scispace - formally typeset

Journal ArticleDOI

The Pt-catalyzed ethylene hydroamination by aniline: a computational investigation of the catalytic cycle.

07 Sep 2010-Journal of the American Chemical Society (American Chemical Society)-Vol. 132, Iss: 39, pp 13799-13812

TL;DR: A full QM DFT study without system simplification and with the inclusion of solvation effects in anilines as solvent has addressed the addition of aniline to ethylene catalyzed by PtBr(2)/Br(-.
Abstract: A full QM DFT study without system simplification and with the inclusion of solvation effects in aniline as solvent has addressed the addition of aniline to ethylene catalyzed by PtBr2/Br−. The resting state of the catalytic cycle is the [PtBr3(C2H4)]− complex (II). A cycle involving aniline activation by N−H oxidative addition was found energetically prohibitive. The operating cycle involves ethylene activation followed by nucleophilic addition of aniline to the coordinated ethylene, intramolecular transfer of the ammonium proton to the metal center to generate a 5-coordinate (16-electron) PtIV−H intermediate, and final reductive elimination of the PhNHEt product. Several low-energy ethylene complexes, namely trans- and cis-PtBr2(C2H4)(PhNH2) (IV and V) and trans- and cis-PtBr2(C2H4)2 (VII and VIII) are susceptible to aniline nucleophilic addition to generate zwitterionic intermediates. However, only [PtBr3CH2CH2NH2Ph]− (IX) derived from PhNH2 addition to II is the productive intermediate. It easily tran...
Topics: Oxidative addition (56%), Aniline (56%), Hydroamination (56%), Reductive elimination (55%), Ethylene (52%)

Content maybe subject to copyright    Report

HAL Id: hal-03177581
https://hal.archives-ouvertes.fr/hal-03177581
Submitted on 23 Mar 2021
HAL is a multi-disciplinary open access
archive for the deposit and dissemination of sci-
entic research documents, whether they are pub-
lished or not. The documents may come from
teaching and research institutions in France or
abroad, or from public or private research centers.
L’archive ouverte pluridisciplinaire HAL, est
destinée au dépôt et à la diusion de documents
scientiques de niveau recherche, publiés ou non,
émanant des établissements d’enseignement et de
recherche français ou étrangers, des laboratoires
publics ou privés.
The Pt-Catalyzed Ethylene Hydroamination by Aniline:
A Computational Investigation of the Catalytic Cycle
Pavel Dub, Rinaldo Poli
To cite this version:
Pavel Dub, Rinaldo Poli. The Pt-Catalyzed Ethylene Hydroamination by Aniline: A Computational
Investigation of the Catalytic Cycle. Journal of the American Chemical Society, American Chemical
Society, 2010, 132 (39), pp.13799-13812. �10.1021/ja1051654�. �hal-03177581�

1
The Pt-catalyzed ethylene hydroamination by aniline: a Computational
Investigation of the Catalytic Cycle
Pavel A. Dub
a
and Rinaldo Poli*
,a,b
a
CNRS; LCC (Laboratoire de Chimie de Coordination); Université de Toulouse; UPS, INP; F-
31077 Toulouse, France ; 205, route de Narbonne, F-31077 Toulouse, France; Fax: (+) 33-
561553003; E-mail: poli@lcc-toulouse.fr
b
Institut Universitaire de France, 103, bd Saint-Michel, 75005 Paris, France

2
Summary
A full QM DFT study without system simplification and with the inclusion of solvation effects in
aniline as solvent has addressed the addition of aniline to ethylene catalyzed by PtBr
2
/Br
-
. The
resting state of the catalytic cycle is the [PtBr
3
(C
2
H
4
)]
-
complex (II). A cycle involving aniline
activation by N-H oxidative addition was found energetically prohibitive. The operating cycle
involves ethylene activation followed by nucleophilic addition of aniline to the coordinated
ethylene, intramolecular transfer of the ammonium proton to the metal center to generate a 5-
coordinate (16- electron) Pt
IV
-H intermediate, and final reductive elimination of the PhNHEt
product. Several low energy ethylene complexes, namely trans- and cis-PtBr
2
(C
2
H
4
)(PhNH
2
)
(IV and V) and trans- and cis-PtBr
2
(C
2
H
4
)
2
(VII and VIII) are susceptible to aniline
nucleophilic addition to generate zwitterionic intermediates. However, only
[PtBr
3
CH
2
CH
2
NH
2
Ph]
-
(IX) derived from PhNH
2
addition to II is the productive intermediate. It
easily transfers a proton to the Pt atom to yield [PtHBr
3
(CH
2
CH
2
NHPh)]
-
(XX), which leads to
rate-determining C-H reductive elimination through transition state TS(XX-L) with formation of
the -complex [PtBr
3
(k
2
:C,H-HCH
2
CH
2
NHPh)]
-
(L), from which the product can be liberated
via ligand substitution by a new C
2
H
4
molecule to regenerate II. Saturated (18-electron) Pt
IV
hydride complexes obtained by ligand addition or by chelation of the aminoalkyl ligand liberate
the product through higher energy pathways. Other pathways starting from the zwitterionic
intermediates were also explored (intermolecular N deprotonation followed by C protonation or
chelation to produce platina(II)azacyclobutane derivatives; intramolecular proton transfer from N
to C, either direct or assisted by an external aniline molecule) but all gave higher-energy
intermediates or led to the same rate determining TS(XX-L).
Keywords: platinum, homogeneous catalysis, hydroamination, non-activated olefins, DFT
calculations

3
Introduction
Hydroamination, the direct formation of a new C-N bond by addition of an N-H bond
across an unsaturated CC bond, currently attracts much interest in academia and industry.
1-3
The
intermolecular version of this process is still a great challenge, especially for non-activated
olefins. Seminal work by Coulson showed that ethylene could be hydroaminated by a few highly
basic secondary amines under forcing conditions with RhCl
3
(or IrCl
3
) as catalyst.
4, 5
More
recently, this system was found effective also for less basic amines such as aniline when
modified by the addition of n-Bu
4
PI/I
2
.
6
Other relevant results for the intermolecular
hydroamination of ethylene and other non activated olefins comprise the use of lanthanides,
7, 8
Fe,
9
Ru,
10-12
Rh,
13
Ag,
14
Au,
15-18
Pd,
19, 20
and notably Pt.
21-23
Investigations initiated in our team
by J.-J. Brunet have shown that PtBr
2
, in the presence of nBu
4
PX (X = halide) as activator, is one
of the most performing catalyst so far reported for the hydroamination of ethylene by weakly
basic amines such as aniline and 2-chloroaniline (highest activity for X = Br; TON > 150 after
10 h at 150°C with 0.3 mol % of Pt- precursor).
24-27
Without a clear mechanistic understanding,
however, it is difficult to imagine how to further improve the process efficiency for its potential
application in bulk chemical manufacture.
Two alternative mechanisms are discussed in the literature, one starting with amine
activation by N-H oxidative addition and the other one based on amine nucleophilic addition to a
coordinated olefin. The amine activation mechanism is mostly proposed for Rh- or Ir-based
catalytic systems,
28, 29
whereas the olefin activation mechanism seems adopted by catalysts based
on group 10
30
and 11 metals.
31
Senn and coworkers reported a computational study of the model
NH
3
addition to ethylene catalyzed by the [MCl(PH
3
)(C
2
H
4
)]
z+
complexes of Group 9 (z = 0) and
10 (z = 1) metals.
32
For the group 10 metals, for which only the olefin activation pathway has
been explored, they found that the NH
3
nucleophilic addition is thermodynamically and
kinetically favourable and that the cleavage step is rate-determining (barrier of 34.9 kcal mol
-1

4
for Pt). On the other hand, Tsipis and Kefalidis, using the “Pt
0
model complex Pt(C
2
H
4
)(PH
3
),
explored only the amine activation pathway, finding the reaction to be limited by the product
reductive elimination step from the Pt
II
amido hydrido intermediate (barrier of 39.7 kcal mol
-1
).
33
Other computational studies (e.g. on gold catalysis for diene hydroamination
31
or palladium
catalysis for the intermolecular hydroamination of vinylarenes
34
and for the asymmetric
intramolecular hydroamination of aminoalkenes
35
) have also explored solely the olefin activation
mechanism. To the best of our knowledge, with the exception of the above mentioned study by
Tsipis and Kefalidis and a study on iridium reported only in a Ph.D. thesis,
36
studies of the N-H
activation pathway have only been reported for alkaline-earths,
37
early transition metals
38-41
and
the lanthanides.
42-48
On the basis of known chemical transformations for related systems and on conventional
wisdom, the Brunet Pt-based system was proposed to follow the ethylene activation pathway as
shown in Scheme 1.
26
However, whether the proton transfer from N to C from the zwitterionic
intermediate occurs directly or via a Pt-hydride intermediate remained open to debate. The
proton transfer process was considered as more facile from the anionic tribromo species
[PtBr
3
(CH
2
CH
2
NH
2
Ph)]
-
because of the anticipated increased basicity, a hypothesis consistent
with the observed activity enhancement when using a moderate excess amount of bromide
salts.
24
+CH
2
=CH
2
-Br
-
+ArNH
2
-Br
-
[PtBr
4
]
2-
+ArNH
2
[(ArNH
2
)PtBr
2
CH
2
CH
2
-NH
2
Ar]
+ArNH
2
ArNHCH
2
CH
3
H
+Br
-
-ArNH
2
[PtBr
2
] + 2 Br
-
[PtBr
3
]
-
+ Br
-
[PtBr
3
(C
2
H
4
)]
-
[PtBr
3
CH
2
CH
2
-NH
2
Ar]
-
[PtBr
3
CH
2
CH
2
-NHAr]
-
[PtBr
2
(ArNH
2
)(C
2
H
4
)]

Figures (9)
Citations
More filters

Journal ArticleDOI
Liangbin Huang1, Matthias Arndt1, Käthe Gooßen1, H. Heydt1  +1 moreInstitutions (1)

636 citations


Journal ArticleDOI
TL;DR: This article reviews recent developments and applications in the area of computational electrochemistry, focusing on predicting the reduction potentials of electron transfer and other electrochemical reactions and half-reactions in both aqueous and nonaqueous solutions.
Abstract: This article reviews recent developments and applications in the area of computational electrochemistry. Our focus is on predicting the reduction potentials of electron transfer and other electrochemical reactions and half-reactions in both aqueous and nonaqueous solutions. Topics covered include various computational protocols that combine quantum mechanical electronic structure methods (such as density functional theory) with implicit-solvent models, explicit-solvent protocols that employ Monte Carlo or molecular dynamics simulations (for example, Car–Parrinello molecular dynamics using the grand canonical ensemble formalism), and the Marcus theory of electronic charge transfer. We also review computational approaches based on empirical relationships between molecular and electronic structure and electron transfer reactivity. The scope of the implicit-solvent protocols is emphasized, and the present status of the theory and future directions are outlined.

303 citations


Journal ArticleDOI
Athanassios C. Tsipis1Institutions (1)
Abstract: An overview of recent progress in DFT application to coordination chemistry is presented. Some recent applications that best illustrate the promise of DFT in a number of very active areas of coordination chemistry, such as catalysis (mechanistic studies), bonding (electronic and bonding character) electronic spectroscopy (absorption and emission spectra) and heavy-nucleus NMR spectroscopy are reviewed. Particular emphasis was given to the practical aspects that may be interesting for experimentalists that wish to employ DFT alongside to their experimental work. General instructions of how to select the proper DFT computational protocol for a particular study are outlined.

161 citations



Journal ArticleDOI
Abstract: This Perspective article outlines some of the recent advancements completed in the development of (chiral) metal-free and late-transition metal catalysts for the inter- and intramolecular hydroamination of unactivated alkenes, including allenes, 1,3-dienes and strained alkenes. Particular attention has been given to the description of the substrate scope and functional group tolerance of the noteworthy catalytic developments. The relevant literature from 2009 until 2014 has been covered.

120 citations


References
More filters

Journal ArticleDOI
Abstract: Despite the remarkable thermochemical accuracy of Kohn–Sham density‐functional theories with gradient corrections for exchange‐correlation [see, for example, A. D. Becke, J. Chem. Phys. 96, 2155 (1992)], we believe that further improvements are unlikely unless exact‐exchange information is considered. Arguments to support this view are presented, and a semiempirical exchange‐correlation functional containing local‐spin‐density, gradient, and exact‐exchange terms is tested on 56 atomization energies, 42 ionization potentials, 8 proton affinities, and 10 total atomic energies of first‐ and second‐row systems. This functional performs significantly better than previous functionals with gradient corrections only, and fits experimental atomization energies with an impressively small average absolute deviation of 2.4 kcal/mol.

80,847 citations


Journal ArticleDOI
Chengteh Lee1, Weitao Yang1, Robert G. Parr1Institutions (1)
TL;DR: Numerical calculations on a number of atoms, positive ions, and molecules, of both open- and closed-shell type, show that density-functional formulas for the correlation energy and correlation potential give correlation energies within a few percent.
Abstract: A correlation-energy formula due to Colle and Salvetti [Theor. Chim. Acta 37, 329 (1975)], in which the correlation energy density is expressed in terms of the electron density and a Laplacian of the second-order Hartree-Fock density matrix, is restated as a formula involving the density and local kinetic-energy density. On insertion of gradient expansions for the local kinetic-energy density, density-functional formulas for the correlation energy and correlation potential are then obtained. Through numerical calculations on a number of atoms, positive ions, and molecules, of both open- and closed-shell type, it is demonstrated that these formulas, like the original Colle-Salvetti formulas, give correlation energies within a few percent.

77,776 citations


Journal ArticleDOI
Abstract: A new implementation of the conductor-like screening solvation model (COSMO) in the GAUSSIAN94 package is presented. It allows Hartree−Fock (HF), density functional (DF) and post-HF energy, and HF and DF gradient calculations: the cavities are modeled on the molecular shape, using recently optimized parameters, and both electrostatic and nonelectrostatic contributions to energies and gradients are considered. The calculated solvation energies for 19 neutral molecules in water are found in very good agreement with experimental data; the solvent-induced geometry relaxation is studied for some closed and open shell molecules, at HF and DF levels. The computational times are very satisfying: the self-consistent energy evaluation needs a time 15−30% longer than the corresponding procedure in vacuo, whereas the calculation of energy gradients is only 25% longer than in vacuo for medium size molecules.

6,673 citations


Journal ArticleDOI
Abstract: Two recently published density functionals (A.D. Becke, J. Chem. Phys. 88 (1988) 1053 and C. Lee, W. Yang and R.G. Parr, Phys. Rev. B 37 (1988) 785) are used to calculate the correlation energies of first-row atoms, ions and molecules. The correlation contributions to ionization energies, electron affinities and dissociation energies thus obtained are of comparable quality to those of other density functionals.

5,865 citations


Journal ArticleDOI
TL;DR: The conductor‐like solvation model, as developed in the framework of the polarizable continuum model (PCM), has been reformulated and newly implemented in order to compute energies, geometric structures, harmonic frequencies, and electronic properties in solution for any chemical system that can be studied in vacuo.
Abstract: The conductor-like solvation model, as developed in the framework of the polarizable continuum model (PCM), has been reformulated and newly implemented in order to compute energies, geometric structures, harmonic frequencies, and electronic properties in solution for any chemical system that can be studied in vacuo Particular attention is devoted to large systems requiring suitable iterative algorithms to compute the solvation charges: the fast multipole method (FMM) has been extensively used to ensure a linear scaling of the computational times with the size of the solute A number of test applications are presented to evaluate the performances of the method

5,727 citations


Performance
Metrics
No. of citations received by the Paper in previous years
YearCitations
20213
20201
20184
20171
20164
20156