Isolation and evolution of labile sulfur allotropes via kinetic encapsulation in interactive porous networks.

The isolation and characterization of small sulfur allotropes have long remained unachievable because of their extreme lability. This study reports the first direct observation of disulfur (S2) with X-ray crystallography. Sulfur gas was kinetically trapped and frozen into the pores of two Cu-based porous coordination networks containing interactive iodide sites.

Kinetic assembly of a thermally stable porous coordination network based on labile CuI units and the visualization of I2 sorption.

A net gain: A kinetically assembled, but thermally stable network is obtained using the labile metal species [Cu4 I4 (PPh3 )4 ]. The network uniquely adsorbs I2 by chemisorption through I3 (-) formation. The chemisorbed I2 readily desorbs above 380 K owing to the dynamic motion of the framework.

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.