Borole Derivatives. 24. Synthesis of Cationic (Arene)(phenylborole)rhodium Complexes. Structures of the Trinuclear Complex (η<sup>5</sup>-C<sub>4</sub>H<sub>4</sub>BPh)Rh(μ<sub>3</sub>-I)<sub>3</sub>-Rh(μ,η<sup>5</sup>:η<sup>6</sup>-C<sub>4</sub>H<sub>4</sub>BPh)Rh(η<sup>5</sup>-C<sub>4</sub>H<sub>4</sub>BMe)·CH<sub>2</sub>Cl<sub>2</sub> and of the Polymeric <i>catena</i>-(μ,η<sup>5</sup>:η<sup>6</sup>-1-Phenylborole)rhodium Tetrafluoroborate

The heterocubane [Rh(μ<sub>3</sub>-I)(C<sub>4</sub>H<sub>4</sub>BPh)]<sub>4</sub> (<b>1</b>) reacts with Ag<sup>+</sup> salts in acetonitrile to give the labile salt [Rh(NCMe)<sub>3</sub>(C<sub>4</sub>H<sub>4</sub>BPh)]BF<sub>4</sub> (<b>2</b>). This salt <b>2</b> reacts with hexamethylbenzene (hmb) to give the arene complex [Rh(C<sub>4</sub>H<sub>4</sub>BPh)(hmb)]BF<sub>4</sub> (<b>3</b>), and with mesitylene [Rh(1,3,5-C<sub>6</sub>H<sub>3</sub>Me<sub>3</sub>)(C<sub>4</sub>H<sub>4</sub>BPh)]BF<sub>4</sub> (<b>4</b>) is obtained. Complex <b>2</b> loses acetonitrile under vacuum to produce the polymeric salt <i>catena</i>-[{Rh(μ,η<sup>5</sup>:η<sup>6</sup>-C<sub>4</sub>H<sub>4</sub>BPh)}BF<sub>4</sub>]<i><sub>x</sub></i> (<b>5</b>). Insight into the essential structural features of this polymer provided its radial distribution function obtained from a wide-angle X-ray scattering experiment. When treated with acetonitrile, complex <b>5</b> regenerates <b>2</b> and with pyridine affords [Rh(py)<sub>3</sub>((C<sub>4</sub>H<sub>4</sub>BPh)]BF<sub>4</sub> (<b>6</b>). Crystallization from a solution of [Rh(μ<sub>3</sub>-I)(C<sub>4</sub>H<sub>4</sub>BPh)]<sub>4</sub> (<b>1</b>) and the corresponding methylborole complex [Rh(μ<sub>3</sub>-I)(C<sub>4</sub>H<sub>4</sub>BMe)]<sub>4</sub> (1/1) in CH<sub>2</sub>Cl<sub>2</sub> produces the trinuclear complex (η<sup>5</sup>-C<sub>4</sub>H<sub>4</sub>BPh)Rh(μ<sub>3</sub>-I)<sub>3</sub>Rh(μ,η<sup>5</sup>:η<sup>6</sup>-C<sub>4</sub>H<sub>4</sub>BPh)Rh(η<sup>5</sup>-C<sub>4</sub>H<sub>4</sub>BMe)·CH<sub>2</sub>Cl<sub>2</sub> (<b>7</b>) with a bridging μ,η<sup>5</sup>:η<sup>6</sup>-C<sub>4</sub>H<sub>4</sub>BPh ligand; complex <b>7</b> was characterized by an X-ray structure determination. The resulting molecular structure was used to create a structure model for the monomeric building block of polymer <b>5</b>.