Flexibility of cubane-like Cu4I4 framework: temperature dependence of molecular structure and luminescence thermochromism of [Cu4I4(PPh3)4] in two polymorphic crystalline states

Multitemperature X-ray structure analyses and photoemission spectra of [Cu(4)I(4)(PPh(3))(4)] in two polymorphic crystals reveal that the cubane-like framework is flexibly distorted effecting luminescence thermochromism.