Construction of an M3L2A6 Cage with Small Windows from a Flexible Tripodal Ligand and Cu(hfac)3

An M3L2A6 cage has been prepared with small windows from a tripodal ligand, L, and Cu­(hfac)2. Cold spray ionization mass spectrometry of a mixture of L and Cu­(hfac)2 revealed the formation of a Cu3L2hfac6 cage in solution. X-ray crystallography showed that the Cu3L2hfac6 cage included neutral molecules such as THF and CHCl3. Furthermore, the six hfac anions have been shown to play an important role in holding neutral guest molecules securely in place.