From {Bi22O26} to Chiral Ligand-Protected {Bi38O45}-Based Bismuth Oxido Clusters

The reaction of [Bi22O26(OSiMe2tBu)14] (1) in THF with salicylic acid gave [Bi22O24(HSal)14] (2) first, which was converted into [Bi38O45(HSal)22(OH)2(DMSO)16.5]center dot DMSO center dot H2O (3 center dot DMSO center dot H2O) after dissolution and crystallization from DMSO. Single-crystal X-ray diffraction analysis and ESI mass spectrometry associated with infrared multi-photon dissociation (IRMPD) tandem MS experiments confirm the formation of the large and quite stable bismuth oxido cluster 3. The reaction of compound 2 with the butoxycarbonyl(BOC)-protected amino acids phenylalanine and valine (BOC-PheOH and BOC-ValOH), respectively, resulted in the formation of chiral [Bi38O45(BOC-AA)22(OH)2] (AA=deprotonated amino acid), as shown by a combination of different analytical techniques such as elemental analysis, dynamic light scattering, circular dichroism spectroscopy, and ESI mass spectrometry.