Electrochemically induced processes in the formation of phosphorus acid derivatives. 2. The role of polymerization processes in the electrosynthesis of the esters of phosphorus acids from white phosphorus

The mechanism of the electrosynthesis of phosphate esters from white phosphorus was investigated. It was shown that the reaction takes place by two paths, i.e., monomeric (with the participation of dissolved phosphorus) and polymeric (with the participation of phosphorus on the surface of an emulsion drop). It was established that in an alcohol solution of tetraethylammonium iodide the main part of the final product is formed through an intermediate polymeric compound. It was noticed that by studying the dynamics of the accumulation of the dissolved product during electrolysis it is possible to trace the mechanism of reaction of the phosphorus at the individual stages of the process.A. E. Arbuzov Institute of Organic and Physical Chemistry, Kazan' Scientific Center, Russian Academy of Sciences, 420028 Kazan'. V. I. Ul'yanov-Lenin Kazan' State University, 420028 Kazan'. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 6, pp. 1328–1333, June, 1992.     

Organonickel σ-Complexes—Key Intermediates of Electrocatalytic Cycles

Electrochemical reduction of nickel complexes with 2,2-bipyridyl in the presence of ortho-substituted aromatic bromides or white phosphorus leads to the formation of highly reactive organonickel -complexes that are capable of selectively reacting with diverse substrates with the formation of cross-association products. Mechanisms of electrocatalytic processes involving organic halides, chlorophosphines, white phosphorus, and nickel complexes with 2,2-bipyridyl are studied by the cyclic voltammetry and preparative electrolysis methods. Key intermediates of processes that occur in metallocomplex catalysis are determined.     

Electrochemical reduction of cobalt and nickel complexes with ligands stabilizing metal in low oxidation state

Electrochemical reduction of cobalt(ii) complexes containing -acceptor ligands (L = bpy, Ph₂Ppy) proceeds through three consecutive reversible steps: one-electron transfer to form a more stable Co^IL complex, transfer of two electrons at more negative potentials to form an anionic [NiL]^– complex, and reduction of the ligand to the radical anion. The stability of the cobalt complexes with different ligands decreases in the series Ph₂Ppy > Ph₃P > bpy.     

Electrochemical approaches to generation of phosphinidene complexes of tungsten pentacarbonyl

An alternative approach to synthesis of electrophilic terminal phosphinidene complexes of tungsten pentacarbonyl with various substituents at the phosphorus atom has been developed. The approach is based on the reaction of the electrochemically generated tungsten pentacarbonyl ion with trivalent phosphorus acyl chlorides. Electrochemical reduction of ethyldichlorophosphines in the presence of α-diimines is a one-step process that forms 1,3,2-diazaphospholenes containing an exocyclic P-C bond.     

Synthesis of water-soluble bis-<Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">O</Emphasis>-chelate nickel(II) complexes based on new ligands – <Emphasis Type="Italic">P</Emphasis>-pyridyl-containing phospholane oxides

A series of new N,O-hybrid ligands was synthesized by oxidation of pyridyl-substituted phospholanes. These ligands were employed in the first synthesis of water-soluble mononuclear nickel(II) complexes [NiL₂(H₂O)₂](BF₄)₂ and [NiL₂(MeCN)₂](BF₄)₂. Physicochemical properties and crystalline structures of the synthesized compounds were thoroughly studied.     

The influence of the sacrificial anode nature on the mechanism of electrochemical arylation and alkylation of white phosphorus

The material of the sacrificial anode has a substantial effect on the nature and yield of the target products of electrochemical phosphorylation of organic halides by white phosphorus in the presence of the nickel complexes with 2,2"-bipyridine. The use of the zinc anode results in the products with tricoordinated phosphorus, viz., triorganylphosphines, the reaction on the aluminum anode affords triorganylphosphine oxides, and the presence of Mg²⁺ ions in the reaction mixture provides the transformation of white phosphorus into cyclic phosphines (PhP)₅.     

Reactions of Elemental Phosphorus with Electrophiles in Super Basic Systems: XVII. Phosphorylation of Arylalkenes with Active Modifications of Elemental Phosphorus

The example of the phosphorylation of styrene and 2-vinylnaphthalene with elemental phosphorus in the KOH-DMSO system at room or elevated temperature was used to show that the activated red phosphorus prepared from white phosphorus under ionizing radiation has a reactivity comparable with that of white phosphorus and significantly higher than that of ordinary technical red phosphorus.     

Generation of a Hetero Spin Complex from Iron(II) Iodide with Redox Active Acenaphthene-1,2-Diimine

The reaction of the redox active 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene (dpp-BIAN) and iron(II) iodide in acetonitrile led to a new complex [(dpp-BIAN)Fe^III₂] (1). Molecular structure of 1 was determined by the single crystal X-ray diffraction analysis. The spin state of the iron cation in complex 1 at room temperature and the magnetic behavior of 1 in the temperature range of 2–300 K were studied using Mossbauer spectroscopy and magnetic susceptibility measurements, respectively. The neutral character of dpp-BIAN in 1 was confirmed by IR and UV spectroscopy. The electrochemistry of 1 was studied in solution and solid state using cyclic voltammetry. The generation of the radical anion form of the dpp-BIAN ligand upon reduction of 1 in a CH₂Cl₂ solution was monitored by EPR spectroscopy.     

Electrocatalytic reactions involving the NiII—ZnII—2,2"-bipyridine system

Factors determining the effect of Zn^II ions on the catalytic activity of the Ni^II complexes with 2,2"-bipyridine (bpy) in the reduction of organohalides were elucidated by cyclic voltammetry and electrolysis. The mechanism proposed involves the reduction of the Ni^IIbpy complex to Ni⁰bpy, the oxidative addition of organohalides to the Ni⁰bpy complex, and nickel transmetallation with the cathode-generated Zn⁰ to form an organozinc compound.