The Butterfly Complex [{Cp*Cr(CO)3}2(μ, η1:1‐P4)] as a Versatile Ligand and Its Unexpected P1/P3 Fragmentation. Issue 51 (17th August 2020)

• Record Type: Journal Article
• Authors: Grünbauer, Rebecca; Balázs, Gábor; Scheer, Manfred
• Is Part Of: Chemistry. Volume 26:Issue 51(2020)
• Page Start: 11722
• Page End: 11726
• Publication Date: 2020-08-17
• Subjects: coordination -- P1/P3-fragmentation -- P4 activation -- phosphinidene -- polyphosphorus complexes; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.202002957
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: The versatile coordination behavior of the P4 butterfly complex [{Cp*Cr(CO)3 }2 (μ, η 1:1 ‐P4 )] (1 ) towards Lewis acidic pentacarbonyl compounds of Cr, Mo and W is reported. The reaction of 1 with [W(CO)4 (nbd)] (nbd=norbornadiene) yields the complex [{Cp*Cr(CO)3 }2 (μ3, η 1:1:1:1 ‐P4 ){W(CO)4 }] (2 ) in which 1 serves as a chelating P4 butterfly ligand. In contrast, reactions of 1 with [M(CO)4 (nbd)] (M=Cr (a ), Mo (b )) result in the step‐wise formation of [{Cp*Cr(CO)2 }2 (μ3, η 3:1:1 ‐P4 ){M(CO)5 }] (3 a, b ) and [{Cp*Cr(CO)2 }2 ‐(μ4, η 3:1:1:1 ‐P4 ){M(CO)5 }2 ] (4 a, b ) which contain a folded cyclo‐P4 unit. Complex 4 a undergoes an unprecedented P1 /P3 ‐fragmentation yielding the cyclo‐P3 complex [Cp*Cr(CO)2 (η 3 ‐P3 )] (5 ) and the as yet unknown phosphinidene complex [Cp*Cr(CO)2 {Cr(CO)5 }2 (μ3 ‐P)] (6 ). The identity of 6 is confirmed by spectroscopic methods and by the in situ formation of [{Cp*Cr(CO)2 ( t BuNC)}P{Cr(CO)5 }2 ( t BuNC)] (7 ). DFT calculations throw light on the bonding situation of the reported products. Abstract : Unprecedented P1 /P3 ‐fragmentation : The versatile P4 butterfly complex [{Cp*Cr(CO)3 }2 (μ, η 1:1 ‐P4 )] reacts with [Cr(CO)4 ] fragments to afford a folded deltoid cyclo ‐P4 unit stabilized by [Cp*Cr(CO)2 ] and [Cr(CO)5 ] moieties. The new chromium compound undergoes a selective P1 /P3 ‐fragmentation. Hereby, the cyclo ‐P3 complex [Cp*Cr(CO)2 (η 3 ‐P3 )] and the as yet unknown phosphinidene complex [Cp*Cr(CO)2 {Cr(CO)5 }2 (μ3 ‐P)] are obtained (see scheme).