Which Metals are Green for Catalysis? Comparison of the Toxicities of Ni, Cu, Fe, Pd, Pt, Rh, and Au Salts

New metal-free catalytic degradation systems with carbon dots for thymol blue

A metal-free catalytic system with carbon dots as a catalyst for thymol blue degradation in slightly alkaline aqueous media.

A triazine-based Ni(II) PNP pincer complex as catalyst for Kumada-Corriu and Negishi cross-coupling reactions

ABSTRACT

Kumada-Corriu and Negishi cross-coupling reactions, catalyzed efficiently by a Ni(II) PNP pincer complex containing a triazine backbone, are described. The catalyst is able to react with both activated and inactivated aryl halides including chlorides as well as phenol derivatives such as tosylates and mesylates to give the corresponding cross-coupling products in good to excellent isolated yields. A high diversity of substrates was tested under moderate conditions for both types of reactions.

GRAPHICAL ABSTRACT

Iron Catalysis in Organic Synthesis: A Critical Assessment of What It Takes To Make This Base Metal a Multitasking Champion

The current status of homogeneous iron catalysis in organic chemistry is contemplated, as are the reasons why this particular research area only recently starts challenging the enduring dominance of the late and mostly noble metals over the field. Centered in the middle of the d-block and able to support formal oxidation states ranging from -II to +VI, iron catalysts hold the promise of being able to encompass organic synthesis at large. They are expected to serve reductive as well as oxidative regimes, can emulate "noble tasks", but are also able to adopt "early" transition metal character. Since a comprehensive coverage of this multidimensional agenda is beyond the scope of an Outlook anyway, emphasis is laid in this article on the analysis of the factors that perhaps allow one to control the multifarious chemical nature of this earth-abundant metal. The challenges are significant, not least at the analytical frontier; their mastery mandates a mindset that differs from the routines that most organic chemists interested in (noble metal) catalysis tend to cultivate. This aspect notwithstanding, it is safe to predict that homogeneous iron catalysis bears the chance to enable a responsible paradigm for chemical synthesis and a sustained catalyst economy, while potentially providing substantial economic advantages. This promise will spur the systematic and in-depth investigations that it takes to upgrade this research area to strategy-level status in organic chemistry and beyond.