Experimental and Theoretical Study of the Silicon-Hydrogen Bond Activation by Rhodium Dicarbonyl Complex in Solution

The photoreactivity of hydrotris-(3,5-dimethylpyrazolyl)boratedicarbonylrhodium(I) or HB(Pz*)3Rh(CO)2 complex has been studied at room-temperature n-pentane solution in the presence of 0.05 M Et3SiH (Et = C2H5). The IR spectra show that the decline of νCO parent complex at 1980 and 2054 cm-1 is followed by growing bands at 2029 and 2020 cm-1. In light of the photolysis of the parent complex in neat n-pentane solution the feature at 2020 cm-1 is tentatively assigned to the νCO band of the Si-H bond activation product. Upon standing in the dark, the 2020 cm-1 increases slightly in contrast with the 2029 cm-1 peak which decreases over time. These observations raise question whether the intensity increase of the 2020 cm-1 peak occurs unimolecularly resulting from the intramolecular rearrangement of the C-H bond activation of Et3SiH or bimolecularly as a result of the elimination of the C-H bond activation of the solvent and subsequent re-addition of the Si-H bond of the Et3SiH ligand. To gain more insight to reaction dynamics of the Si-H bond activation, the experimental results are compared to the photolysis of the parent complex in neat Et3SiH. The quantum efficiency (ϕSi-H) of this photoreaction yields a low value of 0.16. The results indicate that the Si-H bond activation is facilitated by intramolecular rearrangement mode. In addition, a theoretical study was conducted using density functional study at B3LYP/LanL2DZ level of theory, and the findings implicate that the final complex product was produced by the Si-H bond activation of Et3SiH.

Novel phosphorescent triptycene-based Ir(iii) complexes for organic light-emitting diodes

OLED based on triptycene complex 6 shows promising efficiencies of 12.6% and 41.2 cd A−1 which are 31% higher than that of the parent complex.

Fluorination on non-photolabile dppz ligands for improving Ru(ii) complex-based photoactivated chemotherapy

Fluorination on the retaining ligand of Ru(ii) PACT agents enhanced phototoxicity but diminished dark cytotoxicity compared with the parent complex, more favorable for PACT application.

Reactions of the organoplatinum complex [Pt(cod) (neoSi)Cl] (neoSi = trimethylsilylmethyl) with the non-coordinating anions SbF6– and BPh4–

Reactions of the organoplatinum complex [Pt(cod)(neoSi)Cl] (neoSi = (trimethylsilylmethyl) with the Ag(I) salts of oxo or fluoride containing anions A– = NO3–, ClO4–, OTf – (trifluoromethanesulfonate) and SbF6– lead to the desired abstraction of the chlorido ligand and precipitation of AgCl. However, further reaction of the resulting Pt complexes [Pt(cod)(neoSi) (solvent)]+ with diverse N-heterocyclic ligands L such as pyridines, caffeine, and guanine did not yield the targeted complexes [Pt(cod)(neoSi)(L)](A) in most of the cases, but to extensive decomposition yielding [Pt(cod)(Me) (solvent)]+, thus transforming the neoSi into a methyl ligand. A detailed study on the reaction with SbF6– combining DFT calculations with NMR and MS revealed that Pt catalysed decomposition of SbF6‒ and fluorination of the neoSi silicon atom leading to FSiMe3. When reacting the parent complex with Ag(BPh4), the arylated derivative [Pt(cod)(neoSi)(Ph)] was obtained and characterised by multinuclear NMR, MS and single crystal XRD.

Pinpointing the active species of the Cu(DAT) catalyzed oxygen reduction reaction

The activity of the 3,5-diamino-1,2,4-triazole copper system for the oxygen reduction reaction was found to originate from an electrodeposition rather than the parent complex.