A Remarkable cis‐ and trans‐Spanning Dibenzylidene Acetone Diphosphine Chelating Ligand (dbaphos). Issue 19 (11th March 2013)

• Record Type: Journal Article
• Authors: Jarvis, Amanda G.; Sehnal, Petr E.; Bajwa, Somia E.; Whitwood, Adrian C.; Zhang, Xiangbiao; Cheung, Man Sing; Lin, Zhenyang; Fairlamb, Ian J. S.
• Is Part Of: Chemistry. Volume 19:Issue 19(2013)
• Page Start: 6034
• Page End: 6043
• Publication Date: 2013-03-11
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201203691
• Languages: English
• ISSNs: 0947-6539

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>A multidentate and flexible diolefin–diphosphine ligand, based on the dibenzylidene acetone core, namely dbaphos (<bold>1</bold>), is reported herein. The ligand adopts an array of different geometries at Pt, Pd and Rh. At Pt^II the dbaphos ligand forms <italic>cis‐</italic> and <italic>trans</italic>‐diphosphine complexes and can be defined as a wide‐angle spanning ligand. ¹H NMR spectroscopic analysis shows that the β‐hydrogen of one olefin moiety interacts with the Pt^II centre (an anagostic interaction), which is supported by DFT calculations. At Pd⁰ and Rh^I, the dbaphos ligand exhibits both olefin and phosphine interactions with the metal centres. The Pd⁰ complex of dbaphos is dinuclear, with bridging diphosphines. The complex exhibits the coordination of one olefin moiety, which is in dynamic exchange (intramolecular) with the other "free" olefin. The Pd⁰ complex of dbaphos reacts with iodobenzene to afford <italic>trans</italic>‐[Pd^II(dbaphos)I(Ph)]. In the case of Rh^I, dbaphos coordinates to form a structure in which the phosphine and olefin moieties occupy both axial and equatorial sites, which stands in contrast to a related bidentate olefin, phosphine ligand ("Lei" ligand), in which the olefins occupy the equatorial sites and phosphines the axial sites, exclusively.</p> </abstract>