Dalton Transactions Blog

Stronger crystal field interactions give actinides advantage over lanthanides in single-molecule magnet construction at high temperatures.

17 Aug 2012

This article is HOT as recommended by the referees. And we’ve made it free to access for 4 weeks.

Jeffrey Rinehart and Jeffrey Long compare the dynamic properties of the 4f³ complex, NdTp₃ (Tp^– = trispyrazolylborate), and its isostructural 5f³ congener, UTp₃. This is the first direct comparison of slow magnetic relaxation behaviour for isostructural and valence isoelectronic lanthanide and actinide complexes.

Download the manuscript which is free to access for 4 weeks to find out more.

Slow magnetic relaxation in homoleptic trispyrazolylborate complexes of neodymium(III) and uranium(III)
Jeffrey D. Rinehart and Jeffrey R. Long
Dalton Trans., 2012
DOI: 10.1039/C2DT31352A, Communication

This manuscript is part of a themed issue titled Frontier and Perspectives in Molecule-Based Quantum Magnets which is due to be published later in the year. Below is a selection of papers also due to be included in this themed issue:

Single-ion magnet behaviour in [U(TpMe₂)₂I]
Joana T. Coutinho, Maria A. Antunes, Laura C. J. Pereira, Hélène Bolvin, Joaquim Marçalo, Marinella Mazzanti and Manuel Almeida
Dalton Trans., 2012
DOI: 10.1039/C2DT31421E, Communication

Controlling magnetic communication through aromatic bridges by variation in torsion angle
Thomas B. Faust, Floriana Tuna, Grigore A. Timco, Marco Affronte, Valerio Bellini, Wolfgang Wernsdorfer and Richard E. P. Winpenny
Dalton Trans., 2012
DOI: 10.1039/C2DT31292A, Paper

A oximato-bridged linear trinuclear [MnIVMnIIIMnIV] single-molecule magnet
Chang-Long Zhou, Zhe-Ming Wang, Bing-Wu Wang and Song Gao
Dalton Trans., 2012
DOI: 10.1039/C2DT31039B, Paper

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Ball milling oxides

09 Aug 2012

By Fiona McKenzie, Executive Editor.

This article is HOT as recommended by the referees. And we’ve made it free to access for 4 weeks.

Mechanochemistry has been used for centuries – according to some, as early as 371 B.C. The pestle and mortar still has a place in many chemistry labs but nowadays mechanically-induced chemistry is performed with the help of a high-energy ball mill.

In their latest Dalton Transactions Perspective, Vladimir Šepelák, Sylvie Bégin-Colin and Gérard Le Caër describe how ball milling is used to effect transformations in oxides. Whilst understanding of the mechanochemical processes involved in ball-milling metalllic compounds is growing, for the more-complex oxide materials, the field is still relatively immature.

The authors explain the various uses of ball milling oxides which can be grouped into either homogeneous or heterogeneous processes (determined by whether there is a net exchange of atoms across boundaries or not). Homogeneous processes encompass polymorphic transformations and titania phase transformations; heterogeneous processes involve compound formations, decompositions and redox reactions.

To read more about the interesting nanocrystalline characteristics that ball milling offers, read the Perspective article now.

Transformations in oxides induced by high-energy ball-milling
Vladimir Šepelák, Sylvie Bégin-Colin and Gérard Le Caër

Interested in other mechanochemistry articles? Read the growing number of articles being added to the ChemComm web theme in mechanochemistry – guest edited by Stuart James and Tomislav Friščić.

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A solid solution for MOF stabilisation

09 Aug 2012

By Katie Renouf, Web Writer.

This article is HOT as recommended by the referees. And we’ve made it free to access for 4 weeks.

Research in metal-organic frameworks (MOFs) or porous coordination polymers (PCPs) has exploded lately due to their potential applications in diverse areas from gas storage to drug delivery, but the Kitagawa group has been looking at yet another application that has rarely been considered: proton conductivity. This process would work in a similar way to Nafion, a DuPont product produced since the 1960s in which protons on SO₃H groups hop between acid sites that extend from a Teflon backbone. Modified Nafion’s excellent mechanical and thermal stability allow it to be used as a proton conductor for proton exchange membrane (PEM) fuel cells.

Foo et al. have synthesised a framework containing sulphonic acid groups, where sodium cations were exchanged in situ for protons. The resultant framework proved to be unstable to loss of guest molecules and, as such, its use in most future applications is limited.

However, through a solid solution approach, where a mixture of ligands was used in differing proportions, mixed MOFs were produced. The stand-out product was a framework in which 18% of the linkers contained sulphonic acid groups, which retained crystallinity and porosity following evacuation of guest molecules. The incorporation of this small proportion of acidic groups increased both the total uptake and the heat of adsorption of CO₂ at 288 K.

Read about a solid solution approach as an alternative route to stabilising MOFs in this HOT article.

Ligand-based solid solution approach to stabilisation of sulphonic acid groups in porous coordination polymer Zr₆O₄(OH)₄(BDC)₆ (UiO-66)
Maw Lin Foo, Satoshi Horike, Tomohiro Fukushima, Yuh Hijikata, Yoshiki Kubota, Masaki Takata and Susumu Kitagawa

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Frontier and Perspectives in Molecule-Based Quantum Magnets

06 Aug 2012

By Matthew Cude, Development Editor.

A report on ‘The 62nd Fujihara Seminar’, 7th – 10th May, 2012, hosted and organised by Dalton Transactions Associate Editor, Professor Masahiro Yamashita.

Photo 1. The participants of the 62nd Fujihara Seminar

The 62nd Fujihara Seminar titled “Frontier and Perspectives in Molecule-Based Quantum Magnets” was held this spring in Sendai, Japan. The Seminar was organized and hosted by Professor Masahiro Yamashita from Tohoku University with the financial support from the Fujihara Foundation of Science. The Fujihara Foundation of Science was founded in 1959 by Mr. Ginjiro Fujihara, the former president of Oji Paper Co. Ltd. who revolutionized the paper industry in Japan and has been recognized as “King of Paper-making”. The main goal of the Fujihara Foundation of Science is to encourage cutting-edge research, leading to significant scientific and technological progress in Japan.

The Fujihara Seminars are usually held at Tomakomai in Hokkaido, where the headquarters of Oji Paper Company is located. This year, however, the Council of the Foundation agreed to make an exception and decided to hold the 62nd Fujihara Seminar in Sendai – the heart of Tohoku area, which was struck last year by the destructive earthquake, followed by a devastating tsunami and the Fukushima nuclear power plant disaster – to support its recovery. The Fujihara Foundation of Science covered all expenses of the Seminar including travel fees, accommodation and organization expenses.

Thirty leading scientists in the field of molecular quantum magnetism from all over the world accepted the invitation and participated in this fascinating scientific event (Photo 1). The Scientific program featured 29 lectures covering all recent aspects in the development of molecular quantum magnets, introduction of multifunctionality into these systems, and the yet unexplored blank spots on the map of quantum magnetism. The atmosphere of the seminar allowed for many fruitful discussions and for significant strengthening of the molecular magnetism community. The scientific level of the talks was very high, most of the presented results were very recent, sometimes not yet published and stimulated vigorous discussions about the future possible developments and directions in quantum magnetism. The talks given at the 62nd Fujihara Seminar are subject of the special issue of Dalton Transactions titled “Frontiers and Perspectives in Molecule-Based Quantum Magnets”, due to be published later this year.

Photo 2. Discussion between Professor Masahiro Yamashita and Professor Dante Gatteschi

Professor Masahiro Yamashita (Tohoku University, Japan) opened the seminar with a lecture on the history of Single-Molecule (SMM) and Single-Chain (SCM) Magnets. Despite the fact that most of the participants were already familiar with the development of the concept, such introduction based on the “milestones” of quantum magnetism offered a valuable insight into the past, present, and future directions of the field. One future direction was introduced in the second talk given by Professor George Christou (University of Florida, USA). Prof. Christou noted that, for future applications of molecular quantum magnets in spin-based quantum computation and spintronic devices, coupling of two or more SMMs to each other is essential. Such coupling must be very weak in order to maintain the intrinsic quantum properties of each individual SMM, but strong enough to allow them to “feel each other”. Professor Christou presented several examples of SMM aggregates coupled with specially designed organic ligands. Some of them display an exchange-bias of the quantum tunneling of magnetization steps in the hysteresis loops, which is a hallmark of weak interactions between SMM units.

Photo 3. Informal discussions during the excursion to Hiraizumi – a World Heritage site

In the subsequent talk, Professor Michel Verdaguer (Université Pierre et Marie Curie, France) discussed early results in the field of SCMs and the usefulness of X-Ray Magnetic Circular Dichroism (XMCD) in the characterization of magnetic molecules (especially those deposited on various surfaces). He also presented research on the salicyamidoxime-based Mn₆ SMMs and summarized the successes and failures of the cyanide chemistry of transition metals in the field of high-spin molecules and SMMs.

Professor Dante Gatteschi, one of the founding fathers of molecular magnetism (Univeristà degli Studi di Firenze, Italy) gave the last talk of the first day. Professor Gatteschi summarized the last 30 years of research in the field of nanomagnetism by focusing on the comparison of molecular nanomagnets MNMs with magnetic nanoparticles MNPs. He pointed out that there are still blank spots on the map of MNMs and strongly encouraged the exploration of the no man’s land of magnetic molecules comprising 100–1000 paramagnetic ions. In addition, he reminded the participants that there is “plenty of room” in between the MNMs and MNPs regimes. Synthesis and investigation of 100–1000 ion clusters might be challenging, but the emergence of new fascinating physical phenomena is expected (Photo 2).

The second day of the Seminar was also filled with extremely stimulating talks and discussions. The lecture of Professor Song Gao (Peking University, China) reflected the strong current trend in molecular quantum magnetism to re-discover the importance of rare-earth elements in the design of SMMs with enhanced characteristics. Professor Gao pointed out that, thanks to the large spin-orbit coupling effect, several mononuclear lanthanide or actinide complexes have been found to be single ion magnets. Lanthanide-based SMMs seem to be the most promising from an application point of view. Especially the double decker complex TbPc₂ (Pc = phthalocyanine) with high single-ion anisotropy and a very high blocking temperature is particularly appealing for the construction of supramolecular spintronic devices, according to Professors Mario Ruben (Université de Strasbourg, France and Karlsruhe Institute of Technology, Germany) and Masahiro Yamashita (Tohoku University, Japan), who gave the last two talks. Professor Ruben demonstrated the potential of TbPc₂ in the construction of spin-valves, and Professor Yamashita showed, for the first time, that TbPc₂ could act as single-molecule memory device.

The third and last day of the conference was designated as an informal discussion day. The participants could freely interact during an excursion to Hiraizumi (a World Heritage site) – temples, gardens and archeological sites representing the Buddhist Pure Land – and during a river cruise (Photo 3).

The 62nd Fujihara Seminar ended with a banquet at Shozankan. This final event began with a traditional ceremony of kagami biraki – opening of wooden casks of iwai-zake (“celebration sake”) (Photo 4). During the Banquet the host, Professor Masahiro Yamashita, asked all the participants to visit Sendai again in three years during the next conference on Molecular Quantum Magnets to “report” their advances in this particular field. He suggested that the next meeting would be a great opportunity to verify how fruitful the discussions and new ideas spawned during the 62nd Fujihara Seminar have been.

Photo 4. Ceremony of kagami biraki – opening of wooden casks of iwai-zake (“celebration sake”) – during the Seminar Banquet.

In summary, the 62nd Fujihara Seminar “Frontier and Perspectives in Molecule-Based Quantum Magnets” was a great opportunity for the top molecular magnetism scientists to interact and discuss how to further advance the field. Look out for the upcoming themd issue later this year.

Written by Dr. Dawid Pinkowicz (Tohoku University)

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Talking inorganic chemistry in Toronto

30 Jul 2012

By Jamie Humphrey, Editor.

Editor Jamie Humphrey spends a few days in Canada at ISACS8: Challenges in Inorganic and Materials Chemistry

Growing herbs at the University of Toronto

The conference series International Symposium on Advancing the Chemical Sciences was launched in 2010, to celebrate the launch of the RSC’s new flagship journal, Chemical Science. ISACS8 was the eighth meeting in the series, and the second to have a focus on challenges in inorganic and materials chemistry. This year’s meeting was held at the University of Toronto, Canada.

A slight break in some unusually hot weather meant that for our time in Toronto, we were blessed with perfect weather – neither too hot nor too cold, but just right! The good weather was clearly being utilised by some members of the university , as was evident in the very healthy looking herbs being growing in the courtyard just outside lecture theatre. I was very good, and did not help myself to any (but I was sorely tempted!).

The conference began on the Thursday evening with an extra special event – a lecture by Profesor Joan Valentine , who was recently awarded an RSC Honorary Fellowship. Her award lecture ‘Manganese and superoxide: Curiosity-driven research at the inorganic chemistry-biology interface’, was a perfect way to open the meeting.

During the next three days, we covered a diverse range of inorganic and materials topics: main group chemistry, materials for chemistry, magnetism, porous materials and catalysis. The conference featured 16 Plenaries, by Warren Piers, Francois Gabbai, Viola Birss, Sossina Haile, Clare Grey, Simon Aldridge, Joe Hupp, George Christou, Russell Morris, Annie Powell, Noritaka Mizuno, Tom Baker, Kyoko Nozaki, Paul Chirik, Roberta Sessoli and William Dichtel. The conference programme was completed with a number of contributed talks. As you might expect from ISACS conferences, all the talks were of the highest quality. Snippets of information I learnt from the conference are that Uranium is the Jekyll and Hyde of the Periodic Table, Chemical Science Editors work on Christmas Eve and that we need about 80 of the elements to live our lives.

One of the social highlights of the meeting for me was the speakers’ dinner, held at the top of the CN Tower. With great food and stunning views, the evening was an excellent way to round off the first full day of the conference. The conference was a good size ( about 150 delegates) and this allowed many opportunities to meet new friends and catch up with old ones at the poster sessions, coffee/tea breaks and lunchtimes. It was good to see a number of people at the conference who I have not seen for a while, including previous Dalton Transactions Development Editor, Anna Roffey, who left the Editorial Office to study for a PhD at UCL, UK over a year ago!

Many thanks to the organisers for arranging a great meeting, in particular local host Doug Stephan and Rachel Thompson from RSC, who in addition to ensuring a well organised meeting, also ensured that we had plenty of sweet treats to keep us going though the day (I have never seen so many cookies…)

Read some articles by the Plenary speakers by following the links below:

Probing the influence of steric bulk on anion binding by triarylboranes: comparative studies of FcB(o-Tol)2, FcB(o-Xyl)2 and FcBMes2, Inke Siewert, Philip Fitzpatrick, Alexander E. J. Broomsgrove, Michael Kelly, Dragoslav Vidovic and Simon Aldridge Dalton Trans., 2011,40, 10345 DOI=10.1039/C1DT10185D

Cyclisation of α,ω-dienes promoted by bis(indenyl)zirconium sandwich and ansa-titanocene dinitrogen complexes, Doris Pun, Donald J. Knobloch, Emil Lobkovsky and Paul J. Chirik Dalton Trans., 2011,40, 7737 DOI=10.1039/C1DT10149H

“Squaring the clusters”: a MnIII4NiII4 molecular square from nickel(II)-induced structural transformation of a MnII/III/IV12 cage Dimitris I. Alexandropoulos, Manolis J. Manos, Constantina Papatriantafyllopoulou, Shreya Mukherjee, Anastasios J. Tasiopoulos, Spyros P. Perlepes, George Christou and Theocharis C. Stamatatos Dalton Trans., 2012,41, 4744 DOI=10.1039/C2DT00030J

Structural and dynamical aspects of alkylammonium salts of a silicodecatungstate as heterogeneous epoxidation catalysts Sayaka Uchida, Keigo Kamata, Yoshiyuki Ogasawara, Megumi Fujita and Noritaka Mizuno Dalton Trans., 2012, Advance Article, DOI=10.1039/C2DT30492A

Metal–organic frameworks for the storage and delivery of biologically active hydrogen sulfide Phoebe K. Allan, Paul S. Wheatley, David Aldous, M. Infas Mohideen, Chiu Tang, Joseph A. Hriljac, Ian L. Megson, Karena W. Chapman, Guy De Weireld, Sebastian Vaesen and Russell E. Morris Dalton Trans., 2012,41, 4060 DOI=10.1039/C2DT12069K

Using the flexible ligand bis(2-hydroxyethyl)amino–tris (hydroxymethyl)methane (“bis–tris”) to access a family of 3d–4f MnIII4Ln4 complexes Amin Khan, Yanhua Lan, George E. Kostakis, Christopher E. Anson and Annie K. Powell Dalton Trans., 2012,41, 8333 DOI=10.1039/C2DT30127J

Magnetic and optical bistability in tetrairon(III) single molecule magnets functionalized with azobenzene groups Thazhe Kootteri Prasad, Giordano Poneti, Lorenzo Sorace, Maria Jesus Rodriguez-Douton, Anne-Laure Barra, Petr Neugebauer, Luca Costantino, Roberta Sessoli and Andrea Cornia Dalton Trans., 2012,41, 8368 DOI=10.1039/C2DT30172E

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Sulfur oxygenation at non-heme iron centers

27 Jul 2012

By Jennifer Newton, Publishing Editor.

This article is HOT as recommended by the referees. And we’ve made it free to access for 4 weeks.

McQuilken and Goldberg discuss the synthesis, structure and reactivity of non-heme iron(II/III)-thiolate model complexes that are known to react with O₂ to give sulfur oxygenates in this hot Perspective. Comprehension of the pathways involved in sulfur oxygenation will aid research towards catalytic applications involving metal-mediated O₂ oxidations as well as developing understanding surrounding nonheme iron enzymes, many of which are vital of important biochemical pathways.

To find out more, read the full Dalton Transactions Perspective now…

Sulfur oxygenation in biomimetic non-heme iron–thiolate complexes
Alison C. McQuilken and David P. Goldberg
Dalton Trans., 2012
DOI: 10.1039/C2DT30806A, Perspective

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Hydrazine based hydrogen storage materials

20 Jul 2012

By Leah Morris, Web Writer.

This recent Dalton Transactions cover is by Nikolas Kaltsoyannis and team from UCL and my PhD supervisor, David Antonelli. Doing a PhD in hydrogen storage materials myself, I thought that this would be a good opportunity to blog about some of our group’s research…

The big challenge in hydrogen storage materials research is to develop materials that have a high storage capacity, are fully reversible, and can operate at ambient temperature and pressure. Our group have previously reported chromium hydrazide gels that store hydrogen via the Kubas interaction. The material has a gravimetric hydrogen storage performance of 3.2 wt% at 298K which corresponds to a volumetric capacity of 40.8 kg H₂/m³, meeting the US Department of Energy’s 2015 target for volumetric density (40 kg/m³).

In this latest Dalton Transactions article, the Cr(II) binding sites were studied computationally to further study the interaction with H₂. Strong evidence suggests that the metal-H₂ interaction is Kubas type (confirming our previously reported results) – the Kubas interaction between a transition metal and H₂ involves σ-donation from the filled H‑H σ-bonding orbital into an empty transition metal d orbital, and is strengthened by back-donation from a filled metal d orbital into the vacant σ* orbital of the H₂ molecule. The binding model is similar to the Dewar-Chatt-Duncanson model for the bonding of CO ligands to transition metals.

Kaltsoyannis and team extended the system to incorporate other transition metal binding sites: Ti(II), V(II) and Mn(II). They found that H₂ did not bind to Mn(II) suggesting that Mn(II) materials may not perform well for hydrogen storage. Hydrogen did bind to V(II) and Ti(II) and calculations indicate 5 and 7 wt% gravimetric storage respectively, surpassing the DOE’s goal for gravimetric storage.

This paper shows that materials based on V(II) and Ti(II) could potentially perform better than the experimentally-realised chromium hydrazide gels.

To find out more, read the full Dalton Transactions article now…

The Kubas interaction in M(II) (M = Ti, V, Cr) hydrazine-based hydrogen storage materials: a DFT study
Claire V. J. Skipper, Ahmad Hamaed, David M. Antonelli and Nikolas Kaltsoyannis

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Frustrated Lewis pairs themed issue now published

20 Jul 2012

By Fiona McKenzie, Executive Editor.

We strongly recommend you have a browse of Dalton Transactions’ latest themed issue in Frustrated Lewis Pairs.

As Guest Editor, Doug Stephan says in his Editorial: there’s nothing frustrating about frustrated Lewis pairs! Particularly as these highly reactive compounds are gaining increasing attention from researchers wishing to activate dihydrogen, olefins, disulfides, CO₂… the list continues…

The issue contains 18 articles dedicated to the topic – a small selection is below:

Hydrogen activation by 2-boryl-N,N-dialkylanilines: a revision of Piers’ ansa-aminoborane
Konstantin Chernichenko, Martin Nieger, Markku Leskelä and Timo Repo

Frustrated Lewis pair addition to conjugated diynes: Formation of zwitterionic 1,2,3-butatriene derivatives
Philipp Feldhaus, Birgitta Schirmer, Birgit Wibbeling, Constantin G. Daniliuc, Roland Fröhlich, Stefan Grimme, Gerald Kehr and Gerhard Erker

Fixation of carbon dioxide and related small molecules by a bifunctional frustrated pyrazolylborane Lewis pair
Eileen Theuergarten, Janin Schlösser, Danny Schlüns, Matthias Freytag, Constantin G. Daniliuc, Peter G. Jones and Matthias Tamm

Access the issue here

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Winners at the X Congresso del Gruppo Interdivisionale di Chimica Organometallica

19 Jul 2012

By Matthew Cude, Development Editor.

Congratulaions to the Dalton Transactions Poster Prize winners at the X Co.G.I.C.O, held in Padua, Italy, 5-8 June 2012

Blerina Gjoka (left) and Daniela Intrieri (right) after winning their Dalton Transactions Poster Prizes at the X Co.G.I.C.O

The Congresso del Gruppo Interdivisionale di Chimica Organometallica della Societa’ Chimica Italiana (Co.G.I.C.O) recently held their 10th meeting in the beautiful city of Padua, in the North of Italy. Founded in 1991, the group meets every 2 years to discuss recent developments in the field of organometallic chemistry.

Attracting established international scientists and young researchers alike, this year the delegates enjoyed a range of talks from the plenary speakers:

Paul J. Dyson, Lausanne, “Organoruthenium agents for the treatment of invasive tumours”

Steven P. Nolan, St Andrews, “Recent advances in late transition metal-NHC mediated catalysis”

Kay Severin, Lausanne, “Chemistry with organometallic half-sandwich complexes: sensors, nanostructures, and catalysts”

Christophe Coperet, Zurich, “Control functionalization of surfaces towards single-site catalysts”

Poster sessions were also held during the meeting and we are delighted to announce that the winners of the two Dalton Transactions Poster Prize’s were Daniela Intrieri of Università degli Studi di Milano, and Blerina Gjoka of Università degli studi di Padova.

Daniela’s poster was on the topic of ‘Ru(TPP)CO-Catalysed 2-Azido Biaryls Annulation to Afford Phenanthridine and Dihydrophenanthridine Derivatives’, and Blerina’s on ‘Iron(III) Amino Triphenolate Complexes as Catalysts for CO2 Fixation’.

See the conference homepage for more details

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Dalton Transactions Blog

Stronger crystal field interactions give actinides advantage over lanthanides in single-molecule magnet construction at high temperatures.

Ball milling oxides

A solid solution for MOF stabilisation

Top ten most accessed articles in June

Frontier and Perspectives in Molecule-Based Quantum Magnets

Talking inorganic chemistry in Toronto

Sulfur oxygenation at non-heme iron centers

Hydrazine based hydrogen storage materials

Frustrated Lewis pairs themed issue now published

Winners at the X Congresso del Gruppo Interdivisionale di Chimica Organometallica

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