Robust and efficient hydrogenation of carbonyl compounds catalysed by mixed donor Mn(I) pincer complexes

Abstract

Any catalyst should be efficient and stable to be implemented in practice. This requirement is particularly valid for manganese hydrogenation catalysts. While representing a more sustainable alternative to conventional noble metal-based systems, manganese hydrogenation catalysts are prone to degrade under catalytic conditions once operation temperatures are high. Herein, we report a highly efficient Mn(I)-CNP pre-catalyst which gives rise to the excellent productivity (TOF° up to 41 000 h−1) and stability (TON up to 200 000) in hydrogenation catalysis. This system enables near-quantitative hydrogenation of ketones, imines, aldehydes and formate esters at the catalyst loadings as low as 5–200 p.p.m. Our analysis points to the crucial role of the catalyst activation step for the catalytic performance and stability of the system. While conventional activation employing alkoxide bases can ultimately provide catalytically competent species under hydrogen atmosphere, activation of Mn(I) pre-catalyst with hydride donor promoters, e.g. KHBEt3, dramatically improves catalytic performance of the system and eliminates induction times associated with slow catalyst activation.

Genetic diversity and structure of Musa balbisiana populations in Vietnam and its implications for the conservation of banana crop wild relatives

“…In contrast, populations at the edge of their distribution range are generally believed to be more fragmented, smaller, and exhibit lower genetic diversity and higher genetic differentiation, though several studies report the lack of this latitudinal trend (e.g. [ 56 ] and [ 57 ]). Edge populations are often subjected to biotic or abiotic environmental conditions not present in these core populations [ 55 , 58 ].…”

COVID-19 Apps as a Digital Intervention Policy: A Longitudinal Panel Data Analysis in South Korea

“…Recently, Rodríguez et al. [29] conducted an experiment in the Canary Islands, Spain, in a controlled environment and revealed potential effectiveness of tracing apps in identifying simulated contacts. To summarize, these studies discovered that COVID-19 tracing apps could be effective under two conditions: i) many people adopt and employ the apps, and ii) infectious people should register their status on the apps.…”

An mRNA SARS-CoV-2 Vaccine Employing Charge-Altering Releasable Transporters with a TLR-9 Agonist Induces Neutralizing Antibodies and T Cell Memory

“…In this study, we present an alternative 3-component mRNA vaccine utilizing mRNA encoding the receptor binding domain (RBD) of the SARS-CoV-2 spike protein formulated with a highly efficient, nontoxic, PEG-free mRNA delivery platform called charge-altering releasable transporters (CARTs) 14 − 16 and a TLR9 agonist (CpG) as a coformulated adjuvant 16 , 17 ( Figure 1 A). Prior studies had indicated that the RBD is a promising antigen target 18 − 20 as antibodies elicited against RBD are often strongly neutralizing. CARTs offer a promising new gene delivery platform and have proven to be effective deliverers of mRNA vaccines in preclinical mouse studies.…”