A series of new rhodium (I) complexes supported by bidentate nitrogen-donor ligands with varying electronic and steric properties were synthesized in situ and evaluated for catalytic arene C-HID activation. In trifluoroacetic acid (HTFA), these complexes are proposed to mediate HAD exchange of arene C-H/D bonds by an electrophilic aromatic substitution mechanism that involves Rh-mediated activation of HTFA (or DTFA). DFT calculations support the proposed pathway for the HAD exchange reactions. (C) 2016 Elsevier B.V. All rights reserved.