Stereochemical aspects of phosphorus-containing cyclohexanes

All J(PH) and J(PC) values, including signs, have been obtained in acetylenic and propynylic phosphorus derivatives, R2P(X)CCH and R2P(X)CCCH3 (X oxygen, lone pair and R C6H5, N(CH3)2, OC2H5, N(C6H5)2, Cl) from 1H and 13C NMR spectra. In PIV derivatives the following signs are obtained: 1J(PC)+, 2J(PC)+, 3J(PC)+, 3J(PH)+, 4J(PH). Linear relations are observed between 1J(PC), 2J(PC) and 3J(PC) versus 3J(PH), indicating that these coupling constants are mainly dependent on the Fermi contact term, though the other terms of the Ramsey theory do not seem to be negligible for 1J(PC) and 2J(PC).



In PIII derivatives these signs are: 1J(PC)- and +, 2J(PC)+, 3J(PC)-, 3J(PH)-, 4J(PH)+. Only 3J(PC) and 3J(PH) reflect a small contribution of the Fermi contact term while in 1J(PC) and 2J(PC) this contribution seems to be negligible relative to the orbital and/or spin dipolar coupling mechanisms.

1H and 13C NMR study of α‐acetylenic PIII and PIV derivatives. Signs and magnitudes of J(PC) and J(PH)

Durch nucleophile Substitutionsreaktionen an 3,6-Dichlor-1,2,4,5-tetramethyl-perhydro-1,2,4,5,3,6-tetrazadiphosphorin (1) wurden neue 3,6-Derivate dargestellt und der PIII-Phosphor mit Schwefel und Selen zu Pv oxidiert. AlCl3 reagiert mit 1 zu einem „Addukt”, das als Tetrachloroaluminat eines neuen cyclischen Kations mit P der Koordinationszahl 2 aufgefast werden kann. Reaktionen von 1 mit Heptamethyldisilazan, Hexamethyldisilthian oder H2O fuhren zu den bicyclischen Verbindungen 24–26, wahrend Hydrazin und Methylhydrazin die Hydrazinophosphine 20 und 18 mit Bicyclo [2,2,2]octan-Struktur liefern. Die spektroskopischen Daten der neuen Verbindungen werden diskutiert.



New Cyclic and Bicyclic Hydrazinebis(phosphines)



Nucleophilic substitutions at 3,6-dichloro-1,2,4,5-tetramethyl-perhydro- 1,2,4,5,3,6-tetrazadiphosphorine (1) led to new 3,6-derivatives. The III phosphorus was oxidized to Pv by sulfur and selenium. AlCl3 reacts with 1 to yield an „adduct” which can be regarded as a tetrachloroaluminate of a new cyclic cation with dicoordinate phosphorus. Reactions of 1 with heptamethyldisilazane, hexamethyldisilthiane or H2O lead to the bicyclic compounds 24–26 while hydrazine and methylhydrazine yield the hydrazinophosphines 20 and 18 with bicyclo[2,2,2]octane structure The spectroscopic data of the new compounds are discussed.

Über cyclische und bicyclische Hydrazinbis (phosphine)

The nature and mechanism of intramolecular electronic interactions in compounds of three- and four-coordinate phosphorus have been critically examined on the basis of a review of the results of the study of their three-dimensional structure and physical properties. The high ?-acceptor power of phosphorus-containing groups, capable of stabilising conformations with the trans-orientation of the interacting orbitals of the donors (the n-orbitals of the unshared electron pairs of the heteroatoms or the ?-orbitals of unsaturated systems) and the acceptors (bonds of the phosphorus atom) has been proved. The bibliography contains 193 references.

Intramolecular Electronic Interactions in Phosphorus Compounds in the Light of Recent Structural Studies

Dioxaphospholanes-1,3,2, dimerisation, obtention de composes heterocycliques phosphores et oxygenes a dix chainons: tetra-oxa-1,3,6,8 diphosphecanes-2,

Le spectre de resonance magnetique nucleaire du proton de divers dioxaphosphorinanes-1,3,2, qui portent au niveau du phosphore une liaison PN extracyclique a ete analyse. Cette etude confirme que, pour une disposition geometrique donnee des atomes P, O, C et H, le couplage 3J(POCH) depend fortement de l'orientation des liaisons au niveau du phosphore. Suivant la nature des restes attaches a l'atome d'azote, le cycle dioxaphosphorinane adopte une forme du type chaise rigide a liaison PN axiale ou equatoriale, ou au contraire une forme chaise qui s'inverse rapidement pour le temps d'observation de la RMN.



The 1H NMR spectra of several 1,3,2-dioxaphosphorinanes bearing an extracyclic PN bond have been analysed. The 3J(POCH) couplings are strongly dependent upon the orientation of the bond around the phosphorus atom. Depending upon the nature of the bonds attached to the nitrogen atom, the dioxaphosphorinane ring may adopt either a fixed chair conformation with the PN bond in the axial or equatorial orientation, or it may be in equilibrium between two chair conformations where the PN bond is alternately axial or equatorial. The equilibrium is fast on the NMR time scale.

Etude par Résonance Magnétique Nucléaire de dioxaphosphorinanes-1,3,2 à liaison PN extracyclique. Exemple de changement d'orientation de la liaison PN

Les spectres de resonance magnetique du proton de huit dithiaphospholanes-1,3,2 qui different par la nature du substituant attache au niveau du phosphore ont ete analyses. Les spectres du type AA′BB′X (X atome de phosphore) montrent que les deux couplages 3J(PSCH) sont faibles en valeur absolue et de signe oppose. Une etude de la torsion autour de la liaison C4—C5 est faite en examinant les valeurs des constantes de couplage 3J(HH). Les conformations des deux isomeres du phenyl 2, methyl-4 dithiaphospholane-1,3,2 sont egalement discutees.



The proton NMR spectral analysis of eight different 1,3,2-dithiaphospholanes with various groups attached to the phosphorus atom has been performed. The AA′BB′X (X phosphorus atom) system shows that the two 3J(PSCH) coupling constants have a small magnitude and opposite signs. Using the 3J(HH) values, the torsion about the C4—C5 bond has been evaluated. The conformational requirements in the two isomers of the 2 phenyl-4-methyl-1,3,2-dithiaphospholane are also discussed.

Etude par Résonance Magnétique Nucléaire de dérivés phosphores. Etude de dithiaphospholanes-1,3,2

On a realise l'analyse complete des spectres de RMN des fluorophospholanes (1 a 3). Les signes absolus des constantes de couplage 3J(PH) et 4J(FH) ont ete determines, par rapport au signe absolu connu de la constante 1J(PF), a partir d'experiences de double resonance heteronucleaire selective. Les constantes 3J(POCH) et 3J(PNCH) observees sont toutes positives. Les deux constantes 3J(PSCH) du dithiaphospholane (2) presentent des faibles valeurs de signes opposes, la plus grande etant positive. Toutes les constantes 4J(FPXCH) sont positives et ces constantes semblent peu stereospecifiques.



The NMR spectra of the trivalent fluorophospholanes (1, 2, 3) have been analysed at length. The absolute signs of the 3J(PH) and 4J(FH) coupling constants have been referred to the known negative sign of the 1J(PF) coupling constant from selective heteronuclear double resonance experiments. The 3J(POCH) and 3J(PNCH) coupling are positive. The weak values observed for 3J(PSCH) have opposite signs, the larger being positive. All the 4J(FPXCH) coupling constants are positive showing a lack of stereospecificity.

Jean Martin

Papers

Etude par Résonance Magnétique Nucléaire de dioxaphosphorinanes-1,3,2 à liaison PN extracyclique. Exemple de changement d'orientation de la liaison PN

Etude par Résonance Magnétique Nucléaire de dérivés phosphores. Etude de dithiaphospholanes-1,3,2

Etude des Signes des Constantes de Couplage 3J(PXCH) et 4J(FPXCH) dans les Diaza-, Dioxa- et Dithiaphospholanes Fluores

Twelve-membered-ring molecules containing phosphorus and sulfur. Preparation and identification