An unexpected cluster opening upon the formation of electronically unsaturated η3-(cyclooctenyl)metallacarboranes of rhodium(III) and iridium(III) with sterically reduced [(PhCH2)2C2B9H9]2− 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.…”

“…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. The similar pseudocloso structure was observed for the related [3-{(1-3-η 3 )-C 8 H 13 }-1-SPh-2-Ph-pseudocloso-3,1,2-RhC 2 B 9 H 9 ].…”

“…[1][2][3] Contrary to Cp dicarbollide dianion bears double negative charge which makes it possible to stabilize higher oxidation states of transition metals which may be useful in some cases. Another peculiarity of the dicarbollide ligand is the observed possibility of elongation of the bond between carbon atoms of carborane cage (C c À C c ) leading to the formation of hypercloso (or isocloso), [4][5][6] arachno [7] or pseudocloso [8][9][10][11][12][13][14] complexes. Hypercloso and arachno-metallacarboranes have respectively fewer or extra skeletal pairs while pseudocloso ones are isoelectronic to closo complexes.…”

Studies of Multicenter and Intermolecular Dihydrogen B–H···H–C Bonding in [4,8,8′‐exo‐{PPh3Cu}‐4,8,8′‐(μ‐H)3‐commo‐3,3′‐Co(1,2‐C2B9H9)(1′,2′‐C2B9H10)]

“…[21][22][23][24][25] Experimental data relating to electron density (ED) distribution are limited, to the best of our knowledge, to a metallacarborane of nontransition metals: {Na(thf) 2 [9-SMe 2 -7,8-C 2 B 9 H 10 ]} 2 . [26] QTAIM [27] is a powerful method with which to study various types of chemical bonding.…”