A Crystalline σ Complex of Copper

Gualco, Pauline; Amgoune, Abderrahmane; Miqueu, Karinne; Ladeira, Sonia; Bourissou, Didier

doi:10.1021/ja200789z

Cited by 58 publications

(50 citation statements)

References 26 publications

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“…In the group, it was shown previously that the coordination of diphosphine-disilane ligands proceeds very differently with copper and gold: side-on coordination of the σ-SiSi bond was observed with copper [30], while gold undergoes spontaneous oxidative addition and forms bis(silyl) gold(III) complexes [31]. This prompted us to investigate the influence of the metal center on the coordination behavior of the diphosphine-hydrosilane ligand.…”

Section: Comparison To a Corresponding Au(i) Complexmentioning

confidence: 99%

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Copper: σ-SiH Coordination to Cu(I)

Joost

2015

Synthesis and Original Reactivity of Copper and Gold Complexes

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This chapter gives firstly an introduction concerning σ-complexes and in particular σ-SiH complexes. Afterwards, the obtained results concerning the coordination of diphosphino-hydrosilanes to Cu(I) will be described. Introduction σ-Bond Coordination to Transition MetalsThe activation of σ-bonds by transition metals to undergo oxidative addition is a fundamental reaction in the field of coordination chemistry. Coordination of a σ-bond to a metal center to form a σ-complex is generally involved on the way to complete bond cleavage ( Fig. 2.1). Such complexes that may be observed or even isolated, play key roles as intermediates or transition states in oxidative addition processes.The field of σ-complexes evolved significantly following the pioneering studies of Kubas et al. [1,2] in 1980s. The finding that an intact dihydrogen molecule coordinates to a transition metal was at first highly debated [2], but the relevance of this discovery for transition metal-catalyzed bond activation processes was soon recognized and stimulated the field of coordination chemistry.The coordination of a σ-bond is nowadays well understood and can be considered as an early state of bond activation or "arrested oxidative addition" [3]. The precise understanding of the bonding interaction in a σ-complex is therefore of paramount importance for synthetic applications, as knowledge of structure and reactivity of such complexes will lead to more active and selective catalysts. The side-on coordination of σ-bonds has become a textbook example for weak metal-ligand interactions [4] and a number of complexes containing HH [2], HSi [3,[5][6][7][8] HB [9], HC [10][11][12], SiSi [13][14][15][16] and even CC [17][18][19] bonds has been characterized.A σ-complex can be described as a 3-center 2-electron interaction where a σ-bond acting as a 2-electron donor is coordinated in a slide-on fashion (η 2 ) to a metal, in close relationship to the Dewar-Chatt-Duncanson model that rationalizes the bonding interaction of an alkene (or an alkyne) to a metal center to form a π-complex. The σ-orbital of the ligand overlaps with a vacant metal d-orbital which leads to donation of electron density from the ligand to the metal. Furthermore, such a complex may be stabilized by backbonding, i.e. retrodonation of electron density from the metal to the ligand by interaction of a filled metal orbital of suitable symmetry with the σ*-orbital of the ligand ( Fig. 2. 2).In analogy to other 3-center 2-electron bonds involving p-block elements like in polyboranes or carbonium ions, the bonding situation of a σ-complex cannot be depicted by a single Lewis structure and is therefore also categorized as a "nonclassical interaction".Equally important and closely related to σ-complexes are agostic interactions. Originally, this weak bonding interaction was defined as the intramolecular 3-center 2-electron coordination of a CH-bond to a transition metal, i.e. the ligand coordinating to a metal center is tethered to a CH-bond that is interacting in a side-on fashion wit...

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Section: Comparison To a Corresponding Au(i) Complexmentioning

confidence: 99%

“…This chelating approach was extrapolated to the coordination and activation of σ-SiSi bonds at Cu (I) and Au(I) [30,31]. In case of copper, this strategy led to the isolation of the first structurally characterized σ-complex of a coinage metal (Fig.…”

Section: Synthesis and Characterization Of Cu(i) Complexesmentioning

confidence: 99%

Copper: σ-SiH Coordination to Cu(I)

Joost

2015

Synthesis and Original Reactivity of Copper and Gold Complexes

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“…In the first place we strived for the study of a copper-SiH interaction, not observed before, but proposed as intermediate species in various catalytic cycles [8]. Since one should expect a rather weak bonding interaction, we based our investigation on the chelate assistance approach.…”

Section: Research Objectives and Thesis Outlinementioning

confidence: 99%

“…The use of multifunctional ligands containing a chelating phosphine motif has been already successfully applied in our group [9][10][11] and elsewhere [12] for the identification of elusive and otherwise difficult characterizable bonding modes. For example, the characterization of the first σ-complex of copper was achieved by employing a diphosphine-disilane ligand [8].…”

Section: Research Objectives and Thesis Outlinementioning

confidence: 99%

General Introduction

Joost¹

2015

Synthesis and Original Reactivity of Copper and Gold Complexes

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“…72 Using a similar ligand, Bourissou observed κ 2 -P,P-coordination of Ph 2 P(C 6 H 4 )Me 2 SiSiMe 2 (C 6 H 4 )PPh 2 to silver(I), but a weak interaction between the SiSi backbone and copper(I). 73 …”

Section: Inorganic Chemistrymentioning

confidence: 99%

Coordination of a Hemilabile Pincer Ligand with an Olefinic Backbone to Mid-to-Late Transition Metals

Barrett

Iluc

2014

Inorg. Chem.

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The coordination chemistry of a neutral tPCH═CHP pincer (tPCH═CHP = 2,2'-bis(di-iso-propylphosphino)-trans-stilbene) with metals that form stable complexes in the +1 oxidation state was studied and (tPCH═CHP)CoCl, (tPCH═CHP)CoCl(CO), (tPCH═CHP)RhCl, (tPCH═CHP)Cu(OTf), [(tPCH═CHP)Cu][PF6], and [(tPCH═CHP)Ag][PF6] were synthesized and characterized. In order to determine whether the coordination mode is dependent on the oxidation state of the metal, some +2 metal complexes, (tPCH═CHP)CoCl2 and (tPCH═CHP)FeBr2, were also investigated. The coordination of the olefinic backbone is not observed in (tPCH═CHP)FeBr2, (tPCH═CHP)CoCl2, (tPCH═CHP)Cu(OTf), or [(tPCH═CHP)Ag][PF6], but η(2)-coordination is present in [(tPCH═CHP)CoCl][BAr(F)4], [(tPCH═CHP)FeBr][BAr(F)4], (tPCH═CHP)CoCl, (tPCH═CHP)CoCl(CO), (tPCH═CHP)RhCl, and [(tPCH═CHP)Cu][PF6]. Cobalt(II), iron(II), and copper(I) formed complexes with the ligand in both coordination modes. All metal complexes were characterized by multinuclei NMR spectroscopy, X-ray crystallography, and elemental analysis.

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A Crystalline σ Complex of Copper

Cited by 58 publications

References 26 publications

Copper: σ-SiH Coordination to Cu(I)

Copper: σ-SiH Coordination to Cu(I)

General Introduction

Coordination of a Hemilabile Pincer Ligand with an Olefinic Backbone to Mid-to-Late Transition Metals

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