0000000000205243
AUTHOR
Andreas Heilmann
Arene C−H Activation at Aluminium(I): meta Selectivity Driven by the Electronics of S N Ar Chemistry
The reactivity of the electron-rich anionic Al(I) ('aluminyl') compound K 2 [(NON)Al] 2 (NON = 4,5-bis(2,6-diisopropylanilido)-2,7-di- tert -butyl-9,9-dimethylxanthene) towards mono- and disubstituted arenes is reported. C-H activation chemistry with n -butylbenzene gives exclusively the product of activation at the arene meta position. Mechanistically, this transformation proceeds in a single step via a concerted Meisenheimer-type transition state. Selectivity is therefore based on similar electronic factors to classical S N Ar chemistry, which implies the destabilization of transition states featuring electron-donating groups in either the ortho or the para positions. In the cases of tolu…
Cooperative N–H bond activation by amido-Ge(ii) cations
N-heterocyclic carbene (NHC) and tertiary phosphine-stabilized germylium-ylidene cations, [R(L)Ge:]+, featuring tethered amido substituents at R have been synthesized via halide abstraction. Characterization in the solid state by X-ray crystallography shows these systems to be monomeric, featuring a two-coordinate C,N- or P,N-ligated germanium atom. The presence of the strongly Lewis acidic cationic germanium centre and proximal amide function allows for facile cleavage of N-H bonds in 1,2-fashion: the products resulting from reactions with carbazole feature a tethered secondary amine donor bound to a three-coordinate carbazolyl-GeII centre. In each case, addition of the components of the N…
Carbon monoxide activation by a molecular aluminium imide: C-O bond cleavage and C-C bond formation
Anionic molecular imide complexes of aluminium are accessible via a rational synthetic approach involving the reactions of organo azides with a potassium aluminyl reagent. In the case of K2 [(NON)Al(NDipp)]2 (NON=4,5-bis(2,6-diisopropylanilido)-2,7-di-tert-butyl-9,9-dimethyl-xanthene; Dipp=2,6-diisopropylphenyl) structural characterization by X-ray crystallography reveals a short Al-N distance, which is thought primarily to be due to the low coordinate nature of the nitrogen centre. The Al-N unit is highly polar, and capable of the activation of relatively inert chemical bonds, such as those found in dihydrogen and carbon monoxide. In the case of CO, uptake of two molecules of the substrate…
Probing the Extremes of Covalency in M-Al bonds: Lithium and Zinc Aluminyl Compounds.
Synthetic routes to lithium, magnesium, and zinc aluminyl complexes are reported, allowing for the first structural characterization of an unsupported lithium-aluminium bond. Crystallographic and quantum-chemical studies are consistent with the presence of a highly polar Li-Al interaction, characterized by a low bond order and relatively little charge transfer from Al to Li. Comparison with magnesium and zinc aluminyl systems reveals changes to both the M-Al bond and the (NON)Al fragment (where NON=4,5-bis(2,6-diisopropylanilido)-2,7-di-tert-butyl-9,9-dimethylxanthene), consistent with a more covalent character, with the latter complex being shown to react with CO<sub>2</sub> vi…
Trapping and Reactivity of a Molecular Aluminium Oxide Ion
Aluminium oxides constitute an important class of inorganic compound that are widely exploited in the chemical industry as catalysts and catalyst supports. Due to the tendency for such systems to aggregate via Al‐O‐Al bridges, the synthesis of well‐defined, soluble, molecular models for these materials is challenging. Here we show that reactions of the potassium aluminyl complex K 2 [( NON )Al] 2 ( NON = 4,5‐bis(2,6‐diiso‐propylanilido)‐2,7‐di‐tert‐butyl‐9,9‐dimethylxanthene) with CO 2 , PhNCO and N 2 O all proceed via a common aluminium oxide intermediate. This highly reactive species can be trapped by coordination of a THF molecule as the anionic oxide complex [( NON )AlO(THF)] ‐ , which …
A crystalline radical cation derived from Thiele’s hydrocarbon with redox range beyond 1 V
Thiele’s hydrocarbon occupies a central role as an open-shell platform for new organic materials, however little is known about its redox behaviour. While recent synthetic approaches involving symmetrical carbene substitution of the CPh2 termini yield isolable neutral/dicationic analogues, the intervening radical cations are much more difficult to isolate, due to narrow compatible redox ranges (typically 1 V), permitting its isolation in crystalline form. Further single-electron oxidation affords borenium dication 12+, thereby establishing an organoboron redox system fully characterized in all three redox states. We perceive that this strategy can be extended to other transient organic rad…
Carbon Monoxide Activation by a Molecular Aluminium Imide: C−O Bond Cleavage and C−C Bond Formation
Anionic molecular imide complexes of aluminium are accessible via a rational synthetic approach involving the reactions of organo azides with a potassium aluminyl reagent. In the case of K 2 [( NON )Al(NDipp)] 2 ( NON = 4,5‐bis(2,6‐di iso propylanilido)‐2,7‐di‐tert‐butyl‐9,9‐dimethyl‐xanthene; Dipp = 2,6‐di iso propylphenyl) structural characterization by X‐ray crystallography reveals a short Al‐N distance, which is thought to be due primarily to the low coordinate nature of the nitrogen centre. The Al‐N unit is highly polar, and capable of the activation of relatively inert chemical bonds, such as those found in dihydrogen and carbon monoxide. In the case of CO, uptake of two molecules of …
Arene C‐H activation at aluminium(I) : meta selectivity driven by the electronics of SNAr chemistry
The reactivity of the electron-rich anionic Al(I) (‘aluminyl’) compound K 2 [(NON)Al] 2 (NON = 4,5-bis(2,6-diisopropylanilido)-2,7-di- tert -butyl-9,9-dimethylxanthene) towards mono- and disubstituted arenes is reported. C-H activation chemistry with n -butylbenzene gives exclusively the product of activation at the arene meta position. Mechanistically, this transformation proceeds in a single step via a concerted Meisenheimer-type transition state. Selectivity is therefore based on similar electronic factors to classical S N Ar chemistry, which implies the destabilization of transition states featuring electron-donating groups in either the ortho or the para positions. In the cases of tolu…
Cooperative N–H bond activation by amido-Ge(ii) cations
N-heterocyclic carbene (NHC) and tertiary phosphine-stabilized germylium-ylidene cations, [R(L)Ge:]+, featuring tethered amido substituents at R have been synthesized via halide abstraction. Characterization in the solid state by X-ray crystallography shows these systems to be monomeric, featuring a two-coordinate C,N- or P,N-ligated germanium atom. The presence of the strongly Lewis acidic cationic germanium centre and proximal amide function allows for facile cleavage of N–H bonds in 1,2-fashion: the products resulting from reactions with carbazole feature a tethered secondary amine donor bound to a three-coordinate carbazolyl-GeII centre. In each case, addition of the components of the N…
CCDC 2095879: Experimental Crystal Structure Determination
Related Article: Matthew M. D. Roy, Jamie Hicks, Petra Vasko, Andreas Heilmann, Anne-Marie Baston, Jose M. Goicoechea, Simon Aldridge|2021|Angew.Chem.,Int.Ed.|60|22301|doi:10.1002/anie.202109416
CCDC 1952095: Experimental Crystal Structure Determination
Related Article: Xueer Zhou, Petra Vasko, Jamie Hicks, M. Ángeles Fuentes, Andreas Heilmann, Eugene L. Kolychev, Simon Aldridge|2020|Dalton Trans.|49|9495|doi:10.1039/D0DT01960G
CCDC 2008538: Experimental Crystal Structure Determination
Related Article: Jamie Hicks, Petra Vasko, Andreas Heilmann, Jose M. Goicoechea, Simon Aldridge|2020|Angew.Chem.,Int.Ed.|59|20376|doi:10.1002/anie.202008557
CCDC 1972056: Experimental Crystal Structure Determination
Related Article: Andreas Heilmann, Jamie Hicks, Petra Vasko, Jose M. Goicoechea, Simon Aldridge|2020|Angew.Chem.,Int.Ed.|59|4897|doi:10.1002/anie.201916073
CCDC 2005219: Experimental Crystal Structure Determination
Related Article: Xueer Zhou, Petra Vasko, Jamie Hicks, M. Ángeles Fuentes, Andreas Heilmann, Eugene L. Kolychev, Simon Aldridge|2020|Dalton Trans.|49|9495|doi:10.1039/D0DT01960G
CCDC 1972053: Experimental Crystal Structure Determination
Related Article: Andreas Heilmann, Jamie Hicks, Petra Vasko, Jose M. Goicoechea, Simon Aldridge|2020|Angew.Chem.,Int.Ed.|59|4897|doi:10.1002/anie.201916073
CCDC 2063254: Experimental Crystal Structure Determination
Related Article: Ying Kai Loh, Petra Vasko, Caitil��n McManus, Andreas Heilmann, William K. Myers, Simon Aldridge|2021|Nat.Commun.|12|7052|doi:10.1038/s41467-021-27104-y
CCDC 1972057: Experimental Crystal Structure Determination
Related Article: Andreas Heilmann, Jamie Hicks, Petra Vasko, Jose M. Goicoechea, Simon Aldridge|2020|Angew.Chem.,Int.Ed.|59|4897|doi:10.1002/anie.201916073
CCDC 1943804: Experimental Crystal Structure Determination
Related Article: Jamie Hicks, Andreas Heilmann, Petra Vasko, Jose M. Goicoechea, Simon Aldridge|2019|Angew.Chem.,Int.Ed.|58|17265|doi:10.1002/anie.201910509
CCDC 1943806: Experimental Crystal Structure Determination
Related Article: Jamie Hicks, Andreas Heilmann, Petra Vasko, Jose M. Goicoechea, Simon Aldridge|2019|Angew.Chem.,Int.Ed.|58|17265|doi:10.1002/anie.201910509
CCDC 1972054: Experimental Crystal Structure Determination
Related Article: Andreas Heilmann, Jamie Hicks, Petra Vasko, Jose M. Goicoechea, Simon Aldridge|2020|Angew.Chem.,Int.Ed.|59|4897|doi:10.1002/anie.201916073
CCDC 2063252: Experimental Crystal Structure Determination
Related Article: Ying Kai Loh, Petra Vasko, Caitil��n McManus, Andreas Heilmann, William K. Myers, Simon Aldridge|2021|Nat.Commun.|12|7052|doi:10.1038/s41467-021-27104-y
CCDC 1972052: Experimental Crystal Structure Determination
Related Article: Andreas Heilmann, Jamie Hicks, Petra Vasko, Jose M. Goicoechea, Simon Aldridge|2020|Angew.Chem.,Int.Ed.|59|4897|doi:10.1002/anie.201916073
CCDC 1952092: Experimental Crystal Structure Determination
Related Article: Xueer Zhou, Petra Vasko, Jamie Hicks, M. Ángeles Fuentes, Andreas Heilmann, Eugene L. Kolychev, Simon Aldridge|2020|Dalton Trans.|49|9495|doi:10.1039/D0DT01960G
CCDC 1952094: Experimental Crystal Structure Determination
Related Article: Xueer Zhou, Petra Vasko, Jamie Hicks, M. Ángeles Fuentes, Andreas Heilmann, Eugene L. Kolychev, Simon Aldridge|2020|Dalton Trans.|49|9495|doi:10.1039/D0DT01960G
CCDC 1943805: Experimental Crystal Structure Determination
Related Article: Jamie Hicks, Andreas Heilmann, Petra Vasko, Jose M. Goicoechea, Simon Aldridge|2019|Angew.Chem.,Int.Ed.|58|17265|doi:10.1002/anie.201910509
CCDC 2095878: Experimental Crystal Structure Determination
Related Article: Matthew M. D. Roy, Jamie Hicks, Petra Vasko, Andreas Heilmann, Anne-Marie Baston, Jose M. Goicoechea, Simon Aldridge|2021|Angew.Chem.,Int.Ed.|60|22301|doi:10.1002/anie.202109416
CCDC 2095877: Experimental Crystal Structure Determination
Related Article: Matthew M. D. Roy, Jamie Hicks, Petra Vasko, Andreas Heilmann, Anne-Marie Baston, Jose M. Goicoechea, Simon Aldridge|2021|Angew.Chem.,Int.Ed.|60|22301|doi:10.1002/anie.202109416
CCDC 2063253: Experimental Crystal Structure Determination
Related Article: Ying Kai Loh, Petra Vasko, Caitil��n McManus, Andreas Heilmann, William K. Myers, Simon Aldridge|2021|Nat.Commun.|12|7052|doi:10.1038/s41467-021-27104-y
CCDC 1943808: Experimental Crystal Structure Determination
Related Article: Jamie Hicks, Andreas Heilmann, Petra Vasko, Jose M. Goicoechea, Simon Aldridge|2019|Angew.Chem.,Int.Ed.|58|17265|doi:10.1002/anie.201910509
CCDC 2005217: Experimental Crystal Structure Determination
Related Article: Xueer Zhou, Petra Vasko, Jamie Hicks, M. Ángeles Fuentes, Andreas Heilmann, Eugene L. Kolychev, Simon Aldridge|2020|Dalton Trans.|49|9495|doi:10.1039/D0DT01960G
CCDC 1952093: Experimental Crystal Structure Determination
Related Article: Xueer Zhou, Petra Vasko, Jamie Hicks, M. Ángeles Fuentes, Andreas Heilmann, Eugene L. Kolychev, Simon Aldridge|2020|Dalton Trans.|49|9495|doi:10.1039/D0DT01960G
CCDC 1952097: Experimental Crystal Structure Determination
Related Article: Xueer Zhou, Petra Vasko, Jamie Hicks, M. Ángeles Fuentes, Andreas Heilmann, Eugene L. Kolychev, Simon Aldridge|2020|Dalton Trans.|49|9495|doi:10.1039/D0DT01960G
CCDC 1943807: Experimental Crystal Structure Determination
Related Article: Jamie Hicks, Andreas Heilmann, Petra Vasko, Jose M. Goicoechea, Simon Aldridge|2019|Angew.Chem.,Int.Ed.|58|17265|doi:10.1002/anie.201910509
CCDC 2008540: Experimental Crystal Structure Determination
Related Article: Jamie Hicks, Petra Vasko, Andreas Heilmann, Jose M. Goicoechea, Simon Aldridge|2020|Angew.Chem.,Int.Ed.|59|20376|doi:10.1002/anie.202008557
CCDC 2008537: Experimental Crystal Structure Determination
Related Article: Jamie Hicks, Petra Vasko, Andreas Heilmann, Jose M. Goicoechea, Simon Aldridge|2020|Angew.Chem.,Int.Ed.|59|20376|doi:10.1002/anie.202008557
CCDC 1972055: Experimental Crystal Structure Determination
Related Article: Andreas Heilmann, Jamie Hicks, Petra Vasko, Jose M. Goicoechea, Simon Aldridge|2020|Angew.Chem.,Int.Ed.|59|4897|doi:10.1002/anie.201916073
CCDC 2008536: Experimental Crystal Structure Determination
Related Article: Jamie Hicks, Petra Vasko, Andreas Heilmann, Jose M. Goicoechea, Simon Aldridge|2020|Angew.Chem.,Int.Ed.|59|20376|doi:10.1002/anie.202008557
CCDC 2008541: Experimental Crystal Structure Determination
Related Article: Jamie Hicks, Petra Vasko, Andreas Heilmann, Jose M. Goicoechea, Simon Aldridge|2020|Angew.Chem.,Int.Ed.|59|20376|doi:10.1002/anie.202008557
CCDC 2010397: Experimental Crystal Structure Determination
Related Article: Jamie Hicks, Petra Vasko, Andreas Heilmann, Jose M. Goicoechea, Simon Aldridge|2020|Angew.Chem.,Int.Ed.|59|20376|doi:10.1002/anie.202008557
CCDC 1952091: Experimental Crystal Structure Determination
Related Article: Xueer Zhou, Petra Vasko, Jamie Hicks, M. Ángeles Fuentes, Andreas Heilmann, Eugene L. Kolychev, Simon Aldridge|2020|Dalton Trans.|49|9495|doi:10.1039/D0DT01960G
CCDC 2008539: Experimental Crystal Structure Determination
Related Article: Jamie Hicks, Petra Vasko, Andreas Heilmann, Jose M. Goicoechea, Simon Aldridge|2020|Angew.Chem.,Int.Ed.|59|20376|doi:10.1002/anie.202008557
CCDC 2005218: Experimental Crystal Structure Determination
Related Article: Xueer Zhou, Petra Vasko, Jamie Hicks, M. Ángeles Fuentes, Andreas Heilmann, Eugene L. Kolychev, Simon Aldridge|2020|Dalton Trans.|49|9495|doi:10.1039/D0DT01960G