Theisonido-Metalladicarbaborane [1,1,1-H{P(CH₃)₃}₂-6-Cl-1,2,4-IrC₂B₈H₉]

Unusual cationic rhodathiaboranes: synthesis and characterization of [8,8,8-(H)(PR3)2-9-(Py)-nido-8,7-RhSB9H10]+and [1,3-μ-(H)-1,1-(PR3)2-3-(Py)-isonido-1,2-RhSB9H8]+

“…This structural motif can be formed by a simple diamondsquare process in a canonical closo-structure based on an octadodecahedron, giving a more open structure that is usually classified as isonido. [48][49][50][51][52][53][54] In the neutral cluster [Fig. 6(d )], the Rh-B lengths of boron vertices, 4 and 5, flanking the sulfur atom, lie just on the upper part of the bonding limit that leads to the generation of a triangular closo-face.…”

“…This structural motif can be formed by a simple diamond-square process in a canonical closo-structure based on an octadodecahedron, giving a more open structure that is usually classified as isonido. [48][49][50][51][52][53][54] In the neutral cluster [ Figure 6 These structural changes found in the cationic conformers with respect to the neutral counterparts indicate that the metalthiaborane linkage is non-rigid and that conformational changes can be produced at a low energy cost in this system. In order to evaluate this fact, we carried out DFT-optimizations starting from the X-ray determined structure of isonido-20b, adding a hydrogen atom along the Rh (1) 7) where the cluster is protonated.…”

Organometallic Chemistry on a Metallathiaborane Cluster: Reactions of [8,8-(PPh3)2-nido-8,7-RhSB9H10] with Bidentate Phosphine Ligands

“…The intimate nature of the transition state of this fluxional process is unknown; however, as suggested elsewhere, it is likely to consist of an 11-vertex intermediate of C s symmetry, with the bridging hydrogen bonded to the metal atom in either a terminal (M−H) or a bridging (M−H−B) fashion. The equilibrium observed in solution between the nido -metallacarborane [9,9-(PEt 3 ) 2 -9,7,8-RhC 2 B 8 H 11 ] ( 9 ) and its isonido isomer 13 [1,1,1-H(PEt 3 ) 2 -1,2,4-RhC 2 B 8 H 10 ] ( 10 ) and the formation of the isonido species [1,1,1-H(PMe 3 ) 2 -1,2,4-IrC 2 B 8 H 10 ] ( 11) , obtained from the thermolysis of [9,9,9-CO(PMe 3 ) 2 -9,7,8-IrC 2 B 8 H 11 ] ( 12 ), 5a, provide chemical support for the proposal of a closed or pseudo-closed species of C s symmetry as the transition state in the fluxional process described above. This is further suggested by the nido to closo structural change that compound 2 undergoes upon deprotonation to give the closo anion [1,1-(η 2 -dppe)-1,2-RhSB 9 H 9 ] - ( 13 ), which, upon addition of proton, is reversibly transformed to the parent neutral nido compound, 2 . , …”

Organometallic chemistry on rhodaheteroborane clusters: reactions with bidentate phosphines and organotransition metal reagents

“…the previously studied species. The transition state shown in Scheme 4 is comparable to the species in solution equilibrium with the nido-metallacarborane analogue of 2, [9,9- 21,22 Further support for the closo-type transition state comes from the observation of the reversible nido to closo change that compound 1 undergoes on deprotonation, which is illustrated in Scheme 3. 9,12,13 When the reactions of compound 1 with dppe and dppp are carried out in 1 : 3 metallathiaborane to phosphine molar ratios, compounds 7 and 10 are formed together with the yellow nido-rhodathiaboranes, [8,8-(η 2 -dppp)-9-(η 1dppp)-nido-8,7-RhSB 9 H 10 ] (8) and [8,8-(η 2 -dppe)-9-(η 1 -dppe)nido-8,7-RhSB 9 H 10 ] (11).…”