Dalton Transactions Blog

Light emitting diodes provide an efficient form of lighting while solar cells give us energy from sunlight. Thienyl carboxylates attached to MM quadruple bonds have shown interesting photophysical properties with potential applications in these areas. Malcolm Chisholm et al. discuss in their Hot Article the electronic properties of four new compounds which are based on Mo and W complexes bound to 5 membered heterocycles containing either O or Se.

The authors thoroughly characterize the complexes, computationally calculate the electronic structures, examine the electronic absorption spectra and steady state emission spectra, use transient absorption spectroscopy and electrochemical studies. The results are very interesting and indicate these complexes may have potential in solar cells given their different electronic states.

For full details of the investigation you can access the full article for free for 4 weeks

Furan- and selenophene-2-carboxylato derivatives of dimolybdenum and ditungsten (MM): a comparison of their chemical and photophysical properties
Samantha E. Brown-Xu, Malcolm H. Chisholm, Judith C. Gallucci, Yagnaseni Ghosh, Terry L. Gustafson and Carly R. Reed
Dalton Trans., 2012, Advance Article
DOI: 10.1039/C1DT11889G, Paper

Photoluminescent substances have many applications including dopants for organic light-emitting diodes (OLEDs), luminescent bio-labeling reagents, photocatalysts and chemosensors for oxygen. Cyclometalated Ir(III) complexes are particularly interesting in this capacity as they have high photochemical stability, high quantum efficiencies and a broad range of emission properties that allow their luminescence to span from near infra-red to blue light. Yanfang Li, Yang Liu and Ming Zhou prepare and characterize a dendritic FRET donor–acceptor system with cationic Ir(III) complex core in their Hot Article in Dalton Transactions. Their biocompatible system displays efficient photoluminescence of the Ir(III) complexes via a FRET pathway and the luminophore core is protected from quenching by molecular oxygen under the photo excitation.

Read the full article which is free to access for 4 weeks

Synthesis and properties of a dendritic FRET donor–acceptor system with cationic iridium(III) complex core and carbazolyl periphery
Yanfang Li, Yang Liu and Ming Zhou
Dalton Trans., 2012, Advance Article
DOI: 10.1039/C1DT11716E

This HOT Article presents the facile synthesis of Pd(0) complexes that could be utilized as catalyst precursors.  The weak donor power of the PR₂Cl ligand may make this route a simple entry to the reactive “Pd(NHC)” moiety for catalysis applications.

Read more for FREE until the 9th January 2012 at:

Generation of [(IPr)Pd(PR₂Cl)] complexes via P–Cl reductive elimination
Bennett J. Tardiff, Kevin D. Hesp, Michael J. Ferguson and Mark Stradiotto
Dalton Trans., 2012, Advance Article
DOI: 10.1039/C1DT11910A

The title of the ‘Hot Article’ by John Slattery and Sharifa Hussein quite succinctly describes their research ‘How Lewis acidic is your cation? Putting phosphenium ions on the fluoride ion affinity scale’. The authors calculated the fluoride ion affinities (FIA’s) using ab initio and DFT methods to find out the relative Lewis acidities of over thirty phosphenium ions with a range of substituents, while I wouldn’t want to spoil the paper by giving away the reactivity series I will report that the authors noted there is “some hope that phosphenium ions that are currently unknown as “free” ions may yet be isolable without recourse to mesomeric stabilisation”.

Read the full article which is free to access for 4 weeks

How Lewis acidic is your cation? Putting phosphenium ions on the fluoride ion affinity scale
John M. Slattery and Sharifa Hussein
Dalton Trans., 2012, Advance Article
DOI: 10.1039/C1DT11636C

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