David J. Linton

Group 12 and heavier Group 13 alkali metal 'ate complexes

Abstract Heterobimetallic complexes in which a Group 1 metal centre counteracts the negative charge placed on a Group 12 or higher Group 13 metal have been known for some years. Their usefulness in chemical transformations is discussed in the context of the regiospecificity with which they effect reaction and the manner in which it differs to that resulting from the use of homometallic alkali metal reagents. Their structural properties are reported both in solution and in the solid state. Theoretical studies are presented where appropriate.

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.

Synthesis and Solid‐State Structure of (Li4Am3)+·{Li[(μ‐Me)2Al(Me)tBu]2}− {Am = [PhNC(Ph)NPh]−}: A Polymeric Species Incorporating a Lithium‐Nitrogen Cluster Cation

The sequential reaction of PhN(H)C(Ph)NPh (AmH) with AlMe3 and tBuLi leads to the isolation of both the cluster (Li4Am3)+·{Li[(μ-Me)2Al(Me)tBu]2}−(5) and the aluminium tris(amidinate) AlAm3(6). In the solid state, 5 has a polymeric structure based on tetranuclear Li4-cluster cations and lithium bis(aluminate) anions which associate by the formation of weak Li···MeAl bonds.

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.

Ligand Effects in the Syntheses of Molecular Main Group Metal Species Containing Interstitial Hydride

In seeking to investigate whether structures of the type observed for {[Me3Al(TMP)]Li}∞ (TMP = 2,2,6,6-tetramethylpiperidide) can be oligomerised by the use of polyfunctional N-centred ligands, we report lithium aluminates incorporating RN−C(H)−NR residues. For PhN−C(Ph)−NPh = Am cluster cation-containg (Li4Am3)+·{Li[(μ-Me)2Al(Me)But]2}− is afforded. However, the empolyment of PhN(H)(2-pyr) (pyr = pyridyl) instead affords both {Li8(H)[N(2-pyr)Ph]6}+·[Li(Me2AlBut 2)2]− and Li7(H)[N(2-pyr)Ph]6: the first molecular Main Group clusters to incorporate interstial hydride. Results indicate that β-elimination from ButLi represents the source of H− in these reactions.

Oxygen scavenging by lithium zincates: the synthesis, structural characterisation and derivatisation of [Ph(2-C5H4N)N]2ZnRLi·nthf (R = But, Bun; n= 1, 2)

The 1 ∶ 2 reaction of ZnMe2 with N-2-pyridylaniline, Ph(2-C5H4N)NH 1, affords [Ph(2-C5H4N)N]2Zn 10, the treatment of which with BuLi and thf affords the diastereomeric lithium zincate [Ph(2-C5H4N)N]2ZnRLi·nthf (R = Bun, n = 2; 11a; R = But, n = 1, 11b). The sequential treatment of 10 (either in situ or after isolation) with organolithium substrates and molecular oxygen has afforded insights into the oxygen-scavenging capacity of mixed Group 1–Group 12 species. Hence, 10 reacts with BunLi, O2 and thf or dimethoxyethane (dme) to give {[Ph(2-C5H4N)N]2ZnOBunLi·nL}2 (n = 1, L = thf, 12a; n = 0.5, L = dme, 12b), with the structural relationship between 11a and 12a strongly suggesting that for R = Bun oxygenation proceeds by insertion into the Zn–C bond of an {[Ph(2-C5H4N)N]2ZnR}− ion. The employment of ButLi, O2 and thf together with 10 affords only the previously reported complex [Ph(2-C5H4N)N]2Zn[(μ3-O)But]2(Li·thf)24, the formation of which may be rationalised in terms of the But van der Waals radius and cone angle.

The Synthesis and Structural Properties of Aluminium Oxide, Hydroxide and Organooxide Compounds

By virtue of the oxophilicity of aluminium, many compounds exist in which at least one of the metal’s formal valencies is occupied by oxygen or, alternatively, where the coordination state of the metal is raised to 4, 5 or 6 by the donation of electron density from oxygen. This review presents aluminium oxides first and thereafter aluminium hydroxides and organooxides. Although the discussion concentrates on the solid-state structural properties of such systems, solution structural, theoretical and reactivity studies are also presented.

Selective oxygen capture in lithium zincate chemistry: the syntheses and solid-state structures of (µ-O)Zn4[N(2-C5H4N)Bz]6 and But(µ3-O)Li3(µ6-O)Zn3[N(2-C5H4N)Me]6 (Bz = benzyl)

Sequential reaction of ZnMe2 with the (2-pyridyl)amines HN(2-C5H4N)R (R = Bz = benzyl 1, Me 2), ButLi and oxygen affords species which demonstrate oxo-encapsulation {(µ4-O)Zn4[N(2-C5H4N)Bz]6 3}, and both encapsulation and insertion into a CLi bond {But(µ3-O)Li3(µ6-O)Zn3[N(2-C5H4N)Me]6 4}; in the solid-state 4 has a new type of fac-isomeric (µ6-O)M3M′3 octahedral core.

Variations in the solid-state, solution and theoretical structures of a laterally deprotonated aromatic tertiary amideElectronic supplementary information (ESI) available: synthetic and analytical data for (4)3thf and computed structures I, (IIa?d)?(Va?d). See http://www.rsc.org/suppdata/cc/b3/b302283h/

Reaction of 2-ethyl-N,N-diisopropyl-1-naphthamide 3 with ButLi in tetrahydrofuran (thf) affords a laterally metallated derivative which exists as a tris(thf) solvated monomer with no Li–C interaction and an sp2 hybridised carbanionic centre in the solid-state; NMR spectroscopy suggests that this structure is viable in solution but that Li–C bonded atropisomers are also possible and calculations corroborate these data.

A solid state and theoretical study of the solvent effects controlling the mono- and di-lithiation of aromatic primary amines

Reaction of 1-naphthylamine, 4-tritylaniline or 4-methylaniline with two equivalents of BunLi in Et2O or thf affords rare geminal N,N-dilithiates of general formula (L)n·(Li2NAr)10 (L = Et2O, n = 6, Ar = 1-C10H71, C6H4-4-CPh32; L = thf, n = 10, Ar = C6H4-4-Me 3). X-Ray crystal structure analyses reveal that the core (Li14N10)6− frameworks consist of two fused rhombic dodecahedra. Ab initio M.O. calculations on the mono- and di-lithiation of 1-naphthylamine and 4-methylaniline suggest that the selectivity with which polymetallation occurs is solvent dependent and so help to rationalise the experimentally observed structures.