Dataset Information

The thermochemistry of london dispersion-driven transition metal reactions: getting the 'right answer for the right reason'.

ABSTRACT: Reliable thermochemical measurements and theoretical predictions for reactions involving large transition metal complexes in which long-range intramolecular London dispersion interactions contribute significantly to their stabilization are still a challenge, particularly for reactions in solution. As an illustrative and chemically important example, two reactions are investigated where a large dipalladium complex is quenched by bulky phosphane ligands (triphenylphosphane and tricyclohexylphosphane). Reaction enthalpies and Gibbs free energies were measured by isotherm titration calorimetry (ITC) and theoretically 'back-corrected' to yield 0 K gas-phase reaction energies (?E). It is shown that the Gibbs free solvation energy calculated with continuum models represents the largest source of error in theoretical thermochemistry protocols. The ('back-corrected') experimental reaction energies were used to benchmark (dispersion-corrected) density functional and wave function theory methods. Particularly, we investigated whether the atom-pairwise D3 dispersion correction is also accurate for transition metal chemistry, and how accurately recently developed local coupled-cluster methods describe the important long-range electron correlation contributions. Both, modern dispersion-corrected density functions (e.g., PW6B95-D3(BJ) or B3LYP-NL), as well as the now possible DLPNO-CCSD(T) calculations, are within the 'experimental' gas phase reference value. The remaining uncertainties of 2-3 kcal mol(-1) can be essentially attributed to the solvation models. Hence, the future for accurate theoretical thermochemistry of large transition metal reactions in solution is very promising.

SUBMITTER: Hansen A

PROVIDER: S-EPMC4234214 | biostudies-literature | 2014 Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

The thermochemistry of london dispersion-driven transition metal reactions: getting the 'right answer for the right reason'.

Hansen Andreas A Bannwarth Christoph C Grimme Stefan S Petrović Predrag P Werlé Christophe C Djukic Jean-Pierre JP

ChemistryOpen 20140904 5

Reliable thermochemical measurements and theoretical predictions for reactions involving large transition metal complexes in which long-range intramolecular London dispersion interactions contribute significantly to their stabilization are still a challenge, particularly for reactions in solution. As an illustrative and chemically important example, two reactions are investigated where a large dipalladium complex is quenched by bulky phosphane ligands (triphenylphosphane and tricyclohexylphospha ...[more]

PMID: 25478313

Similar Datasets

Project description:BackgroundAt the start of the COVID-19 pandemic, guidance was needed more than ever to direct frontline healthcare and national containment strategies. Rigorous guidance based on robust research was compromised by the emergence of the pandemic and the urgency of need for guidance. Rather than aiming to "get guidance right", guidance developers needed to "get guidance right now".AimTo examine how guidance developers have responded to the need for credible guidance at the start of the COVID-19 pandemic.MethodsAn exploratory mixed-methods study was conducted among guidance developers. A web-based survey and follow-up interviews were used to examine the most pertinent challenges in developing COVID-19 guidance, strategies used to address these, and perspectives on the implications of the COVID-19 pandemic on future guidance development.ResultsThe survey was completed by 46 guidance developers. Survey findings showed that conventional methods of guidance development were largely unsuited for COVID-19 guidance, with 80% (n = 37) of respondents resorting to other methods. From the survey and five follow-up interviews, two themes were identified to bolster the credibility of guidance in a setting of extreme uncertainty: (1) strengthening end-user involvement and (2) conjoining evidence review and recommendation formulation. 70% (n = 32) of survey respondents foresaw possible changes in future guidance production, most notably shortening development time, by reconsidering how to balance between rigour and speed for different types of questions.Conclusion"Getting guidance right" and "getting guidance right now" are not opposites, rather uncertainties are always part of guidance development and require guidance developers to balance scientific robustness with usability, acceptability, adequacy and contingency. This crisis points to the need to acknowledge uncertainties of scientific evidence more explicitly and points to mechanisms to live with such uncertainty, thus extending guidance development methods and processes more widely.

Dataset Information

The thermochemistry of london dispersion-driven transition metal reactions: getting the 'right answer for the right reason'.

Publications

The thermochemistry of london dispersion-driven transition metal reactions: getting the 'right answer for the right reason'.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets