Raymonde Mathis

Influence de l'environnement moleculaire sur la frequence de vibration de valence Ge—H

Abstract The frequency of the Ge—H valence mode of vibration has been measured for about twenty alcoylgermanium hydrides and halogenohydrides. This frequency is raised by —I substituents on the Ge atom, and lowered by + I substituents. This substituent effect is additive and may be used for an estimation of inductive effect. The ν Ge—H frequency in R 1 R 2 R 3 GeH can be approximately related to the sum of Taft σ ∗ coefficients for R 1 , R 2 and R 3 by equation: v Ge—H (cm −1 ) = 2008 + 16·5 Σσ ∗ .

FROM ALLENIC PHOSPHORUS DERIVATIVES TO HETEROCYCLIC COMPOUNDS. SYNTHESIS OF A 1,2,3-DIAZAPHOSPHOLE COMPOUND WITH A STRONGLY POLAR NH GROUP LINKED TO A DICOORDINATE PHOSPHORUS ATOM

Abstract The synthesis of several derivatives containing an allenic group directly linked to a phosphoryl phosphorus atom is described. The addition of alcohol, water, hydrazines to this compounds is studied. The reaction of hydrazones (obtained from allenyldiphenylphosphine oxide) with trichlorophosphine gives rise to derivatives of 1,2,3-diazaphosphole. The hydrazone deriving from unsubstituted hydrazine leads to a compound with an NH group spectroscopically much more acidic than that of pyrrole; this NH group is presumably directly linked to the dicoordinated phosphorus atom.

Fréquence d'absorption de la liaison PN dans des composés du phosphore tricoordonne

Abstract The stretching frequency ν PN in trivalent phosphorous compounds varies considerably (790–1010 cm −1 ), and appears essentially linked to the possibility of conjugative resonance of the nitrogen doublet with the vacant “ d ” orbitals of the phosphorous atoms. A low frequency results from the engagement of nitrogen in an unsatured ring (PN linkage practically simple). This effect is more important than those from the substituents of phosphorus, the latter being linked, on the one hand, to the inductive effect (a highly electro-negative substitute lowers the energy phosphorus “ d ” orbital and helps the conjugative resonance with the nitrogen) and on the other hand, to the possibilities of the conjugation of the substituent with phosphorus (which lowers the possibility of return of the nitrogen doublet). The PN frequency has been correlated with the barrier to rotation of that linkage determined by Nuclear Magnetic Resonance (Δ G + ) and the chemical exchange rate between the methyl-trifluoroacetate and the aminophosphines. The results have been explained in terms of nitrogen—phosphorus orbital overlapping.

Variation de la fréquence νNH de quelques spirophos- phoranes dans les solvants; évaluation de l'acidité du groupement Pv-NH dans ces composés

Abstract A spectroscopical study of N-H bond in spirophosphoranes containing one or two such groups had been made. The value of 2Δν 1–2 = 2ν 0–1 − ν 0–2 (CCl 4 solution) give information on the anharmonicity of N-H stretching vibration. The frequency of the fundamental N-H stretching transition has been measured in several solvents and compared with the ν N-H frequency of pyrrol in the same solvents. The N-H group in these compounds seem to be analogous to the same group in pyrrol. This can be interpreted as a result of sp 2 hybridization of the nitrogen atom and a strong conjugation of the p orbital of the latter with a vacant d orbital of phosphorus atom.

Aziridines—VII. Mise en évidence par spectrographie infrarouge d'invertomères résultant de l'inversion de l'azote dans les aziridines secondaires☆

Resume Study of the stretching bands ν NH and ν ND for twenty C-alkylated and C-arylated secondary aziridines and their deuteriated homologs, allowed us to distinguish invertomers of different energies which can exist when aziridines are dissymetrically substituted on the carbon atoms. The major invertomer is that with hydrogen atom (N)H or deuterium atom (N)D situated in the ring side the least sterically hindered. The influence of carbon atom substituents on the frequencies ν NH or ν ND appeared essentially like a “through space” effect and not like a bond transmitting effect. When one side is more hindered than the other, the most thermodynamically stable invertomer ((N)H in the side the least hindered) exists alone.

Etude en spectrographie infrarouge et de résonance magnétique nucléaire de l'hydrolyse et de l'acidolyse d'un amido-phosphite bicyclique contraint

Abstract Benzoic acid reacts with the bicyclic amidophosphite ( I ) to give a stable compound which could be isolated as a solid. On hydrolysis of I , the PN and PO bonds are cleaved, to give three other products and the ratio of PN to PO cleavage is a function of reaction conditions. A compound with pentacoordinated phosphorus is then formed, the structure of which is given. No hydroxyphosphorane could be detected.

The N–H link as a ‘probe’ for the electronic structure of the phosphorus–nitrogen bond in aminophosphines. An infrared spectroscopic study

Mechanical anharmonicity and hydrogen bond donor ability of the NH group in 26 aminophosphines X2P–NHR have been measured; large variations have been observed, which are related to the effect of substituents X on the s character of the nitrogen part of the NH bond orbital.

Pseudopotential calculations on aminophosphine H2P–NH2

The electronic structure of the H2P–NH2 molecule has been calculated using a pseudopotential method, considering independently the HNP and HNH, then the HPN and HPH angles; the optimized geometry corresponds to a gauche conformation in which the nitrogen atom is pyramidal (sum of bond angles 347°).