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A series of novel N-heterocyclic carbene coinage metal complexes containing a naphthalimide (NI) chromophore has been prepared and fully characterized. Two types of molecules are described those where the NI unit is directly attached to the carbene unit with the general formulae [(L 1 )-M-X], M = Cu, X = Cl (1a); M = Ag, X = I (1b) and M = Au, X = Cl, (1c). While in the second family, a π-extended carbene ligand precursor L 2 -H + I − (3) was prepared where the NI unit is distant from the imidazole unit via a phenyl-alkyne bridge. Only two N-heterocyclic carbene metal complexes were prepared [(L 2 )-M-Cl], M = Cu (2a) and M = Au (2c). The related silver carbene compound could not be isolated. The molecular structure of the carbene complex 1c was determined and confirmed the formation of the target compound. Interestingly, the structure shows the presence of an aurophilic interaction Au···Au at 3.407 Å between two individual molecules. The photophysical properties of the compounds were investigated in solution at room temperature. Preliminary results suggested that all compounds are luminescent and act as blue emitters (420-451 nm). These transition emissions can be attributed to the intraligand origin of the NI chromphore. Moreover, the carbene complexes featuring L 2 ligand with π-extended system were found to be more luminescent.

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