Cyclometalated (NNC)Ru(ii) complex catalyzed β-methylation of alcohols using methanol

Abstract

Indolyl fragment containing phenanthroline based new ligands and their corresponding Ru(ii) complexes were synthesized and utilized for β-methylation of alcohols using methanol.

Integrated CO2 Capture and Conversion to Methanol Leveraged by the Transfer Hydrogenation Approach

“…A well resolved triplet having a coupling constant ( 2 J H–P ) of ∼26.6 Hz in the upfield region at around −8.41 ppm was observed when the organic layer of the reaction mixture was subjected to 1 H NMR spectroscopy using CD 3 CN solvent. The observed 1 H NMR spectral feature of the Ru–H species was in accordance with the previously reported similar Ru–pincer-based hydride complexes. , On the other hand, the signature of glycolate as a side product from ethylene glycol following the hydride transfer to Ru was observed in the 1 H NMR spectrum of the aqueous layer (see the SI for details), in line with Prakash and co-workers’ investigation in the case of CO 2 hydrogenation in the presence of amine (tetramethyl-1,4-butanediamine, TMBDA)/EG . Of note, the reaction of the complex Ru–CNN and EG only did not form the Ru–hydride species or the glycolate product.…”

(NNC)Ru(II) Complex Catalyzed Selective Functionalization of Ketones with Methanol: Understanding the Role of Ancillary Ligands

“…The Ru1–N1 (2.266 (4) Å) and Ru1–N2 (2.023 (4) Å) bond lengths in B were longer compared to the corresponding Ru–N distances in D and E (2.194–2.198 (4) Å or 1.980–1.981 (4) Å), previously reported from our group (Scheme and Figure ). However, the Ru1–C1 bond length (2.026 (5) Å) in B was shorter than in D (2.049 (5) Å).…”

“…This led to the formation of a 2:3 mixture of the neutral and cationic acetonitrile bound (NNC)Ru(II) complexes (A) as predicted by 1 1). 23 However, the Ru1−C1 bond length (2.026 (5) Å) in B was shorter than in D (2.049 (5) Å).…”

“…Recently, few reports have been developed for the β-methylation of alcohols with methanol. ,,,− However, most of them required harsh reaction conditions such as 130–150 °C temperature and stoichiometric amounts of base. Hence, an alternative route for the synthesis of β-methylated alcohols using methanol is desirable.…”

Selective Transfer Hydrogenation of C=O and Conjugated C=C Bonds Using An NHC‐Based Pincer (CNC)MnI Complex in Methanol**

“…Under the same, conditions, catalytic activity of the previously reported Mn I , Ru II and Ir III complexes which were well explored towards methanol dehydrogenation and related reactions were tested (Table 2, entries 8-10). [53,54] Notably, these complexes were unable to deliver the product 2 b selectively.…”