Figure 3.

(a) Linear molecular structure of two-coordinate CAAC-Cu^I-amido complexes (at the top) and structures of exemplary CAAC and amido ligands.³⁸ (b) Key frontier orbitals in CAAC-Cu^I-amido complexes and direction of charge transfer upon LLCT excitation.³⁸ (c) Renner–Teller distortion upon MLCT excitation of linear d¹⁰ complexes.⁴¹ (d) Energy-level diagram illustrating emission processes of CAAC-Cu^I-amido complexes. (e) Molecular structures of linear Cu^I complexes based on cyclic mono- or diamidocarbene ligands.³⁹ (f) Molecular structures of some exemplary CAArC-Cu^I complexes.⁴⁵ R′ = H, CN. R″ = H, CN. R^a = CH₃, Ph. R^b = H, CH₃. ^CNCz, when R′ = CN and R″ = H.