Relativistic Hirshfeld atom refinement of an organo-gold(I) compound

Sylwia Pawlędzio; Maura Malinska; Magdalena Woińska; Jakub Wojciechowski; Lorraine Andrade Malaspina; Florian Kleemiss; Simon Grabowsky; Krzysztof Woźniak

doi:10.1107/S2052252521004541

Relativistic Hirshfeld atom refinement of an organo-gold(I) compound

IUCrJ. 2021 May 26;8(Pt 4):608-620. doi: 10.1107/S2052252521004541. eCollection 2021 Jul 1.

Authors

Sylwia Pawlędzio¹, Maura Malinska¹, Magdalena Woińska¹, Jakub Wojciechowski², Lorraine Andrade Malaspina³, Florian Kleemiss³, Simon Grabowsky³, Krzysztof Woźniak¹

Affiliations

¹ Biological and Chemical Research Centre, Department of Chemistry, University of Warsaw, Żwirki i Wigury 101, Warszawa 02-089, Poland.
² Rigaku Europe SE, Hugenottenallee 167, 63263 Neu-Isenburg, Germany.
³ Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, Bern 3012, Switzerland.

Abstract

The main goal of this study is the validation of relativistic Hirshfeld atom refinement (HAR) as implemented in Tonto for high-resolution X-ray diffraction datasets of an organo-gold(I) compound. The influence of the relativistic effects on statistical parameters, geometries and electron density properties was analyzed and compared with the influence of electron correlation and anharmonic atomic motions. Recent work in this field has indicated the importance of relativistic effects in the static electron density distribution of organo-mercury compounds. This study confirms that differences in electron density due to relativistic effects are also of significant magnitude for organo-gold compounds. Relativistic effects dominate not only the core region of the gold atom, but also influence the electron density in the valence and bonding region, which has measurable consequences for the HAR refinement model parameters. To study the effects of anharmonic motion on the electron density distribution, dynamic electron density difference maps were constructed. Unlike relativistic and electron correlation effects, the effects of anharmonic nuclear motion are mostly observed in the core area of the gold atom.

Keywords: Hirshfeld atom refinement; aspherical atom model; relativistic effects.

Grants and funding

This work was funded by Narodowe Centrum Nauki grant UMO-2018/31/N/ST4/02141; European Social Fund; European Regional Development Fun; Foundation for Polish Science grant 115.