Cuprophilicity: Spectroscopic and Structural Evidence for Cu−Cu Bonding Interactions in Luminescent Dinuclear Copper(I) Complexes with Bridging Diphosphane Ligands

Abstract

Die eindeutige Zuordnung der 3 dσ*→4 pσ‐Metall‐Metall‐Übergänge anhand spektroskopischer und struktureller Untersuchungen belegt die Existenz cuprophiler CuI⋅⋅⋅CuI‐Wechselwirkungen in diskreten zweikernigen, Diphosphan‐verbrückten CuI‐Komplexen (siehe Bild). Die an den CuI‐Zentren beobachtete Lumineszenz hängt in erster Linie von den Metall‐Ligand‐Bindungen ab.

Precise Implantation of an Archimedean Ag@Cu12 Cuboctahedron into a Platonic Cu4Bis(diphenylphosphino)hexane6 Tetrahedron

“…The inner Ag@Cu 12 cluster is an Ag-centered cuboctahedral framework of 12 Cu atoms (Figure b), where the average Ag–Cu distance is 2.85 Å from the central Ag to the surrounding 12 Cu atoms (Ag–Cu: 2.80–2.91 Å). This average distance is slightly longer than the sum (2.72 Å) of interatomic distances in copper metal ( r a(Cu) = 1.28 Å) and silver metal ( r a(Ag) = 1.44 Å), but it is much shorter than the sum (3.12 Å) of the van der Waals radii of copper ( r vdW(Cu) = 1.40 Å) and silver ( r vdW(Ag) = 1.72 Å), indicating the important CuAg metallophilicity. − In addition, the surface CuCu distances, ranging from 2.67 to 2.96 Å, suggest cuprophilicity between Cu­(I) atoms. , r a(M) and r vdW(M) represent the atomic radius and van der Waals radius of M, respectively, M = Cu, Ag. The structural features of Ag–Cu and Cu–Cu distance expansions with respect to those in metals also indicate their +1 oxidation state, which can also be deduced on the basis of subsequent mass spectrometry results.…”

“…70−75 In addition, the surface CuCu distances, ranging from 2.67 to 2.96 Å, suggest cuprophilicity between Cu(I) atoms. 76,77 r a(M) and r vdW(M) represent the atomic radius and van der Waals radius of M, respectively, M = Cu, Ag. The structural features of Ag− Cu and Cu−Cu distance expansions with respect to those in metals also indicate their +1 oxidation state, which can also be deduced on the basis of subsequent mass spectrometry results.…”

From Short-Bite Ligand Assembled Ribbons to Nanosized Networks in Cu(I) Coordination Polymers Built Upon Bis(benzylthio)alkanes (BzS(CH2)nSBz; n = 1–9)

“…However, despite the isomorphism of several 1D series [{Cu­(μ 2 -X) 2 Cu}­{μ- L } 2 ] n , no unambigous correlation between the nature of X and the Cu···Cu separation can be established. Although the occurrence of relativistic effects in Cu···Cu complexes is discussed in the literature, a possible contribution of such cuprophilic interactions remains speculative for our materials, since the short contacts in several compounds, notably, in the case of Cu 4 I 4 , are also certainly a consequence of the bridging bonding mode of the I atoms. − …”

Synthesis and reactivity of dinuclear copper(i) pyridine diimine complexes

“…22–24 The occurrence of cuprophilic interactions were suggested by short copper-copper distances between 2.4 and 2.8 Å, but were later observed by spectroscopic studies. 25,26 A few dicopper( i ) bridging CO complexes are reported and show Cu–Cu distances between 2.417(2) Å and 2.422(1) Å. 14–16 Here, it should be emphasized that the sum of the van der Waals radii (2.80 Å) and even the Cu–Cu distance in bulk copper (2.556 Å) are longer than the reported distances in the dicopper( i ) μ-C,C carbonyls.…”