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Abstract: The series of cyanide‐bridged coordination polymers [(P2)CuCN]n (1), [(P2)Cu{M(CN)2}]n (M=Cu 3, Ag 4, Au 5) and molecular tetrametallic clusters [{(P4)MM'(CN)}2]2+ (MM′=Cu26, Ag27, AgCu 8, AuCu 9, AuAg 10) were obtained using the bidentate P2 and tetradentate P4 phosphane ligands (P2=1,2‐bis(diphenylphosphino)benzene; P4=tris(2‐diphenylphosphinophenyl)phosphane). All title complexes were crystallographically characterized to reveal a zig‐zag chain arrangement for 1 and 3–5, whereas 6–10 possess metallocyclic frameworks with different degree of metal‐metal bonding. The d10–d10 interactions were evaluated by the quantum theory of atoms in molecules (QTAIM) computational approach. The photophysical properties of 1–10 were investigated in the solid state and supported by theoretical analysis. The emission of compounds 1 and 3–5, dominated by metal‐to‐ligand charge transfer (MLCT) transitions located within {CuP2} motifs, is compatible with thermally activated delayed fluorescence (TADF) behaviour and a small energy gap between the T1 and S1 excited states. The luminescence characteristics of 6–10 are strongly dependent on the composition of the metal core; the emission band maxima vary in the range 484–650 nm with quantum efficiency reaching 0.56 (6). The origin of the emission for 6–8 and 10 at room temperature is assigned to delayed fluorescence. AuCu cluster 9, however, exhibits only phosphorescence that corresponds to theoretically predicted large value ΔE(S1−T1). DFT simulation highlights a crucial impact of metallophilic bonding on the nature and energy of the observed emission, the effect being greatly enhanced in the excited state. [ABSTRACT FROM AUTHOR]

The bifunctional aminopyridine ligands H2N-(CH2) n-4-C5H4N ( n=0, L1; 1, L2; 2, L3) have been utilized for the preparation of the rhenium complexes [Re(phen)(CO)3( L1- L3)]+ ( 1- 3; phen=phenanthroline). Complexes 2 and 3 with NH2-coordinated L2 and L3, respectively, were coupled with cycloplatinated motifs {Pt(ppy)Cl} and {Pt(dpyb)}+ (ppy=2-phenylpyridine, dpyb=dipyridylbenzene) to give the bimetallic species [Re(phen)(CO)3(μ- L2/ L3)Pt(ppy)Cl]+ ( 4, 6) and [Re(phen)(CO)3(μ- L2/ L3)Pt(dpyb)]2+ ( 5, 7). In solution, complexes 4 and 6 show 3MLCT {Re}-based emission at 298 K, which changes to the 3IL(ppy) state at 77 K. The photophysical properties of compounds 5 and 7 display a pronounced concentration dependence, presumably due to the formation of bimolecular aggregates. Analysis of the spectroscopic data, combined with TD-DFT simulations, suggest that unconventional heteroleptic {Re(phen)}⋅⋅⋅{Pt(dpyb)} π-π stacking operates as the driving force for ground-state association. The latter, together with intra- and intermolecular energy-transfer processes, determines the appearance of multiple emission bands and results in nonlinear relaxation kinetics of the excited states. [ABSTRACT FROM AUTHOR]

Reactions of the [(tppm)Au3Cl3] [tppm = tris(diphenylphosphanyl)methane] precursor and CuI ions with a stoichiometric amount of the corresponding linear mono- [HC2(C6H4) nC6H5; n = 1, 2] and diacetylenes [HC2(C6H4) nC2H; n = 1-3] that contain extended polyaryl moieties afford a series of luminescent heterometallic complexes with a common structural motif based on the {(AuC2)3Cu} cluster core. The complexes obtained were characterized by using X-ray crystallography and NMR spectroscopy. All compounds studied display dual singlet and triplet luminescence, the former component of which can be completely suppressed in concentrated solution by a self-absorption phenomenon. The results of the photophysical measurements together with the quantum chemical calculations (PBE0-DFT level of theory) indicate that singlet emission originates mainly from copper-perturbed intraligand transitions, whereas the phosphorescence can be assigned to the {(AuC2)3Cu} core-centered transitions. Due to the low contribution of the gold atoms to the orbitals responsible for the singlet and triplet emission, the emissive excited states are very weakly coupled, thereby resulting in a negligible energy transfer between these excited states. [ABSTRACT FROM AUTHOR]