Electrochemical synthesis of phosphorus esters from white phosphorus in the presence of copper complexes and ethanol

In the presence of white phosphorus the redox potentials of the copper ions change and the potential of the reduction wave of Cu^I/Cu⁰ shifts noticeably toward more positive values. The Cu^I—P₄ complex is characterized by a lower value of the electrochemical gap, that is, higher polarizability and reactivity compared to those of the free Cu^I cation. Phosphorus esters can be synthesized from P₄ and ethanol. The latter is in the composition of the copper(ii) complexes, which act as a catalyst-charge mediator.     

Oxidation of white phosphorus by peroxides in water

A mixture of hypophosphorous, phosphorous, and phosphoric acids is formed during the anaerobic oxidation of white phosphorus by peroxides [ROOН; R = Н, 3-ClC₆H₄CO, (СН₃)₃С] in water. The rate of reactions grows considerably upon adding nonpolar organic solvents. The activity series of peroxides and solvents are determined experimentally. NMR spectroscopy shows that the main product of the reaction is phosphorous acid, regardless of the nature of the peroxide and solvent. A radical mechanism of oxidation of white phosphorus by peroxides in water is proposed. It is initiated by the homolysis of peroxide with the formation of НO^? radicals that are responsible for the homolytic opening of phosphoric tetrahedrons. Further oxidation and stages of the hydrolysis of intermediate phosphorus-containing compounds yield products of the reaction.     

Quantum chemical study of the mechanism of the reaction of tetraphosphorus with alcohol in the coordination sphere of copper(II)

We have used the CNDO Method to study ^–1-tetraphosphorus complexes of copper (II) containing MeOH, MeO^–, H₂O, HO^–, Cl^–, Br^–, I^–, formed during the new reaction of oxidative alkoxylation of P₄ to trialkylphosphates in alcohol-benzene solutions of Cu(II). We studied the nature of the activation of the coordinated molecules and ions by comparing the charges on al the atoms and the values of the total, vocalent, and ionic energies of the intramolecular and intermolecular bonds. We observed the effect of conversion of the tetraphosphorus (which does not display acid-base properties) to a strong electron acceptor, tending toward electrophilic addition of coordinated nucleophiles. The calculated quantum chemical characteristics of the tetraphosphorus complexes correlate well with experiment.D. V. Sokol'skii Institute of Organic Catalysis and Electrochemistry, Kazakh Academy of Sciences, Alma-Ata. Translated from Teoreticheskaya i Eksperimental'naya Khimiya, Vol. 27, No. 6, pp. 659–672, November–December, 1991. Original article submitted April 19, 1990.     

Functionalization of white phosphorus in the coordination sphere of transition metal complexes

This review highlights the stoichiometric functionalization of both white phosphorus and naked P_n fragments derived from the metal-mediated demolition of the P₄ tetrahedron. In a first section, the alkylation of P_n ligands is discussed giving specific examples such as: (i) the electrophilic alkylation of η³-P₃ or, μ,η³-P₃ ligands: (ii) the transfer of a methyl group from molybdenum to η⁵-P₅ ligands to yield a norbornadiene-like μ₃,η⁴:η¹:η¹-MeP₇ ligand; (iii) the formation of P-C or P-H bonds mediated by rhodium and iron complexes; (iv) the use of ammonium salts to transfer an alkyl to polyphosphido clusters. Different methods to functionalise white phosphorus or other P_n ligands, including the cyclization of acrolein with diphosphenes and the insertion of CO or carbenes across P-P, P-M bonds, and P-E bonds (E = S, Se), are illustrated in appropriate sections. Finally, the last part of the article, reports on the astounding coupling of alkynes and phosphalkynes with P_n ligands which is a versatile, not yet completely explored, method to form an unprecedented variety of carbon-phosphorus heterocycles.