A promising class of luminescent derivatives of Silver(I) and Gold(I)‐N‐heterocyclic carbene

Abstract

Starting from proligand 1-methyl-2-(phenyl)imidazo[1,5-a]pyridine-2-iumchloride (1.HCl), 1-methyl-2-(phenyl)imidazo[1,5-a]pyridine silver(I) chloride, (2) has been prepared. Synthesis, structures and photophysical properties of (2,2 / −bipyridyl)-1-methyl-2-(phenyl)imidazo[1,5-a]pyridinesilver(I) hexaflurophosphate, (3), 1-methyl-2-(phenyl)imidazo[1,5-a]pyridinesilver(I) carbazolate, (4) and 1-methyl-2-(phenyl)imidazo[1,5-a]pyridinegold(I)carbazolate, (5) are focused. Herein we have first reported the NHC-Ag-(bpy/carbazole). All the complexes have been characterized by elemental analysis, various spectroscopic studies and finally screened for luminescent properties. All the complexes are strongly emissive. Solid state structures of 2, 3, 4 and 5 have been determined by X-ray diffraction studies. Conventionally, complex 2 adopts linear geometry whereas complex 3 embraces triangular planar geometry around Ag; complex 4 and 5 clinches linear geometry around Ag/Au. All the complexes absorb light within 275-343 nm. Complex 3 is luminous at~407 mn, whereas complex 4 and 5 luminous at~360 nm having short life time 1.00-6.97 ns. The quantum yield (Φ em) of the complexes varies 0.106-0.186. It is expected variation of luminescence arises due to change of metal and the chromophore (bpy/carbazole). Density Functional Theory (DFT) and Temparature Dependent Density Functional Theory (TDDFT) calculations were performed to verify crystallographically derived parameters and to calculate the UV-Vis properties of the ground state as well as of the first excited state of the complexes.

A Green Synthesis of Carbene‐Metal‐Amides (CMAs) and Carboline‐Derived CMAs with Potentin vitroandex vivoAnticancer Activity

“…The carbene ligand is usually a cyclic (alkyl)(amino) carbene or monoamido-(MAC) or diamido-carbene DAC), [4][5][6][7][8][9][10][11][12][13][14][15] and less often a (benz)imidazolylidene or mesoionic carbene. [16][17][18][19][20][21][22][23] The ligand combination in the former case renders these materials ideal for Thermally Activated Delayed Fluorescence (TADF) applications. The latter cases have received comparatively much less attention because of limited potential for OLED materials applications, even though recent advances show that modifications of the acceptor imidazol(in)ylidene ligand enable throughspace TADF.…”

“…These tunable emitters are comprised of three, simple components; an amido fragment acting as a donor which is usually based on the carbazole template, a linear d 10 Cu, Ag or Au center and a carbene ligand occupying the second coordination position of the linear complex and acting as the acceptor. The carbene ligand is usually a cyclic (alkyl)(amino) carbene or monoamido‐ (MAC) or diamido‐carbene DAC), [4–15] and less often a (benz)imidazolylidene or mesoionic carbene [16–23] . The ligand combination in the former case renders these materials ideal for Thermally Activated Delayed Fluorescence (TADF) applications.…”

Luminescent Complexes of Platinum, Iridium, and Coinage Metals Containing N-Heterocyclic Carbene Ligands: Design, Structural Diversity, and Photophysical Properties

“…Dinda and co-workers described some silver and gold carbene cationic complexes displaying trigonal geometry around the metal center (Figure ). , …”

“…DFT calculations suggested again that the HOMOs were mostly on the metal and carbene ligand, while the LUMOs were on the bpy ligand. Despite the very short lifetime of the observed emission, the authors suggest that the emission might be due to MLCT and (IL) transitions …”

“…Dinda and co-workers described some silver and gold carbene cationic complexes displaying trigonal geometry around the metal center (Figure 48). 216,217 The X-ray molecular structure of complex 220 was determined, and the crystal packing showed that the individual molecules displayed a head to tail fashion with π−π and Ag−Ag (3.130 Å) interactions between two adjacent molecules. Compounds 220 and 221 were emissive in solution and in solid state at room temperature.…”