Liquid helium quartz cryostat

All electronic absorption spectra were collected in a 1 cm quartz cuvette with a magnetic spin bar inside. Room temperature electronic absorption spectra for determining extinction coefficients were recorded on a Cary 50 spectrometer. Temperature controlled time dependent electronic absorption spectra were recorded either on a Cary 60 spectrometer equipped with Quantum Northwest TC1 temperature controller and stirrer, or on an 8453E Agilent UV-vis spectrometer equipped with an Unisoku Unispeks cryostat. Cyclic voltammetry was performed using a CHI600C electrochemical analyzer under Ar atmosphere with 0.1 M tetrabutylammonium hexafluorophosphate as the supporting electrolyte. A 2.0 mm glassy carbon electrode was used as working electrode; a Pt wire was used as counter electrode; a Ag wire was used as references electrode with ferrocenium/ferrocene(FeCp₂^+/0) couple as internal standard. All potentials are referenced to FeCp₂^+/0 couple. Solid-state IR spectra were collected on a Thermo Scientific Nicolet iS5 FT-IR spectrometer equipped with an iD5 ATR accessory. X-band EPR spectra were recorded as frozen solutions using a Bruker EMX spectrometer equipped with an ER041XG microwave bridge, an Oxford Instrument liquid-helium quartz cryostat, and a dual-mode cavity (ER4116DM). Magnetic moments were done by Evans's method at 298 K in CH₂Cl₂ on a Bruker DRX NMR spectrometer.⁴¹

Room temperature electronic absorbance spectra were collected on a Cary 50 spectrometer and low-temperature electronic absorbance spectra were collected on a 8453 Agilent UV-vis spectrophotometer equipped with an Unisoku Unispeks cryostat with a 1.00 cm quartz cuvette. Electronic paramagnetic resonance (EPR) spectra were recorded using a Bruker EMX spectrometer equipped with an ER041XG microwave bridge, an Oxford Instrument liquid-helium quartz cryostat, and a dual mode cavity (ER4116DM). Fourier-transform infrared (FTIR) spectra were collected on a Varian 800 Scimitar series FTIR spectrometer in Nugol. ¹H and ¹³C nuclear magnetic resonance (NMR) spectroscopies were conducted using a Bruker DRX500 spectrometer. Solution magnetic moments were determined by the Evan’s method using a Bruker DRX500 spectrometer.²⁵ Cyclic voltammetric experiments were conducted using a CHI600C electrochemical analyzer. A 2.0 mm glassy carbon electrode was used as the working electrode at scan velocities of 100 mV s⁻¹. A cobaltocenium/cobaltocene couple (CoCp₂⁺/CoCp₂) (ΔE_p = 0.136 V) was used to monitor the Ag wire reference electrode and all potentials are reference to the Fc⁺/Fc couple.