A Copper(I)-Arene Complex With an Unsupported η6Interaction

Crystal structure and synthesis of the bis(anthracene)dicuprate dianion as the dipotassium salt, [K(tetrahydrofuran)2]2[{Cu(9,10-η2-anthracene)}2], the first anionic arene complex of copper

Reactions of (tricyclohexylphosphane)copper(I) chloride with two equivalents of potassium anthracene (KAn) in tetrahydrofuran (THF) at 200 K provides air-sensitive but thermally stable (at 293 K) solutions from which yellow crystalline blocks of bis[bis(tetrahydrofuran-κO)potassium] bis(μ-anthracene-κ2C9:C10)dicopper, [K(THF)2]2[{Cu(9,10-η2-C14H10)}2] or [K(C4H8O)2]2[Cu2(C14H10)2], 1, were isolated in about 50% yield. Single-crystal X-ray crystallographic analysis of 1 confirmed the presence of the first known (arene)cuprate. Also, unlike all previously known homoleptic (anthracene)metallates of d-block elements, which contain metals coordinated only to terminal rings, the organocuprate unit in 1 contains copper bound to the 9,10-carbons of the central ring of anthracene. No other d- or f-block metal is known to afford an anthracene or other aromatic hydrocarbon complex having the architecture of organodicuprate 1.

Ligation of Boratabenzene and 9-Borataphenanthrene to Coinage Metals

The reactions of boratabenzene and borataphenanthrene anions with group 11 Ph₃PMCl reagents furnished η² coordination complexes, with the exception of the copper boratabenzene species that adopted an η⁶ mode. The binding of arene ligands to copper in an η⁶ manner is rare, and altering the ancillary ligand on copper to an N-heterocyclic carbene switched the binding of the boratabenzene to η², indicating that such ligands are capable of vacating coordination sites. The η² coordination complexes bind side-on, akin to olefins, via a borataalkene unit, although with the carbon atom much more proximal to the metal center than boron.

N-Heterocyclic silylenes in coinage metal chemistry: an account of recent advances

This article intends to highlight and comprehensively summarize the recent developments in the field of silylene-coinage metal chemistry. Recent years have witnessed exponential growth in the utilization of N-heterocyclic silylenes as ligands in transition metal chemistry. Still, silylene-coinage metal complexes have only started to appear very recently. Particular attention is focused on the synthetic approaches to silylene-coinage metal complexes and their unusual properties derived from the spectroscopic and crystallographic data. Recent studies have demonstrated that silylene-coinage metal complexes exhibit catalytic efficiency towards hydrosilylation, copper-catalyzed alkyne azide cycloaddition (CuAAC), and glycosidation reactions. Although the chemistry of silylene-coinage metal complexes has only begun to blossom, these findings justify the need for a review at this stage of development. This article will summarize the previous work on silylene-coinage metal complexes followed by recent advances and conclude with future possibilities.

The core of the matter - arene substitution determines the coordination and catalytic behaviour of tris(1-phosphanyl-1'-ferrocenylene)arene gold(I) complexes

Changing the aromatic core of C3-symmetric tris(ferrocenyl)arene-based tris-phosphanes has profound effects on their coordination behaviour towards gold(i). Depending on the arene (s-triazine, benzene, or trifluorobenzene), four different coordination modes can be distinguished and their preference has been rationalised using computational methods. The corresponding 1 : 1 ligand-to-metal complexes, studied by variable-temperature NMR spectroscopy, revealed fluctional behaviour in solution. Given the presence of up to three or six ferrocenylene spacers per complex, their electrochemistry was investigated. The redox-responsive nature of the complexes can be advantageously exploited in the catalytic ring-closing isomerisation of N-(2-propyn-1-yl)benzamide, where the benzene-based 2 : 3 ligand-to-metal complex has been shown to display multiple activity states depending on the degree of (reversible) oxidation in a preliminary trial.

Tricoordinate Coinage Metal Complexes with a Redox-Active Tris-(Ferrocenyl)triazine Backbone Feature Triazine-Metal Interactions

2,4,6-Tris(1-diphenylphosphanyl-1'-ferrocenylene)-1,3,5-triazine (1) coordinates all three coinage metal(I) ions in a 1:1 tridentate coordination mode. The C3 -symmetric coordination in both solid state and solution is stabilised by an uncommon cation-π interaction between the triazine core and the metal cation. Intramolecular dynamic behaviour was observed by variable-temperature NMR spectroscopy. The borane adduct of 1, 1BH3 , displays four accessible oxidation states, suggesting complexes of 1 to be intriguing candidates for redox-switchable catalysis. Complexes 1Cu, 1Ag, and 1Au display a more complicated electrochemical behaviour, and the electrochemical mechanism was studied by temperature-resolved UV/Vis spectroelectrochemistry and chemical oxidation.

Enhanced and Heteromolecular Guest Encapsulation in Nonporous Crystals of a Perfluorinated Triketonato Dinuclear Copper Complex

The flexible host framework of a perfluorinated mononuclear copper complex, [Cu(L¹ )₂ ] (1, HL¹ =3-hydroxy-1,3-bis(pentafluorophenyl)-2-propen-1-one), with a CuO₄ core reversibly encapsulated several organic guest molecules through electrostatic interactions in its crystals. Hence, the corresponding dinuclear complex, [Cu₂ (L² )₂ ] (2, H₂ L² =1,5-dihydroxy-1,5-bis(pentafluorophenyl)-1,4-pentadien-3-one), was prepared to enhance guest recognition and the ability to separate molecular mixtures. Complex 2 comprises a Cu₂ O₆ core and four pentafluorophenyl groups. In crystal 2, cavities are formed on the axial sites of the metal core that are surrounded by pentafluorophenyl groups. The crystal of 2 encapsulates various guest molecules, that is, benzene (3), toluene (4), xylene (5), mesitylene (6), durene (7), and anisole (8). X-ray crystallographic and thermogravimetric (TG) studies show that three guest molecules are present in the crystal cavities. The number of guest molecules found in complex 2 was higher than that in complex 1, for example, (2)₃ ⋅(6)₁₀ >1⋅(6)₂ , (2)₂ ⋅(7)₇ >1⋅7, or 2⋅(8)₃ >1⋅(8)₂ . Naphthalene (9), was encapsulated in 2 to give 2⋅(9)₃ , but not in 1. In the crystal of complex 2, heteromolecular guest encapsulation was confirmed, designated as 2⋅(3)₂ ⋅9. TG analysis indicates that the thermal stability of the guest-included crystals of 2 is higher than that of 1.

N-heterocyclic silylene stabilized monocordinated copper(i)–arene cationic complexes and their application in click chemistry

Herein, we report N-heterocyclic silylene and N-heterocyclic carbene supported monocoordinated cationic Cu(i) complexes with unsymmetrical arenes (toluene and m-xylene], their reactivity and catalytic application in CuAAC reactions.

Isolable arene sandwiched copper(i) pyrazolates

The π-acidic, trinuclear, copper(i) pyrazolate {[3,5-(CF₃)₂Pz]Cu}₃ reacts with simple π-basic aromatic hydrocarbon compounds forming sandwich complexes of various types.