Luminescent Cycloplatinated(Ii) Complexes: Impact of Ancillary Ligands and Second Metals

Cycloplatinated(ii) complexes are an important class of organoplatinum(ii) compounds with impressive photophysical properties. the luminescent cycloplatinated(ii) complexes have been employed in many aspects such as optoelectronic devices and bio-imaging applications. the center of emission in these complexes is significantly attributed to the cyclometalated ligand. the emission properties of this chromophoric ligand is perturbed by pt(ii) center as a heavy metal ion and also can be controlled by other ancillary ligands. the role of ancillary ligand seems to be crucial in tuning the photophysical properties of such complexes. in addition to the normal emissions that arise from the cyclometalated ligand, the ancillary ligand(s) may induce some emissions which are created by intra- or inter-molecular pt…pt and π…π interactions. in this regard, the presence of the other metal centers like ag(i), au(i), tl(i) and pb(ii) in the structures of cycloplatinated(ii) complexes may considerably affect their emission properties. since almost 10 years ago, we have started to employ different kinds of ancillary ligands toward different cycloplatinated(ii) precursor complexes and study their influences on the structural and photophysical properties of these complexes. in this direction, the new complexes were predominantly identified by means of nmr and mass spectroscopies together with x-ray crystallography. for photophysical investigations, the uv-vis and photoluminescence spectroscopies were applied and the obtained results were rationalized with the help of dft calculation method. in this review article, we tried to share our experiences in this attractive field of research and mention how some of these luminescent complexes synthesized during these years.