{'fraction_non_alphanumeric': 0.042923433874709975, 'fraction_numerical': 0.02320185614849188, 'mean_word_length': 5.034965034965035, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
A Frustrated and Confused Lewis Pair.

We report a new class of frustrated Lewis pairs (FLPs) by the hydroboration of bulky isocyanates iPr2 ArNCO (iPr2 Ar=2,6-iPr2 C6 H3 ) and Ph2tBu ArNCO (Ph2tBu Ar=2,6-Ph2 -4-tBuC6 H2 ) with Piers' borane (HB(C6 F5 )2 ). While hydroboration of smaller isocyanates such as iPr2 ArNCO leads to isocyanate-N/B FLP adducts, hydroboration of the bulkier Ph2tBu ArNCO allows isolation of the substrate-free aminoborane with a short, covalent N-B bond. This confused FLP reversibly binds unsaturated substrates such as isocyanates and isocyanides, suggesting the intermediacy of a "normal" FLP along the reaction pathway, supported by high-level DFT studies and variable-temperature NMR spectroscopy. These results underscore the possibility of FLP behavior in systems that possess no obvious frustrated Lewis acid-base interaction.