Dalton Transactions Blog

Alkali-Metal Mediated Metallation (AMMM) is a recent advance in C–H to C–metal exchange and it could be very useful synthetic chemistry community. AMMM involves the mixing of a typically powerful metallating reagent (e.g. an alkali-metal compound) with a weaker metallating reagent to make a single ligand-shared molecular compound which seemingly displays the reactivity of the alkali-metal coupled with the selectivity and functional group tolerance of the subordinate metal. Hey Presto – a great metallation!

AMMM can be carried out in relatively cheap, non-polar solvents without the need for high temperatures. Usually Mg and Zn reagents are used in AMMM but recently +3 oxidation state aluminium reagents have proved effective. In this Hot Article, Robert Mulvey, Stuart Robertson and their team from Strathclyde have examined AMMM reactions with Al and studied the after effects of lithium-mediated alumination of 3-iodoanisole. To find out what they discovered read the article itself:

After-effects of lithium-mediated alumination of 3-iodoanisole: isolation of molecular salt elimination and trapped-benzyne products
Elaine Crosbie, Alan R. Kennedy, Robert E. Mulvey and Stuart D. Robertson
Dalton Trans., 2012, DOI: 10.1039/C2DT11893A

In this paper, the authors investigate Cp*Ta(amidate) complexes as potential precursors for the synthesis of valuable dinitrogen complexes. The results indicate that the Cp*, amidate ligand environment can be useulf in support‌ing dinitrogen complexation by low valent tantalum species.

Oxygen extrusion from amidate ligands to generate terminal TaO units under reducing conditions. How to successfully use amidate ligands in dinitrogen coordination chemistry
Patricia Horrillo-Martinez, Brian O. Patrick, Laurel L. Schafer and Michael D. Fryzuk
Dalton Trans., 2012, DOI: 10.1039/C1DT11595B

Hydrogen-bond bridges between lithium cubane clusters can give tetrahedral, square planar and linear supramolecular networks.

Pingyun Feng and colleagues report the integration of lithium cubane clusters into 3D supramolecular networks in this communication.  Formation of the lithium cubane clusters, which then act as building blocks that are pre-programmed to assemble assorted hydrogen-bonded geometries, can be done in situ, under mild reaction conditions and using readily available chemicals.  Key to the success of the strategy is the use of ditopic ligands with both phenol and pyridine functionality.  Phenol facilitates the assembly of the cubane cluster and pyridine acts as an H-bond acceptor.  In addition, an H-bond donor comes from methanol occupying the fourth coordination site of the lithium atom.  Future studies building on this work will look at extending the ligand design to create new supramolecular networks with greater porosity and improved gas sorption properties.

To find out more, download this Dalton Trans. communication today…

Lithium cubane clusters as tetrahedral, square planar, and linear nodes for supramolecular assemblies
Xiang Zhao, Tao Wu, Xianhui Bu and Pingyun Feng
Dalton Trans., 2012
DOI: 10.1039/C1DT11975C

Do also take a look at previous work from the same team:

Hydrogen-bonded boron imidazolate frameworks
Jian Zhang, Tao Wu, Pingyun Feng and Xianhui Bu
Dalton Trans., 2010, 39, 1702-1704
DOI: 10.1039/B924633A

In their Dalton Transactions paper Hui Gao and Xian-Ming Zhang detail the synthesis of three new bismuth complexes, the preparation is under ambient conditions, using an environmentally friendly bismuth reagent and involves the in situ oxidation of dimethyl 1,4-cyclohexanedione-2,5-dicarboxylate. The authors propose an interesting reaction mechanism during complex formation, involving hydroxylation, condensation and oxidative cleavage, with two of the reactions producing in situ oxalate. Orange or red crystals were obtained from the experiments and the three complexes revealed to form diamond, brick-wall and herringbone nets. To read more about these interesting compounds, as well as the authors future plans in the preparation of molecular magnets, read the full article which is available free for 4 weeks.

Three novel Bi(III) complexes with in situ generated anilate ligands: unusual oxidation of cyclohexanedione to dihydroxy benzoquinone
Hui Gao and Xian-Ming Zhang
Dalton Trans., 2012, Advance Article
DOI: 10.1039/C1DT11258A

IL-nanofluids were produced in a simple, inexpensive and reproducible manner.

Małgorzata Swadźba-Kwaśny, Peter Nockemann and colleagues from The Queen’s University Belfast describe the one-pot synthesis of ionic liquid-nanofluids in this HOT paper.  The ionic-liquid nanofluids consist of copper(II) oxide nanoparticles and copper(I,II), oxide clusters in acetate-based ionic liquids.  Combining ionic liquids and nanoparticles can create ionic liquids with additional or significantly improved properties that could then be used as catalysts or as heat transfer fluids.

It’s currently free so do take a look!

Facile in situ synthesis of nanofluids based on ionic liquids and copper oxide clusters and nanoparticles
Małgorzata Swadźba-Kwaśny, Léa Chancelier, Shieling Ng, Haresh G. Manyar, Christopher Hardacre and Peter Nockemann
Dalton Trans., 2012
DOI: 10.1039/C1DT11578B

The reactivity of ligands upon coordination to a metal ion is currently a very exciting area.

Read about the rare and novel transformations of the oxime ligand, 2-pyridinealdehyde oxime, when it is reacted with Zn(II) sources, in this HOT communication from Annie Powell, Spyros Perplepes et al.

It’s currently free to access so do take a look!

Metal ion-assisted transformations of 2-pyridinealdoxime and hexafluorophosphate
Konstantis F. Konidaris, Christina D. Polyzou, George E. Kostakis, Anastasios J. Tasiopoulos, Olivier Roubeau, Simon J. Teat, Evy Manessi-Zoupa, Annie K. Powell and Spyros P. Perlepes
Dalton Trans., 2012
DOI: 10.1039/C1DT11881A

You might also find the following perspective interesting:

Diol-type ligands as central ‘players’ in the chemistry of high-spin molecules and single-molecule magnets
Anastasios J. Tasiopoulos and Spyros P. Perlepes
Dalton Trans., 2008, 5537-5555
DOI: 10.1039/B805014G

The dual nature of donor ligands is explored in Oxygen Atom Transfer (OAT) in this hot article by Adam Veige and co-workers.  In this study, donor ligands enhance the rate of OAT by hindering µ-O dimer formation; however, the addition of a too strongly coordinating ligand can actually prevent OAT by
making the transfer thermodynamically unfavorable.

Read more about this ligand duality for FREE until 13th December 2012:

The influence of reversible trianionic pincer OCO^3– µ-oxo Cr^IV dimer formation ([Cr^IV]₂(µ-O)) and donor ligands in oxygen-atom-transfer (OAT)
Matthew E. O’Reilly, Trevor J. Del Castillo, Khalil A. Abboud and Adam S. Veige
Dalton Trans., 2012, Advance Article
DOI: 10.1039/C1DT11104C