Title: Is the Inversion of Phosphorus Trihalides (PF3, PCl3, PBr3, and PI3) a Diradical Process?

Journal Article · · Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory
ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [2]
  1. University of Minnesota, Minneapolis, MN (United States); University of Minnesota
  2. University of Minnesota, Minneapolis, MN (United States)
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This work explores possible reaction paths for the inversion of a series of trigonal pyramidal phosphorus trihalides, PF3, PCl3, PBr3, and PI3, and it especially addresses the question of whether and when the bonding of the lowest-energy species along the inversion paths should be described as a hyper open-shell diradical. The various paths for inversion are calculated using a single-reference method within the framework of Kohn-Sham density functional theory and also with multi-reference wave function methods. Our calculated results using both kinds of methods show that, for all the halogens studied (F, Cl, Br, and I), the lowestenergy singlet path for the inversion occurs by the formation of a C2v transition structure rather than a D3h transition structure. This geometrical preference agrees with what has been inferred previously based on closed-shell singlet calculations. But in the present study, we examined not only closed-shell singlet transition states but also open-shell singlet states and triplet states for calculating stationary points and inversion paths, and for some of the phosphorus trihalides, we found that paths involving open-shell configurations are lower in energy than those restricted to closed-shell configurations. We analyzed the changes along the paths in terms of hybridization and orientation of the frontier orbitals and in terms of locally avoided crossings, and the extent of diradical character was quantified by calculating the effective number of unpaired electrons. Even for the singlet inversion path that goes via a D3h structure, the barrier for PF3, PCl3, and PBr3 is higher for a closed-shell singlet spin state than for the open-shell singlet configuration. Furthermore, the energy of the triplet D3h structure is below even the open-shell D3h singlet for PCl3, PBr3, and PI3. This necessitates rethinking the role of open-shell states in nominally closedshell processes.

Research Organization:
University of Minnesota, Minneapolis, MN (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences & Biosciences Division (CSGB)
Grant/Contract Number:
SC0008688
OSTI ID:
2311179
Journal Information:
Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory, Journal Name: Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory Journal Issue: 1 Vol. 123; ISSN 1089-5639
Publisher:
American Chemical SocietyCopyright Statement
Country of Publication:
United States
Language:
English

References (38)

Variational Transition State Theory with Multidimensional Tunneling book January 2007
The complete active space SCF method in a fock-matrix-based super-CI formulation journal March 1980
Molpro: a general-purpose quantum chemistry program package: Molpro
  • Werner, Hans-Joachim; Knowles, Peter J.; Knizia, Gerald
  • Wiley Interdisciplinary Reviews: Computational Molecular Science, Vol. 2, Issue 2 https://doi.org/10.1002/wcms.82
journal July 2011
Distribution of odd electrons in ground-state molecules journal January 1978
The M06 suite of density functionals for main group thermochemistry, thermochemical kinetics, noncovalent interactions, excited states, and transition elements: two new functionals and systematic testing of four M06-class functionals and 12 other functionals journal July 2007
Why edge inversion? Theoretical characterization of the bonding in the transition states for inversion in F n NH(3−n) and FnPH(3−n) (n = 0–3) journal May 2014
An efficient second-order MC SCF method for long configuration expansions journal April 1985
On the inversion barriers of group 15 tricoordinate hydrides and halides: An ab initio study using analytical gradients journal March 1988
Characterizing unpaired electrons from the one-particle density matrix journal April 2003
Understanding the reactivity of transition metal complexes involving multiple spin states journal March 2003
Spin-state changes and reactivity in transition metal chemistry: Reactivity of iron tetracarbonyl book July 2009
Comment on ‘Characterizing unpaired electrons from one-particle density matrix’ [M. Head-Gordon, Chem. Phys. Lett. 372 (2003) 508–511] journal October 2003
Reply to comment on ‘characterizing unpaired electrons from the one-particle density matrix’ journal October 2003
Hyper Open-Shell Excited Spin States of Transition-Metal Compounds: FeF 2 , FeF 2 ···Ethane, and FeF 2 ···Ethylene journal February 2018
Two-State Reactivity as a New Concept in Organometallic Chemistry § journal March 2000
Low coordinate hypervalent phosphorus journal July 1994
Intermolecular interactions from a natural bond orbital, donor-acceptor viewpoint journal September 1988
Using Hessian Updating To Increase the Efficiency of a Hessian Based Predictor-Corrector Reaction Path Following Method journal October 2004
The restricted active space self-consistent-field method, implemented with a split graph unitary group approach journal July 1990
Trends in Inversion Barriers of Group 15 Compounds. 2. Ab-Initio and Density Functional Calculations on Group 15 Fluorides journal October 1994
Electronic Structures and Gas-Phase Reactivities of Cationic Late-Transition-Metal Oxides journal November 1994
Periodic trends in the edge and vertex inversion barriers for tricoordinate pnicogen hydrides and fluorides journal January 1987
A new inversion process at Group VA (Group 15) elements. Edge inversion through a planar T-shaped structure journal April 1986
Direct determination of the barrier to edge inversion at trivalent phosphorus: verification of the edge inversion mechanism journal October 1986
Exact tunneling calculations journal April 1971
Hyper Open-Shell States: The Lowest Excited Spin States of O Atom, Fe 2+ Ion, and FeF 2 journal August 2017
Recoupled Pair Bonding in PFn(n= 1−5)† journal August 2010
Inversion Processes in Phosphines and Their Radical Cations:  When Is a Pseudo-Jahn−Teller Effect Operative? journal July 1998
A look at the density functional theory zoo with the advanced GMTKN55 database for general main group thermochemistry, kinetics and noncovalent interactions journal January 2017
Balanced basis sets of split valence, triple zeta valence and quadruple zeta valence quality for H to Rn: Design and assessment of accuracy journal January 2005
Electronic and substituent effects on the barrier to edge inversion journal January 1987
The inversion barriers of PH3, PH2F, PHF2, and PF3 journal October 1981
A second order multiconfiguration SCF procedure with optimum convergence journal June 1985
Determinant based configuration interaction algorithms for complete and restricted configuration interaction spaces journal August 1988
Reaction path power series analysis of NH3 inversion journal November 1990
Second‐order perturbation theory with a complete active space self‐consistent field reference function journal January 1992
Theory of electronic transitions in slow atomic collisions journal April 1981
Implicit and Explicit Coverage of Multi-reference Effects by Density Functional Theory journal June 2002

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