Heterometallic\nClusters with Thorium–Rhodium\nBonds Supported by Double-Layer Nitrogen–Phosphorus Ligands

The investigation of metal–metal bonds involving\nf-block\nactinides has significantly lagged behind extensive research on d-block\ntransition metal bonds. Species featuring thorium-transition metal\nbonds are exceptionally rare. In this study, we report the synthesis\nof the first species containing Th–Rh bonds. Using two nitrogen–phosphorus ligands, [CH<sub>3</sub>N(CH<sub>2</sub>CH<sub>2</sub>NHP<sup>i</sup>Pr<sub>2</sub>)<sub>2</sub>]\nand {[CH<sub>2</sub>O(CH<sub>2</sub>)<sub>2</sub>NHP<sup>i</sup>Pr<sub>2</sub>]<sub>2</sub>}, we synthesized the Th(IV) chloride precursors <b>1</b> and <b>5</b>. Reactions of precursor <b>1</b> with [RhCl(COD)]<sub>2</sub> or [IrCl(COD)]<sub>2</sub> at room\ntemperature produced heterometallic clusters <b>2</b> and <b>3</b>, respectively. Similarly, precursor <b>5</b> reacted\nwith [RhCl(COD)]<sub>2</sub> or [IrCl(COD)]<sub>2</sub> under the\nsame conditions to yield analogues <b>6</b> and <b>7</b>. Notably, heating complexes <b>1</b> or <b>5</b> with\n[RhCl(COD)]<sub>2</sub> at 90 °C led to the formation of complexes <b>4</b> and <b>8</b>, each featuring two Th–Rh bonding\ninteractions. The Th–Rh bonding interaction in complex <b>8</b> is stronger than that in complex <b>7</b>, as confirmed\nby both experimental observations and theoretical analysis.