Tp'Rh[P(OMe)3](Me)H, loses methane in pentane solution containing CH2F2 to give the scorpionate complex bis(μ-dimethyl phosphito)-κ(2)P:O;κ(2)O:P-bis{methyl[tris(3,5-dimethyl-1H-pyrazol-1-yl-κN(2))borato]rhodium(III)}, [Rh2(CH3)2(C2H6O3P)2(C15H22BN6)2], in which the phosphine O-Me bond is cleaved. The product is dimeric and resembles the Arbusov-type rearrangement product known to form from trimethyl phosphite.