Atomically Precise Expansion of Unsaturated Silicon Clusters

• Published in: Angewandte Chemie International Edition Vol. 58; no. 15; pp. 5124 - 5128
• Main Authors: Leszczyńska, Kinga I., Huch, Volker, Präsang, Carsten, Schwabedissen, Jan, Berger, Raphael J. F., Scheschkewitz, David
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01-04-2019; John Wiley and Sons Inc
• Edition: International ed. in English
• Subjects: anions; Apexes; Catalysis; Chemical vapor deposition; cluster compounds; Clusters; Communication; Communications; Expansion; Intermediates; Lithium; main group elements; Naphthalene; Organic chemistry; Reducing agents; Silicon; subvalent compounds; cluster compounds; silicon; subvalent compounds; main group elements; anions
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.201811331

Small‐ to medium‐sized clusters occur in various areas of chemistry, for example, as active species of heterogeneous catalysis or as transient intermediates during chemical vapor deposition. The manipulation of stable representatives is mostly limited to the stabilizing ligand periphery, virtually excluding the systematic variation of the property‐determining cluster scaffold. We now report the deliberate expansion of a stable unsaturated silicon cluster from six to seven and finally eight vertices. The consecutive application of lithium/naphthalene as the reducing agent and decamethylsilicocene as the electrophilic source of silicon results in the expansion of the core by precisely one atom with the potential of infinite repetition.
A stable unsaturated Si6R6 cluster was consecutively expanded to the stable neutral and anionic clusters Si7R6, Si7R5−, and Si8R6. Key to this method is the use of decamethylsilicocene (Cp*2Si) as the electrophile with Cp*− as the leaving group.