Spectroscopic and adsorptive studies of a thermally robust pyrazolato-based PCP

The pyrazolato-based PCP [Ni-8(mu(4)-OH)(4)(mu(4)-OH2)(2)(mu(4)-PBP)(6)] (NiPBP, H2PBP = 4,4'-bis(1H-pyrazol-4-yl) biphenyl), whose 3-D architecture is built upon octametallic hydroxo clusters reciprocally connected by organic spacers, is a very promising candidate for gas adsorption applications, owing to its remarkable thermal stability (up to 400 degrees C in air) and its high void volume (70%). As such, NiPBP was selected as a proof-of-concept material to demonstrate how an optimized set of solid state techniques can concur to create a comprehensive and coherent picture, relating (average and local) structural features to adsorptive properties. To this aim, the response of NiPBP toward different gases, retrieved by gas adsorption measurements (N-2 at 77 K, in the low pressure region; H-2 at 77 K, in the high pressure region), was explained in terms of local-level details, as emerged by coupling electronic, X-ray (absorption and emission), and variable temperature IR spectroscopy.