Neutral Six-Coordinate and Cationic Five-Coordinate Silicon(IV) Complexes with Two Bidentate Monoanionic <i>N</i>,<i>S</i>‑Pyridine-2-thiolato(−) Ligands

Abstract

A series of neutral six-coordinate silicon­(IV) complexes (<b>4</b>–<b>11</b>) with two bidentate monoanionic <i>N</i>,<i>S</i>-pyridine-2-thiolato ligands and two monodentate ligands R¹ and R² was synthesized (<b>4</b>, R¹ = R² = Cl; <b>5</b>, R¹ = Ph, R² = Cl; <b>6</b>, R¹ = Ph, R² = F; <b>7</b>, R¹ = Ph, R² = Br; <b>8</b>, R¹ = Ph, R² = N₃; <b>9</b>, R¹ = Ph, R² = NCO; <b>10</b>, R¹ = Ph, R² = NCS; <b>11</b>, R¹ = Me, R² = Cl). In addition, the related ionic compound <b>12</b> was synthesized, which contains a cationic five-coordinate silicon­(IV) complex with two bidentate monoanionic <i>N</i>,<i>S</i>-pyridine-2-thiolato ligands and one phenyl group (counterion: I^–). Compounds <b>4</b>–<b>12</b> were characterized by elemental analyses, NMR spectroscopic studies in the solid state and in solution, and crystal structure analyses (except <b>7</b>). These structural investigations were performed with a special emphasis on the sophisticated stereochemistry of these compounds. These experimental investigations were complemented by computational studies, including bonding analyses based on relativistic density functional theory