DFT study of the mechanism of hydroamination of ethylene with ammonia catalyzed by diplatinum(II) complexes: Inner‐ or outer‐sphere?

A detailed analysis of the reaction profiles of the hydroamination reaction between ethylene and ammonia catalyzed by the diplatinum(II) [{Pt(NH2)(μ‐H)(PPh3)}2] complex is presented herein using density functional theory computational techniques. The coordinatively unsaturated 14e T‐shaped [Pt(NH2)(PPh3)H] species resulted from the dissociation of the diplatinum [{Pt(NH2)(μ‐H)(PPh3)}2] precatalyst are identified as the active catalytic species. All possible reaction pathways that constitute the entire catalytic cycle have exhaustively been investigated. Overall, the rate‐determining step of all catalytic cycles constructed was found to be the oxidative addition of ammonia that leads to the regeneration of the catalyst. According to the energy span model, the outer‐sphere mechanism for the hydroamination of ethylene with ammonia catalyzed by the diplatinum complexes is favored over the inner‐sphere one, whereas TOF values are in favor of the inner‐sphere mechanism. © 2012 Wiley Periodicals, Inc.

[1]  T. Müller,et al.  Hydroamination: direct addition of amines to alkenes and alkynes. , 2008, Chemical reviews.

[2]  Gernot Frenking,et al.  A set of f-polarization functions for pseudo-potential basis sets of the transition metals ScCu, YAg and LaAu , 1993 .

[3]  A. Odom.  New C-N and C-C bond forming reactions catalyzed by titanium complexes. , 2005, Dalton transactions.

[4]  J. Spencer,et al.  Hydrosilylation of olefins catalysed by trans-di-µ-hydrido-bis(tricyclohexylphosphine)bis(silyl)diplatinum complexes , 1977 .

[5]  H. Senn,et al.  Toward an alkene hydroamination catalyst: static and dynamic ab initio DFT studies , 2000 .

[6]  S. Tobisch.  Mechanism and exo-regioselectivity of organolanthanide-mediated intramolecular hydroamination/cyclization of 1,3-disubstituted aminoallenes: a computational study. , 2006, Chemistry.

[7]  A. Ellern,et al.  A zwitterionic zirconium complex that catalyzes hydroamination of aminoalkenes at room temperature. , 2010, Chemical communications.

[8]  R. L. Cowan,et al.  Syntheses, reactions, and molecular structures of trans-hydrido(phenylamido)bis(triethylphosphine)platinum(II) and trans-hydridophenoxobis(triethylphosphine)platinum(II) , 1989 .

[9]  Richard L Martin,et al.  Revised Basis Sets for the LANL Effective Core Potentials. , 2008, Journal of chemical theory and computation.

[10]  Stephen J. Lee,et al.  Electrophilic activation of alkenes by platinum(II): so much more than a slow version of palladium(II). , 2007, Angewandte Chemie.

[11]  Frauke Pohlki,et al.  The catalytic hydroamination of alkynes. , 2003, Chemical Society reviews.

[12]  S. Tobisch.  Intramolecular hydroamination/cyclisation of aminoallenes mediated by a neutral zirconocene catalyst: a computational mechanistic study. , 2007, Chemistry.

[13]  C. Bender,et al.  Platinum-catalyzed intramolecular hydroamination of unactivated olefins with secondary alkylamines. , 2005, Journal of the American Chemical Society.

[14]  D. Roundhill,et al.  Addition of water and ammonia to the carbon–carbon double bond of acyclic alkenes and strained bicyclic dienes; a computational study , 1999 .

[15]  S. Tobisch.  Organolanthanide-mediated intramolecular hydroamination/cyclization of conjugated aminodienes: a computational exploration of diverse mechanistic pathways for the regioselective generation of functionalized azacycles supported by a lanthanocene-based catalyst complex. , 2005, Journal of the American Chemical Society.

[16]  S. Buchwald,et al.  Rhodium-catalyzed asymmetric intramolecular hydroamination of unactivated alkenes. , 2009, Angewandte Chemie.

[17]  T. Emge,et al.  Intramolecular aminoalkene hydroamination catalyzed by magnesium complexes containing multidentate phenoxyamine ligands , 2010 .

[18]  S. Shaik,et al.  What makes for a good catalytic cycle? A theoretical study of the role of an anionic palladium(0) complex in the cross-coupling of an aryl halide with an anionic nucleophile , 2005 .

[19]  L. Schafer,et al.  Zirconium bis(pyridonate): a modified amidate complex for enhanced substrate scope in aminoalkene cyclohydroamination. , 2010, Dalton transactions.

[20]  S. Ge,et al.  Neutral and Cationic Rare Earth Metal Alkyl and Benzyl Compounds with the 1,4,6-Trimethyl-6-pyrrolidin-1-yl-1,4-diazepane Ligand and Their Performance in the Catalytic Hydroamination/Cyclization of Aminoalkenes , 2008 .

[21]  W. Gan,et al.  Monoalkyllanthanide Complexes with New β-Diketiminato Derivative Dianionic Ligands , 2009 .

[22]  C. Tsipis,et al.  Hydrosilylation, hydrocyanation, and hydroamination of ethene catalyzed by bis(hydrido-bridged)diplatinum complexes: Added insight and predictions from theory , 2007 .

[23]  Pavel A. Dub,et al.  Hydroamination of ethylene by aniline: catalysis in water , 2010 .

[24]  Seong Du Lee,et al.  Intermolecular hydroamination of ethylene and 1-alkenes with cyclic ureas catalyzed by achiral and chiral gold(I) complexes. , 2009, Journal of the American Chemical Society.

[25]  A. Tsipis.  Upright or In-Plane Conformational Preference: Dilemma of η2-Coordinated C═C Double Bond in PtX2(CO)(η2-ene) (X = H, Cl, or C6F5) Complexes , 2008 .

[26]  Giovanni Scalmani,et al.  Energies, structures, and electronic properties of molecules in solution with the C‐PCM solvation model , 2003, J. Comput. Chem..

[27]  P. Swiderek,et al.  Low-energy-electron-induced hydroamination of an alkene. , 2009, Angewandte Chemie.

[28]  Pavel A. Dub,et al.  A computational study of solution equilibria of platinum-based ethylene hydroamination catalytic species including solvation and counterion effects: Proper treatment of the free energy of solvation , 2010 .

[29]  Carsten Müller,et al.  Mechanism of the intramolecular hydroamination of alkenes catalyzed by neutral indenyltitanium complexes: a DFT study. , 2008, Chemistry.

[30]  T. Marks,et al.  Phenylene-Bridged Binuclear Organolanthanide Complexes as Catalysts for Intramolecular and Intermolecular Hydroamination , 2009 .

[31]  Pavel A. Dub,et al.  The Pt-catalyzed ethylene hydroamination by aniline: a computational investigation of the catalytic cycle. , 2010, Journal of the American Chemical Society.

[32]  S. Shaik,et al.  How to conceptualize catalytic cycles? The energetic span model. , 2011, Accounts of chemical research.

[33]  A. Lledós,et al.  Mechanistic Comparison of Acid- and Gold(I)-Catalyzed Nucleophilic Addition Reactions to Olefins , 2010 .

[34]  David Feller.  The role of databases in support of computational chemistry calculations , 1996 .

[35]  R. Bergman,et al.  The mechanism of hydroamination of allenes, alkynes, and alkenes catalyzed by cyclopentadienyltitanium-imido complexes: a density functional study. , 2001, Angewandte Chemie.

[36]  N. Chu,et al.  The First Platinum-Catalyzed Hydroamination of Ethylene , 2004 .

[37]  Jun Li,et al.  Basis Set Exchange: A Community Database for Computational Sciences , 2007, J. Chem. Inf. Model..

[38]  M. Stradiotto,et al.  [Ir(COD)Cl]2 as a catalyst precursor for the intramolecular hydroamination of unactivated alkenes with primary amines and secondary alkyl- or arylamines: a combined catalytic, mechanistic, and computational investigation. , 2010, Journal of the American Chemical Society.

[39]  S. Tobisch.  Intramolecular hydroamination/cyclisation of aminoallenes mediated by a cationic zirconocene catalyst: a computational mechanistic study. , 2006, Dalton transactions.

[40]  R. L. Cowan,et al.  Regioselective insertion of acrylonitrile into the platinum-nitrogen bond of hydrido(phenylamido)bis(triethylphosphine)platinum(II). A model step for olefin amination , 1987 .

[41]  M. Eisen,et al.  Recent advances in organothorium and organouranium catalysis. , 2008, Chemical Society reviews.

[42]  N. Chu,et al.  Platinum‐Catalyzed Intermolecular Hydroamination of Alkenes: Halide‐Anion‐Promoted Catalysis , 2007 .

[44]  V. Barone,et al.  Quantum Calculation of Molecular Energies and Energy Gradients in Solution by a Conductor Solvent Model , 1998 .

[45]  I. Fragalà,et al.  Energetics and Mechanism of Organolanthanide-Mediated Aminoalkene Hydroamination/Cyclization. A Density Functional Theory Analysis , 2004 .

[46]  R. Hoffmann,et al.  Ethylene complexes. Bonding, rotational barriers, and conformational preferences , 1979 .

[47]  G. Clarkson,et al.  Mechanism of catalytic cyclohydroamination by zirconium salicyloxazoline complexes. , 2010, Journal of the American Chemical Society.

[48]  J. Hartwig,et al.  Catalytic organometallic reactions of ammonia. , 2011, Angewandte Chemie.

[49]  J. Yadav,et al.  Recent progress in transition metal catalysed hydrofunctionalisation of less activated olefins , 2011 .

[50]  P. Diaconescu,et al.  Inter- and Intramolecular Hydroamination with a Uranium Dialkyl Precursor , 2010 .

[51]  W. R. Wadt,et al.  Ab initio effective core potentials for molecular calculations. Potentials for main group elements Na to Bi , 1985 .

[52]  W. R. Wadt,et al.  Ab initio effective core potentials for molecular calculations , 1984 .

[53]  T. Marks,et al.  Organolanthanide-catalyzed hydroamination. , 2004, Accounts of chemical research.

[54]  R. Widenhoefer,et al.  Platinum-Catalyzed Intermolecular Hydroamination of Unactivated Olefins with Carboxamides , 2004 .

[55]  S. Tobisch.  Is an M-N sigma-bond insertion route a viable alternative to the M=N [2+2] cycloaddition route in intramolecular aminoallene hydroamination/cyclisation catalysed by neutral zirconium bis(amido) complexes? A computational mechanistic study. , 2008, Chemistry.

[56]  W. R. Wadt,et al.  Ab initio effective core potentials for molecular calculations. Potentials for K to Au including the outermost core orbitals , 1985 .

[57]  S. Blechert,et al.  Diethylzinc: A Simple and Efficient Catalyst for the Swift Hydroamination at Room Temperature , 2009 .

[58]  S. Tobisch.  Mechanistic exploration of intramolecular aminodiene hydroamination/cyclisation mediated by constrained geometry organoactinide complexes: a DFT study. , 2010, Chemistry.

[59]  W. Leitner,et al.  A computational study of rhodium pincer complexes with classical and nonclassical hydride centres as catalysts for the hydroamination of ethylene with ammonia. , 2010, Chemistry.

[60]  A. Reznichenko,et al.  C2-Symmetric Zirconium Bis(Amidate) Complexes with Enhanced Reactivity in Aminoalkene Hydroamination , 2010 .

[61]  D. Truhlar,et al.  A new local density functional for main-group thermochemistry, transition metal bonding, thermochemical kinetics, and noncovalent interactions. , 2006, The Journal of chemical physics.

[62]  T. Marks,et al.  Mechanistic investigation of intramolecular aminoalkene and aminoalkyne hydroamination/cyclization catalyzed by highly electrophilic, tetravalent constrained geometry 4d and 5f complexes. Evidence for an M-N sigma-bonded insertive pathway. , 2007, Journal of the American Chemical Society.

[64]  C. Tsipis.  Investigation of the factors controlling the regioselectivity of the hydrosilylation of alkynes catalysed by trans-di-μ-hydridobis(tricylcohexylphosphine)bis(silyl)diplatinum complexes , 1980 .

[65]  Joseph Haggin,et al.  Chemists Seek Greater Recognition for Catalysis , 1993 .

[66]  R. Widenhoefer,et al.  Platinum(II)-catalyzed intermolecular hydroamination of monosubstituted allenes with secondary alkylamines. , 2010, Chemical communications.

[67]  P. Hunt.  Organolanthanide mediated catalytic cycles: a computational perspective. , 2007, Dalton transactions.

[68]  C. Tsipis.  Relative reactivities of alkynes in hydrosilylation reactions catalysed by trans-di-μ-hydridobis(tricyclohexylphosphine)bis(silyl)diplatinum complexes , 1980 .