Themed collection New Expeditions in Polar Organometallic Chemistry

Welcome to this themed issue of Dalton Transactions entitled “New Expeditions in Polar Organometallic Chemistry”.

Advances in directed aromatic deprotometallation are reported in the context of recent developments in our understanding of lithium cuprates.

This Frontier highlights and analyses, from the authors’ perspective, some recent selected contributions from the organolithium field with an eye towards new challenging research directions.

A boryl scandium complex supported by the silylene-linked cyclopentadienyl-amido ligand was synthesized for the first time.

The C4-lithiated N-heterocyclic carbene : BEt₃ complex was synthesized by low-temperature lithiation of the N-heterocyclic carbene : BEt₃ adduct, which may react with GaCl₃ in THF to form the first abnormal N-heterocyclic carbene : GaCl₃ complex.

N,N,O-Chelate zinc complexes efficiently catalyze the controlled polymerization of ε-CL and rac-LA and their copolymerization, and the aluminum complexes show good activity for the controlled polymerization of ε-CL.

Just like Grignard reagents, heteroleptic sodium magnesiate complexes can exhibit a complicated solution chemistry often giving rise to unexpected isolated products, including examples of inverse magnesiates.

Based on the metallodipyridylamine-dialkylzinc template [{(TMEDA)Na(dpa)}₂Zn^tBu₂], new alkali metal dpa complexes have been co-complexed with ^tBu₂Zn, and the co-complexes studied with benzophenone.

An oxazolinyl–carbene borate zinc ethyl compound reacts with O₂ at room temperature to provide a monometallic zinc ethylperoxide.

Synthesis of heteroleptic strontium complexes containing aminoalkoxide and β-diketonate ligands was demonstrated.

The structural isomers of a number of lithium heteroamidocuprates LiCuR(NR^′₂) have been studied in the solid state and in solution, with the steric and electronic properties of the amido group (NR^′₂) shown to significantly influence the solid-state structures and the position of the solution equilibrium.

The formation of strong bonds between calcium ions and neutral π-systems requires preorientation of the aryl groups by a sterically protecting ligand sphere.

[(Ap^9MeLu)₃(μ²-H)₃(μ³-H)₂(CH₂SiMe₃)(thf)₂] was synthesized. For Y and Yb C–Si bond activation occurs affording [(Ap^9MeLu)₃(μ²-H)₃(μ³-H)₂(CH₂SiMe₃)(thf)₂] and [(Ap^9MeLn)₃(μ²-H)₃(μ³-H)₂(CH₂SiH₂Ph)(thf)₂].

Bis(iminophosphoryl) substituted Li/Cl carbenoids – accessable via different preparation methods – show high thermal stabilities, which however depend on the N-substituent.

The reactivity of a series of organometallic rare earth and actinide complexes with hemilabile NHC-ligands towards substrates with acidic C–H and N–H bonds is described.

NMR shows a direct correlation between the concentration of a chiral lithium amide/n-BuLi complex and ees of a test reaction.

In the heterometallic species prepared [AlMMe₂{2,6-(MeO)₂C₆H₃O}₂]_n (M = Li, Na and K), the {AlMe₂{(2,6-(MeO)₂C₆H₃O}₂}⁻ moiety acts as a claw that grasps alkali metals of very different sizes.

Hydrometallation of amino-alkynylsilanes afforded highly functionalized alkenyl–alkynylsilanes with a fascinating diversity of intramolecular donor–acceptor interactions.

5-Coordinate, THF-free scandium complexes are less active but provide a better control than their 6-coordinate, THF-coordinated analogous yttrium complexes for the heteroselective ring-opening polymerization of rac-lactide.

Sequential lithiation of a sterically demanding bis(iminophosphoranyl)methane afforded di- and trianionic methandiide lithium complexes and their structures and coordination behaviour have been studied with solid state and solution methods.

A series of group 13 complexes containing deprotonated bisheterocyclomethanes have been prepared as well as structurally and spectroscopically characterised.

Exhibiting unprecedented supramolecular assemblies, made up exclusively of metal–carbon interactions, the structures of a homologous series of solvent-free alkali-metal zincates have been uncovered.

Magnesium compounds supported by N,N’-chelating ligands are shown to be active (pre)catalysts for a number of catalytic bond forming reactions.

Alkali metal triphenylsilyls [Li(12-crown-4)SiPh₃]·(thf)_0.5, [Na(15-crown-5)SiPh₃]·(thf)_0.5 and [K(18-crown-6)SiPh₃(thf)] were synthesized using 1,1,1-trimethyl-2,2,2-triphenyldisilane and shown to catalyze the regioselective hydrosilylation of 1,1-diphenylethene.

Reaction of the novel organo-potassium compound [:C[N(2,6-ⁱPr₂C₆H₃)]₂(CH)CK(THF)₂] (KIPr·2THF) with M[N(SiMe₃)₂]₂ (M = Zn, Sn, Ge, Pb) afforded salts of the anionic three coordinate complexes [M{C(CH)[N(2,6-ⁱPr₂C₆H₃)]₂C:}{N(SiMe₃)₂}₂]⁻ (M = Zn (1), Sn (2), Ge (3), Pb (4)).

The multinuclear magnetic resonance and computational study of the structure of N-lithium (R)-Ph₂P(NCO₂Me)NHCH(Me)Ph revealed the origin of its diastereoselective ortho lithiation.

Reactivity of a uranium(IV)–carbene towards carbonyls and heteroallenes is described.

A series of alkali metal 2- and 4-picolyl (methylpyridyl) complexes have been prepared and their metal–anion bonding probed in the solid state and solution.

Thermal decomposition of a magnesium hydride complex with four Mg²⁺ and four H⁻ ions leads to H₂ elimination and ligand reduction.

The analysis of three series of two-coordinate Group 12 bis-terphenyl complexes highlights how subtle changes to ligand properties, particularly sterics, and, to a smaller extent, electronics have a large effect on the solid state structures adopted.

The homoleptic alkaline earth hexamethyldisilazides, [M{N(SiMe₃)₂}₂(THF)₂] (M = Mg, Ca, Sr), are shown to be efficient precatalysts for the hydroacetylenation of organic carbodiimides with alkyl- and arylacetylenes.