A 11B NMR study of 5,6-dicarba-nido-decaborane (12)

Unusual Cage Rearrangements in 10-Vertex nido-5,6-Dicarbaborane Derivatives: An Interplay between Theory and Experiment

“…Inspection of Table 1 and α shifts in ref 5 also suggest that deshielding by chlorine substituted into different vertices of 1 decreases remarkably in the order B4 > B3 > B7 > B10, in agreement with decreasing negative charge. 16 Table 1 shows a very good agreement between the GIAO-MP2/II-computed and experimental 11 B chemical shifts for all eight compounds, apart from those boron atoms that are bonded to bromine and iodine substituents, with the disagreement more pronounced for iodine. Since inclusion of spin-free relativistic effects by pseudopotentials in the GIAO calculations does not solve the problem, these discrepancies at this level may be seen as an indicator of the need for an appropriate level of theory that takes into account relativistic spin−orbit effects 17 on the chemical shifts.…”

Unusual Cage Rearrangements in 10-Vertex nido-5,6-Dicarbaborane Derivatives: An Interplay between Theory and Experiment

“…Inspection of Table 1 and α shifts in ref 5 also suggest that deshielding by chlorine substituted into different vertices of 1 decreases remarkably in the order B4 > B3 > B7 > B10, in agreement with decreasing negative charge. 16 Table 1 shows a very good agreement between the GIAO-MP2/II-computed and experimental 11 B chemical shifts for all eight compounds, apart from those boron atoms that are bonded to bromine and iodine substituents, with the disagreement more pronounced for iodine. Since inclusion of spin-free relativistic effects by pseudopotentials in the GIAO calculations does not solve the problem, these discrepancies at this level may be seen as an indicator of the need for an appropriate level of theory that takes into account relativistic spin−orbit effects 17 on the chemical shifts.…”

Transition Metal Metallacarbaboranes

“…As a class these compounds are structurally well characterized, most o f them conforming to the geometries predicated f r o m skeletal electron-count theory. The decaboranelike structure of the mVfo-ruthenacarbaborane in Figure 3 With one exception, all of these complexes have a single metal atom in the cage framework; the sole example of a dimetallic species is 6,7,l-Cp 2 Ni 2 (CB 7 H 8 ), prepared f r o m Na + [CB 8 H 1 3 ]~ and nickelocene, 19 and structurally defined as a closo 10-vertex polyhedron with the nickels occupying adjacent vertices. 29 Monocarbon metallacarbaboranes have been synthesized via carbon insertion into metallaborane clusters (Equation (10)).…”

Unusual Cage Rearrangements in 10-Vertex nido-5,6-Dicarbaborane Derivatives: An Interplay between Theory and Experiment

“…Inspection of Table 1 and α shifts in ref 5 also suggest that deshielding by chlorine substituted into different vertices of 1 decreases remarkably in the order B4 > B3 > B7 > B10, in agreement with decreasing negative charge. 16 Table 1 shows a very good agreement between the GIAO-MP2/II-computed and experimental 11 B chemical shifts for all eight compounds, apart from those boron atoms that are bonded to bromine and iodine substituents, with the disagreement more pronounced for iodine. Since inclusion of spin-free relativistic effects by pseudopotentials in the GIAO calculations does not solve the problem, these discrepancies at this level may be seen as an indicator of the need for an appropriate level of theory that takes into account relativistic spin−orbit effects 17 on the chemical shifts.…”

Transition Metal Metallacarbaboranes

“…As a class these compounds are structurally well characterized, most o f them conforming to the geometries predicated f r o m skeletal electron-count theory. The decaboranelike structure of the mVfo-ruthenacarbaborane in Figure 3 With one exception, all of these complexes have a single metal atom in the cage framework; the sole example of a dimetallic species is 6,7,l-Cp 2 Ni 2 (CB 7 H 8 ), prepared f r o m Na + [CB 8 H 1 3 ]~ and nickelocene, 19 and structurally defined as a closo 10-vertex polyhedron with the nickels occupying adjacent vertices. 29 Monocarbon metallacarbaboranes have been synthesized via carbon insertion into metallaborane clusters (Equation (10)).…”

Unusual Cage Rearrangements in 10-Vertex nido-5,6-Dicarbaborane Derivatives: An Interplay between Theory and Experiment

“…Inspection of Table 1 and α shifts in ref 5 also suggest that deshielding by chlorine substituted into different vertices of 1 decreases remarkably in the order B4 > B3 > B7 > B10, in agreement with decreasing negative charge. 16 Table 1 shows a very good agreement between the GIAO-MP2/II-computed and experimental 11 B chemical shifts for all eight compounds, apart from those boron atoms that are bonded to bromine and iodine substituents, with the disagreement more pronounced for iodine. Since inclusion of spin-free relativistic effects by pseudopotentials in the GIAO calculations does not solve the problem, these discrepancies at this level may be seen as an indicator of the need for an appropriate level of theory that takes into account relativistic spin−orbit effects 17 on the chemical shifts.…”

Transition Metal Metallacarbaboranes

“…As a class these compounds are structurally well characterized, most o f them conforming to the geometries predicated f r o m skeletal electron-count theory. The decaboranelike structure of the mVfo-ruthenacarbaborane in Figure 3 With one exception, all of these complexes have a single metal atom in the cage framework; the sole example of a dimetallic species is 6,7,l-Cp 2 Ni 2 (CB 7 H 8 ), prepared f r o m Na + [CB 8 H 1 3 ]~ and nickelocene, 19 and structurally defined as a closo 10-vertex polyhedron with the nickels occupying adjacent vertices. 29 Monocarbon metallacarbaboranes have been synthesized via carbon insertion into metallaborane clusters (Equation (10)).…”