Chemical recycling of polymers to true monomers is pivotal for a circular plastics economy. Here, the first catalyzed chemical recycling of the widely investigated carbon dioxide derived polymer, poly(cyclohexene carbonate), to cyclohexene oxide and carbon dioxide is reported. The reaction requires dinuclear catalysis, with the di‐MgII catalyst showing both high monomer selectivity (>98 %) and activity (TOF=150 h−1, 0.33 mol %, 120 °C). The depolymerization occurs via a chain‐end catalyzed depolymerization mechanism and DFT calculations indicate the high selectivity arises from Mg‐alkoxide catalyzed epoxide extrusion being kinetically favorable compared to cyclic carbonate formation.

Silver complexes of tethered N-heterocyclic carbene-carboranyl ligands have been prepared and fully characterized. The first example of silver bonded directly to the cage of o-carborane has been identified in the solid state. The presence of a carboranyl N substituent on the N-heterocyclic carbene significantly enhances the in vitro cytotoxicity of the silver complex against HCT116 p53+/+ and HCT116 p53–/– colon cancer cells in comparison to a phenyl derivative. Conversely, the presence of a carboranyl on the backbone of a xanthine-derived N-heterocyclic carbene decreases the in vitro cytotoxicity of the silver complex in comparison to its phenyl derivative. Stability studies on the xanthine-derived ligands and complexes show that decomposition via deboronation occurs in hydrous dimethyl sulfoxide, which may attribute to the contrasting in vitro behaviors of the carborane-containing complexes.

Chemical recycling of polymers to true monomers is pivotal for a circular plastics economy. Here, the first catalyzed chemical recycling of the widely investigated carbon dioxide derived polymer, poly(cyclohexene carbonate), to cyclohexene oxide and carbon dioxide is reported. The reaction requires dinuclear catalysis, with the di‐MgII catalyst showing both high monomer selectivity (>98 %) and activity (TOF=150 h−1, 0.33 mol %, 120 °C). The depolymerization occurs via a chain‐end catalyzed depolymerization mechanism and DFT calculations indicate the high selectivity arises from Mg‐alkoxide catalyzed epoxide extrusion being kinetically favorable compared to cyclic carbonate formation.

A range of precious metal complexes incorporating either benzyl or carbaboranyl functionalised tethered Nheterocyclic carbenes have been prepared, including single X-ray crystallography for one new complex. The library has been screened for their anti-cancer potential against colorectal, ovarian, cisplatin-resistant ovarian and breast cancer cell lines and their selectivity determined by comparing the cytotoxicity towards normal cells. Overall, these complexes show significant selectivity for ovarian carcinoma, and are up to 3-fold more cytotoxic than cisplatin against cisplatin-resistant human ovarian carcinoma. Upon replacing the benzyl moiety of the NHC ligand with a carbaboranyl there is a general increase observed in the potency of the complexes, with the cytotoxicity of the ruthenium complex increasing by >16-fold against human ovarian carcinoma. Generally, the rhodium complex with the benzyl tethered NHC shows the greatest selectivity for cancer, with a selectivity index of 15, which is >2x, >9x and >6x higher than that of cisplatin, carboplatin and oxaliplatin, respectively.