Triplet Metallovinylidenes of Palladium and Platinum Based on a Chelating P/Diazoalkene Ligand.

ABSTRACT: Triplet carbenes featuring a metal adjacent to the carbene center (metallocarbenes; R─C─M) are an emerging class of diradicals within the field of reactive intermediates. Here, we report the synthesis of the first spectroscopically characterized triplet metallovinylidenes (R─C→M; M = Pt, Pd). The synthetic access is based on a rigid P/C chelating diazoalkene ligand and its coordination to Pt and Pd. The C/P chelating ligand geometrically constrains the R─C→M angle and inhibits free bending. Irradiation of the free diazoalkene ligand generates a triplet vinylidene, characterized by Q-band electron paramagnetic resonance (EPR) spectroscopy. Irradiation of the metal coordination complexes (Pt and Pd) affords triplet metallovinylidenes, which were characterized at low temperatures including photochemically triggered in crystallo X-ray diffraction. Combined FD-FT THz-EPR spectroscopy and SQUID measurements allowed the determination of the large triplet zero-field splitting (ZFS) with D values of 124.5 cm^-1 (Pt) and 8.0 cm^-1 (Pd) in excellent agreement with the electronic structure obtained by high-level quantum chemical calculations.

SUBMITTER: Amann M 

PROVIDER: S-EPMC12759197 | biostudies-literature | 2026 Jan

REPOSITORIES: biostudies-literature