Coordination-induced O-H/N-H bond weakening by a redox non-innocent, aluminum-containing radical.

Several renewable energy schemes aim to use the chemical bonds in abundant molecules like water and ammonia as energy reservoirs. Because the O-H and N-H bonds are quite strong (>100 kcal/mol), it is necessary to identify substances that dramatically weaken these bonds to facilitate proton-coupled electron transfer processes required for energy conversion. Usually this is accomplished through coordination-induced bond weakening by redox-active metals.

Activation of robust bonds by carbonyl complexes of Mn, Fe and Co.

Metal carbonyl complexes possess among the most storied histories of any compound class in organometallic chemistry. Nonetheless, these old dogs continue to be taught new tricks. In this Feature, we review the historic discoveries and recent advances in cleaving robust bonds (, C-H, C-O, C-F) using carbonyl complexes of three metals: Mn, Fe, and Co.

Cooperative Activation of CO and Epoxide by a Heterobinuclear Al-Fe Complex via Radical Pair Mechanisms.

Activation of inert molecules like CO is often mediated by cooperative chemistry between two reactive sites within a catalytic assembly, the most common form of which is Lewis acid/base bifunctionality observed in both natural metalloenzymes and synthetic systems. Here, we disclose a heterobinuclear complex with an Al-Fe bond that instead activates CO and other substrates through cooperative behavior of two radical intermediates. The complex L(Me)AlFp (, L = HC{(CMe)(2,6-PrCHN)}, Fp = FeCp(CO), Cp = η-CH) was found to insert CO and cyclohexene oxide, producing LAl(Me)(μ:κ-OC)Fp () and LAl(Me)(μ-OCH)Fp (), respectively.

Cobalt-Catalyzed ()-β-Selective Hydrogermylation of Terminal Alkynes.

A cobalt-catalyzed method for the hydrogermylation of alkynes is reported, providing a selective and accessible route to ()-β-vinyl(trialkyl)germanes from terminal alkynes and HGeBu. As shown in multiple examples, the developed method demonstrates a broad functional group tolerance an practical utility for late-stage hydrogermylation of natural products. The method is compatible with alkynes bearing both aryl and alkyl substituents, providing unrivaled selectivity for previously challenging 1° alkyl-substituted alkynes.