Steric Pruning Unlocks Hierarchical Structuring, Thermochromism, C-H/O Activation, and 6-electron Redox Transmetalation in Planar Bismuth Triamides.

Planar bismuth triamides with tunable stereoelectronics offer a versatile platform for studying the effects of geometric constraints in p-block elements. Here we show that exploring the low steric bulk regime in these compounds unlocks categorically new phenomena such as epitaxial hierarchical ordering, thermochromism, C─H/O activation, and 6-electron pincer-to-pincer redox transmetalation. These behaviors are not observed in sterically encumbered derivatives, emphasizing the role of steric modulation in unlocking new phenomena in geometrically-constrained main group complexes.