*4.6. Q-ToF 2 Instrument Settings and Data Aquisition*

Nano-ESI-MS measurements were performed using a Q-TOF 2 instrument (Waters MS-Technologies, Manchester, UK). The pressure in the source region of the mass spectrometer was manually adjusted to 2.24 mbar using the speedy valve [16]. ITEM-TWO measurements were performed with the following instrumental settings: source temperature, 50 ◦C; capillary voltage, 1.3 kV; sample cone voltage, 30 V; extractor cone voltage, 3 V; collision voltage, 4 V; pusher time, 124 µs. The Quadrupole and ToF analyzer pressures were typically between ca. 2.0 × 10−<sup>5</sup> mbar and 2.50 × 10−<sup>7</sup> mbar, respectively. All mass spectra were acquired in positive-ion mode with a mass window of *m*/*z* 200–4000. The *m*/*z* axis was calibrated using 50% TFE in 1% orthophosphoric acid. The collision gas was then switched on (1.25 bar) and collision cell voltage differences were increased in a stepwise manner (5–20 V/step) to cause dissociation of the complexes. At each collision cell voltage difference setting, a mass spectrum was recorded for 2 min, each. All scans for a given collision cell voltage difference were combined to generate an average spectrum. Q-ToF MS data were acquired and minimally processed using the MassLynx software version 4.0 (Waters MS-Technologies, Manchester, UK). From each spectrum, the ion intensities (in arbitrary units) were deduced [16].
