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Metal organic frameworks (MOFs) that incorporate metal oxide cluster nodes, exemplified by UiO-66, have been widely studied, especially in terms of their deviations from the ideal, defect-free crystalline structures. Although defects such as missing linkers, missing nodes, and the presence of adventitious synthesis-derived node ligands (such as acetates and formates) have been proposed, their exact structures remain unknown. Previously, it was demonstrated that defects are correlated and span multiple unit cells. The highly specialized techniques used in these studies are not easily applicable to other MOFs. Thus, there is a need to develop new experimental and computational approaches to understand the structure and properties of defects in a wider variety of MOFs. Here, we show how low-frequency phonon modes measured by inelastic neutron scattering (INS) spectroscopy can be combined with density functional theory (DFT) simulations to provide unprecedented insights into the defect structure of UiO-66. We are able to identify and assign peaks in the fingerprint region (<100 cm −1 ) which correspond to phonon modes only present in certain defective topologies. Specifically, this analysis suggests that our sample of UiO-66 consists of predominantly defect-free fcu regions with smaller domains corresponding to a defective bcu topology with 4 and 2 acetate ligands bound to the Zr 6 O 8 nodes. Importantly, the INS/DFT approach provides detailed structural insights ( e.g. , relative positions and numbers of acetate ligands) that are not accessible with microscopy-based techniques. The quantitative agreement between DFT simulations and the experimental INS spectrum combined with the relative simplicity of sample preparation, suggests that this methodology may become part of the standard and preferred protocol for the characterization of MOFs, and, in particular, for elucidating the structure defects in these materials. 

p-Type molecular dopants are a class of high electron affinity (EA) molecules used to ionize organic electronic materials for device applications. It is extremely challenging to ionize high-performance, high-ionization energy (IE) polymers because the dopant molecule needs to be compatible with solution processing. Here, we describe the synthesis and characterization of two new solution processable molecular dopants with the highest EA values yet reported. These molecules, based on the parent hexacyanotrimethylenecyclopropane (CN6-CP) structure, achieve solubility by the substitution of one or more of the cyano groups with esters, which both reduces the volatility relative to CN6-CP and allows for solution processing. The efficacy of these new molecular dopants, which have EA values up to 5.75 eV with respect to vacuum, was tested by performing sequential solution doping experiments with a series of thiophene and alternating diketopyrrolopyrrole polymers with IEs ranging from 5.10 eV to 5.63 eV. For completeness, the new dopant results are compared to a previously reported tri-ester substituted CN6-CP analogue with an EA of 5.50 EV. The increased EA of these stronger dopants induces a 10–100 fold increase in film conductivity and saturation of the conductivity at 15–100 S cm −1 for almost all polymers tested. These new dopant structures enable controlled solution doping at high doping levels for most alternating co-polymers of interest to the organic electronics community.