Dalton Transactions Blog

This Dalton Transactions Hot article explores metalloligands inspired by the active site of enzymes.

Marcetta Y. Darensbourg and colleagues from Texas A& M University, look at NiFe-heterobimetallic complexes, and their bonding and structure, to increase their understanding of the features of natural bimetallic sites in enzymes.

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cis-Dithiolatonickel as metalloligand to dinitrosyl iron units: the di-metallic structure of Ni(μ-SR)[Fe(NO)2] and an unexpected, abbreviated metalloadamantyl cluster, Ni2(μ-SR)4[Fe(NO)2]3
Chung-Hung Hsieh, Rachel B. Chupik, Scott M. Brothers, Michael B. Hall and Marcetta Y. Darensbourg
Dalton Trans., 2011, DOI: 10.1039/C1DT10438A

In this Dalton Transactions Hot article, Yongge Wei, Yuan Wang and colleagues from Peking University and Tsinghua University make three rigid-rod conjugated organic-hexamolybdate hybrids, a type of organic-polyoxometalate or Lindqvist ion.

Polyoxometalates have potential for use in medicine for anti-tumour and anti-viral applications, and their unusual properties make them useful in catalysis and potentially in the electonics industry.

In this work the organic-polyoxometalates have different amino groups at the terminus, which allows the fabrication of more complicated polyoxometalate (POM) hybrid materials. The amino groups can have different rod lengths and substituents allowing tuning of the materials properties.

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Monosubstituted arylimido hexamolybdates containing pendant amino groups: synthesis and structural characterization
Yi Zhu, Zicheng Xiao, Longsheng Wang, Panchao Yin, Jian Hao, Yongge Wei and Yuan Wang
Dalton Trans., 2011, DOI: 10.1039/C1DT10168D

In this HOT article, a  low-dimensional compound [C₆-Apy][Ni(mnt)₂] (where mnt^2- = maleonitriledithiolate, C₆-Apy⁺ = 4-amino-1-hexylpyridinium) has been designed and synthesized, which has a layer arrangement of anions and cations and shows two steps of magnetic transitions. The low temperature magnetic transition has an uncommon hysteresis loop, while the crystal structure investigations disclosed no structural transition with the magnetic transition. The high temperature magnetic transition exhibits two remarkable features: (1) it synchronously occurs with a crystalline-to-mesophase transition in the first heating process and (2) the structural changes that accompany the solid-mesophase transition are irreversible. It is hoped that the results will shed new light on the design and preparation of a new low-dimensional molecular system combining magnetic transition and liquid crystal properties.

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A low-dimensional molecular spin system with two steps of magnetic transitions and liquid crystal property
Hai-Bao Duan, Xiao-Ming Ren, Lin-Jiang Shen, Wan-Qin Jin, Qing-Jin Meng, Zheng-Fang Tian and Shi-Ming Zhou
Dalton Trans., 2011, Advance Article
DOI: 10.1039/C0DT01704C

This Dalton Transactions Hot article looks at the self assembly of polyhedral cages.

This builds on the authors previous work looking at coordination cages based on simple bis-bidentate bridging ligands with transition metal dications. In this paper they use new ligands with central thiophene or furan spacers, which affect the structure of the cages formed, and so the properties of these compounds.

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Molecular squares, cubes and chains from self-assembly of bis-bidentate bridging ligands with transition metal dications
Andrew Stephenson and Michael D. Ward
Dalton Trans., 2011, Advance Article
DOI: 10.1039/C1DT10263J, Paper

In this Dalton Transactions Hot Article, Sathiyendiran Malaichamy and colleagues prepared stable, luminescent rhenium-based metallacycles decorated with furan units.

The 2D rectangle with four furans and the 3D trigonal prism with six furans were synthesised from readily available starting materials in a one-pot procedure.

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Furan-decorated neutral Re(I)-based 2D rectangle and 3D trigonal prism
Deepak Gupta, Palanisamy Rajakannu, Bhaskaran Shankar, Ramasamy Shanmugam, Firasat Hussain, Biprajit Sarkar and Malaichamy Sathiyendiran
Dalton Trans., 2011, Advance Article
DOI: 10.1039/C0DT01227K, Communication

In this Dalton Transactions Hot article, Herbert W. Roesky and Dietmar Stalke and collegues from
Universitat Gottingen, Germany, make a stable silicon(II) monohydride and examine its electronic structure.

Group 14 hydrides are used in synthetic chemistry, and as precursors to make alloys, such as amorphous silicon, that are used in  electronic devices. For this reason the ability to make stable compounds is very desirable, and an understanding of their structure will help develop the field of silicon chemistry.

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A stable silicon(II) monohydride
Anukul Jana, Dirk Leusser, Ina Objartel, Herbert W. Roesky and Dietmar Stalke
Dalton Trans., 2011, Advance Article
DOI: 10.1039/C0DT01675F, Paper

FREE TO READ until 6th May

In this Dalton Transactions Hot article by William T. Eckenhoff and Tomislav Pintauer, Duquesne University, Pittsburgh, USA, copper(II) complexes with the Me₆TREN ligand and AIBN were used as atom transfer radical addition catalysts.

Atom transfer radical addition is a way of making carbon-carbon bonds using a transition metal catalyst. This method can require a large ratio of catalyst to get a good yield, and can be difficult to recycle, so new ways to optimise this system are crucial.

Here the authors use a free radical diazo initiator (AIBN) to regenerate the catalyst in situ, and use the Me₆TREN ligand to reduce the amount of copper in a higher oxidation state, which would otherwise deactivate the catalyst. This makes for a much more efficient reaction, and here this system was used to catalyze the addition of CCl₄, CHCl₃, CBr₄, and CHBr₃ to a series of alkenes.

Read the full article to find out more about this method for controlled radical addition…

Atom transfer radical addition (ATRA) catalyzed by copper complexes with tris[2-(dimethylamino)ethyl]amine (Me6TREN) ligand in the presence of free-radical diazo initiator AIBN
William T. Eckenhoff and Tomislav Pintauer
Dalton Trans., 2011, Advance Article
DOI: 10.1039/C1DT10189G, Paper

FREE TO READ until 21st April

John Stride from the University of New South Wales, Sydney and colleagues have prepared a copper-based metal–organic framework that demonstrates gas selective adsorption of hydrogen over nitrogen.

The microporous framework has potential application in the isolation of hydrogen from nitrogen in ammonia sythesis waste streams.

Read more in this Dalton Transactions Hot article available FREE until 11th April 2011:

A flexible copper based microporous metal–organic framework displaying selective adsorption of hydrogen over nitrogen
Muhammad Arif Nadeem, Aaron W. Thornton, Matthew R. Hill and John Arron Stride
Dalton Trans., 2011, Advance Article
DOI: 10.1039/C0DT01531H, Hot Article

In this Dalton Transactions Hot Article, chemists from Australia and the US have studied the solution behaviour of two novel platinum-based antitumour complexes.

The dinuclear, polyamine-linked complexes show significant cytotoxicity and antitumour activity compared to other polynuclear platinum complexes.

The rate constants for hydrolysis of the two complexes and the acid dissociation constants of the aquated aqua ligands of their aquated derivatives are reported. The values are of interest because the aquated species are more reactive than their hydroxo counterparts in the context of DNA binding.

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Solution studies of dinuclear polyamine-linked platinum-based antitumour complexes
Rasha A. Ruhayel, Ibrahim Zgani, Susan J. Berners-Price and Nicholas P. Farrell
Dalton Trans., 2011, Advance Article
DOI: 10.1039/C1DT00001B, Paper