Synthesis, Optical Properties and Photophysics of Group 10-12 Transition Metal Complexes and Polymer Derived from a Central Tris(p-ethynylphenyl)amine Unit

A new series of luminescent group 10-12 metal alkynyl complexes and polyyne polymer containing a central tris(p-ethynylphenyl)amine bridging chromophore were prepared. The regiochemical structures of these triangular-shaped trinuclear compounds and polymer were studied by various spectroscopic and photophysical analyses. Upon photoexcitation, each of them emits an intense purple-blue fluorescence emission in the near UV region in dilute fluid solutions at room temperature. Harvesting of organic triplet emissions observed in the low-energy region harnessed through the strong heavy-atom effects of group 10-12 transition metals was examined and the results were compared among these three neighboring late transition metal elements. The influence of group 15 nitrogen-based heteroatom on the intersystem crossing rate and the spatial extent of the lowest singlet and triplet excitons was fully elucidated and a comparison was made to the nearest group 14 and 16 neighbors in the same row of the Periodic Table.