*3.2. Synthesis of the Pd–Sulfosalan Complexes*

3.2.1. Synthesis of Na2[Pd(PrHSS)]

In water (4 mL), 106.75 mg (0.24 mmol) of PrHSS and 73.9 mg (0.26 mmol) of (NH4)2[PdCl4] were dissolved. The pH was set to 7.5 with concentrated NaOH, and the reaction mixture was stirred at 60 ◦C for 10 h. Then, the solution was cooled to room temperature, and Na2[Pd(PrHSS)] was precipitated by addition of 25 mL ice-cold ethanol. The solid was filtered, washed with absolute ethanol and dried under vacuum.

Yield: 129 mg (0.22 mmol), 92%, yellow solid.

1H-NMR (D2O, 273 K, 360 MHz, <sup>δ</sup>): 1.37–1.49 (m, 1H, <sup>−</sup>CH2CH2−), 1.89 (d, *J* = 15.9 Hz, 1H, −CH2CH2−), 2.48 (d, *J* = 12.7 Hz, 2H,−CH2CH2−), 2.73 (t, *J* = 12.4 Hz, 2H, CH2CH2), 3.23 (d, *J* = 12.5 Hz, 2H, CH2−NH), 3.29 (d, *J* = 12.5 Hz, 2H, CH2−NH), 6.84 (d, *J* = 9.0 Hz, 2H, CHarom), 7.36 (s, 2H, CHarom), 7.44–7.47 (m, 2H, CHarom).

13C{1H} NMR (D2O, 90 MHz, δ/*ppm*): 167.27, 130.40, 128,17, 127.69, 126.47, 118.43, 52.47, 51.98, 26.67. IR (ATR), ν/cm<sup>−</sup>1: 602.5, 707.8, 823.7, 1038.48, 1103.5, 1198.2, 1290.5, 1477.9

ESI-MS C17H18N2O8S2PdNa2 (*m*/*z*): calcd for [M <sup>−</sup> Na+] − 570.945, found 570.945.
