Characterization and instrumental procedures. Single-crystal X-ray diffraction data were collected on a Rigaku VariMax diffractometer with a HyPix-6000 detector (details of of crystallographic data collection described on CIF files). FT-IR spectra were acquired on a JASCO FT/IR 6700 spectrometer using the attenuated total reflectance (ATR) method. UV/vis spectra were acquired on a Shimadzu UV3100 spectrometer with an integrating sphere (BaSO4 background). The elemental analysis was performed on a J-SCIENCE LAB CO., Ltd JM-11 microanalyzer. The Raman spectra were carried out on a JASCO NRS-7200.