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Updated: Aug 5, 2026

Experimental Approaches for the Synthesis of Low-Valent Metal-Organic Frameworks from Multitopic Phosphine Linkers
Published on: May 12, 2023
Diphosphaindenyl π-complexes as a platform for hapticity-controlled metaloligand design
David Zuber1, Michael Neuwirt1, Peter Coburger1
1Department of Inorganic Chemistry, TU München, Lichtenbergstraße 4, 85747 Garching, Germany. peter.coburger@tum.de.
Abstract:
Owing to the indenyl effect, phosphonium-substituted diphosphaindenyl (PPIAr) π-complexes of 3d metal carbonyl fragments provide access to distinct η5 and η3 coordination modes, enabling systematic modulation of their metaloligand behavior. Specifically, reaction of [Cr(CO)3(η5-PPItol)] (1) and [Fe(CO)3(η3-PPIPh)] (2) with coinage metal salts leads to the formation of the trimetallic complexes [AuCl{Fe(CO)3(η3-PPIPh)}2] (4), [Ag{Fe(CO)3(η3-PPIPh)}2][OTf] ([5][OTf]) and [Ag{Cr(CO)3(η5-PPItol)}2][BF4] ([6][BF4]). While the iron-based metaloligands act as σ-donors via phosphorus lone pairs, the chromium complex adopts a distinct η4, μ2 bridging coordination mode enabling covalent metal-metal interactions. As such, [6][BF4] represents a rare example of a structurally characterised complex featuring Cr-Ag bonding. Energy decomposition analysis attributes the divergent metaloligand behavior primarily to a balance between non-orbital interaction terms and geometric preparation energies.
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