Reaction of nido-7,8-C2B9H13 with pentacarbonyl(methyl)manganese: Crystal structure of the charge-compensated complex [Mn(CO)3{η5-7,8-C2B9H10-10-O(CH2)4}]

Revisiting [Mn(CO)3(η5-nido-7,8-C2B9H11)]-, the Dicarbollide Analogue of [(η5-C5H5)Mn(CO)3]: Reactivity Studies Leading to Boron Atom Functionalization

“…The formation of compounds 7a − e closely mirrors that of compounds 8 , which were similarly obtained from compound 3 . , Compound 7a was previously isolated from the reaction between [Mn(Me)(CO) 5 ] and [ nido -7,8-C 2 B 9 H 13 ] in refluxing THF . Initial identification of 7a 31 and 7b − e (Tables and ) was made on the basis of their spectroscopic data.…”

“…In the latter case the sulfide moiety is bonded to an α -boron atom in the belt bonded to manganese, giving rise to an asymmetric molecule. Conversely, compound 7a was earlier characterized by an X-ray diffraction experiment that confirmed the THF unit to be attached to a β -boron atom in the metal-bound face . Substitution at that boron atom does not disrupt the C s symmetry of the parent anion, so that molecular mirror symmetry is retained in 7a , consistent with its NMR data; a similar situation was assumed for 7b − e .…”

“…Mechanistically, this transformation may readily be understood in terms of Scheme . Nucleophilic attack at a site adjacent to the formally positively charged center in such zwitterions is well established. − Thus, in the present system, coordination of PMe 3 at the iminium C terminus of 7d , e produces a canonical form ( A ) with a C−N single bond, allowing rotation about this vector to give form B . Subsequent dissociation of PMe 3 then regenerates the isomeric iminium moiety of 7h , j .…”

Revisiting [Mn(CO)3(η5-nido-7,8-C2B9H11)]-, the Dicarbollide Analogue of [(η5-C5H5)Mn(CO)3]: Reactivity Studies Leading to Boron Atom Functionalization

“…The formation of compounds 7a − e closely mirrors that of compounds 8 , which were similarly obtained from compound 3 . , Compound 7a was previously isolated from the reaction between [Mn(Me)(CO) 5 ] and [ nido -7,8-C 2 B 9 H 13 ] in refluxing THF . Initial identification of 7a 31 and 7b − e (Tables and ) was made on the basis of their spectroscopic data.…”

“…In the latter case the sulfide moiety is bonded to an α -boron atom in the belt bonded to manganese, giving rise to an asymmetric molecule. Conversely, compound 7a was earlier characterized by an X-ray diffraction experiment that confirmed the THF unit to be attached to a β -boron atom in the metal-bound face . Substitution at that boron atom does not disrupt the C s symmetry of the parent anion, so that molecular mirror symmetry is retained in 7a , consistent with its NMR data; a similar situation was assumed for 7b − e .…”

“…Mechanistically, this transformation may readily be understood in terms of Scheme . Nucleophilic attack at a site adjacent to the formally positively charged center in such zwitterions is well established. − Thus, in the present system, coordination of PMe 3 at the iminium C terminus of 7d , e produces a canonical form ( A ) with a C−N single bond, allowing rotation about this vector to give form B . Subsequent dissociation of PMe 3 then regenerates the isomeric iminium moiety of 7h , j .…”

Synthesis and Reactivity of Monocarbollide Carbonyl Complexes of Iron and Molybdenum with Icosahedral Frameworks

“…The NMR data leave no doubt about the nature of this product. The resonance observed in the 11 B{ 1 H} NMR spectrum at δ 22.8 is diagnostic of the BOEt 2 nucleus 16a. Again, only one isomer is formed, and that is most likely to be the β -system as observed for 7 .…”

Frustrated Lewis pair-mediated C–O or C–H bond activation of ethers

“…6,7 The ring-opening of THF was first described by Wittig and Ru ¨ckert in 1950, 9 who showed C-O bond scission by combination of the anion [Ph 3 C] À and THF(BPh 3 ) affording [Ph 3 C(CH 2 ) 4 OBPh 3 ] À . Subsequent reports have shown similar THF ring-opening reactions by phosphine/ ZrCl 4 (THF) 4 , 10 and other transition metal Lewis acids based on U, 11 Sm, 12 Ti 13 Zr 14 and Mn, 15 as well as other main group systems, like Al Lewis acids 16 and Te nucleophiles. 17 Nonetheless, reactions of acyclic ethers with combinations of Lewis acids and bases have drawn less attention.…”

Revisiting [Mn(CO)3(η5-nido-7,8-C2B9H11)]-, the Dicarbollide Analogue of [(η5-C5H5)Mn(CO)3]: Reactivity Studies Leading to Boron Atom Functionalization

“…The formation of compounds 7a − e closely mirrors that of compounds 8 , which were similarly obtained from compound 3 . , Compound 7a was previously isolated from the reaction between [Mn(Me)(CO) 5 ] and [ nido -7,8-C 2 B 9 H 13 ] in refluxing THF . Initial identification of 7a 31 and 7b − e (Tables and ) was made on the basis of their spectroscopic data.…”

“…In the latter case the sulfide moiety is bonded to an α -boron atom in the belt bonded to manganese, giving rise to an asymmetric molecule. Conversely, compound 7a was earlier characterized by an X-ray diffraction experiment that confirmed the THF unit to be attached to a β -boron atom in the metal-bound face . Substitution at that boron atom does not disrupt the C s symmetry of the parent anion, so that molecular mirror symmetry is retained in 7a , consistent with its NMR data; a similar situation was assumed for 7b − e .…”

“…Mechanistically, this transformation may readily be understood in terms of Scheme . Nucleophilic attack at a site adjacent to the formally positively charged center in such zwitterions is well established. − Thus, in the present system, coordination of PMe 3 at the iminium C terminus of 7d , e produces a canonical form ( A ) with a C−N single bond, allowing rotation about this vector to give form B . Subsequent dissociation of PMe 3 then regenerates the isomeric iminium moiety of 7h , j .…”

Synthesis and Reactivity of Monocarbollide Carbonyl Complexes of Iron and Molybdenum with Icosahedral Frameworks

“…The NMR data leave no doubt about the nature of this product. The resonance observed in the 11 B{ 1 H} NMR spectrum at δ 22.8 is diagnostic of the BOEt 2 nucleus 16a. Again, only one isomer is formed, and that is most likely to be the β -system as observed for 7 .…”

Frustrated Lewis pair-mediated C–O or C–H bond activation of ethers

“…6,7 The ring-opening of THF was first described by Wittig and Ru ¨ckert in 1950, 9 who showed C-O bond scission by combination of the anion [Ph 3 C] À and THF(BPh 3 ) affording [Ph 3 C(CH 2 ) 4 OBPh 3 ] À . Subsequent reports have shown similar THF ring-opening reactions by phosphine/ ZrCl 4 (THF) 4 , 10 and other transition metal Lewis acids based on U, 11 Sm, 12 Ti 13 Zr 14 and Mn, 15 as well as other main group systems, like Al Lewis acids 16 and Te nucleophiles. 17 Nonetheless, reactions of acyclic ethers with combinations of Lewis acids and bases have drawn less attention.…”

Revisiting [Mn(CO)3(η5-nido-7,8-C2B9H11)]-, the Dicarbollide Analogue of [(η5-C5H5)Mn(CO)3]: Reactivity Studies Leading to Boron Atom Functionalization

“…The formation of compounds 7a − e closely mirrors that of compounds 8 , which were similarly obtained from compound 3 . , Compound 7a was previously isolated from the reaction between [Mn(Me)(CO) 5 ] and [ nido -7,8-C 2 B 9 H 13 ] in refluxing THF . Initial identification of 7a 31 and 7b − e (Tables and ) was made on the basis of their spectroscopic data.…”

“…In the latter case the sulfide moiety is bonded to an α -boron atom in the belt bonded to manganese, giving rise to an asymmetric molecule. Conversely, compound 7a was earlier characterized by an X-ray diffraction experiment that confirmed the THF unit to be attached to a β -boron atom in the metal-bound face . Substitution at that boron atom does not disrupt the C s symmetry of the parent anion, so that molecular mirror symmetry is retained in 7a , consistent with its NMR data; a similar situation was assumed for 7b − e .…”

“…Mechanistically, this transformation may readily be understood in terms of Scheme . Nucleophilic attack at a site adjacent to the formally positively charged center in such zwitterions is well established. − Thus, in the present system, coordination of PMe 3 at the iminium C terminus of 7d , e produces a canonical form ( A ) with a C−N single bond, allowing rotation about this vector to give form B . Subsequent dissociation of PMe 3 then regenerates the isomeric iminium moiety of 7h , j .…”

Synthesis and Reactivity of Monocarbollide Carbonyl Complexes of Iron and Molybdenum with Icosahedral Frameworks

“…The NMR data leave no doubt about the nature of this product. The resonance observed in the 11 B{ 1 H} NMR spectrum at δ 22.8 is diagnostic of the BOEt 2 nucleus 16a. Again, only one isomer is formed, and that is most likely to be the β -system as observed for 7 .…”

Frustrated Lewis pair-mediated C–O or C–H bond activation of ethers

“…6,7 The ring-opening of THF was first described by Wittig and Ru ¨ckert in 1950, 9 who showed C-O bond scission by combination of the anion [Ph 3 C] À and THF(BPh 3 ) affording [Ph 3 C(CH 2 ) 4 OBPh 3 ] À . Subsequent reports have shown similar THF ring-opening reactions by phosphine/ ZrCl 4 (THF) 4 , 10 and other transition metal Lewis acids based on U, 11 Sm, 12 Ti 13 Zr 14 and Mn, 15 as well as other main group systems, like Al Lewis acids 16 and Te nucleophiles. 17 Nonetheless, reactions of acyclic ethers with combinations of Lewis acids and bases have drawn less attention.…”