Figure 1
A) Positive ion ESI-MS spectra of rhodium (II) citrate: [Rh 2 (C 6 H 7 O 7 ) 4 +H]+ ( m/z 970,8). Ordinate: relative intensity. B) 13C NMR spectra of Rh 2 (H 2 Cit) 4 complex. The upper detail shows that the signals of α- and β-carboxyl carbon atoms in the complex (195.3 and 192.8 ppm, respectively) appear shifted.