6476-36-4Relevant academic research and scientific papers
Bis-alkynyl- and hydrido-alkynyl-osmium(II) and ruthenium(II) complexes containing triisopropylphosphine as ligand
Werner, H.,Meyer, U.,Esteruelas, M. A.,Sola, E.,Oro, L. A.
, p. 187 - 196 (1989)
The five-coordinate bis-alkynyl complexes (M=Os, Ru) have been prepared by reaction of with OsH4(CO)(P-i-Pr3)2 or MH(h2-H2BH2)(CO)(P-i-Pr3)2 (M=Os, Ru).They react with ligands L such as P(OMe)3, PMe3, CO and to giv
The first all-cyanide Fe4S4 cluster: [Fe 4S4(CN)4]3-
Scott, Thomas A.,Zhou, Hong-Cai
, p. 5628 - 5631 (2004)
A compound with potential: The title compound (see structure) not only resembles the relevant protein active sites geometrically and spectroscopically, but also possesses the least negative [Fe4S4(L) 4]2-/3- and [Fe4S4(L) 4]3-/4- (L is a monoanionic ligand) redox potentials of all protein Fe4S4 analogues. The value of the Fe 4S4+/0 redox potential implies a new route to the isolation of the elusive Fe4S40 cluster.
A Lewis Base Nucleofugality Parameter, NFB, and Its Application in an Analysis of MIDA-Boronate Hydrolysis Kinetics
García-Domínguez, Andrés,Gonzalez, Jorge A.,Leach, Andrew G.,Lloyd-Jones, Guy C.,Nichol, Gary S.,Taylor, Nicholas P.
supporting information, (2022/01/04)
The kinetics of quinuclidine displacement of BH3 from a wide range of Lewis base borane adducts have been measured. Parameterization of these rates has enabled the development of a nucleofugality scale (NFB), shown to quantify and predict the leaving group ability of a range of other Lewis bases. Additivity observed across a number of series R′3-nRnX (X = P, N; R′ = aryl, alkyl) has allowed the formulation of related substituent parameters (nfPB, nfAB), providing a means of calculating NFB values for a range of Lewis bases that extends far beyond those experimentally derived. The utility of the nucleofugality parameter is explored by the correlation of the substituent parameter nfPB with the hydrolyses rates of a series of alkyl and aryl MIDA boronates under neutral conditions. This has allowed the identification of MIDA boronates with heteroatoms proximal to the reacting center, showing unusual kinetic lability or stability to hydrolysis.
Direct β-Alkenylation of Ketones via Pd-Catalyzed Redox Cascade
Wang, Chengpeng,Rago, Alexander J.,Dong, Guangbin
supporting information, p. 3377 - 3381 (2019/05/10)
A direct β-alkenylation of simple ketones with alkenyl bromides is reported via a Pd-catalyzed redox cascade strategy. The reaction is redox neutral and directing-group-free, in the absence of strong acids or bases. Both cyclic and linear ketones are suitable substrates, and various alkenyl bromides can be coupled. The resulting β-alkenyl ketones are readily derivatized through diverse alkene functionalization.
Structural, Kinetic, and Computational Characterization of the Elusive Arylpalladium(II)boronate Complexes in the Suzuki-Miyaura Reaction
Thomas, Andy A.,Wang, Hao,Zahrt, Andrew F.,Denmark, Scott E.
supporting information, p. 3805 - 3821 (2017/03/20)
The existence of the oft-invoked intermediates containing the crucial Pd-O-B subunit, the “missing link”, has been established in the Suzuki-Miyaura cross-coupling reaction. The use of low-temperature, rapid injection NMR spectroscopy (RI-NMR), kinetic studies, and computational analysis has enabled the generation, observation, and characterization of these highly elusive species. The ability to confirm the intermediacy of Pd-O-B-containing species provided the opportunity to clarify mechanistic aspects of the transfer of the organic moiety from boron to palladium in the key transmetalation step. Specifically, these studies establish the identity of two different intermediates containing Pd-O-B linkages, a tri-coordinate (6-B-3) boronic acid complex and a tetra-coordinate (8-B-4) boronate complex, both of which undergo transmetalation leading to the cross-coupling product. Two distinct mechanistic pathways have been elucidated for stoichiometric reactions of these complexes: (1) transmetalation via an unactivated 6-B-3 intermediate that dominates in the presence of an excess of ligand, and (2) transmetalation via an activated 8-B-4 intermediate that takes place with a deficiency of ligand.
Synthesis and Crystal Structures of Copper Zinc Phenylthiolate and the First Copper Zinc Selenolate and Tellurolate Complexes
Fuhrmann, Daniel,Severin, Tobias,Krautscheid, Harald
, p. 932 - 937 (2017/08/11)
Five copper zinc phenylchalcogenolate complexes [(iPr3PCu)3(ZnMe2)2(SPh)3] (1), [(iPr3PCu)2(ZnPh)4(SPh)6] (2), [(iPr3PCu)2(ZnEt)4(SPh)6] (3), [(iPr3PCu)3(ZnEt)(SePh)4] (4), and [(iPr3PCu)3Cu(iPr3PZn)(TePh)6] (5) were synthesized by the reaction of phosphine stabilized copper phenylchalcogenolate complexes with ZnR2 (R = Me, Et, Ph) with and without additional chalcogenol. The novel mixed metal compounds were characterized by single-crystal X-ray structure analysis and NMR spectroscopy. 4 and 5 are the first examples of compounds with a Zn–Se–Cu or a Zn–Te–Cu linkage, respectively.
Elusive Phosphine Copper(I) Boryl Complexes: Synthesis, Structures, and Reactivity
Borner, Corinna,Anders, Lisa,Brandhorst, Kai,Kleeberg, Christian
supporting information, p. 4687 - 4690 (2018/02/07)
We report the first isolation of phosphine copper boryl complexes - species pivotal to numerous copper-catalyzed borylation reactions. The reaction of diboron(4) derivatives with copper tert-butoxide complexes of phosphine ligands allows the isolation of the dimeric μ-boryl-bridged Cu(I) complexes [(iPr3P)Cu-Bdmab]2 (4) and [(C6H4(Ph2P)2)Cu-Bpin]2 (6) with Cu···Cu distances of 2.24-2.27 ? (dmab = (NMe)2C6H4, pin = (OCMe2)2)). A slightly more sterically demanding boryl ligand furnishes the unprecedented multinuclear copper boryl complex [(iPr3P)2Cu8(B(iPrEn))3(OtBu)3] (5), a potential intermediate of the decomposition of an initial Cu(I) boryl complex (iPrEn = (NiPr)2C2H4). All complexes were characterized by single-crystal X-ray diffraction, NMR spectroscopy, and elemental analysis. DFT computations support the nature of these unique complexes and give insight into their electronic structures.
Synthesis and crystal structures of [(iPr3P)2Cu(μ- ESiMe3)(InMe3)] (E = S, Se): Lewis acid-base adducts with chalcogen atoms in planar coordination
Biedermann, Ralf,Kluge, Oliver,Fuhrmann, Daniel,Krautscheid, Harald
, p. 4727 - 4731 (2013/09/24)
The structures of [(iPr3P)2Cu(μ-SSiMe 3)(InMe3)] and [(iPr3P)2Cu(μ- SeSiMe3)(InMe3)] were determined by single-crystal X-ray diffraction. Both complexes are Lewis acid-base adducts of the InMe3 acceptor and the chalcogen donor atom linking a Me3Si group and a (iPr3P)2Cu moiety. They are very unstable under atmospheric conditions and decompose at ambient temperatures. Results of DFT calculations for these complexes and the related hypothetical [(Me 3P)2Cu(μ-SSiMe3)(InMe3)] compound show that the unusual planar coordination of the chalcogen atoms is due to steric crowding. Lewis acid-base adducts of trimethylindium and phosphane-stabilized copper(I) (trimethylsilyl)chalcogenolates were synthesized and characterized by X-ray crystal structure determination. They are very unstable under atmospheric conditions and decompose at ambient temperatures. DFT calculations reveal that the unusual planar coordination of the chalcogen atoms is due to steric crowding. Copyright
Synthesis and chemistry of bis(triisopropylphosphine) nickel(i) and nickel(0) precursors
Beck, Robert,Shoshani, Manar,Krasinkiewicz, Jonathan,Hatnean, Jillian A.,Johnson, Samuel A.
, p. 1461 - 1475 (2013/03/13)
High yield syntheses of (iPr3P)2NiX (3a-c), (where X = Cl, Br, I) were established by comproportionation of ( iPr3P)2NiX2 (1a-c) with ( iPr3P)2Ni(η2-C2H 4) (2). Reaction of 1a with either NaH or LiHBEt3 provided (iPr3P)2NiHCl (4), along with 3a as a side-product. Reduction of (iPr3P)2NiCl (3a-c) with Mg in presence of nitrogen saturated THF solutions provided the dinitrogen complex [(iPr3P)2Ni]2(μ- η1:η1-N2) (5). In aromatic solvents such as benzene and toluene a thermal equilibrium exists between 5 and the previously reported monophosphine solvent adducts (iPr 3P)Ni(η6-arene) (6a,b). Reaction of 5 with carbon dioxide provided (iPr3P)2Ni(η2- CO2) (7). Thermolysis of 9 at 60 °C provided a mixture of products that included the reduction product (iPr3P) 2Ni(CO)2 (8) along with iPr3PO, as identified by NMR spectroscopy. Complex 8 was also prepared in high yield from the reaction of 5 with CO. Reaction of 5 with CS2 gave the dimeric carbon disulfide complex [(iPr3P)Ni(μ- η1:η2-CS2)]2 (9). Diphenylphosphine reacts with 5 to form the dinuclear Ni(i) complex [( iPr3P)Ni(μ2-PPh2)]2 (10). Complex 5 reacts with PhSH to form (iPr3P) 2Ni(SPh)(H) (11), which slowly loses H2 and iPr3P to form the dimeric Ni(i) complex [( iPr3P)Ni(μ2-SPh)]2 (12) at room temperature. Complex 12 was also accessed by salt metathesis from the reaction of (iPr3P)2NiCl (3a) with PhSLi, which demonstrates the utility of 3a as a Ni(i) precursor. With the exception of 6a,b, all compounds were structurally characterized by single-crystal X-ray crystallography. The Royal Society of Chemistry 2013.
An acidity scale for phosphorus-containing compounds including metal hydrides and dihydrogen complexes in THF: Toward the unification of acidity scales
Abdur-Rashid, Kamaluddin,Fong, Tina P.,Greaves, Bronwyn,Gusev, Dmitry G.,Hinman, Justin G.,Landau, Shaun E.,Lough, Alan J.,Morris, Robert H.
, p. 9155 - 9171 (2007/10/03)
More than 70 equilibrium constants K between acids and bases, mainly phosphine derivatives, have been measured in tetrahydrofuran (THF) at 20 °C by 1H and/or 31P NMR. The acids were chosen or newly synthesized in order to cover the wide pK(α)(THF) range of 5-41 versus the anchor compound [HPCy3]BPh4 at 9.7. These pK(α)(THF) values are approximations to absolute, free ion pK(a)(THF) and are obtained by crudely correcting the observed K for 1:1 ion-pairing effects by use of the Fuoss equation. The acid/base compounds include 14 phosphonium/phosphine couples, 17 cationic hydride/neutral hydride couples, 9 neutral polyhydride/anionic hydride couples, 14 dihydrogen/hydride couples, and 4 other nitrogen- and phosphorus-based acids. The effects on pK(α) of the counterions BAr'4- and BF4- vs BPh4- and [K(2,2,2-crypt)]+ versus [K(18-crown-6)+ are found to be minor after correcting for differences in inter-ion distances in the ion-pairs involved. Correlations with v(M-H) noted here for the first time suggest that destabilization of M-H bonding in the conjugate base hydride is an important contributor to hydride acidity. It appears that Re-H bonding in the anions [ReH6(PR3)2- is greatly weakened by small increases in the basicity of PR3, resulting in a large increase in the pK(α) of the conjugate acid ReH7(PR3)2. Correlations with other scales allow an estimate of the pK(α)(THF) values of more than 1000 inorganic and organic acids, 20 carbonyl hydride complexes, 46 cationic hydrides complexes, and dihydrogen gas. Therefore, many new acid-base reactions can be predicted and known reactions explained. THF, with its low dielectric constant, disfavors the ionization of neutral acids HA over HB+ and therefore separate lines are found for pK(α)(THF)(HA) and pK(α)(THF)(HB+) when plotted against pK(a)(DMSO) or pK(a)(MeCN). The crystal structure of [Re(H)2(PMe3)5]BPh4 is reported.
