Robert P. Davies

The first molecular main group metal species containing interstitial hydride

Lithium cages containing hydride: The reaction of tBuLi with Me(2)AlN(2-Pyr)Ph in toluene gave [Li(8)(H){N(2-Pyr)Ph}(6)](+)[Li(Me(2)AltBu(2))(2)](-), whose cation is the first molecular main group metal species to contain interstitial hydride (the cluster core is shown in the picture). Treatment of the reaction mixture with THF gave the neutral hydride Li(7)(H)[N(2-Pyr)Ph](6), which has a capped octahedral (Li(+))(7) cluster core. 2-Pyr=2-pyridyl.

Unique and contrasting mixed-metal lithium-calcium and lithium-barium hexamethyldisilazide complexes

Abstract Addition of lithium hexamethyldisilazide to calcium or barium bis(hexamethyldisilazide) in THF resulted in the synthesis of two unique but very different mixed-metal complexes: X-ray crystallography shows these to be, respectively, the heterobimetallic complex [Ca{N(SiMe3)2}3Li(THF)] (1), containing two calcium–lithium bridging amide ligands and the remarkable co-crystalline compound [Ba{N(SiMe3)2}2(THF)3][Li2{N(SiMe3)2}2(THF)2] (2).

The first crystallographic evidence for the structures of ortho-lithiated aromatic tertiary amides

Herein is reported the first crystal structures of the products of tertiary amide directed orthometalation reactions. Thus, reaction of N,N-diisopropylbenzamide with tBuLi in di-Et ether gives the corresponding N,N-diisopropyl-2-lithiobenzamide-diethylether complex, 4. Reaction of N,N-diisopropyl-1-naphthamide in THF with tBuLi gives the corresponding N,N-diisopropyl-2-lithionaphthamide-THF complex, 5. The crystal structures of 4 and 5 are presented. [on SciFinder (R)]

Die ersten molekularen Hauptgruppenmetallverbindungen mit einem interstitiellen Hydridion

Lithiumkafige, die Hydridionen enthalten: Die Reaktion von tBuLi mit Me2AlN(2-Pyr)Ph in Toluol lieferte [Li8(H){N(2-Pyr)Ph}6]+[Li(Me2AltBu2)2]−, dessen Kation die erste molekulare Hauptgruppenmetallspezies ist, die ein interstitielles Hydridion enthalt (abgebildet ist der Clusterkern). Die Behandlung der Reaktionsmischung mit THF lieferte das neutrale Hydrid Li7(H)[N(2-Pyr)Ph]6, das einen uberdachten oktaedrischen (Li+)7-Cluster-Kern enthalt. 2-Pyr=2-Pyridyl.

Selective oxygen capture by lithium aluminates: a solid state and theoretical structural study

Reaction of PhC(O)N(Me)H with AlMe3 in toluene results in facile CH4 evolution and formation of the amidoalane PhC(O)N(Me)AlMe2, 6. The addition of 1 eq. ButLi affords the lithium aluminate [PhC(O)N(Me)Al(Me)2But]Li, 7, which on treatment with oxygen yields the mixed-anion species [PhC(O)N(Me)Al(Me)(But)OMe]Li·[PhC(O)N(Me)Al(Me)(OBut)OMe]Li, 8. In the solid state 8 forms a dimer based on a tetranuclear (LiO)4 ladder structure in which terminal mono-oxygenated aluminate ligands and tripodal bis-oxygenated aluminate ligands span end and central Li+ cations. Replacement of PhC(O)N(Me)H in the above reaction sequence with the more sterically congested amide PhC(O)N(Ph)H results in the formation of the amidoalane PhC(O)N(Ph)AlMe2, 9, which in turn affords the lithium aluminate [PhC(O)N(Ph)Al(Me)2But]Li, 10, and upon treatment of this with oxygen, the 70∶30 11a∶11b mixture [PhC(O)N(Ph)Al(Me)(OR)R′]Li, 11 (Rxa0=xa0But, R′xa0=xa0Me, 11a; R′xa0=xa0But, Rxa0=xa0Me, 11b). Both 10 and 11 are dimeric in the solid state, suggesting that the selective oxygenation process, and therefore the character of the oxygenated product, is templated by the structure of the precursor aluminate complex. Calculations are presented which corroborate the competitive nature of the inclusion of oxygen atoms into Al–Me and Al–But groups in species of the type reported here.

Selective oxygen capture to give a unique mixed-anion lithium aluminate: the synthesis and solid-state structure of {[PhC(O)N(Me)Al(Me)(But)OMe]Li·[PhC(O)N(Me)Al(Me)(OBut)OMe]Li}2

While reaction of a solution of the amidoalane nPhC(O)N(Me)AlMe2 3 with 1 equiv. of ButLi affords the nlithium aluminate PhC(O)N(Me)Al(Me)2(But)Li 4, ndeliberate treatment of the reaction mixture with oxygen affords the unique nmixed-anion species {[PhC(O)N(Me)Al(Me)(But)OMe]- nLi·[PhC(O)N(Me)Al(Me)(OBut)OMe]Li}2 5; in nthe solid state 5 has a (LiO)4 ladder structure containing nterminal mono-oxygenated aluminate ligands and tripodal bis-oxygenated naluminate ligands spanning end and central Li+ cations.

A unique Li12-aggregate containing both —NLi2 and —CHLi ∼ NLi units

Abstract Dilithiation of 2-methylpyridine followed by PhCN insertion affords the complex [C5H4N · CHC(Ph)N]2− · 2Li+6 · (THF)4, 5. The crystal structure of 5 reveals an unusual Li12 aggregate containing four types of Li+ cation and two types of dianionic ligand which bond to the metal centres via exclusively N-Li interactions or via combinations of C-Li and N-Li coordinations.