Dalton Transactions Blog

Zinc alkyl complexes have an interesting role in a wide variety of stoichiometric and catalytic transformations and understanding how the ligands affect reactivity is important in understanding these structures and their reactivity. This Hot Article from Andrew Wheatley and Janusz Lewinski et al. details experiments involving the reactions of Et₂Zn with a bicyclic guanidine.

Exposure of the produced complex (EtZn(hpp)) to undried air alters the composition depending on whether THF or CH₂Cl₂ is used as the solvent (displayed above). You can read the full details of the teams investigation by downloading their article below, which is free to access for 4 weeks.

Synthesis, structure and unique reactivity of the ethylzinc derivative of a bicyclic guanidine
Karolina Zelga, Michał Leszczyński, Iwona Justyniak, Arkadiusz Kornowicz, Maciej Cabaj, Andrew E. H. Wheatley and Janusz Lewiński
Dalton Trans., 2012, Advance Article
DOI: 10.1039/C2DT11959E

Most metal organic frameworks are based on 3-d or 4-f elements such as Zn, Cu, Co, Ni and there are notably fewer containing lighter metals such as Li, Be, B, Mg, and Al. This Hot Communication by Pingyun Feng and Xianhui Bu et al. reports the first Mg-MOF example constructed from the [Mg₃(μ₃-OH)(CO₂)₆] trimer and opens up the possibility of further Mg-MOF systems.

The porous crystal shows relatively high H₂ uptake (1.37% at 77 K and 1 atm) showing that Mg-MOF systems may have great potential. The applications of MOFs include gas storage, separation, purification and catalysis, undoubtedly developing these applications requires the design and improvement of new MOFs.

You can download this Dalton Transactions Hot Article below, which is free to access for 4 weeks.

Induction of trimeric [Mg3(OH)(CO2)6] in a porous framework by a desymmetrized tritopic ligand
Quanguo Zhai, Qipu Lin, Tao Wu, Shou-Tian Zheng, Xianhui Bu and Pingyun Feng
Dalton Trans., 2012, Advance Article
DOI: 10.1039/C2DT12215D

Multinary chalcogenides have been synthesised for decades, some of these structures have interesting magnetic, thermoelectric and optical properties. Many contain at least one alkali metal while there are relatively few containing alkaline earths, examples of the latter variety include BaM₄Se₇ (M = Al, Ga) and Ba₅Ga₄Se₁₀.

Jiyong Yao et al. describe in their HOT article the synthesis of the first two members of the alkaline-earth/group XI/group XIII/chalcogen system, which is not only an interesting alkaline earth chalcogenide but also the first reported quaternary arrangement. The analogue Ba₄LiGa₅Se₁₂ was also synthesised and the three new types of structure were fully characterized and the optical properties determined.

To find out more about this Dalton Transactions Hot Article read the full paper which is free to access for 4 weeks.

Ba2AgInS4 and Ba4MGa5Se12 (M = Ag, Li): syntheses, structures, and optical properties
Wenlong Yin, Kai Feng, Dajiang Mei, Jiyong Yao, Peizhen Fu and Yicheng Wu
Dalton Trans., 2012, Advance Article
DOI: 10.1039/C2DT11895E

Cytochrome P450 are an enzyme superfamily with a diverse range of functions and are particularly interesting in pharmaceutical, bioanalytical and environmental applications. They are able to metabolise drugs, degrade toxins and catalyse reactions for valuable products. Looking for new substrates which are active with P450 is a very active area of research however determining if a new substrate has reacted isn’t always easy.

There are known substrates for Cytochrome P450 BM3 which do not induce a spin shift on the heme iron, making the reaction undetectable by UV-vis. Expensive and time consuming assays with cofactors and LC-MS studies is one option but Gianfranco Gilardi et al. have developed a fluorescence probe which indicates binding for both physiological and non-physiological substrates and can be used to determine dissociation constants.

To find out more read the full Hot Article which is free to access for 4 weeks.

Fluorescence detection of ligand binding to labeled cytochrome P450 BM3
Valentina E. V. Ferrero, Giovanna Di Nardo, Gianluca Catucci, Sheila J. Sadeghi and Gianfranco Gilardi
Dalton Trans., 2012, Advance Article
DOI: 10.1039/C1DT11437A

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

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

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