Circularly polarized luminescence of pinene-modified tetradentate platinum(II) enantiomers containing fused 5/6/6 metallocycles

Platinum complexes with aggregation-induced emission

“…Additionally, the incorporation of multiple C-HÁ Á Áp interactions played a synergistic role, leading to the observed AEE phenomenon. 16 As mentioned above, platinum(II) porphyrins, platinum(II) tetrapyrrolic macrocycles, and platinum(II) phthalocyanines have larger p-p stacking and more planar geometries, which typically show the ACQ rather than AIE effect. To overcome the ACQ phenomenon, on the one hand, we need to introduce functional groups with large spatial hindrances to prevent intermolecular p-p stacking.…”

“…56 In the same year, Zhang et al reported a rigid oxygen-bridged p -menthane-modified tetradentate cyclometalated platinum( ii ) complex ( Pt12 ). 16 Pt12 exhibited significant aggregation-enhanced emission (AEE) in a DMSO/H 2 O mixture (5 × 10 −5 mol L −1 ) with a high PLQY of 73.2%. Single-crystal structure analysis (Fig.…”

“…7A) with a 5/6/6 ring system. 16 This molecule possesses a more flexible molecular structure compared to the 5/5/6 ring cyclometalated platinum( ii ) complexes. The six-membered ring can undergo up-and-down vibrations, resulting in weak luminescence in dilute DMSO solution (5 × 10 −5 mol L −1 ) with a PLQY of less than 1%.…”

“…1C, the development history of AIE platinum complexes is detailed according to the number of ligands, and the corresponding molecular structures as well as their AIE mechanisms are provided for better understanding. So far, there have been approximately ten proposed AIE mechanisms based on cyclometalated platinum complexes, including restriction of intramolecular motion (RIM), 5–8,16–19 Pt–Pt interactions, 10,20–23 restricted distortion of excited-state structure (RDES), 24,25 restriction of coordination skeletal deformation (RCSD), 26–28 restrained D 2d deformation of the coordinating skeleton, 29 restriction of molecular configuration transformation (RMCT), 30 dimer emission, 31 and the oxygen-shielding effect. 32 These mechanisms will be further explained in the subsequent section.…”