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This report is important to achieving SWCNT solvation, understanding adsorption of molecules on SWCNT surfaces, and SWCNT characterization by NMR. Complexation of 1-methyl-2-pyrrolidone (NMP) and other selected organonitrogens with single-walled carbon nanotubes (SWCNTs) was studied by proton nuclear magnetic resonance (NMR). The magnitude of 1H NMR chemical shift change upon SWCNT:organonitrogen complex formation represents the strength of the association. Magnitudes of changes in NMR signals of different protons in the organonitrogen reveal which protons are in close proximity to SWCNTs. Results reveal that (1) in amides and aminoketones, SWCNT association with carbonyls is stronger than with nitrogen, (2) in aminoalcohols, SWCNT association with nitrogen is stronger than with oxygen, and (3) protons bonded to heteroatoms have greater changes in their chemical shifts than those bonded to carbons. Changes (broadening and downfield shifts) in 1H NMR signals of the organonitrogen compounds, which accompany SWCNT:organonitrogen association, are dependent upon (1) type of proton within R (α, β, etc.), (2) proximity to the carbonyl (R-CO versus NR2), (3) steric effects of alkyls, (4) electronic effects of alkyls, and (5) effects of tethering two ends of a molecule.

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Select amides have been widely used to suspend nanoarchitectures in organic solvents. In order to determine factors enabling these suspensions, interactions of single-walled carbon nanotubes (SWCNTs) with representative amides 1 were examinedsR(CdO)NMe 2 , when R ) H, Me, Et, i-Pr, t-Bu, Ph. 1 H NMR spectra gave evidence for two types of SWCNT: amide associations, formed after evaporation of the reaction mixture to either a concentrated solution or a wet paste, followed by sonication in NMR solvent. NMR spectra of SWCNTs associated with 1 (SWCNT:1) after evaporation to concentrated solution show broadening and small downfield changes, suggesting weak interactions. Evaporation of SWCNT:1 to a wet paste causes larger spectral changes, predominantly in aldehydic and R proton signals. These are often 10 times those in concentrated solution, especially when R has small steric requirements, which suggests a stronger interaction of 1 with SWCNTs under wet paste conditions. 1 H NMR signal changes of 1, which accompany SWCNT:1 association, depend upon (1) degree of evaporation of residual amide and organic solvent, (2) organic and NMR solvent combination, (3) type of proton in R, (4) proximity effects to the carbonyl (R versus NMe 2 ), and (5) steric requirements of R.

A simple and convenient approach to the synthesis of symmetrical N,N′-alkylidine bisamides is described. Aromatic and aliphatic nitriles react with aromatic aldehydes in the presence of sulfamic acid to give the corresponding bisamides in moderate yields.Key words: alkylidine bisamides, nitrile, sulfamic acid.

The activity levels of glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT) enzymes were estimated in liver, muscle and brain tissues of the ®sh, Sarotherodon mossambicus (Peters), which had been exposed to sub-lethal (3 mg litre À1) and lethal (25 mg litre À1 ) concentrations of the carbamate insecticide carbaryl. Based on the results obtained, the changes in GOT and GPT levels in liver, muscle and brain following different periods of sub-lethal and lethal carbaryl exposures suggested that S mossambicus showed adaptive elevation in the activity levels of the two aminotransferase enzymes in the tissues, thereby probably aiding gluconeogenesis through transamination of glucogenic amino acids to meet the energy demand under carbaryl toxicity.