Diphosphorus Tetrafluoride and Diphosphorus Oxytetrafluoride' Sir :Although diphosphorus tetrachloride and diphosphorus tetraiodide have been prepared, the corresponding fluoride is unknown. A report concerning its possible existence has appeared, but little evidence was given. We have now obtained diphosphorus tetrafluoride,
had a drop-time of 3.3 seconds (open circuit in 0.1 N potassium chloride solution) and a flow of 1.63 mg of mercury/sec. The solutions (ca. 2X10-4 M) contained several drops of 0.1% gelatin in 80% water-dioxane and were deoxygenated by passing nitrogen, previously saturated with the same solvent, for 20 minutes. Voltages were measured against a Beckman calomel electrode (with capillary collar) dipping into the solution. No correction was necessary for the voltage drop in the cell since a t this low internal resistance and low concentration the error was <0.005 v. The polarograms were run three or four times and the average values are reported in Table I. A gift of t-butylnitrobenzenes from Professor H. C. Brown is gratefully acknowledged.Some of the data were checked by Cesar Reyes, under a National Science Foundation undergraduate research participation grant. 2,3-DIPHENYLBUTANE-2,3-DIOL. SOLVENT EFFECTS H. AGAHIGIAN, J . F. MORAVECK, AND H. GAUTHIERThe effect of concentration on the chemical shift of the hydroxyl resonance of alcohols has been reported (1 (a) ; 1 (b) and references cited therein) and the position of the hydroxyl proton is an estimate of the extent and nature of the hydrogen bonding. The use of different solvents may lend some insight into the nature of the hydrogen bonding, as has been suggested by Jardetsky (2).The n.1n.r. studies on the butanes have been quite coinprehensive (3, 4) in an effort to establish the rotamer populatioil as well as the coupling constants of the protons in possible rotamer configuration; however, butanediols, in particular the meso-and the dl-2,3-diphenylbutane-2,3-diols, have not been investigated with respect to solvent effects. Various diastereoineric alcohols have been studied (5) and the hydroxyl resonances have been determined and evidence was given to show the extent hydrogen bonding is dependent on the stereocheinistry.The meso-and dl-2,3-diphei1ylbutane-2,3-diol isomers were characterized (6) by their infrared spectra. An interesting feature of the infrared spectrum of the dl-2,3-diphenylbutane-2,3-diol was the broad hydroxyl band. NIolecular models indicate that the intramolecular hl-drogei~ bonding is enhanced in the dl form whereas in the meso form the intramolecular hydrogen bonding is not sterically favored.The proton i1.m.r. spectra of the dl-and mes0-2,3-diphenylbutai1e-2,3-diol in benzene,
NOTES 2913 N.M.R. SOLVENT STUDIES: HYDRAZINE AS A SOLVENTThe studies of hydrogen bonding (I, pp. 400-407; 2-4, 5 and references cited therein) with respect to proton chemical shifts have shown effects the order of magnitude of which was dependent on causes such as concentration, solvent-solute interactions, and the nature of the solvents, to mention a few. I t is interesting to note that, for none of the solvent systems studied, has work been done with anhydrous hydrazine as a solvent. In most cases, the solvent systems used are polar to non-polar with varying concentrations of solute. No study concerning groups such as amino or hydroxyl groups in aromatic systems has been done and the hope is that some information might be obtained which will lead to a better understanding of hydrogen bonding.Recently, the methyl resonances (6) in steroids were assigned by using pyridine as a solvent, and from the published spectra, a dramatic change was effected which made the assignment possible. In addition, a study of pyrrole and N-substituted pyrroles (7), as well as substituted quinolines ( 8 ) , and a study of interactions in benzene (9) have shown that the solvent effects are not a function of the extent of hydrogen bonding but require an explanation which involves a preferred orientation of solvent-solute interaction. The scope of this study embodies the use of hydrazine as a solvent in nuclear magnetic resonance (n.m.r.) studies and its effects on the various aromatic protons in systems where the substituents are electron-donating, and will themselves be more susceptible to hydrogen bonding or association with the solvent. The spectra of the saturated heterocyclics, 2-pyrrolidone, and N-methyl 2-pyrrolidone were observed in anhydrous hydrazine using tetramethylsilane as an external standard, as well as in deuterochloroform with external tetramethylsilane, and the spectra were identical. A similar experiment with about 10% solution dl-2,3 diphenyl-2,3-butanediol yielded spectra which were essentially unchanged, indicating little or no effect on the aromatic protons in this type of system. The aromatic proton resonance of dl-2,3-diphenyl-2,3-butanediol in hydrazine was 456 c i s from external tetramethylsilane; in deuterochloroform the phenyl resonance was 457 cis from external tetramethylsilane, i.e., essentially unchanged in the two solvents. Although hydrazine is a compound which has applicability in synthetic chemistry it appears to be of value as a solvent for some organic compounds.The spectrum of o-phenylenediamine in deuterochloroform was a single peak; however, in anhydrous hydrazine the aromatic protons were a typical AzBz case similar to o-dichlorobenzene (I).* The spectrum of 1,3-phenylenediamine was obtained in both deuterochloroform and hydrazine and marked low field displacement of the ortho protons (H* and H6) in hydrazine compared to the deuterochloroform solution suggested a change in the amino functions possibly due to association.The spectrum of 2,4-dichlorophenol was obtained in deuterochloroform, d...
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