Emissive lanthanide dicyanoaurate coordination polymers with 2,2′-bipyridine dioxide antenna groups and their hydration states

Abstract

Ln–Au(CN)2-based coordination polymers with 2,2′-bipyridine dioxide ligands in several hydration states show aurophilic interactions, hydrogen bonding and high quantum yields for Ln = Eu and Tb, which decrease with a lowering of the hydration level.

Anisotropic Thermal Expansion of Structurally Related Lanthanide–Mercury(II) Cyanide Coordination Polymers

“…Lanthanide-cyanometallate coordination polymers are well-known: they contain cyanide-bridged frameworks with C-bound d -block metal centers and N-cyano-bound lanthanides (according to the hard–soft Lewis acid preferences of the respective metals, although direct CN – binding to lanthanide centers has been demonstrated in solution). , Their structures are primarily directed by the shape and denticity of the cyanometallate group, with the lanthanide adopting the geometry necessitated by the topology . Often, the coordination sphere of the lanthanide is completed with solvent moleculessuch as water or dimethylformamide ligandsor can be otherwise supplemented with organic ligands. ,− The short cyanide bridges can facilitate magnetic exchange interactions in 3d–4f systems, and the structures and magnetic properties of many lanthanide cyanoferrate coordination polymers have been reported. − Luminescent networks with d-block or organic ligand sensitization of the lanthanide emission have also been investigated. ,− As the geometry of the node often greatly influences a coordination polymer’s structure, the lanthanides’ tendency to have flexible coordination geometries makes it difficult to predict the structures of new lanthanide-based coordination polymers. , Therefore, a strategy to control the self-assembly of lanthanide–cyanometallate coordination polymers was targeted.…”

Unusually short unsupported Au(iii)⋯Au(iii) aurophilic contacts in emissive lanthanide tetracyanoaurate(iii) complexes

“…4 reveals bipyO 2 -sensitized Eu 3+ 5 D 0 → 7 F J ( J = 1–4) transitions analogous to the luminescence reported for [Eu(bipyO 2 ) 4 ](ClO 4 ) 3 and other Eu-bipyO 2 compounds. 39,46 The ligand-based excitation band is located at 325 nm (300 K), and displays a temperature shift to 310 nm at 77 K. With comparison to [Eu(bipyO 2 ) 4 ](ClO 4 ) 3 , a charge transfer transition at lower energy ( λ max = 380 nm) could also be assigned; this band does not greatly shift with temperature. 41…”

“…Concurrently, we have been interested in cyanometallatebased assemblies of lanthanide-N,N 0 -dioxide-2,2 0 -bipyridine (bipyO 2 ) complexes, as Ln-bipyO 2 cations have shown emissive and magnetic properties suitable for luminescent thermometry, LED, and single molecule magnet applications. [36][37][38][39] Interestingly, metallophilic interactions feature prominently in the reported Ln-bipyO 2 -based cation systems incorporating the (thio)cyanometallates [Au(CN) 2 ] À , [Ag(CN) 2 ] À , and [Au(SCN) 2 ] À . 36,39 Thus, we considered the possibility that the high charge of the [Ln(bipyO 2 ) 4 ] 3+ cations could conceivably induce aurophilic interactions with [Au(CN) 4 ] À units in a similar fashion.…”

“…[36][37][38][39] Interestingly, metallophilic interactions feature prominently in the reported Ln-bipyO 2 -based cation systems incorporating the (thio)cyanometallates [Au(CN) 2 ] À , [Ag(CN) 2 ] À , and [Au(SCN) 2 ] À . 36,39 Thus, we considered the possibility that the high charge of the [Ln(bipyO 2 ) 4 ] 3+ cations could conceivably induce aurophilic interactions with [Au(CN) 4 ] À units in a similar fashion.…”

“…S9 and S10, ESI †), revealing ligand-based excitation at l max = 340 nm and emission via Tb 3+ 5 D 4 -7 F J ( J = 1-6) transitions, analogous to the ligand-sensitized luminescence observed for other Tb-bipyO 2 compounds. 39,41 A photoluminescence quantum yield (PLQY) of 14.0(9)% was measured at 300 K when excited at 340 nm.…”