Half‐ and Mixed‐Sandwich Transition Metal Dicarbollides andnido‐Carboranes(–1) for Medicinal Applications

Metallacarboranes in Medicinal Chemistry: Current Advances and Future Perspectives

“…82 Additionally, both ferrabis(dicarbollide) moieties were tested in terms of their application in PBCT, which besides BNCT carries a great potential for aggressive glioblastoma treatment. In the first step of reaction underlying PBCT, an 11 B isotope fuses with a proton yielding an excited state carbon nucleus 12 C, which decays to a single α particle and a beryllium nucleus 8 Be further decaying to two additional alpha particles. This, in theory, results in the generation of a 3-fold higher alpha particles number per reaction than the BNCT 83 (the comparison between these reactions is pictured in Figure 6).…”

“…However, these two ligands show differences in charge and organometallic symmetry they make. 10,12 As a result, the character of the aromacity is different for both moieties: metallacarboranes display global aromaticity, whereas metallocenes present local aromaticity only in the ligands. 13 Therefore, metallacarboranes present a completely different set of physical, chemical, and biological properties than the corresponding cyclopentadienyl-based metallocenes.…”

“…At this point, it is worth highlighting the structural similarities and differences between metallocenes and metallacarboranes: both cyclopentadienyl ligand and dicarbollide anion [C 2 B 9 H 11 ] 2– coordinate via the pentagonal face donating six electrons to the metal center. However, these two ligands show differences in charge and organometallic symmetry they make. , As a result, the character of the aromacity is different for both moieties: metallacarboranes display global aromaticity, whereas metallocenes present local aromaticity only in the ligands . Therefore, metallacarboranes present a completely different set of physical, chemical, and biological properties than the corresponding cyclopentadienyl-based metallocenes .…”

“…In BNCT 10 B isotope is irradiated with neutron giving11 B nucleus which further decays to7 Li and one α particle. In PBCT, however,11 B isotope (which makes up around 80% of natural boron) after fusion with proton gives12 C nuclei which decays to one α particle and8 Be nuclei further decaying to two alpha particles. Therefore, a total number of generated alpha particles in PBCT is three.…”

Ruthenacarborane–Phenanthroline Derivatives as Potential Metallodrugs

“…Thus, the development of drugs in which the carborane moiety mimics a phenyl group or is the pharmacophore itself is actively studied [23][24][25][26][27][28][29]. Applications of such carborane-containing drugs are for example cancer therapeutics and enzyme inhibitors [11,14,19,20,22,23,[30][31][32][33][34][35][36][37]. Due to its isolobal relationship with the cyclopentadienyl ligand (Cp − ) the dicarbollide anion (nido-carborate(2−), C2B9H11 2− , Cb 2− ) is a suitable replacement as ligand for transition metals [38,39].…”