Themed collection Reactions Facilitated by Ligand Design

Welcome to this themed issue of Dalton Transactions entitled “Reactions facilitated by ligand design”.

Recent advances in the use of tethered π-coordinating ligands for metal–ligand cooperation.

β-Diketiminate (BDI) ligands are widely used supporting ligands in modern organometallic chemistry and are capable of stabilizing various metal complexes in multiple oxidation states and coordination environments.

This Perspective illustrates the state-of-the-art of stereoselective carbene transfer reactions catalysed by chiral metal porphyrin complexes. A particular attention is focused on the active role of the porphyrin ligand to drive the carbene insertion into the target organic skeleton.

A key part of the development of metal based Positron Emission Tomography probes is the chelation of the radiometal.

Zwitterionic all-metal aromatic tri-palladium complexes can catalyse the cis-selective semi-reduction of internal alkynes at ppm levels.

Splitting of CO₂ across the tungsten-carbon triple bond in [CF₃-ONO]WCC^tBu(THF)₂ (1) yields the tungsten oxo ketene [CF₃-ONO]W(O){(CH₃)₃CCCO} (6).

Treatment of the lithium salt of β-ketimine with FeCl₂(THF)_1.5 in the presence of LiN(SiMe₃)₂ and water affords the multimetallic iron(II)–lithium complex 1, [(L^Me)₂Fe]₃Li₂O [where L^Me = MeC(O)CHC(NMe)Me].

The catalytic aerobic oxidation of benzylic alcohols to corresponding aldehydes has been investigated employing a tetradentate copper(II) complex that incorporates N-methyl imidazole (NMI) as an integral part of an N₄-ligand framework.

The unusual situation presented by a silicon centre coordinating four 1,3-dipolar ligands is exploited in thermally activated cycloaddition reactions with nitriles that lead to six-coordinate poly(tetrazolato) complexes of silicon.

Two lower-oxidation state uranium cations can be readily combined and controlled in a robust and derivatisable tetra-aryloxide ligand framework. These di-U^III/IV systems are a new platform at which to use the multi-electron reductive capacity of the two actinide centres.

Metal–ligand cooperative activation of nitriles by a de-aromatized Ru pincer complex leads to equilibrium mixtures (tautomers) as a result of ligand deprotonation by the Brønsted basic Ru-ketimido moiety.

Bifunctional hydroquinone-based PC(sp³)P pincer complexes.

The preparation of the bulky diphosphine synthon 1 is described and used to generate a tridentate enamido diphosphine ligand platform that can be installed on Ru(II).

The electronic structures of dinuclear copper complexes of the general formula [GFA(CuX₂)₂], where X = Br or Cl and GFA denotes a redox-active bridging Guanidino-Functionalized Aromatic ligand, were analysed and compared.

Two new heterobimetallic [LNiO₂Cu(RPY2)]⁺ (RPY2 = N-substituted bis 2-pyridyl(ethylamine) ligands with R = indane, 3a or R = Me, 3b) complexes have been spectroscopically trapped at low temperatures.

In dinuclear aluminum complexes, opportunely designed to have proximal coordinative pockets, the communication between the two reactive centers allows enhanced catalytic performances.

NHC–carborane ligands, with flexible coordination through either the carbon or the boron atom of the carborane, provide effective transfer hydrogenation catalysts.

Monocationic Ni(II) complexes featuring variously substituted POCOP-type pincer ligands promote the addition of primary amines to crotonitrile, methacrylonitrile, and cinnamonitrile.

Pyridine- and pyrimidine-appended triazolylidene donors are used as ligands for the transfer hydrogenation of a series of functionalities.

The use of hydrogen-bonding interactions to direct the non-covalent assembly of a heterobimetallic supramolecular system with Re and Mn bipyridine-based electrocatalysts is reported.

The first examples of aluminum complexes containing biphenolate phosphine ligands are prepared, structurally characterized, and demonstrated to have catalytic competence in the living ring-opening (co)polymerization of ε-caprolactone and rac-lactide.

A new electron deficient iridium complex demonstrates an improved TON in alkane transfer dehydrogenation reactions compared to similar pre-catalysts.

Dinitrogen-derived molybdenum alkyldiazenides and alkylhydrazides were synthesized with various trans ligands. The thermodynamics of N–H bond formation were studied both experimentally and computationally.

Interactions between the uranyl oxo atom and group 14 metal cations in macrocyclic Pacman complexes depend on both molecular cleft constraints and the fifth equatorial ligand of the uranyl.

Relativistic DFT calculations present accurate geometries of complexes and redox properties, confirmed by the newly-developed experimental syntheses.

Size matching of a flexible macrocycle with low-valent actinide(III/IV) ions as well as their bonding determines different coordination modes.

A new long-tethered boron-containing (P–B–P)-pincer ligand has been synthesized. This ligand was introduced to Ir to form (P–B–P)Ir(H)Cl complex. Subsequent reaction with ⁿBuLi led to the formation of dihydride complex (P–B–P)Ir(H)₂. Both complexes were found to be moderately active for the catalytic dehydrogenation of alkanes.

A zirconium naphthalene complex containing a C-capped triaryloxide ligand, which can act as a Zr(II) synthon, was synthesized and fully characterized.

The reversible ligand-directed methanolysis of a series of copper(II) Schiff base complexes reveal slightly favorable equilibrium constants with addition and eliminations rates influenced by the identity of the axial ligand.

The performance of Fe-amine pre-catalysts in a representative Kumada reaction is inversely proportional to the lability of the chelate ligand.

Ligand effect studies on (^RN3C)Ni^IIIL₂ complexes reveal aerobically-induced aromatic cyanation with tBuNC at room temperature for the (^NpN3C)Ni system.

The non-innocence of the bis-amido dpp-bian ligand has been documented by the reactions of compound 1 with acidic substrates, e.g. water.

The synthesis and characterization of a terminal titanium oxo complex generated by alkylidene benzophenone cross-metathesis is reported.

New electronically and coordinatively unsaturated complexes of the type (Cy-PSiP)RuX(L) (Cy-PSiP = κ³-(2-Cy₂PC₆H₄)₂SiMe) are reported, including examples of 16-electron allyl and azido Ru species.

Metalation of novel ditriazolium salts containing a trimethylene (–CH₂CH₂CH₂–) or dimethylether linker (–CH₂OCH₂–) was probed with different rhodium(III) and iridium(III) precursors.

A series of novel iron(II) β-ketiminate complexes have been prepared and screened in styrene and methyl methacrylate CRP.