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

The pyrazolato-based PCP [Ni8(μ4-OH)4(μ4-OH2)2(μ4-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 °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 (N2 at 77 K, in the low pressure region; H2 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.