Mono-Substitution of iron pentacarbonyl catalyzed by polynuclear iron carbonyl anions

The specific formation of LFe(CO)₄ (L = PPh₃, P(OPh)₃, P(OMe)₃ can be achieved by the reaction of Fe(CO)₅ with L in the presence of a catalytic amount of iron carbonyl anion. A convenient synthetic procedure was developed in which the iron carbonyl anion catalyst is generated in situ. It is shown that the mechanism does not proceed by the simple cleavage of the Fe₂(CO)₈^2? or Fe₃(CO)₁₁^2? anions, because triphenylphosphine reacts with these anions in the absence of Fe(CO)₅ to produce (PPh₃)₂Fe(CO)₃.     

A new method for the preparation of some carbonyl metalate anions

Reaction of anhydrous metal halides with sodium metal in the presence of cyclooctatetraene in tetrahydrofuran under carbon monoxide at atmospheric pressure yields the hexacarbonyl metalate anions of vanadium, niobium and tantalum, [M(CO)₆]^?. Yields as high as 85% of [V(CO)₆]^? were achieved by this method.     

Synthesis and some reactions of silicon phthalocyanine anions

The reactions of PcSi(OH)₂ or Me₃Si(OSiPc)_1–3 OSiMe₃ with Na or K afford anions of silicon mono-, di-, and triphthalocyanines (Pc_1–3) characterized by electronic absorption and EPR spectra. The reactions of the Pc_1–3 anions with proton donors (H₂O and CH₃COOH), Me₃SiCl, and O₂ are carried out. The Pc_1–3 anions in THF are reduced to the Pc ₁ ^3? monophthalocyanine trianion with the partial rearrangement of the phthalocyanine into corrole. In benzene the reactions of Pc_1–3 with Na or K occur only with an additive of crown ether (15C5): Na reduces Pc₁ to the Pc ₁ ^2? dianion, Pc₂ and Pc₃ do not react with Na, and potassium reduces Pc_1–3 to the P trianion.     

Intermolecular reactions of chlorohydrine anions: acetalization of carbonyl compounds under basic conditions

[reaction: see text] Nonenolizable aldehydes and ketones react with 2-chloroethanol and 3-chloropropanol under basic conditions (t-BuOK, DMF/THF) with formation of 2-substituted 1,3-dioxolanes and 1,3-dioxanes, respectively. Conversion of the two-step addition-alkylation process depends on the electrophilicity of the carbonyl group that governs the equilibrium of addition of chloroalkoxides. This method of protection of carbonyl groups in the form of cyclic acetals under kinetically controlled conditions is complementary to the acid-catalyzed reaction with diols.     

The reactions of some 1,1,1-tribromo-alkyl systems with thiolate anions

Compounds containing a 1,1,1-tribromoethyl group are normally dehydrobrominated by reaction with sodium thiolates. If a 1,1,1-tribromobut-3-ene fragment is present cyclisation to a 2,2-dibromocyclopropylmethyl thioether or rearrangement are also observed.     

Matrix isolated metal carbonyl anions

Cocondensation at 20K of sodium atoms with transition metal carbonyls (e.g. Cr(CO)₆) diluted in argon gives IR spectroscopic evidence for carbonyl anions (e.g. Cr(CO)₅⁻).     

Stereoselective reactions of α-silylallyl anions with carbonyl compounds.

α-silylallyl anions of the type 6 react with carbonyl compounds at the γ-position, and stereoselectively to give the E- or Z-isomer depending on the reaction conditions. Solvent and reaction temperature play a critical role in the controle of stereoselectivity.     

Addition reactions of a polynuclear osmium hydrido compound leading to associative carbonyl substitution and catalytic alkene isomerisation

The ability of H₂Os₃(CO)₁₀ to undergo addition reactions under mild conditions allows associative CO substitution via isolable intermediates of the type H₂Os₃(CO)₁₀ (L = CO, PMe₂Ph, PPh₃ or PhCN) whose spectra and structures are discussed. It is probable that simple addition of alkenes to H₂Os₃(CO)₁₀ is in part responsible for its facile catalysis of alkene isomerisation. The kinetics of catalytic conversion of terminal to internal alkenes and of allylic alcohols to aldehydes or ketones are reported and discussed. The reactions of H₂Os₃(CO)₁₀ with allylic halides to give the complexes HOs₃X(CO)₁₀ and Os₃X₂(CO)₁₀ where X = Cl, Br or I are described. Compound H₂Os₃(CO)₁₀ complies with the 18ρ-rule but nevertheless has a chemistry much like that of coordinatively unsaturated molecules.     

1-Amino-2-hydrazinobenzimidazole and its reactions with some carbonyl compounds

1-Amino-2-hydrazinobenzimidazole was obtained for the first time by treating 1-aminobenzimidazole-2-sulfonic acid with hydrazine hydrate. This compound readily condensed with aromatic aldehydes involving both amino groups. The condensation with 2,4-pentanedione affords 1-amino-2-(3,5-dimethylpyrazol-1-yl)benzimidazole, and with α-ketoacids in glacial acetic acid yields mixtures of 10-acetylamino-3-R-1,2,4-triazino[4,3-a]benzimidazol-4(10H)-ones and 4-amino-2-R-1,2,4-triazino[2,3-a]benzimidazol-3(4H)-ones.     

The formation of iron carbonyl radical anions in the reactions of iron carbonyls with trimethylamine N-oxide

The interaction of iron carbonyls, Fe(CO)₅, Fe₂(CO)₉ and Fe₃(CO)₁₂ with Me₃NO occurs according to a one-electron redox-disproportionation scheme giving rise to iron carbonyl radical anions: Fe₂(CO)₈^·− (1), Fe₃(CO)₁₂^·− (2), Fe₃(CO)₁₁^·− (3) and Fe₄(CO)₁₃^·− (4). The role of Me₃NO, inducing CO-substitution, consists of the generation of reactive 17-electron species with a labile coordination sphere in which the substitution for other ligands occurs, resulting from fast ligand and electron exchange in the confines of the ETC-reaction.     

A synthesis and some reactions of 2-thiocyanato-2-ethylenic carbonyl compounds

A synthesis of 2-thiocyanato-2-ethylenic carbonyl compounds was achieved by the reaction of epoxy ketones with Ph₃P(SCN)₂ (TPPT). Some useful transformations of 2-thiocyanato-2-cyclohexenone to 2,3-disubstituted cyclohexanones and iminothiazolines are described.     

Complexing,exchange and reactions of tungsten hexafluoride with some simple anions

Complex formation is observed between WF₆ and many anions. Arrhenius activation energies for exchange between free and complexed WF₆ are given for WF₆N₃⁻ and WF₆CN⁻. It is shown that exchange occurs via a displacement mechanism. Bands in the vibrational spectra of N₃⁻, WF₆N₃⁻ and WF₅N₃ are presented.     

Gas-phase reactivity of ruthenium carbonyl cluster anions

Partially-ligated anionic ruthenium carbonyl clusters react with alkenes, arenes, and alkanes in the gas phase; the products undergo extensive C-H activation and lose dihydrogen and carbon monoxide under collision-induced dissociation conditions. Triethylsilane and phenylsilane are also reactive towards the unsaturated clusters, and oxygen was shown to rapidly break down the cluster core by oxidative cleavage of the metal-metal bonds. These qualitative gas-phase reactivity studies were conducted using an easily-installed and inexpensive modification of a commercial electrospray ionization mass spectrometer. Interpretation of the large amounts of data generated in these studies is made relatively straightforward by employing energy-dependent electrospray ionization mass spectrometry (EDESI-MS).     

A potentiometric study of the reactions of some anions with 1,2,4,6-tetraphenylpyridinium acetate. II. Organic anions

Summary A new titrant, 1,2,4,6-tetraphenylpyridinium acetate, has been evaluated for the potentiometric precipitation titration of semimicro amounts of a series of organic anions. Emf's were monitored with a perchlorate ion-selective electrode and a double-junction reference electrode. The nitrate and fluoroborate ion-selective electrodes also responded to the various anions. The classes of compounds which can be determined are nitroform and some nitroform-yielding compounds, phenylborates, 2,4,6-trinitro compounds, some dinitrophenols and nitrophenols, some halogenated phenols and others.

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Zusammenfassung 1,2,4,6-Tetraphenyrpyridiniumacetat wurde für die potentiometrische Fällungstitration von Halbmikromengen einer Reihe organischer Anionen herangezogen. Die elektromotorische Kraft wurde mit einer ionenselektiven Perchloratelektrode und einer doppelt verbundenen Bezugselektrode gemessen. Auch ionenselektive Nitrat- und Fluoboratelektroden sprechen auf die verschiedenen Anionen an. Folgende Verbindungsgruppen können so bestimmt werden: Nitroform und dessen Verbindungen, Phenylborate, 2,4,6-Trinitroverbindungen, einige Dinitro- und Mononitrophenole, manche Halogenphenole und dgl.

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Parts of this paper were presented at the 9th Meeting of the JANNAF Propellant Characterization Subcommittee Meeting at the U. S. Air Force Academy, Colorado Springs, CO, June 6–8, 1978. — Work performed under the auspices of the U. S. Department of Energy by the Lawrence Livermore Laboratory under contract number W-7405-ENG-48.     

Substitution reactions of pyrroloanthrones

Pyrroloanthrone (6H-naphth[1,2,3-c,d]indol-6-one) and N-methylpyrroloanthrone, which was obtained from it by methylation in alkaline media, undergo electrophilic substitution (nitration, bromination, and diazo coupling) selectively in the 1 position. Nucleophilic substitution of 1-bromopyrroloanthrone is hindered by ionization at the nitrogen atom but takes place smoothly in the case of its N-methyl derivative. N-Methylpyrroloanthrone iscapable of undergoing substitution of the hydrogen atom in the 1 position by a nucleophile residue.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1356–1360, October, 1978.     

Bond strengths in cyclopentadienyl metal carbonyl anions

Energy-resolved collision-induced dissociation of metal cyclopentadienyl carbonyl anions CpM(CO)_x⁻(Cpc-C₅H₅, MV, Cr, Mn, Fe, Co) is used to determine metal–carbonyl bond energies in these systems. These bond energies are, in general, slightly stronger than those for the corresponding homoleptic metal carbonyl anions. The bond strength in CpCo(CO)₂⁻, a 19-electron complex, is notably weaker than most of the others. D[CpMn⁻-CO] is also weak; this is attributed to a mismatch in the electronic ground states of CpMn⁻ and CpMnCO⁻. D[CpCo⁻-CO], on the other hand, is substantially larger than the others, and is comparable to the bond energy measured in solution for CpMn(CO)₃.     

Reactions of carbon dioxide with metal carbonyl anions

The reactivity of a series of metal carbonyl anions with CO₂ has been found to parallel their relative nucleophilicities. The highly nucleophilic species, C₅H₅Fe(CO)^?₂, reacts readily to give the dimer, (C₅H₅Fe(CO)₂)₂, and carbonate while Co(CO)^?₄ is unreactive. The reaction of ¹³CO₂ with C₅H₅Fe(CO)^?₂ results in the formation of the ¹³CO enriched dimer.