An efficient synthesis of 12-vertex closo-rhodacarboranes [3-(η5-C5Me5)-1-R1-2-R2-3,1,2-closo-RhC2B9H9] (R1, R2=H, Alk) via two-step reactions of [K][7-R1-8-R2-7,8-nido-C2B9H10] mono-anions with [Rh2(η5-C5Me5)2Cl4]: structural characterization of the first purely closo-type metallacarborane with sterically demanding C,C′-dibenzylsubstituted carborane ligand

Synthesis of Novel Pseudocloso Ruthenacarboranes based on an Unsubstituted nido‐C2B9H112− Ligand

“…Among them the upper mentioned rhodacarboranes with donating pentamethylcyclopentadienyl and less donating with η 3 -cyclooctenyl ligand obtained by Chizhevsky and Viñas. [11,17,18] The similar situation is observed for 1-CCPh-2-Ph-3-(η-L)-3,1,2-RhC 2 B 9 H 9 synthesized by Welch. [32] The complex with less donating ligand (L=C 5 H 5 ) exists in pseudocloso state while its analogue with more bulky but more donating C 5 Me 5 ligand may exist in closo form in crystalline state.…”

“…The cleavage of C c À C c bond results in the tetragonal open face C1À RuÀ C2À B6 and distortion of the carborane cage. In spite of the examples of such type of metallacarboranes are known for years, [8][9][10][11][12][13][14][15][16][17][18] the obtained complexes exhibit the first examples of pseudocloso metallacarboranes based on unsubstituted C 2 B 9 H 11 2À , thus its formation was much unexpected.…”

“…[12][13][14] The influence of the donating ability of auxiliary ligands coordinated to metal on the closo or pseudocloso configurations of the carborane cage was shown by Chizhevsky on the example of rhodacarboranes. Thus, the complex [3-(η 5 -C 5 Me 5 )-1,2-(PhCH 2 ) 2 -3,1,2-closo-RhC 2 B 9 H 9 ] with donating pentamethylcyclopentadienyl ligand exists in the closo state with C c À C c bond equal to 1.7397 Å [17] while the similar electronically unsaturated complex with η 3 -cyclooctenyl ligand [3-{(1-3-η 3 )-C 8 H 13 }-1,2-(PhCH 2 ) 2 -pseudocloso-3,1,2-RhC 2 B 9 H 9 ] is a pseudocloso metallacarborane with C c À C c distance equal to 2.200 Å. [11] In the latter case the cleavage of skeletal C c À C c bond is required to stabilize formally 16-electron rhodium center.…”