A Diborylcarbazolyl Ligand for Stabilizing Low-Coordinate and Low-Valent Metal Complexes

We report the synthesis of a novel ligand L (3,6-di-<i>tert</i>-butyl-1,8-bis(dimesitylboryl)carbazolide) based on a carbazolyl scaffold bearing two sterically demanding boryl groups at the 1,8-positions. This diborylcarbazolyl framework effectively supports a range of transition metal complexes, including two-coordinate halide complexes <b>LM</b>^<b>II</b><b>Cl</b> [M = Fe (<b>2</b>), Co (<b>3</b>), and Zn (<b>4</b>)], trinuclear complex (<b>LCr</b>)<b>₂</b>(<b>CrCl</b>_<b>4</b>) (<b>5</b>), and pseudo-one-coordinate complexes <b>LM</b>^<b>I</b> [M = Ni (<b>6</b>) and Cu (<b>7</b>)]. Coinage metal complexes derived from L exhibit a preference for two-coordinate geometries, as demonstrated by the isolation of <b>LMPPh</b>_<b>3</b> [M = Ag (<b>8</b>) and Au (<b>9</b>)] and <b>LCu</b>(<b>DMAP</b>) (<b>10</b>).