Assembly of Heterometallic AuICu₂I₂ Cores on the Scaffold of NPPN-Bridging Cyclic Bisphosphine

Abstract

The row of metallocyclic dinuclear gold­(I) complexes with cyclic diphosphines, namely, P-pyridylethyl-substituted 1,5-diaza-3,7-diphosphacyclooctanes, has been obtained. Further interaction of the dinuclear gold­(I) complexes with copper­(I) iodide gave the first examples of hexanuclear AuI/CuI complexes containing two unusual trinuclear AuICu2I2 fragments. The structures of di- and hexanuclear complexes were confirmed by NMR spectroscopy, ESI mass spectrometry, elemental analysis, and single-crystal X-ray diffraction. All of the obtained complexes are moderate emitters in the solid state. Dinuclear gold­(I) complexes displayed a greenish emission with the maxima in the emission spectra at ca. 550 nm. The obtained hexanuclear heterobimetallic AuI/CuI complexes are triplet solid-state blue emitters with the maximum in the emission spectra at 463 and 484 nm. According to the TD-DFT calculations, the observed emission of all studied complexes had a triplet origin and was caused by the 3CC or 3(MLCT) T1 → S0 transitions for dinuclear and hexanuclear complexes, respectively.

Heterometallic Au(I)–Cu(I) Clusters: Luminescence Studies and1O2Production

“…The resulting emission is red-shifted with respect to the gold­(I) homometallic compounds as previously observed with other Au/Cu heterometallic systems containing the same pyPPh 2 phosphane previously reported in the literature. These transitions have been ascribed to an admixture of IL/LL′/LAuMCT transitions. ,,,− In particular, the ligand-to-metal charge-transfer character of the transitions has been previously attributed thanks to time-dependent density-functional theory (TDDFT) calculations, and this charge-transfer process is observed to increase in the heterometallic compounds with respect to the homometallic, with the main role of the copper center. , This would correlate with the observed resulting emission red shift.…”

“…34−36 by heterometallic interactions with the different metals in the cluster core. 37,38 Population of the T 1 triplet excited state is quite common in this type of complexes containing heavy atoms that are responsible for the resulting phosphorescence emission.…”

“…Different donor atoms in these ligands can coordinate to several metal centers, keeping them close to each other and establishing heterometallic metallophilic interactions. Thus, the inclusion of a second metal ion, such as Ag­(I) or Cu­(I), in Au­(I) complexes with multidentate ligands may promote the formation of cluster structures. − These structures generate a change in the emission spectra of compounds following diverse processes such as CC, MMLCT, or LMMCT caused by heterometallic interactions with the different metals in the cluster core. , Population of the T 1 triplet excited state is quite common in this type of complexes containing heavy atoms that are responsible for the resulting phosphorescence emission.…”

TADF and X-ray Radioluminescence of New Cu(I) Halide Complexes: Different Halide Effects on These Processes

“…Metal halide complexes continue to attract ever-increasing attention because of their remarkable functional properties, stability, and facile synthesis [ 1 , 2 , 3 , 4 ]. Especially promising are Cu(I) halide complexes featuring intriguing luminescent properties as well as rich structural diversity, various molecular complexity, and robustness [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 ]. It is well known that upon excitation, the Cu(I) complexes supported by C-, N-, P-, S-, and As-donating ligands can generate the excited states of metal-to-ligand charge transfer type (MLCT) [ 15 , 16 ].…”

Controllable Synthesis and Luminescence Behavior of Tetrahedral Au@Cu4 and Au@Ag4 Clusters Supported by tris(2-Pyridyl)phosphine

“…Additionally, a high tendency of the d 10 ions to form metallophilic contacts , often affords polymeric aggregates instead of the designed clusters. To overcome these problems, several powerful approaches were proposed, e.g., via exploiting phosphine ligands that allow growth of a cluster scaffold to be controlled. − Among diverse phosphines, pyridylphosphines proved to be excellent ligands for the stabilization of unique Au I -Ag I , Au I -Cu I , and Ag I -Cu I clusters displaying interesting luminescence properties. − For instance, using (2-pyridyl)­diphenylphosphine (PPh 2 Py), the controlled synthesis of a series of unique clusters of Au 2 Cu 6 , Au 6 Cu 2 , Au 13 Cu n ( n = 2, 4, 8), C@Au 6 Cu 2 , Au 10 Ag 2 , C@Au 6 , and C@Au 6 Ag 2 , was developed (C@ is hexacoordinated carbon atom). These clusters consist of remarkable structures and reveal intense phosphorescence, including near-IR and thermochromic ones. − Another structurally intriguing set of clusters engineered on the basis of bis­(2-pyridyl)­phenylphosphine (PPhPy 2 ) is C@Au 6 Ag 6 , Au 6 Ag 7 , and Au 6 AgCu 6 .…”