Structurally Characterized Coinage‐Metal–Ethylene Complexes

Abstract

Despite the interest in them, easily isolable and thermally stable CuI, AgI, and AuI complexes of ethylene are stilllimited and get increasingly sparse as one descends the group 11 triad towards gold. Recently, there have been some notable developments in this field, including the isolation of gold–ethylene complexes and coinage‐metal adducts with more than one ethylene molecule on a metal center. This article focuses on the chemistry of coinage‐metal–ethylene adducts that have been synthesized and characterized by X‐ray crystallography. Thus far, bidentate and tridentate donors based on nitrogen appear to be the ligands of choice forstabilizing species with an M–C2H4 (M = CuI, AgI, and AuI) moiety. Weakly donating ligands and anions are also commonly used, as they do not interfere with and displace the ethylene from the metal center. The ethylene 13C NMR chemical shift provides useful information about the nature of the metal–ethylene interaction. In some adducts (especially those with relatively weak M–C2H4 interactions), the change in the C=C bond length upon coordination to the metal site is difficult to discern because it falls within the errors associated with the crystallographically determined C=C bond length value. IR and Raman C=C stretching data would be useful but, probably due to the very weak nature of the IR band and the lack of convenient access to the Raman instruments, are often not reported. In this microreview, results from some computational and gas‐phase spectroscopic studies are also provided for comparison.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

On the Dewar–Chatt–Duncanson Model for Catalytic Gold(I) Complexes

“…Remarkably, for example, Au I carbonyls are "nonclassical" in that they display a blueshift of the CO stretching frequency, [21] which is commonly associated with a lack of back-donation. [11,22,23] In the case of Au I -alkynes or Au I -alkenes, relevant unambiguous experimental evidence is more difficult to obtain due to the fact that both the S!M donation and M!S back-donation components tend to weaken the C À C bond, [24][25][26] but recently reported data were also deemed consistent with the lack, or marginal role, of back-donation. [27] The lack of back-donation may have an impact on the peculiar and powerful catalytic properties of Au I because, quite simply, it should tend to increase the electrophilicity of the coordinated substrate.…”

Chromatography with silver nitrate: part 2

“…alkane from an alkene). A number of review articles have been published, which detail to a greater extend the theory behind silver complexation, 5,6,7 and therefore these aspects will not be discussed in detail herein. It has been 15 years since our first review on this topic, 8 which has inspired us to provide an up-date covering the years [2001][2002][2003][2004][2005][2006][2007][2008][2009][2010][2011][2012][2013][2014][2015].…”

Structural Diversity of Copper(I)–N‐Heterocyclic Carbene Complexes; Ligand Tuning Facilitates Isolation of the First Structurally Characterised Copper(I)–NHC Containing a Copper(I)–Alkene Interaction

“…Most of the complexes examined involve copper(I)-L-(ethylene), in which L is a chelating nitrogen-donor ancillary ligand. [9][10][11] Several copper(I)-tris(pyrazolyl)borate-ethylene complexes have been isolated and structurally characterised.…”