Unveiling the new function of uranyl molecular clusters as fluorometric sensors for UV and X-ray dosimetry

Cluster-in-Cluster Approach for Computing MP2-Level Vibrational Infrared Spectra of Large Molecular Clusters

Constructing the Hessian matrix (HM) for large molecules demands huge computational resources. Here, we report a cluster-in-cluster (CIC) procedure for efficiently evaluating HM and dipole derivatives for large molecular clusters by employing the second-order Møller-Plesset perturbation (MP2) theory. The highlight of the proposal is the separation of the estimations of Hartree-Fock (HF) and post-HF components. The parent cluster with n molecules is divided (virtually) into n subclusters centering each monomer and accommodating its near neighbors decided by a distance cutoff. The HF-level HM is obtained by doing full calculation (FC), while the correlation part is approximated by the respective subclusters. A software automating the procedure [followed by calculating infrared (IR) frequencies and intensities] is applied to deduce the IR spectrum for a variety of molecular clusters, particularly water clusters of various sizes, containing up to ∼2000 basis functions. The accuracy of the IR spectrum constructed using CIC is remarkable, with a substantial time advantage (with respect to its FC counterpart). The reduced computational resources and the tractability of the computations are other major benefits of the procedure.

Enhancing photosensitivity via the assembly of a uranyl coordination polymer

Synergistic assembly of uranyl centres and luminescent 2,6-bis(pyrazol-1-yl)pyridine-4-carboxylates (bppCOOH) gives rise to a uranyl coordination polymer, namely U-bppCOO, which exhibits a luminescence quenching response toward UV or X-ray irradiation doses. Notably, the photosensitivity of U-bppCOO has been significantly enhanced via metal-ligand assembly compared with that of the naked bppCOOH ligand.