A novel [(3,5-lutidine)2Co(OAc)2(H2O)2] complex (1) shows impressive OER activity, two and half times higher than that of a state-of-the-art IrO2 catalyst.

We examine the effect of organic fluorine in the molecular conformation and supramolecular packing in a series of α-fluoroketones in comparison to the analogous α-hydroxyketones. Crystal structures of a series of seven α-fluoroketone analogues have been analyzed using single-crystal XRD, and their crystal-packing features have been investigated using a variety of computational tools. Analysis of molecular conformations in this series of αfluoroketone structures, along with conformational energy scans, revealed a preference for a near-antiperiplanar conformation for α-fluoroketones as opposed to a syn conformation in their α-hydroxy analogues. A quantitative analysis of intermolecular interaction motifs such as C−Hetc. in terms of interaction energies and electron density topological parameters from a QTAIM (quantum theory of atoms in molecules) approach reveal their relative strengths and distance dependence. Electron localization function (ELF) and deformation density maps bring out the electrostatic nature of weak interactions involving organic fluorine. Lattice energy values estimated using the CE-B3LYP method show dominant contributions from dispersion in all these structures, which are around 3−4-fold higher than the electrostatic contribution. While the lattice energy values of the α-fluoroketones are found to be lower than those of their hydroxy analogues, a molecular docking study with a common protein receptor site reveals comparable docking scores for αfluoroketones with respect to the analogous α-hydroxyketones.

Crystal structures of a series of six α-hydroxy ketone derivatives have been analysed in the context of their molecular conformational preferences. The crystal structures obtained by single crystal X-ray diffraction...

Ethyl chloroformate (ClC(O)OC2H5), a room-temperature liquid, adopts two crystalline structures under different cryogenic conditions. Lattice cohesive energies indicate thatcontrary to a common notionthe high symmetry, low Z′ polymorph (R3̅, Z′ = 1; Form II) is a kinetically stable form compared to the low symmetry, high Z′ polymorph (P1̅, Z′ = 2, Form I). This also corroborates our observation of Form II showing a tendency to convert into the thermodynamically more stable Form I in the in situ cryo-crystallography experiments. Interaction topology analysis indicates that the primary packing motif in both polymorphs is formed with an antiparallel CO···CO dipolar interaction. Differences in secondary interactions, particularly those involving chlorine, drive the formation of polymorphs. The Cl atom is engaged in Cl···O halogen bonding in both polymorphs, however, with a striking difference in its mode of interaction. It chooses an ethoxy O atom (O–C2H5) as acceptor in Form I vs a carbonyl O atom (OC) as acceptor in Form II. Quantitative analysis of the intermolecular interactions in both these polymorphs in terms of CE-B3LYP interaction energies, electron density topology analysis using the Quantum Theory of Atoms in Molecules (QTAIM) approach, electron deformation densities, and electron localization function (ELF) provide insights into their nature and explain relative stability trends of these polymorphs.