The Preparation of Luminescent, Mechanochromic Molecular Containers from Non‐Emissive Components: The Box Cations, [Au 6 (Triphos) 4 Br] 5+ and [Au 6 (Triphos) 4 Br 2 ] 4+

Two new molecular boxes, the mono‐bromo box [Au 6 (Triphos) 4 Br](SbF 6 ) 5 ⋅6(CH 2 Cl 2 ), 4 mB , and the dibromo box, [Au 6 (Triphos) 4 Br 2 ⋅H 2 O](SbF 6 ) 4 ⋅4(CH 2 Cl 2 ), 5 dB , have been prepared in crystalline form. Although constructed from non‐luminescent components, both are strongly luminescent. Like its chloro counterpart, the mono‐bromo box [Au 6 (Triphos) 4 Br](SbF 6 ) 5 ⋅6(CH 2 Cl 2 ), 4 mB , is mechanochromic. Under grinding, it loses its luminescence. The bromo‐bridged helicate, [(μ‐Br){Au 3 (Triphos) 2 } 2 ](CF 3 SO 3 ) 5 ⋅2(CH 2 Cl 2 ), 3μ‐H , with a cation that is isomeric with the box [Au 6 (Triphos) 4 Br] 5+ , has also been prepared and crystallographically characterized. Unlike its chloro analogue, [(μ‐Br){Au 3 (Triphos) 2 } 2 ](CF 3 SO 3 ) 5 ⋅2(CH 2 Cl 2 ) is not luminescent. Thus, the cation produced upon grinding may be the cation present in the bromo‐bridged helicate, [(μ‐Br){Au 3 (Triphos) 2 } 2 ](CF 3 SO 3 ) 5 ⋅2(CH 2 Cl 2 ), 3μ‐H . The dibromo box, [Au 6 (Triphos) 4 Br 2 ⋅H 2 O](SbF 6 ) 4 ⋅4(CH 2 Cl 2 ), 5 dB , is not significantly mechanochromic.