%0 Journal Article %1 Tomlinson.2005 %A Tomlinson, Susan %A Zheng, Chong %A Hosmane, Narayan S. %A Yang, Jimin %A Wang, Ying %A Zhang, Hongming %A Gray, Thomas G. %A Demissie, Temesgen %A Maguire, John A. %A Baumann, Frank %A Klein, Axel %A Sarkar, Biprajit %A Kaim, Wolfgang %A Lipscomb, William N. %D 2005 %J Organometallics %K ESR;mol cobalt crystal full half iron metallacarborane metallacarborane;ESR metallacarborane;half metallacarborane;sandwich mol nickel prepn sandwich structure %N 9 %P 2177--2187 %R 10.1021/om048982u %T Chemistry of C-Trimethylsilyl-Substituted Heterocarboranes. 31. New Insights into Reaction Pathways of Carborane Ligand Systems: Synthetic, Structural, Spectroscopic, and Electrochemical Studies on Sandwich and Half-Sandwich Metallacarboranes of Iron, Cobalt, and Nickel %V 24 %X A series of full- and half-sandwich metallacarboranes was synthesized from the reaction of MCl2 (M = Co, Fe) and closo-exo-y,x-Li(L)-1-Li(L)-2,n-(SiMe3)2-2,n-C2B4H4 (y = 4, x = 5, L = 2 THF, n = 3 (1); y = 4, x = 5, L = TMEDA, n = 3 (2); y = 5, x = 6, L = 2 THF, n = 4 (3); y = 5, x = 6, L = TMEDA, n = 4 (4)) in 1:1 molar ratios in benzene. The metallacarborane complexes exo-4,4',5,5'-Fe(TMEDA)-commo-1,1'-Fe2,3-(SiMe3)2-2,3-C2B4H42 (5), M+commo-1,1'-Co2,3-(SiMe3)2-(2,3-C2B4H4)2- (M = CoCl (6a), Co3(TMEDA)3Cl5 (6b)), commo-1,1'-M2,4-(SiMe3)2-2,4-C2B4H42 (M = FeH (7), CoH (8)), and 1-(TMEDA)-closo-2,4-(SiMe3)2-1,2,4-MC2B4H4 (M = Co (9)) were isolated in yields ranging from 80 to 92\%. The reaction of commo-1,1'-Ni2,4-(SiMe3)2-2,4-C2B4H42 (10) with carefully dried TMEDA produced the charge-compensated commo-1,1'-NiIII-(2,4-(SiMe3)2-5,6-B2-σ-N(Me)(CH2)2N(Me)2-2,4-C2B2H2)(2',4'-(SiMe3)2-2',4'-C2B4H4) (12) and 1,2-(SiMe3)2-closo-1,2-C2B4H4. With the exception of 5 and 12, all of the commo-metallacarboranes involved metal oxidn. in addn. to ligation, with M0 as a coproduct. All compds. were characterized by anal. and IR spectroscopy, and 5, 6b, 7, 9, and 12 were also characterized by x-ray diffraction anal. Because of the paramagnetic nature of either the products or their counterions, only 8 could be characterized by 1H, 11B, and 13C NMR spectroscopy; its 1H NMR spectrum showed a broad resonance at d -18.9 attributable to the Co-bound H. The paramagnetic compds. were characterized by EPR spectroscopy. The electrochem. redn. of 10 produced a Ni(III) metallacarborane that was characterized by EPR spectroscopy and a 3d7 species related to nickelocenium derivs. All results are consistent with a mechanism involving the initial formation of a half-sandwich metallacarborane, which can be isolated or can undergo a disproportionation process to give the full-sandwich products. on SciFinder(R)

@article{Tomlinson.2005, abstract = {A series of full- and half-sandwich metallacarboranes was synthesized from the reaction of MCl2 (M = Co, Fe) and closo-exo-y,x-Li(L)-1-Li(L)-2,n-(SiMe3)2-2,n-C2B4H4 (y = 4, x = 5, L = 2 THF, n = 3 (1); y = 4, x = 5, L = TMEDA, n = 3 (2); y = 5, x = 6, L = 2 THF, n = 4 (3); y = 5, x = 6, L = TMEDA, n = 4 (4)) in 1:1 molar ratios in benzene. The metallacarborane complexes exo-4,4',5,5'-Fe(TMEDA)-commo-1,1'-Fe[2,3-(SiMe3)2-2,3-C2B4H4]2 (5), M+[commo-1,1'-Co{2,3-(SiMe3)2-(2,3-C2B4H4)}2]- (M = CoCl (6a), Co3(TMEDA)3Cl5 (6b)), commo-1,1'-M[2,4-(SiMe3)2-2,4-C2B4H4]2 (M = FeH (7), CoH (8)), and 1-(TMEDA)-closo-2,4-(SiMe3)2-1,2,4-MC2B4H4 (M = Co (9)) were isolated in yields ranging from 80 to 92{\%}. The reaction of commo-1,1'-Ni[2,4-(SiMe3)2-2,4-C2B4H4]2 (10) with carefully dried TMEDA produced the charge-compensated commo-1,1'-NiIII-[(2,4-(SiMe3)2-5,6-B2-{σ-N(Me)(CH2)2N(Me)2}-2,4-C2B2H2)(2',4'-(SiMe3)2-2',4'-C2B4H4)] (12) and 1,2-(SiMe3)2-closo-1,2-C2B4H4. With the exception of 5 and 12, all of the commo-metallacarboranes involved metal oxidn. in addn. to ligation, with M0 as a coproduct. All compds. were characterized by anal. and IR spectroscopy, and 5, 6b, 7, 9, and 12 were also characterized by x-ray diffraction anal. Because of the paramagnetic nature of either the products or their counterions, only 8 could be characterized by 1H, 11B, and 13C NMR spectroscopy; its 1H NMR spectrum showed a broad resonance at \textgreek{d} -18.9 attributable to the Co-bound H. The paramagnetic compds. were characterized by EPR spectroscopy. The electrochem. redn. of 10 produced a Ni(III) metallacarborane that was characterized by EPR spectroscopy and a 3d7 species related to nickelocenium derivs. All results are consistent with a mechanism involving the initial formation of a half-sandwich metallacarborane, which can be isolated or can undergo a disproportionation process to give the full-sandwich products. [on SciFinder(R)]}, added-at = {2022-06-15T11:26:56.000+0200}, author = {Tomlinson, Susan and Zheng, Chong and Hosmane, Narayan S. and Yang, Jimin and Wang, Ying and Zhang, Hongming and Gray, Thomas G. and Demissie, Temesgen and Maguire, John A. and Baumann, Frank and Klein, Axel and Sarkar, Biprajit and Kaim, Wolfgang and Lipscomb, William N.}, biburl = {https://puma.ub.uni-stuttgart.de/bibtex/241ada8337e4fc75b5e2c3c184afd3379/huebleriac}, doi = {10.1021/om048982u}, interhash = {7c3fbdd1c52931205903c5ded38c3a4d}, intrahash = {41ada8337e4fc75b5e2c3c184afd3379}, issn = {0276-7333}, journal = {Organometallics}, keywords = {ESR;mol cobalt crystal full half iron metallacarborane metallacarborane;ESR metallacarborane;half metallacarborane;sandwich mol nickel prepn sandwich structure}, number = 9, pages = {2177--2187}, timestamp = {2022-06-15T09:26:56.000+0200}, title = {Chemistry of C-Trimethylsilyl-Substituted Heterocarboranes. 31. New Insights into Reaction Pathways of Carborane Ligand Systems: Synthetic, Structural, Spectroscopic, and Electrochemical Studies on Sandwich and Half-Sandwich Metallacarboranes of Iron, Cobalt, and Nickel}, volume = 24, year = 2005 }