Moist Acetonitrile Research Articles

Entrapment of a linear water pentamer into a uranyl-salophen dimer in the solid state

ABSTRACTIn the solid state, uranyl-salophen complex 1, decorated with bipyridyl sidearms, self-assembles from moist acetonitrile into dimeric species displaying a confined water pentamer, as observed by X-ray diffraction on single crystals. The linear water cluster is incarcerated within the dimeric cavity by coordination to the Lewis acidic uranyl centres and by a network of hydrogen bonds established with the pyridinic nitrogen atoms on the sidearms.

Ruthenium(II) Complexes Containing Bis(2-(diphenylphosphino)phenyl) Ether and Their Catalytic Activity in Hydrogenation Reactions

The half-sandwich complexes [(eta5-C5H5)RuCl(DPEphos)] (1) and [{(eta6-p-cymene)RuCl2}2(mu-DPEphos)] (2) were synthesized by the reaction of bis(2-(diphenylphosphino)phenyl) ether (DPEphos) with a mixture of ruthenium trichloride trihydrate and cyclopentadiene and with [(eta6-p-cymene)RuCl2]2, respectively. Treatment of DPEphos with cis-[RuCl2(dmso)4] afforded fac-[RuCl2(kappa3-P,O,P-DPEphos)(dmso)] (3). The dmso ligand in 3 can be substituted by pyridine, 2,2'-bipyridine, 4,4'-bipyridine, and PPh3 to yield trans,cis-[RuCl2(DPEphos)(C5H5N)2] (4), cis,cis-[RuCl2(DPEphos)(2,2'-bipyridine)] (5), trans,cis-[RuCl2(DPEphos)(mu-4,4'-bipyridine)]n (6), and mer,trans-[RuCl2(kappa3-P,P,O-DPEphos)(PPh3)] (7), respectively. Refluxing [(eta6-p-cymene)RuCl2]2 with DPEphos in moist acetonitrile leads to the elimination of the p-cymene group and the formation of the octahedral complex cis,cis-[RuCl2(DPEphos)(H2O)(CH3CN)] (8). The structures of the complexes 1-5, 7, and 8 are confirmed by X-ray crystallography. The catalytic activity of these complexes for the hydrogenation of styrene is studied.

A Mechanistic Reinvestigation of tris-(p-Bromophenyl)aminium Hexachloroantimonate Induced Deketalization

In 1986 Kim et al. reported an interesting property of the title compound in its ability to deprotect in sub-stoichiometric amounts, functionalities such as acetals, ketals, silylethers, tritylether and tetrahydropyranyl ether in moist acetonitrile (% H2O not reported). They proposed that the hydrolysis of 1,3-dioxalanes such as 1 involved a SET mechanism (Scheme 1). Thus, treatment of 1 with tris-(pbromophenyl)aminium hexachloroantimonate (Ar3N +SbCl6−) was assumed to generate 2 which on H loss originated the radical 3 ↔ 4. At this stage two concurrent reactions are envisaged to occur. In the first, a part of H formed is utilised catalytically, in conjunction with the water contained in the solvent, to regenerate the ketone, and in the second, the other part of H protonates the carbanion 5 formed by the reduction of 4 by the tertiary amine (Ar3N → Ar3N +SbCl6−) thus rendering the overall reaction catalytic for both the aminium salt and acid. Presumably, the purported failure of Et4NSbCl6 to bring about the ketal hydrolysis under similar conditions, led the authors to suppose that the first step was oxidative in nature. In connection with other studies currently in progress in our laboratory it became necessary to confirm the validity of this assumption. Therefore the cyclopropyl ketal 6, with a built-in bias to undergo ring-opening in the event of the formation of a radical 6a, akin to 4, was selected for our study.

Kinetics and mechanisms of the formation of a sitting-atop complex of N-alkylporphyrin with Al(III) in moist acetonitrile

The formation of a sitting-atop complex of a N-alkylporphyrin, containing a 6-hydroxyhexyl group, with Al 3+ was studied in moist acetonitrile by equilibrium and kinetic measurements. A sandwich type of metalloporphyrin, where a metal ion binds two N-alkylporphyrins, appears to be formed under the conditions that porphyrins exist in excess over a metal ion. When a large excess of metal ion was used, a 1:1 type of sitting-atop complex of Al(III) N-alkylporphyrin was produced through formation of the sandwich type of Al(III) N-alkylporphyrin.

Kinetics and mechanisms of the formation of a sitting‐atop complex of N‐alkylporphyrin with Al(III) in moist acetonitrile

Kinetics and mechanisms of the formation of a sitting‐atop complex of N‐alkylporphyrin with Al(III) in moist acetonitrile

Self-Assembled Dinuclear Lanthanide Helicates: Substantial Luminescence Enhancement upon Replacing Terminal Benzimidazole Groups by Carboxamide Binding Units.

The segmental ligands bis{1-alkyl-2-[6'-(N,N-diethylcarbamoyl)pyridin-2'-yl]benzimidazol-5-yl}methane (alkyl = methyl (L(5)), ethyl (L(6))) react with lanthanide perchlorates (Ln = La, Eu, Gd, Tb) in acetonitrile to yield the f-f dinuclear homotopic triple-stranded helicates [Ln(2)(L(i)())(3)](6+) (i = 5, 6) under thermodynamic control. The crystal structure of [Tb(2)(L(6))(3)](ClO(4))(3)(MeCN)(2)(THF)(0.5)(EtOH)(0.5) (11a, C(124)H(145)N(26)O(31)Cl(6)Tb(2), triclinic, P&onemacr;, Z = 2) shows the wrapping of the ligands about a pseudo-C(3) axis passing through the metal ions. The Tb ions are 9-coordinate in facial pseudo-tricapped trigonal prismatic sites and are separated by 9.06 Å. (1)H-NMR and ES-MS data establish that the triple helical structure is maintained in solution. Spectrophotometric titrations (Ln = La, Eu) indicate log beta(23) = 24-25 and the formation of a 2:2 complex [Ln(2)(L(5))(2)](6+) (log beta(22) = 19-20). Quantum yield determination in acetonitrile shows that the terminal N,N-diethylcarboxamide groups in L(5) favor efficient intramolecular L(5) --> Eu(III) energy transfers leading to strong Eu-centered red luminescence, 50 times as intense as the luminescence observed when the carboxamide groups are replaced by substituted benzimidazole units in [Eu(2)(L(4))(3)](6+). Resistance toward hydrolysis also results from the use of carboxamide groups, and no quenching of luminescence is observed for [Eu(2)(L(5))(3)](6+) in moist acetonitrile up to 2.5 M water. The crucial role played by carboxamide groups for the control of structural, electronic, and photophysical properties is discussed. Replacing perchlorates by triflates allows the isolation of the dinuclear double-stranded helicate [Eu(2)(L(6))(2)(CF(3)SO(3))(4)(H(2)O(2))(2)](CF(3)SO(3))(2)(MeOH)(2)(H(2)O)(5)(.5), whose crystal structure (13a, C(85)H(106)Eu(2)F(18)N(16)O(30)S(6), monoclinic, C2/m, Z = 2) reveals a side-by-side arrangement of the two strands and 9-coordinate Eu ions linked through hydrogen-bonded water molecules.

Recognition of linear and bent forms of solid μ-oxo-bis[iodotriphenylantimony(V)] (Ph 3SbI) 2O

Two quite different shapes of the (Ph 3SbI) 2O molecule are found in separate crystals, namely 1a, in which the SbOSb bridge is linear with bond distances of 1.9410–1.9437(6) Å and 1b in which the SbOSb angle is 144.6(4)° and the SbO bonds are longer, averaging 1.971(8) Å. The two species also give distinct vibrational spectra. Both arise from the reaction of triphenylantimony with iodine in moist acetonitrile, 1a as the initial crop of colourless crystals and 1b as organe crystals left when the solution is allowed to evaporate to dryness.

Structural chemistry of organotin carboxylates XV. Diorganostannate esters of dicyclohexylammonium hydrogen oxalate. Synthesis, crystal structure and in vitro antitumour activity of bis(dicyclohexyl‐ammonium) bisoxalatodi‐n‐butylstannate and bis(dicyclohexylammonium) μ‐oxalatobis(aquadi‐n‐butyloxalatostannate)

AbstractDicyclohexylamine, oxalic acid dihydrate and di‐n‐butyltin oxide were reacted in 2:2:1 or 2:3:2 stoichiometries in ethanol solution to yield, respectively bis(dicyclohexylammonium) bisoxalatodi‐n‐butylstannate (1) and bis(dicyclohexylammonium) μ‐oxalatobis(aquadi‐n‐butyloxalatostannate) (2); the hydrate was also obtained upon recrystallization of 1 from moist acetonitrile solution. The crystal structures of the two ammonium stannates have been determined at room temperature. In 1, the tin atom in the dianion exists in a skewtrapezoidal bipyramidal geometry with the basal plane being defined by two bidentate oxalate ligands; each ligand forms asymmetric SnO bonds [SnO 2.348(4), 2.110(4) Å and 2.112(4), 2.363(4) Å]. The apical sites are occupied by the two organo groups disposed over the weaker SnO bonds. In 2, the two tin centres of the dianion are connected via a tetradentate oxalate ligand situated about a centre of inversion and each tin atom exists in a pentagonal bipyramidal geometry. The pentagonal plane is defined by four oxygen atoms, two from the central ligand [SnO 2.282(4), 2.473(4)Å] and two from a ‘terminal’ oxalate ligand [SnO 2.239(4), 2.210(4)Å], and the fifth site is occupied by a water molecule of crystallization [SnO 2.422(4)Å]; the apical sites are filled by the n‐butyl groups. Both compounds feature extended hydrogen‐bonded networks involving the oxygen atoms of the dianion and the N‐bound hydrogen atoms. Crystals of 1 are monoclinic, space group P21/n, with cell dimensions a = 13.408(3), b = 22.461(4), c = 13.996(2)Å, β = 100.97(2)°; full‐matrix least‐squares refinement on 3305 reflections with I≥2.5σ(I) converged to R = 0.042 and Rw = 0.046. Crystals of 2 are monoclinic, space group P21/n, a = 13.729(3), b = 14.694(2), c = 14.889(2)Å, β = 104.83(2)º; refinement on 2093 reflections converged to R = 0.030 and Rw = 0.031. The two di‐n‐butylstannates were screened in vitro against the mammary MCF‐7 and WiDr colon carcinoma cell lines, and were found to be as active as cisplatin, a clinically used antineoplastic drug.

α-Oxidation of ketones using n-cation radicals

Six-membered ring ketones and acyclic ketones were oxidized by stable triarylamminium radical cations in moist acetonitrile at room temperature in the presence of a base to α-hydroxy ketones in good yield. Five-membered ring ketones gave the corresponding αβ-unsaturated compounds.

Preparation and electrochemistry of modified polypyrrole films by anodic copolymerization techniques

AbstractThe anodic copolymerization of pyrrole and N‐(ω‐ferrocenylalkyl)pyrroles, FcPy‐n, at platinum electrodes in an electrolyte consisting of tributylammonium benzenesulfonate in moist acetonitrile is optimized with respect to the absolute and relative concentrations of the monomers and the spacer length of FcPy‐n. The copolymer composition is estimated from cyclic voltammograms of the polymer films. Only films with less than 20% FcPy‐n content show the typical polypyrrole voltammograms. Free standing copolymer films with a conductivity of ca. 10 S cm−1 can be prepared.

In-situ electrochemical ESR the oxidation of triphenylacetic acid in acetonitrile

The oxidation of triphenylacetic acid in acetonitrile on platinum electrodes at + 1.94 V (vs. SCE) results in the formation of triphenylmethylcarbonium ions. If the potential is subsequently stepped to values negative of the Φ 3C +/Φ 3C · standard electrode potential (+0.25 V vs. SCE), reduction to the triphenylmethyl radical is seen. In rigorously anhydrous conditions no radicals other than Φ 3C . can be detected by ESR. However in moist acetonitrile, oxidation at +1.94 V followed by reduction at −1.80 V results in complicated spectrum shown to be due to two radicals, namely the radical anions of benzoquinone and benzophenone. A mechanism to account for the formation of these is suggested.

Hydrolysis mechanism of tetrahydroborate(1-) ion in moist acetonitrile. 2. The nature of the intermediate

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHydrolysis mechanism of tetrahydroborate(1-) ion in moist acetonitrile. 2. The nature of the intermediateB. Spencer Meeks Jr. and M. M. KreevoyCite this: J. Am. Chem. Soc. 1979, 101, 17, 4918–4921Publication Date (Print):August 1, 1979Publication History Published online1 May 2002Published inissue 1 August 1979https://doi.org/10.1021/ja00511a021RIGHTS & PERMISSIONSArticle Views83Altmetric-Citations8LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (492 KB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

Hydrolysis mechanism of tetrahydroborate(1-) in moist acetonitrile. 3. Kinetic isotope effects

The present work and a concurrent paper show that, in the presence of acetic acid, BH/sub 4//sup -/ in acetonitrile is rapidly converted to BH/sub 3/OCOCH/sub 3//sup -/ and that previous kinetic studies of the hydrolysis of BH/sub 4//sup -/ in such solutions actually referred to the hydrolysis of BH/sub 3/OCOCH/sub 3//sup -/. As previously shown, the substrate (now shown to be BH/sub 3/OCOCH/sub 3//sup -/) complexes with acetic acid, with a complexing constant of about 160. That complex hydrolyzes by spontaneous and water-catalyzed paths. The present paper shows that the latter reaction is accelerated 15 to 40% by the substitution of D for H on boron. The rate is reduced, by a factor of approx. 1.75, by replacing all the hydroxylic hydrogen with deuterium. These results are consistent with BH/sub 3/OC(CH/sub 3/)O . HOCOCH/sub 3/ as the acetic acid-substrate complex. The displacement of the incipient biacetate ion by water is rate determining in this process. Isotopic substitution at either position reduces the rate of the spontaneous process. Its mechanism is uncertain. 2 figures, 3 tables.

ChemInform Abstract: HYDROLYSIS MECHANISM OF TETRAHYDROBORATE(1‐) IN MOIST ACETONITRILE

Chemischer InformationsdienstVolume 8, Issue 24 Physical Inorganic Chemistry ChemInform Abstract: HYDROLYSIS MECHANISM OF TETRAHYDROBORATE(1-) IN MOIST ACETONITRILE R. F. MODLER, Search for more papers by this authorM. M. KREEVOY, Search for more papers by this author R. F. MODLER, Search for more papers by this authorM. M. KREEVOY, Search for more papers by this author First published: June 14, 1977 https://doi.org/10.1002/chin.197724032AboutPDF 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 onEmailFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume8, Issue24June 14, 1977 RelatedInformation

Hydrolysis mechanism of tetrahydroborate(1-) in moist acetonitrile

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHydrolysis mechanism of tetrahydroborate(1-) in moist acetonitrileRobert F. Modler and Maurice M. KreevoyCite this: J. Am. Chem. Soc. 1977, 99, 7, 2271–2275Publication Date (Print):March 1, 1977Publication History Published online1 May 2002Published inissue 1 March 1977https://doi.org/10.1021/ja00449a041RIGHTS & PERMISSIONSArticle Views85Altmetric-Citations6LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (550 KB) Get e-Alerts Get e-Alerts

Electron spin resonance study of oxygen-17 enrichedN,N-dimethyl-4-nitroaniline radical anion

N,N-Dimethyl-d6-4-nitroaniline enriched to approximately 11 atom. per cent in oxygen-17 has been prepared and the oxygen-17 isotropic hyperfine interaction in the corresponding radical anion has been examined. In dry dimethylformamide solution we find a O = -8·85 ± 0·02 and a N = 11·39 ± 0·10 gauss, while in moist acetonitrile solution a O = -8·82 ± 0·07 and a N = 12·23 ± 0·11 gauss. These results substantiate the recent suggestion that the isotropic oxygen-17 splittings in π-radicals may be described by a single parameter equation analogous to McConnell's relation for aromatic proton splittings, i.e. a O = Q OρO π, where Q O = -41 ± 3 gauss.

Anodic background reaction in moist acetonitrile

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAnodic background reaction in moist acetonitrileLouis C. Portis, J. Conrad. Roberson, and Charles K. MannCite this: Anal. Chem. 1972, 44, 2, 294–297Publication Date (Print):February 1, 1972Publication History Published online1 May 2002Published inissue 1 February 1972https://doi.org/10.1021/ac60310a018RIGHTS & PERMISSIONSArticle Views161Altmetric-Citations22LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (491 KB) Get e-Alerts Get e-Alerts

The reaction of iodine chloride with triphenylarsine dichloride in moist acetonitrile

The reaction of iodine chloride with triphenylarsine dichloride in moist acetonitrile