Synthesis and Properties of Mononuclear Group 10 Alkoxy‐Biscarbene Complexes

Abstract

The synthesis, isolation, and complete characterization (NMR and X-Ray diffraction techniques) of stable mononuclear (palladium and platinum) alkoxy-biscarbene complexes is reported. These compounds are easily accessible through stoichiometric transmetalation reactions from Fischer alkoxy-chromium(0) carbene complexes. By a combination of experimental (UV/Vis spectroscopy, cyclic voltammetry) and computational methods (DFT), the structure, bonding situation, and the electronic and redox properties of these complexes are studied. Although they have structures quite similar, their electronic properties strongly depend on the metal and also on the substitution in the aromatic rings in the aniline moieties. Electron-withdrawing groups stabilize the HOMO causing the shifting of the oxidation waves to lower anodic potentials in the corresponding cyclic voltammograms.

Synthesis, Structure, and Electronic Properties of Extended π‐Conjugated Group 6 Fischer Alkoxy–Bis(carbene) Complexes

“…Similar to related a,b-unsaturated alkoxy monocarbene complexes 1 [19] most of the considered bisA C H T U N G T R E N N U N G (carbene) complexes 2 exhibit two irreversible oxidation waves in the range + 0.99 to + 1.54 V (Figure 9 and Table 2), which can be ascribed to the irreversible formation of the corresponding radical cation and dication species, respectively. Although the differences in the first oxidation potential (1st E pa ) are small, they are significant.…”

Tuning the Photophysical Properties of BODIPY Molecules by π‐Conjugation with Fischer Carbene Complexes

“…The B3LYP Hamiltonian was chosen because it was shown to provide reasonable UV/Vis spectra for a variety of chromophores, [25] including Fischer carbene complexes [14,18] and other organometallic species. [26] Wiberg bond indices were computed by using the natural bond orbital (NBO) method. [27] Figure 7.…”

Reactive Palladium Carbenes: Migratory Insertion and Other Carbene–Hydrocarbyl Coupling Reactions on Well‐Defined Systems

“…The 13 C NMR chemical shifts for the C carbene resonances cover a wide value range, reflecting quite a different electron density at the carbene center. The carbene in complex 21 is less electrophilic than its monodentate analogues 2 and 3 , due to the presence of the imido alkenyl substituent that allows an effective electron donation over the entire metalacycle …”