Abstract
Anti-van't Hoff-Le Bel configured p-blockelementspecies possess intrinsically high reactivity and are thus challengingto isolate. Consequently, numerous elements in this configuration,including square-planar germanium(IV), remain unexplored. Herein,we follow a concept to reach anti-van't Hoff-Le Belreactivity by ligand dissociation from a rigid calix[4]pyrrole germanein its bis(thf) adduct. While ...
Abstract
Anti-van't Hoff-Le Bel configured p-blockelementspecies possess intrinsically high reactivity and are thus challengingto isolate. Consequently, numerous elements in this configuration,including square-planar germanium(IV), remain unexplored. Herein,we follow a concept to reach anti-van't Hoff-Le Belreactivity by ligand dissociation from a rigid calix[4]pyrrole germanein its bis(thf) adduct. While the macrocyclic ligand assures square-planarcoordination in the uncomplexed form, the labile thf donors providerobustness for isolation on a multigram scale. Unique properties ofa low-lying acceptor orbital imparted to germanium(IV) can be verified,e.g., by isolating an elusive anionic hydrido germanate and exploitingit for challenging bond activations. Aldehydes, water, alcohol, anda CN triple bond are activated for the first time by germanium-ligandcooperativity. Unexpected behaviors against fluoride ion donors disclosecritical interferences of a putative redox-coupled fluoride ion transferduring the experimental determination of Lewis acidity. Overall, weshowcase how ligand lability grants access to the uncharted chemistryof anti-van't Hoff-Le Bel germanium(IV) and line upthis element as a member in the emerging class of structurally constrainedp-block elements.
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