r. spectrum could be observed (1 1).We report here results of n.m.r. studies which establish the structure of the complex formed between cyanide ion and 1,3,5-trinitrobenzene. We also present the first evidence of o-complex formation by 2,4,6-trinitrotoluene and 2,4,6-trinitrobenzaldehyde with cyanide ion. Unexpectedly, the structures of these cyanide ion complexes are not equivalent.The resonance absorption of 1,3,5-trinitrobenzeile in deuterochlorofornl at -30" (singlet at 9.40 p.p.m. downfield relative to tetramethylsilane as external standard) undergoes characteristic changes on the addition of cyanide ion (introduced as the de~~terochloroform soluble tetraphenylarsonium salt). Thus a deuterochloroform solution of 1,3,5-trinitrobenzene (0.6 il4) and cyanide ion (0.4 M) shows, in addition to the parent trinitrobenzene peak now shifted to 9.36 p.

Preparation and properties of σ-bonded picryl platinum compounds

“…spectra of the platinum compounds than is found for other picryl compounds. Indeed, the positions of resonance are approximately the same as for the cyanide adducts of other picryl compounds (4). Again extensive delocalization of electron density from the metal atom into the ring is implied.…”

“…spectrum of the arsine derivative; no satellites due to coupling with the platinum could be observed. In both the triphenylarsine and triphenylphosphine complexes the resonance absorptions of the picryl hydrogens are considerably upfield compared to the resonance absorbances of the ring hydrogens in 1,3,5-trinitrobenzene (0.677) and I-R-2,4,6-trinitrobenzenes, where R = CH, (1.00~), OCH, (0.957) and COH (NOT) (4).…”

The Reaction of 2,4,6-Trinitrotoluene and 2,4,6-Trinitrotoluene-d3 with Sodium Isopropoxide in Isopropyl Alcohol

“…Identification with a o-complex seems possible, especially since cyanide a n d s~~l f i t e ions have been shown to form o-complexes with T N T (6). The formation of the o-coniplex was postulated in our earlier investigation of the TNT-ethoxide system (I) ([TNT] = 5 x lo-' to M , [NaOEt] = 4 x lo-, to 4 x M), even though it was not directly observed, in order to explain the kinetic behavior.…”

Kinetic Studies of the Reactions of Cyanide Ion and 1,3,5-Trinitrobenzene in Ethanol, n-Propanol, Isopropanol, and t-Butanol at 25.0 °C

“…Cyanide ion is known to react with 1,3,5-trinitrobenzene and related nitroaromatic compounds in a wide variety of solvents to form ocomplexes (1)(2)(3)(4). The visible absorption characteristics of o-complex 1 (X = CN), together with equilibrium constants and thermodynamic parameters associated with its formation, in a number of alcohols have been reported (5).…”