Redox Disproportionation Research Articles

Substituted tetraammineruthenium cytochrome c derivatives: Chemistry and electron-transfer reactions

Horse-heart (hh) cytochrome c, modified at His-33, and Candida krusei (Ck) cytochrome c, modified at His-39, with a series of cis- and trans-(L(NH{sub 3}){sub 4}Ru{sup III}cyt c) derivatives, where L is isonicotinamide (isn) or pyridine (py), have been prepared and characterized. Rate constants for intramolecular electron transfer from the heme(II) to Ru(III) in the (L(NH{sub 3}){sub 4}Ru{sup III}cytc c{sup II}) intermediates generated by oxidative pulse radiolysis of the fully reduced modified protein species were as follows (k(s{sup -1}), {triangle}H{sup {double_dagger}} (kcal mol{sup -1}), {triangle}S{sup {double_dagger}} (cal deg{sup -1}mol{sup -1}), -{triangle}G{degrees} (eV)): 440, 7.3, -22, 0.18 for L= trans-isn (hh); 440, 6.2, -26, 0.18 for L = cis-isn (hh); 126, 8.8, -19, 0.11 for L = trans-py, (hh); 220, 6.4, -27, 0.13 for L = trans-isn (hh); 220, 6.4, -27, 0.13 for L = trans-isn (Ck); 154, 2.3, -41, 0.18 for L = NH{sub 3} (Ck). Relative differences in the rates are accounted for by variations in the driving force and reorganization energies in these differences in the rates are accounted for by variations in the driving force and reorganization energies in these ruthenium-modified proteins resulting from the nature of the ligands around the ruthenium center and from the different sitesmore » of modification on the cytochrome. The fully oxidized (L(NH{sub 3}){sub 4}Ru{sup III}cyt c{sup III}) species undergo slow redox disproportionation reactions (k=35M{sup -1}s{sup -1}, pH 7.0) which have been studied by optical and electrochemical methods. The Ru(IV) species thus created subsequently rearranges in an irreversible manner. In the presence of excess oxidant, all of the bound ruthenium is converted to the rearranged form. To avoid this problem, the (L(NH{sub 3}){sub 4}Ru{sup III}cyt c {sup II}) intermediates for intramolecular electron-transfer studies were generated from the stable (L(NH{sub 3}){sub 4}Ru{sup II}cyt c{sup II}) form.« less

High-Valent Oxo, Methoxorhenium Complexes: Models for Intermediates and Transition States in Proton-Coupled Multi-Electron Transfer Reactions

Abstract : Dioxorhenium(V) tetrapyridyl species are currently under active investigation as model systems for interfacial two-electron, two-proton transfer reaction sequences We now find that the corresponding oxo, methoxo complexes can be prepared from dioxo species and methyl trifluoromethanesulfonate. The new complexes behave nearly identically to the analogous oxo, hydroxo complexes-with one important exception: CH3(+), unlike H(+), does not dissociate from the oxo ligand. As a direct consequence, the usually elusive rhenium oxidation state, IV, is stabilized with respect to redox disproportionation and is observable for several complexes at high pH. The ability to detect this state, in turn leads to: (1) direct access to the formal reduction potentials for the isolated 1e(-) redox couples comprising the overall two electron transfer (key information for understanding multi-ET kinetics) (2) elucidation of the profound structural and energetic consequences of the initial protonation (methylation) step in the dioxorhenium(V) reduction kinetics.

Strukturen und Molekül‐Eigenschaften ladungsgestörter Moleküle. 52. Mitteilung. 2, 3‐Diphenylchinoxalin‐Radikalanionen in Lösung und im Kristall

Structures and Molecular Properties of Charge‐Pertubed Molecules. 2, 3‐Diphenylquinoxaline Radical Anions in Solution and in CrystalsThe Na⊕ and K⊕ radical‐ion salts of 2, 3‐diphenylquinoxaline seem to be (according to a structural database search) among the first ones of N‐heterocyclic radical anions in crystals. The one‐electron reduction in aprotic 1, 2‐dimethoxyethan (DME) solution at metal mirrors and the crystallization under Ar have been preceded by cyclovoltammetric (CV) and ESR/ENDOR measurement. The first electron insertion at −1.63 V proves to be reversible, whereas the irreversible second step, which is accompanied by an overcrossing of the CV line, can be rationalized by an ‘ECE‐DISP’ mechanism via a dianion redox disproportionation. The ENDOR spectrum resolves four 1H couplings and allows to simulate the ESR spectrum including the 14N hyperfine splittings. Both dark‐blue single crystals of the radical ion salts \documentclass{article}\pagestyle{empty}\begin{document}$[2,3{\rm - diphenylquinoxaline}^{{.} \ominus} {\rm Met}^ \oplus ({\rm DME})]^.$\end{document} show unexpected similarities for Met⊕ = Na⊕, K⊕ despite the 36‐pm difference in their ionic radii. The largest structural changes inflicted by the one‐electron reduction of the N‐heterocyclic molecule are observed in the vicinity of the N‐centers bearing the highest effective nuclear charge. The DME‐chelated metal cations coordinate at the N electron pairs and form Met⊕(DME)‐bridged polymer chains of the radical anion, which are differently ondulated in the Na⊕ and K⊕ radical anion salts. The take‐home lesson suggests that many more N‐heterocyclic molecules might be analogously reduced under optimized conditions and isolated as single crystals.

Derivate des Hydrazins als Liganden in Vanadium(III)-, -(IV)- und -(V)-Komplexen. Darstellung und Charakterisierung von [V(dipic)(NH2NHCOPh)(H2O)2][VO(dipic)(NHNCOPh)]·2H2O , [VO(dipic) (NHNHCO2Me)], [VO(dipic)(NH2NHCO2Me)], [VO(dipic)(NHNHCSPh)] und [VO('ONO')(NHNHCOPh)]·2H2O / Substituted Hydrazines as Ligands in Vanadium(III), -(IV) and -(V) Complexes. Synthesis and Characterization of [V(dipic)(NH2NHCOPh)(H2O)2][VO(dipic)(NHNCOPh)]·2H2O , [VO(dipic) (NHNHCO2Me)], [VO(dipic)(NH2NHCO2Me)], [VO(dipic)(NHNHCSPh)] und [VO('ONO')(NHNHCOPh)]·2H2O

The reaction of [VO(dipic)(H2O)2]·2H2O with benzoylhydrazine, thiobenzoylhydrazine and O-methylcarbazate yields [V(dipic)(NH2NHCOPh)(H2O)2][VO(dipic)(NHNCOPh)·2H2O (1), [V0(dipic)(NHNHCO2Me)] (2), [VO(dipic)(NH2NHCO2Me)] (3) and [VO(dipic)(NHNHCSPh)] (4). 1 is probably formed in solution by redox disproportionation. The reactions giving 2,3 and 4 also involve redox processes with atmospheric oxygen as oxidant and the respective hydrazine as reductant. [VO('ONO')(NHNHCOPh)]·H2O (5) was formed using aqua-oxo-salicylaldehyde-L-alaninato-vanadium(IV) as precursor. The structures of 1,2,3 and 5 have been determined by single crystal X-ray crystallography. The cation of 1 has a seven-coordinated vanadium(III) center with the two H2O molecules at the apices of a pentagonal bipyramide, the anion contains the doubly deprotonated hydrazido( 2-) ligand NHNCOPh2- as N,O-chelate. 2 and 3 have very similar structures, but differ in the oxidation state of the vanadium atom and in the degree of deprotonation of the hydrazine. In 3 neutral NH2NHCOOMe and in 2 the single deprotonated hydrazido(l -) ligand NHNHCOOMe- are bound as N,O-chelates, with the O-donor in rrans-position to the VO group. The remaining coordination sites are occupied by the ONO-donating dinegative dipic ligand. 5, where dipic is replaced by the three-dentate salicylaldehyde-benzoyl-hydrazone, has a very similar structure to 2. 4 with a VO3N2S coordination sphere is the first vanadiun (V) complex containing the N,S-donating hydrazido(l-) ligand NHNHCSPh-. The following parameters are characteristic for the bonding of the NHNHR- and NHNR2- ligands in 1,2 and 5: V-N 189 ± 1 pm, N-N 134 ± 1 pm and V-N-N 122 ± 2°.

Constitution and Properties of the 8,8'-μ-(H2NO)=(1,2-C2B9H10)2-3-Co Bridged Cobaltaborane

Constitution of 8,8'-μ-H2N(-O-)(1,2-C2B9H10)2-3-Co sandwich has been elucidated 17 years after its first synthesis, via high resolution NMR methods supplemented by mass spectrometry. The species gives relevant "oximes" with acetone and benzaldehyde and is quantitatively methylated to the N,N'-dimethyl derivative, which shows an interesting redox disproportionation to a triatomically bridged sandwich with a 8,8'-μ-O-CH=N(Me)- bridge between both ligands. Several other "peculiar" reactions of this dimethyl derivative are discussed. On reductive cleavage of the parent hydroxylamine the non-bridged 8-HO-8-H3N(1,2-C3B3H10)2-3-Co zwitterion is obtained. Mono-, di- and trimethylated derivatives of this non-bridged species are characterized.

TRANSFORMATIONS OF DIFLUOROPHOSPHINES: THE INFLUENCE OF SOLVENT ON THE REACTION PATHWAY AND RING SIZE IN CYCLOPOLYPHOSPHINES

Abstract The spontaneous transformation reactions of some difluorophosphines in chloroform as solvent are described. First, the redox disproportionation of 2,5-dimethylphenyldifluorophosphine, 1, unexpectedly led to the formation of the cyclopolyphosphine, hexakis-(2,5-dimethylphenyl)cyclohexaphosphine, 2a and 2,5-dimethylphenyltetrafluorophosphorane, 3. Secondly, CF3PF2, 4, was found to undergo a scrambling reaction with formation of (CF3), PF, 5 and PF3, 6, rather than a redox disproportionation. In contrast, the difluorophosphines, RPF2 with R = 2,4,6-trimethylphenyl, 9-anthracenyl, and 9-phenanthryl were found to be stable with regard to such transformations. A single crystal X-ray diffraction study of 2 (as a 1:1 solvate with CDCl3, 2a) was conducted. 2 was found to exist in a chair conformation with a PP bond length of 222.9 pm. The previously known hexamer, (PhP)6, 2b, was formed in the redox disproportionation of a neat sample of PhPF2, held at–20°C for several months. Its X-ray crystal structure, first reported in 1965, was redetermined, and served to establish the nature of the product. 2b was found to display a conformation very similar to that of 2/2a.

Darstellung neuer Monofluorphosphine und einiger ihrer Übergangsmetallkomplexe; Einkristall-Röntgenstrukturanalyse eines Platin(II)-Komplexes / Preparation of New Monofluorophosphines and Some of their Transition Metal Complexes; Single Crystal X-Ray Diffraction Study of a Platinum(II) Complex

The reaction of lithiated precursors with PCl2F led to a number of monofluorophosphines, including the known di-tert-butylmonofluorophosphine, 1. Bis(phenylethinyl)monofluorophosphine (2) was accessible only via this route (the classical method of synthesizing 2 by chlorine/fluorine exchange is impossible, because the corresponding chlorophosphine is unknown). Bis(2-methoxyphenyl)fluorophosphine (5) was prepared via the organolithium/PCl2F route. The NMR results for 5 thus prepared were inconsistent with previous reports, implying that the previously reported synthesis of 5 is in error. From 5 a cis-dichloroplatinum(II) complex (6) was synthesized and subjected to a single crystal X-ray structure analysis, confirming the expected planar coordination. From bis(2,3-dimethoxynaphthyl)monofluorophosphine (7) a rhodium(I) (8) and an iron(0)tetracarbonyl complex (9) were prepared. An iron(0)tetracarbonyl complex (11) was synthesized from bis(9-anthryl)monofluorophosphine (10) which was found to be stable to redox disproportionation.

RECENT DEVELOPMENTS IN THE UNDERSTANDING OF SOLUTIONS OF SULFUR IN LIQUID AMMONIA

RECENT DEVELOPMENTS IN THE UNDERSTANDING OF SOLUTIONS OF SULFUR IN LIQUID AMMONIA

ChemInform Abstract: Anthracenediols as Reactive Dienes in Base‐Catalyzed Cycloadditions: Reduction‐Cycloaddition Reactions of Anthraquinones.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Anthracenediols as reactive dienes in base-catalyzed cycloadditions: reduction-cycloaddition reactions of anthraquinones

Cycloadducts are formed between anthracenediols (and related aminoanthracenols) and reactive dienophiles under mild base conditions. Stronger base/protic medium can lead to a formal redox disproportionation, which is believed to occur mechanistically as a double retro-aldol reaction. The fundamental chemistry appears to be analogous to that described previously for anthrones, 2 in which base-catalyzed Diels-Alder reactions were shown to occur more rapidly than Michael additions

Stability of difluorophosphines and their platinum complexes

Lutz Heuera, Peter G.Jonesa, Dietmar Schomburgb, and Reinhard Schmutzlera Instut für Anorganische und Analytische Chemie der Technischen Universität, Hagenring 30, 3300 Brauschweig. Federal Republic of Germany (a); Gesselschaft für Biotechnologische Forschung mbH, Mascheroder Weg 1, 3300 Braunschweig, Federal Republic of Germany (b).Compounds involving carbon-bonded λ3P-F are normally unstable because of redox disproportionation, e.g. 2n RPF2 → 1/n(RP)n + n RPF4This type of reactions is fairly slow if sterically demanding organic groups (e.g. tert.-butyl) or strongly electronegative groups (e.g. CF3) are used. The reaction of organolithium compounds (RL.i) with PF2CL[1,2] [RLi + PF2Cl → RPF2 + LiCl] therefore provides a n method of preparing difluorophosphines of the type RPF2 (R = organic substituent). With anthracyl lithium we observed the formation of antracyl difluorophosphine, which dimerized on irradiation. The anthracyl difluorophosphine monomer and dimer are stable with respect to redox disproportionation and the dimer is also moderately air stable; it was characterized by an X-ray diffraction study. The partial hydrolysis of the PF2-group gave compounds of type RP(F)(O)(H). In the case of R = 2,6-diphenoxyphenyl the corresponding fluorophosphonic acid was characterized by n.m.r. spectra and by X-ray diffraction study.Organodifluorophosphines reacted with cis-dichloro(η4-1,5-cyclooctadiene)platinum(II) or K2PtCl4 to form cis-dichloro-bis(organodifluorophosphine)platinum(II) or tetrakis(organodifluoro-phosphine)platinum(O), respectively. These complexes were characterized by n.m.r. spectra and by X-ray diffraction studies for R = But, Me5C5[2]. For complexes involving PF2-groups, a correlation between the Pt-P bond length and 2J(PtF) was found.The tetrakis(aryldifluorophosphine)platinum(O) complexes were found to undergo hydrolysis of the PF2-group and oxidation of the platinum with formation of bis(arylphosphonofluoridate)-bis (arylphosphonofluoridous acid)platinum(II). Bis{bis(2,5-dimethylphenylfluorophosphinito)-difluoro-borato)}platinum(II) is the only product of the reaction of the appropriate {RPF(O)}2Pt{RPF(OH)}2 complex with BF3*Et2O and was characterized by a single crystal X-ray diffraction study.

ChemInform Abstract: Reactions of (PtCl(dien))Cl with Glutathione, Oxidized Glutathione and S‐Methyl Glutathione. Formation of an S‐Bridged Dinuclear Unit

Abstract The reaction of the monofunctional platinum compound [PtCl(dien)]Cl with the tripeptide glutathione (GSH), oxidized glutathione (GSSG) and S -methyl glutathione (GS-Me) has been investigated by 1 H, 13 C and 195 Pt magnetic resonance spectroscopy and by potentiometric titrations. It appears that platinum binds with a high degree of specificity to the GSH sulfhydryl group. The reaction of platinum with GSH proceeds in two steps. In the first step only one platinum binds to the sulfur atom and, in the second step, another [Pt(dien)] 2+ unit binds to [Pt(dien)GS] + forming an S-bridged dinuclear unit [{Pt(dien)} 2 GS] 3+ . The rate of the first binding step is pH-dependent, whereas the rate of the second step is not. At pH 10, on the other hand, the rate of the first binding step is faster than the rate of the second binding step. Consequently, at pH 2 GS] 3+ complex. In the presence of free GSH, at pH > 7, one [Pt(dien)] 2+ unit of [{Pt(dien)} 2 GS] 3+ dissociates forming [Pt(dien)GS] + . The mechanism of the pH-dependent rate of the first platinum binding step and the ligand-exchange reaction are discussed. GSSG reacts with [Pt(dien)] 2+ , also forming the S-bridged dinuclear unit [{Pt(dien)} 2 GS] 3+ , probably through a redox disproportionation reaction with a catalytic function of [PtCl(dien)]Cl. GS-Me reacts with [Pt(dien)] 2+ forming the S-coordinated [Pt(dien)GS-Me] 2+ . [Pt(dien)GS-Me] 2+ exists as a pair of diastereomers due to different configurations about sulfur. The rate of the inversion of configuration at the coordinated sulfur atom is slow on the NMR time-scale.

Reactions of [PtCl(dien)]Cl with glutathione, oxidized glutathione and S-methyl glutathione. Formation of an S-bridged dinuclear unit

The reaction of the monofunctional platinum compound [PtCl(dien)]Cl with the tripeptide glutathione (GSH), oxidized glutathione (GSSG) and S-methyl glutathione (GS-Me) has been investigated by 1H, 13C and 195Pt magnetic resonance spectroscopy and by potentiometric titrations. It appears that platinum binds with a high degree of specificity to the GSH sulfhydryl group. The reaction of platinum with GSH proceeds in two steps. In the first step only one platinum binds to the sulfur atom and, in the second step, another [Pt(dien)] 2+ unit binds to [Pt(dien)GS] + forming an S-bridged dinuclear unit [{Pt(dien)} 2GS] 3+. The rate of the first binding step is pH-dependent, whereas the rate of the second step is not. At pH < 7 the rate of the first binding step is slow compared to the rate of the second binding step. At pH > 10, on the other hand, the rate of the first binding step is faster than the rate of the second binding step. Consequently, at pH < 7 one can only isolate the [{Pt(dien)} 2GS] 3+ complex. In the presence of free GSH, at pH > 7, one [Pt(dien)] 2+ unit of [{Pt(dien)} 2GS] 3+ dissociates forming [Pt(dien)GS] +. The mechanism of the pH-dependent rate of the first platinum binding step and the ligand-exchange reaction are discussed. GSSG reacts with [Pt(dien)] 2+, also forming the S-bridged dinuclear unit [{Pt(dien)} 2GS] 3+, probably through a redox disproportionation reaction with a catalytic function of [PtCl(dien)]Cl. GS-Me reacts with [Pt(dien)] 2+ forming the S-coordinated [Pt(dien)GS-Me] 2+. [Pt(dien)GS-Me] 2+ exists as a pair of diastereomers due to different configurations about sulfur. The rate of the inversion of configuration at the coordinated sulfur atom is slow on the NMR time-scale.

A new approach to the synthesis of aryldifluorophosphines. Formation of cis-dichloro-bis(aryldifluorophosphine)platinum(II) complexes

Reaction of chlorodifluorophosphine with aryllithium compounds has been found to furnish aryldifluorophosphines. This type of reaction is applicable to any aromatic system for which a regioselective lithiation is possible. The most stable products are those in which the PF 2 group is protected by two neighbouring groups, in the 2- and 6- position of an aromatic ring. The 19F- and 31P- n.m.r. spectra of the aryldifluorophosphines are presented and discussed. Evidence for several lines of spontaneous transformation of aryldifluorophosphines has been obtained: (i) scrambling reaction with formation of bis-aryl-fluorophosphines and phosphorus trifluoride, and (ii) redox disproportionation with formation of aryltetrafluorophosphoranes and cyclopolyphosphines, respectively. In both cases, the underlying reaction mechanism seems to be similar in nature. A number of cis-dichloro-bis-(aryldifluorophosphine) platinum(II) complexes, involving the new difluorophosphines, have been prepared. The 19F- and 31P - n.m.r. spectra of these complexes are discussed in relation to those of the uncoordinated ligands. Also, the fragmentation pathway of the platinum(II) complexes in their mass spectra has been deduced and is discussed.

ESR study on the reactions of iron carbonyls with nitro and nitrosoparaffines. A mechanism of the reductive carbonylation of nitro compounds

The interaction of Fe n (CO) m , ( n and m equal 1 and 5, 2 and 9, 3 and 12, respectively) with 2-methyl-2-nitrosopropane and sodium salts of nitromethane and nitrocyclohexane was studied. The initial stages of the process, following the activating complex-formation, involves redox disproportionation to give rise to the radical Fe(I) carbonyl complexes and radical anions Fe 2(CO) 8 − . ( I) Fe 3(CO) 11 − . ( II), Fe 4(CO) 13 − . ( III) and Fe 3(CO) 12 − . ( IV). Also, radical anions I– IV are formed in the interaction of salts of carbonyl ferrate anions Na 2Fe(CO) 4·1.5 diox and PPN 2[Fe n (CO) m−1 ] (where PPN = (PPh 3) 2N +), with nitro- and nitroso-tert-butane. Radical anions I– III act as catalytically active species in the coordination sphere of which the nitro compounds undergo a successive deoxygenation to nitrene radical complexes with their subsequent carbonylation to isocyanates. A scheme of the reductive carbonylation is proposed.

A study of the acid-base transformations of oxodihydrothiochrome

The acid-base properties of oxodihydrothiochrome — the product of the redox disproportionation of the vitamin B1 catabolite thiochrome (pH=10.7, 4.5, and 0.5) — have been studied in the pH interval of 0–12 by PMR spectroscopy. It has been established that in acid medium (pH 0–1) the formation of a doubly charged ion is accompanied by a further structural transformation of the molecule of (I) with the formation of a vitamin B1 analogue — oxothiamine (II). A possible mechanism of the action of (I) as an inhibitor of thiamine-dependent enzymes is discussed in the light of the results obtained. Details of the PMR spectra of (I) and (II) are given.

Reactions of anionic nitrogen heterocycles with iron carbonyls

Redox disproportionation of iron carbonyls to carbonylferrate anions and Fe +, Fe 2+ compounds occurs during the reaction of these carbonyls with both free azoles and their sodium salts. It is assumed that coordination of azole anion to iron carbonyl takes place and that the species formed acts as a one-electron reducing agent towards iron, iron carbonyl anion-radicals, detected by ESR, being formed on the initial stage of the reaction.

The reactions of tetrahydrothiophene (tht) with tribromosulphidoniobium(V) and trichlorosulphidoniobium(V) and the crystal structures of three of the products Nb2Cl4S3·4tht, Nb2Br4S3·4tht, and NbBr3S·2tht

The niobium(IV) compounds [(tht)2X2Nb(µ-S)(µ-S2)NbX2(tht)2][X = Cl (1) or Br (2)] are formed through a complex redox–disproportionation reaction when NbX3S is treated with tetrahydrothiophene (tht). The reduction occurs via the oxidation of two formal S2– ions to S22–. It is thought that initially NbX3S·2tht (3) is formed in the reaction. The reaction has been characterised by crystal-structure determinations of compounds (1), (2), and (3; X = Br) : (1), monoclinic, space group P21/c, a= 12.483(15), b= 11.818(17), c= 19.798(17)A, β= 97.3(1)°, and Z= 4; (2), triclinic, space group P, a= 11.826(11), b= 12.021(11), c= 10.813(13)A, α= 101.4(1), β= 96.2(2), γ= 98.8(2)°, and Z= 2; (3), monoclinic, space group P21/m, a= 8.018(12), b= 8.802(15), c= 11.887(12)A, β= 103.9(1)°, and Z= 2.1 968 Independent diffractometer data for (1) have been refined to R 0.068, 522 and 571 to 0.061 and 0.064 for (2) and (3) respectively. The structures of compounds (1) and (2) are similar in that they contain two niobium atoms bridged by a sulphur atom and a disulphide group. The Nb–Nb distances of 2.844(2) and 2.830(5)A respectively are indicative of a single metal–metal interaction. The metal co-ordination spheres are completed by two halogen atoms and two sulphur atoms of the tht ligands. In compound (3) the metal atom is six-co-ordinate, being bonded to a terminal sulphur, three bromine atoms, and two tht ligands through sulphur atoms. The multiple NbS bond is trans to a tht ligand. Both compounds (1) and (3) are disordered.

ChemInform Abstract: HETEROCYCLIC ANALOGS OF PLEIADIENE. XXIII. REDOX DISPROPORTIONATION OF N‐SUBSTITUTED ACEPERIMIDONES. CASE OF THE UNUSUALLY EASY REDUCTION OF THE CARBON‐OXYGEN GROUP

Chemischer InformationsdienstVolume 7, Issue 31 Heterocyclic Compounds ChemInform Abstract: HETEROCYCLIC ANALOGS OF PLEIADIENE. XXIII. REDOX DISPROPORTIONATION OF N-SUBSTITUTED ACEPERIMIDONES. CASE OF THE UNUSUALLY EASY REDUCTION OF THE CARBON-OXYGEN GROUP T. I. VINOKUROVA, T. I. VINOKUROVASearch for more papers by this authorA. F. POZHARSKII, A. F. POZHARSKIISearch for more papers by this author T. I. VINOKUROVA, T. I. VINOKUROVASearch for more papers by this authorA. F. POZHARSKII, A. F. POZHARSKIISearch for more papers by this author First published: August 3, 1976 https://doi.org/10.1002/chin.197631270Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume7, Issue31August 3, 1976 RelatedInformation

Phosphorus-fluorine chemistry—XXXVI: Preparation and chemistry of thienyldifluorophosphine

2-Thienyldifluorophosphine has been prepared by chlorine-fluorine exchange in the corresponding dichlorophosphine; the difluorophosphine has been found to undergo redox disproportionation with formation of 2-thienyltetrafluorophosphorane and pentathienylcyclopentaphosphine. Upon reaction with nickel carbonyl, 2-thienyldifluorophosphine forms a tetrasubstituted derivative which may be oxidized by iodine to give tris(thienyldifluorophosphine)nickel(II)iodide. Di- and tri-substituted derivatives of molybdenum carbonyl have been obtained through displacement of the coordinated cycloolefin by the fluorophosphine in bicycloheptadienetetracarbonyl molybdenum and cycloheptatrient-tricarbonyl molybdenum. All compounds were characterized by i.r., n.m.r., and mass spectrometry. A comparison of δ P values for thienyl-phosphorus compounds with data for the analogous phenyl-phosphorus compounds has shown a high-field shift for the thiophene derivatives in every case. A comparison of δ F values has shown the opposite effect.