Adventures in crystallization. Crystalline salts containing one, two, or even three chemically distinct cations obtained from solutions of [(cyclohexyl isocyanide)(4)Rh(I)]+

By judicious selection of crystallization conditions, it has been possible to obtain the salts of a common building block, (RNC)4Rh(I)]+, in single-crystal form suitable for X-ray diffraction. Salts that contain a single type of cation include deep green (C6H11NC)12Rh(I)3](SbF6)3, deep green (C6H11NC)12Rh(I)3](AsF6)3, and straw yellow (C6H11NC)8Rh(II)2Cl2](BF4)2 (in addition to the previously isolated trimeric deep green (i-PrNC)12RhI3]Cl3 x 4.5 H2O, monomeric, (C6H11NC)4 Rh(I)](BPh4), and (i-PrNC)4Rh(I)](BPh4) (both yellow), and red, dimeric (C6H11NC)8Rh(I)2]Cl2 x 0.5C6H6 x 2H2O). Ordered crystals of (C6H11NC)12Rh(I)3](SbF6)3 contain linear Rh3 units, while those of (C6H11NC)12Rh(I)3](AsF6)3 show disorder which is consistent with the presence of linear or bent Rh3 units. The formation of green (C6H11NC)12Rh(V/III)3Cl2](C6H11NC)12Rh(I)3]Cl6, and brown (C6H11NC)12Rh(V/III)3Cl2](C6H11NC)8Rh(I)2](C6H11NC)4RhI]Cl6 x 16H2O x 3C6H6 along with unidentified red-brown cubes from an air-exposed solution of (C6H11NC)4Rh(I)]Cl is reported. As their formulas indicate, green (C6H11NC)12Rh(V/III)3Cl2](C6H11NC)12Rh(I)3]Cl6, and brown (C6H11NC)12Rh(V/III)3Cl2](C6H11NC)8Rh(I)2](C6H11NC)8Rh(I)]Cl6 x 16H2O x 3C6H6 contain two or three chemically distinct cations, respectively, but again are built from a common precursor, (C6H11NC)4Rh(I)]+.