Ardila-Fierro KJ, Rubčić M, Hernández JG. Cocrystal Formation Precedes the Mechanochemically Acetate-Assisted C-H Activation with [Cp*RhCl
2 ]
2.
Chemistry 2022;
28:e202200737. [PMID:
35274769 DOI:
10.1002/chem.202200737]
[Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Indexed: 12/16/2022]
Abstract
This work reports the experimentally studied mechanochemical formation of rhodacycles by ball milling pyridine- and quinoline-derived substrates and [Cp*RhCl2 ]2 in the presence of NaOAc. Ex-situ analysis of the mechanochemical reactions using powder X-ray diffraction (PXRD), solid-state UV-vis spectroscopy and ATR-FTIR spectroscopy revealed the formation of unexpected cocrystals between the substrates and the rhodium dimer prior to the C-H activation step. This sequence of events differs from the generally accepted steps in solution in which cleavage of [Cp*RhCl2 ]2 is initiated by acetate ions. Additionally, the mechanochemical approach enabled the synthesis of the six-membered rhodacycle [Cp*Rh(2-benzilpyridine)Cl], a metal complex repeatedly reported as inaccessible in solution. Altogether, the results of this investigation clarify some of the fundamental aspects of mechanochemical cyclometallations.
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