Six zinc(II) complexes of the general formula [Zn(LR)X2] (1: R = Me, X = Cl; 2: R = Me, X = Br; 3: R = Me, X = I; 4: R = OH, X = Cl; 5: R = OH, X = Br; 6: R = OH, X = I), in which LR is 1‐(pyridin‐2‐yl)‐3‐o‐tolylimidazo[1,5‐a]pyridine (LMe) or 2‐[1‐(pyridin‐2‐yl)imidazo[1,5‐a]pyridin‐3‐yl]phenol (LOH), have been prepared and characterized. The X‐ray structural analysis performed on complexes 1, 3, and 4 showed that both LMe and LOH act as N,N‐bidentate ligands and coordinate to the ZnII metal center through the pyridine ring (Npy) and the pyridine‐like nitrogen atom of the imidazo[1,5‐a]pyridine group (Nim). The photophysical properties of these compounds have been investigated, both in solution and in the solid state. The complexes showed intense blue luminescence when excited with UV light (λexc = 366–410 nm) with λmax of emission between 440–460 nm in the solid state. Complexes 1–3 showed moderate‐to‐good absolute photoluminescence quantum yields (PLQYs) in the solid state with a maximum PLQY of 0.40 for 1. These values were slightly lower than the PLQY of free LMe (0.60). On the other hand, the PLQY of LOH increased after coordination to ZnCl2, and a PLQY of 0.29 was recorded for 4. A possible interpretation of this behavior is reported.

Two ferrocene derivatives with appended pyrazole substituents, namely, 1,1'-bis(5-methyl-1H-pyrazol-3-yl)ferrocene (H2LH) and 1,1'-bis(5-trifluoromethyl-1H-pyrazol-3-yl)ferrocene (H2LF), were synthesized. In solid state they form distinct H-bonded dimers with orthogonal (H2LH, C2 symmetry) or antiparallel (H2LF, C2h symmetry) arrangement of the two ferrocene/pyrazole hybrid molecules. Supramolecular dimerization was also detected in solution at low temperatures, though diffusion-ordered spectroscopy and variable-temperature NMR spectroscopy revealed several dynamic processes. Redox potentials of the ferrocene derivatives are affected by the nature of the pyrazole substituent (Me, CF3). In their deprotonated form [LR]2-, both ferrocene/pyrazole hybrids serve as ligands and form oligonuclear CuI, AgI, and AuI complexes that were identified by matrix-assisted laser desorption ionization mass spectrometry. X-ray crystallography revealed the structures of Cu6L3H and Ag6L3F, which both contain two parallel and eclipsed [M(μ-pz)]3 metallamacrocycles (M = Cu, Ag) linked by three ferrocene units. MI···MI distances between the two triangular M3N6 decks are shorter in Ag6L3F (3.28-3.30 vs 3.44-3.51 Å in the case of Cu6L3H), indicating substantial intramolecular closed-shell Ag(d10)-Ag(d10) interactions. However, Cu6L3H features close intermolecular Cu···Cu contacts as short as 3.37 Å. Mössbauer data for both the ligands and complexes were collected, and electrochemical properties were measured; preliminary luminescence data are reported.

A new pyrazole ligand with flexible thioether chelate arms was synthesized and was used to obtain an unprecedented class of hexanuclear coinage metal complexes of general formula [MM'L]3Y3 (M, M' = Cu, Ag, Au; Y = OTf, BF4). Three of them were characterized by X-ray crystallography, namely, homometallic [Ag2L]3(OTf)3 and [Ag2L]3(BF4)3 as well as heterometallic [CuAgL]3(OTf)3, revealing that the classical [M(μ-pz)]3 core is crowned by a second deck of S-bound M' ions. Depending on the solvent, these oligonuclear systems undergo rapid dynamics and show cation-anion aggregation in solution, which has been investigated by DOSY and temperature dependent NMR spectroscopy. Preliminary luminescence data for selected hexametallic [MM'L]3Y3 complexes show that the combination of ligand-directed intramolecular and supramolecular d(10) metal ion interactions in the solid state gives rise to synergic emissive properties that allow for a selective addressing of different emission wavelengths.

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