Intramolecular rearrangements guided by adaptive coordination-driven reactions toward highly luminescent polynuclear Cu(i) assemblies

Abstract

Highly luminescent solid-state Cu6, Au2Cu10 and Pt4Cu11 derivatives are obtained in one step reaction thanks to adaptive coordination-driven supramolecular chemistry using pre-assembled flexible Cu(i) precursors.

Coordination‐Driven Supramolecular Synthesis Based on Bimetallic Cu(I) Precursors: Adaptive Behavior and Luminescence

“…This reaction was extended to the longer linear gold(I) dicyanide [Au(CN) 2 ] − connecting ligand leading to the unexpected formation of the large Au 2 Cu 10 polymetallic assembly F 2 in place of the targeted Au 2 Cu 4 compact metallacycle (Figure 10). [31b] Similarly, as [Pt(CN) 4 ] 2− , aimed to act as square planar tetratopic connecting ligand, was also reacted with the pre‐assembled [Cu 2 ( μ 2 ‐dppm) 2 ] 2+ building block, a Pt 4 Cu 11 derivative F 3 was obtained selectively rather than the expected Pt 2 Cu 8 assembly (Figure 10). [31b] Along these syntheses, the [Cu 2 ( μ 2 ‐dppm) 2 ] 2+ unit keeps its unique flexibility (modulation of the intermetallic distances and the coordination bite angle of the chelating dppm ligands) affording new examples of adaptive supramolecular syntheses.…”

“… [31b] Similarly, as [Pt(CN) 4 ] 2− , aimed to act as square planar tetratopic connecting ligand, was also reacted with the pre‐assembled [Cu 2 ( μ 2 ‐dppm) 2 ] 2+ building block, a Pt 4 Cu 11 derivative F 3 was obtained selectively rather than the expected Pt 2 Cu 8 assembly (Figure 10). [31b] Along these syntheses, the [Cu 2 ( μ 2 ‐dppm) 2 ] 2+ unit keeps its unique flexibility (modulation of the intermetallic distances and the coordination bite angle of the chelating dppm ligands) affording new examples of adaptive supramolecular syntheses. Nevertheless, the scope of the self‐assembly processes goes further in these reactions.…”

“…The Au 2 Cu 10 and Pt 4 Cu 11 derivatives F 2 and F 3 present exalted solid‐state luminescence properties (Figure 10b, EQY for F 2 =70 % and EQY for F 3 =63 %) centerd on the Cu(I) metal ions, [31b] and taking benefit from valuable features: Cu(I) metal centers present in such polycyclic supramolecular scaffolds bear reduced possibility of large structural re‐organisation of their coordination sphere in the excited states due to the intrinsic geometrical constraints of being included in a cyclic backbone. In addition, associating in these backbones Cu(I) ions with heavy metal centers bearing high spin‐orbit coupling constants promote efficient radiative deactivation pathways, revealing a ‘heavy atom effect’ to enhance the photoluminescence performances of these Cu(I) supramolecular assemblies.…”

“…In the tetrametallic metallacycle F 1 , the metal centers’ trigonal planar coordination spheres can accept additional coordination of donor ligands, giving access to new polymetallic assemblies. As the metallacycle F 1 is reacted with, respectively KCN, CuCN or K 2 [M(CN) 4 ] metallo‐ligands (M=Ni, Pd, Pt), a series of new solid‐state luminescent supramolecular assemblies is selectively prepared [31a,b] . Their formation can be explained by considering that the derivative F 1 is the result of the dimerization of [Cu 2 ( μ 2 ‐dppm) 2 ]CN fragments F 1 ’ bearing coordinatively highly unsaturated and reactive Cu(I) metal centers (Scheme 2).…”

“…Thus, the cyano ligand can be considered as formally inserted within the metal centers of F 1 ’ affording “[Cu 2 ( μ 2 ‐dppm) 2 ](CN) 2 ” fragments that self‐assemble in the solid‐state forming the remarkable helicoidal 1D‐CP structure of F 4 [31a] . In the case of the reaction with the CuCN building block, a formal inorganic ring extension is observed as a consequence of the coordination of the CuCN fragment to F 1 ’ and the re‐association of the resulting fragments [31b] …”