Cérémonie de lancement, UNESCO, le 20 janvier 2014

Catherine Esterhuysen, Présidente de la Société sudafricaine de cristallographie

La cristallographie en Afrique du Sud

Catherine Esterhuysen

SYNOPSIS

La cristallographie a été implantée en Afrique du Sud sur une base solide dès 1937 avec l'arrivée à l'Université de Cape Town de R. W. James, un ami proche et collaborateur de W. L. Bragg. Dans cette présentation, le développement de la cristallographie en Afrique du Sud sera décrite à partir de ce point de départ jusqu’à la période prospère actuelle que connaît sa communauté de cristallographes. Un court message de soutien du Département des sciences et de la technologie de la République d’Afrique du Sud sera également délivré.

PRESENTATION

COMMENTAIRE

Firstly, I would like to thank Mr Makatu of the South African embassy and Paris and Dr Auf der Heyde and the Department of Science and Technology for their efforts in driving the International Year of Crystallography in South Africa.

We in the South African Crystallographic community, and the South African Crystallographic Society (SACrS) in particular, appreciate everything they are doing and see it as recognition of the long and proud history that crystallography has had in South Africa.

This started with the arrival, in 1937, of R. W. James at the University of Cape Town. He had studied under J. J. Thomson at the Cavendish laboratory in Cambridge between 1912 and 1914, along with Lawrence Bragg, where he was aware of, and interested in, the diffraction work of the Braggs. However, he was already involved with other experiments so did not do any diffraction studies at that time.

Following this period, he spent 14 months stuck on the Antarctic ice cap as part of the Shackleton expedition to the South Pole on the Endurance, whereafter he joined the Royal Engineers during the First World War, where he renewed contact with Lawrence Bragg, who was in charge of technical developments. Bragg inspired James to start working in the field of diffraction and after the war James joined Bragg in Manchester (UK) where he soon became one of the pioneers [of crystallography] and was one of the attendees at the first crystallographic conference held in 1925.

James remained good friends with Lawrence Bragg after his move to the University of Cape Town in 1937, as seen from this photograph. More importantly, he was also still an important member of the international diffraction community, as indicated by the fact that South Africa became one of the first 14 countries to adhere to the International Union of Crystallography (IUCr) upon its inception.

Back at home, James was busy training students, such as Aaron Klug, who, after completing an MSc with James, moved to the Cavendish laboratory at Cambridge. There, he became interested in the structures of biological materials, working with Rosalind Franklin and Francis Crick, and eventually being awarded a Nobel prize for his work. However, Klug was not the first of James' students to be awarded a Nobel prize: Allan Cormack had won the Nobel Prize in physiology two years earlier for his work on the CT scanner.

In the meantime, other students of James' were spreading out within the South African scientific community, with people like Frank Herbstein playing an important role in the first meetings of the South African branch of the IUCr in the late 1950s and early 1960s before he moved to Israel and an illustrious career there. He and a number of other ex-students of James worked at the South African Council for Scientific and Industrial Research (CSIR), which was the powerhouse of scientific research in those days, as can be seen from these two photographs taken at the CSIR in the early 1980s showing many faces recognisable within the crystallographic community today, such as Mike Thackeray, currently at Argonne Labs, Gert Kruger, Peet van Rooyen, Jan Boeyens, whom many people will know as the initiator of the popular series of Indaba conferences held every three years in the Kruger park, and Demi Levendis. In the 1980s policies at the CSIR changed, resulting in many researchers moving to universities and this is where most of the current crystallographic research in South Africa now takes place.

With James's legacy, it is hardly surprising that one the largest crystallographic groups is to be found at the University of Cape Town, where the current crop of enthusiastic postgraduate students and post-docs are being trained by Mino Caira, Susan Bourne and Clive Oliver. Susan Bourne is particularly well-known inIUCr circles, thanks to her membership of the Structural Chemistry Commission and her role on the international programme committee for the IUCr2014 congress, while Mino Caira was recently awarded honorary membership of the Argentine Research Society on Organic Chemistry. Their focus is on supramolecular chemistry, building on from emeritus professor Luigi Nassimbeni's earlier work in this field, with particular focus on crystal engineering of pharmaceutical compounds, metal-organic frameworks and large supramolecular assemblies, with their work having been highlighted in cover articles and the CrystEngComm blog.

In addition, the structural biology unit at the University of Cape Town collaborates with its counterpart at the nearby University of the Western Cape, which houses a Rigaku High Flux Home System diffractometer dedicated to the determination of protein crystal structures, with the focus being the study of infectious diseases and biotechnological applications.

Some 60 km inland from Cape Town lies the University of Stellenbosch, here shown uncharacteristically with snow on the surrounding mountains, which is home to one of the most recently established groups using crystallographic techniques. In addition to myself, Tanya le Roex, Vincent Smith, Len Barbour and Delia Haynes lead the research there. Len Barbour is well-known in crystallographic circles, being on the editorial boards of the New Journal of Chemistry, Crystal Growth and Design and CrystEngComm. Our research focusses on supramolecular chemistry, where we probe the nature of the magnetic, optical and sorption properties of a range of materials. To this end, we utilise our single crystal and powder diffractomers, along with a wide range of other experimental and computational techniques. In particular, Len Barbour has designed and built a number of novel pieces of apparatus, in order to study the structural changes involved in the process of gas sorption by porous materials at an atomic level.

Another large crystallographic group is at the University of the Witwatersrand (also known as Wits) located in Johannesburg. The university is about 90 years old and started as a mining school. This legacy is shown in this aerial photograph of Johannesburg taken in the 1930s, with the mine dumps in the background and the university in the foreground. Also shown are the four crystallographic research leaders there, Demi Levendis, Manuel Fernandes, Dave Billing and Andreas Lemmerer. Dave Billing is currently a member of the IUCr Calendaring committee and its Journals Commission and secretary of the Powder Diffraction Commission, while Demi Levendis has been a stalwart of the South African branch of the IUCr for many years.

Demi Levendis and Manuel Fernandes focus on chemical crystallography, with their particular interest in solid state reactions, while Andreas Lemmerer's research thrust lies in the supramolecular synthesis of drug-drug co-cocrystals, as well as understanding the mechanism of co-crystallization, highlighted recently in this CrystEngComm cover article. Dave Billing's focus is on solid state chemistry using powder diffraction in a facility well-equipped with four diffractometers configured for a wide range of experiments, from multiple in situ setups to stress and texture measurements. In an exciting development, crystallographers at Wits were recently involved in determining the first crystal structure of the South African HIV-1 subtype C protease.

Down the road from Wits is the University of Johannesburg, where Fanie Muller, Charmaine Arderne and emeritus professor Gert Kruger, a long-time member of the South African branch of the IUCr, focus primarily on structure−property relationships of coordination compounds, which have important applications in bioinorganic catalysis and pharmaceuticals. They are also interested in the physical crystallography of functionally engineered materials.

Some 60 km further to the north lies the University of Pretoria, where Peet van Rooyen, Dave Liles and Melanie Rademeyer, who serves on the IUCr teaching commission, run a small but productive group, with a focus on the structural properties of Fischer-carbene complexes and the crystal engineering of multi-functional materials, for which they utilise a Bruker D8 Venture (dual microsource) single crystal diffractometer in combination with a Bruker D2 Phaser powder diffractometer.

Moving to the south, another large grouping which has grown from strength to strength over the last few years due to the vision of André Roodt, currently President of the European Crystallographic Association, is to be found at the University of the Free State. André Roodt is ably assisted by his colleagues Gideon Steyl, Marietjie Schutte, Deon Visser, Alice Brink and Johan Venter, focussing on reaction mechanisms of coordination compounds. To do this they have a Bruker X8 APEXII diffractometer and access to three powder diffractometers, as well as spectrometers for kinetics studies of pharmaceutical compounds and catalysts.

Further east, the crystallographic efforts of the University of KwaZulu-Natal are spread over the campuses in Durban, headed by Bernard Omondi Owaga, and Piermaritzburg, 80 km inland from there, with Orde Munro and Matthew Akermann at the helm. Their focus is on organometallic compounds, particularly for catalysis and pharmaceuticals, with Orde Munro starting to move into the field of protein crystallography. There is also a strong focus on supramolecular structures, with Bernard Omondi studying polymorphism, solid solutions and cocrystalisation.

In addition to these universities where a large amount of crystallographic research is undertaken, there are many research groups at other universities across the country, such as the Nelson Mandela Metropolitan University in Port Elizabeth and the nearby Rhodes University, that also utilise crystallographic techniques. Furthermore, universities which historically have not been involved in research are taking to crystallography. The Cape Peninsula University of Technology was established in 2005, when the Cape Technikon and Peninsula Technikon merged. This merger was part of a national transformation process that changed the higher education landscape in South Africa. The Crystal Engineering Unit there was established by Luigi Nassimbeni who moved from UCT in 2008 to inject research capacity into the Chemistry Department. He is joined by Ayesha Jacobs and Niki Báthori. Together, they focus on inclusion compounds, organic salts and cocrystals, where they study selectivity and chiral discrimination with the aid of a Bruker D2 Powder diffractometer.

Although, nowadays, most of the crystallographic research activity is based at universities, crystallography is used in industry as well, with a particularly dynamic group at Sasol Technology, headed by Esna du Plessis and Roy Forbes. Sasol Technology is the research division of SASOL, which uses Fischer-Tropsch technology to produce oil from coal. Esna du Plessis is an active member of the Science at Synchrotrons in South Africa group, through which South Africans are able to get access to synchrotrons all over the world. This group has members from a number of institutions and fields, among others protein crystallographers, which as you have seen is probably the most active growth point for crystallography in South Africa.

I would like to invite you to participate in IYCr activities in South Africa, in particular the Pan African and South African Crystallography Conference and Summit in October in Bloemfontein, the first all-African conference on crystallography, with an important aim being to bring political leaders together with scientists to try and work out how to develop crystallography in Africa, with a particular focus for us on the historically disadvantaged universities within South Africa. It therefore promises to be an exciting event, so I hope to see you there!

Lastly, I would like to thank the members of SACrS for providing me with the information used in compiling this presentation.

Thank you for your attention.

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