Sargeson, Alan

Alan Sargeson, born in Armidale , northern New South Wales, into the family of Herbert Leslie Sargeson and Alice (Mcleod) Sargeson. He had two older brothers, Leslie Mcleod and John Mcleod Sargeson. His father studied law, and after serving as a judge in various parts of New Wales, he became a senior paid judge in Sydney . His mother was born on a farm in Wentworth in the west of New South Wales. His father and mother were excellent golfers , and his father was also keen on fishing. The athletic abilities of the parents passed on to his son, who was exceptional in sports. Both parents led a disciplined household and insisted that the children carry out their tasks, especially their homework at school. Due to the fact that his father often needed to move to new jobs, Alan Sargeson changed five different schools. At 14, he moved to Koutamandra, where he ran into a teacher named Daphne Morton, who in the two years he spent there found a strong interest in science in young Alan. He spent the last two years of high school at Maitland High School for Boys, Hunter Valley, north of Sydney.

After graduation, he won an educational grant from the New South Wales Department of Education to study at the Teachers College located on the campus of the University of Sydney. The University began with the study of mathematics, physics, chemistry and geography. After the first year, he abandoned geography and continued to study mathematics, physics and chemistry, specializing in chemistry in the last (third) year of study. Chemistry courses were mainly devoted to organic chemistry, especially the study of natural compounds. As a result, Alan devoted his diploma (after 4 years) to organic chemistry. Earlier, he completed a small project on inorganic chemistry with Frank Dwyer, an outstanding specialist in the field of coordination inorganic chemistry. Dwyer saw a unique personality in Alan and invited him to become a graduate student. After the end of World War II , the University of Sydney began to confer PhD degrees . Alan Sargeson's doctoral work was devoted to the stability of acetylacetonate complexes and the separation of tris-oxalate metal complexes. After graduation, he worked as a lecturer at evening courses at the University of Technology in Sydney.

Despite the fact that university vacancies were rare in 1955, a post lecturer in physical and inorganic chemistry at the University of Adelaide became vacant. Alan sent a resume and after an interview with the dean of the faculty, he was offered a job. Initially, Alan worked on problems similar to those that he investigated with Dwyer. These studies included the isolation of EDTA (ethylene diamine tetraacetate) of metal complexes, the separation of tris (dithioocolate) complexes, and an initial study of the cobalt tris-1,2-diaminopropane complexes. He performed the work together with Wolfgang Sasse, a graduate student working under the guidance of Professor Geofri Bagger, an organic chemist. Sassé discovered an effective method for obtaining dipyridines from pyridine using Raney nickel . This study has led to the production of herbicides diquat and paraquat . He also developed the conditions for obtaining a very common ligand of 2,2′-bipyridine in large quantities, which previously required a complex synthesis process. One of the by-products of this reaction was an insoluble neutral complex, including two pyridyl-pyrrolate ligands and a bipyridyl chelate , the structure of which was established by them correctly.

In Adelaide, Alan met and married Mariette Anders from Freeling, South Australia, and daughters of Franky Hilten Anders and Joyce Ann Anders (Barclay) on November 21, 1957 in Freeling. Ancestors of Marietta migrated from Schluswig-Holstein more than a century ago and created a plant in the Barossa area.

Alan and Marietta had 4 children, Kirsten Ann (Kirsten Ann), Frank Leslie Anders (Frank leslie Anders), William Jon Mcleod, Bente Barbara Alice.

After two years in Adelaide, Alan found out that his mentor, Frank Dwyer, had moved to the John Curtin School of Medical Research at the National University of Australia at Carberra. He led a section called biological and inorganic chemistry, an area in which he previously worked. Dwyer planned to move to ANU in 1958 and asked Alan to help him lead the course. The University of Adelaide gave Alan leave, and ANU provided him with a temporary job. After 6 months, ANU offered him a research grant that guaranteed him at least 5 years of employment, and he resigned from his former post in Adelaide.

At the University of Sydney, Dwyer suggested that positively charged tris (o-phenanthroline) metal complexes may be toxic. The assumption turned out to be correct, as it was later shown that these complexes inhibit cholinesterase in animals. This observation was further developed in the course of research conducted in the school. John Curtin in Canberra. There, in collaboration with the Melbourne physiologist Albert Schulman and Roy Douglas Wright, he discovered that the derivatives of these complexes are powerful bacteriostatic agents, which have been used for some time (control of infection of Staphylococcus aureus in children's hospitals). Both the iron complex and nickel are still used by Australian pharmacists as topical remedies for abrasions and herpes. Alan continued to use them for these purposes for 40 years.

In addition to research in the field of bio-organic chemistry , Dwyer and Alan, together with the students of the group, continued research in the field of coordination chemistry; they studied the separation and racemization of tri-o-phenanronyl and bipyridine complexes (JA Broomhead), the synthesis of polypyridine ruthenium complexes (B. Bosnich), similar osmium complexes (DA Buckingham), the separation of EDTA-metal complexes (F. l. Garvan), and diastereoselectivity in chiral complexes using chiral ligands. All of these students, with the exception of Garvan, took academic positions. After two years of working with Dwyer, Alan began his own work. Perhaps the most notable achievement of his early independent work was the discovery that secondary amines associated with a kinetically inert metal exist in a moderately stable chiral form. The cobalt sarcosine complex [Co (NH ₃ ) ₄ (sarcosinato)] ²⁺ is chiral only due to the asymmetry of the kinetically stable sarcosine amino group associated with the cobalt. An asymmetric nitrogen atom loses its configurational integrity during the dissociation of the nitrogen-proton bond.

Although the work was interesting and the result was surprising for that time, it all had much broader implications related to the structures of the polydentate polyamine complexes and for many of his subsequent investigations of the mechanisms. As a result of the stereochemical stability of the coordinated secondary nitrogen atom, new isomers were predicted for the octahedral complexes with the triethylentetramine ligand (NH ₂ CH ₂ CH ₂ NHCH ₂ CH ₂ NHCH ₂ CH ₂ NH ₂ ). This new type of isomer has been isolated and characterized by Greg Shirley (Graham Searle) and Alan. The isolation of the chiral trans-isomer as a result of the stability of the secondary chiral center on the secondary nitrogen atom aroused great interest and surprise at that time.

Having created an independent research program, Alan decided to spend an academic year with Henry Taube , an outstanding inorganic chemist at Stanford University. It was Alan's first trip outside of Australia. It was one of many, almost annual, visits to the United States and Denmark in his career. Alan considered these visits essential in order to keep abreast of developments in his field, he used them diligently. The visit to Stanford was scheduled for the middle of 1962, when, earlier that year, Dwyer died at the age of 51 from a heart attack. Care Dwyer questioned the viability of the research unit at the medical school, and it took some time to resolve the issue. Finally, Alan became the head of the unit, and remained to deal with pressing problems. When this matter was settled, he went to Stanford in October 1963. Around this time, David Buckingham, a former student of Dwyer, was an assistant professor at Brown University. Alan brought Buckingham back to the research unit, and they began the most productive collaboration. The pair had complementary strengths: Alan had extraordinary ingenuity, while Buckingham, though not devoid of good imagination, was accurate in analyzing and conducting experiments. The pair initially continued work on the chiral amine complexes, which Alan began. Later they developed a new field in chemistry. Their studies on alkaline hydrolysis of cobalt complexes were noticeable. At that time there were disputes over the mechanism of alkaline hydrolysis of cobalt amino complexes. For example, it was investigated that the rapid reaction of hydroxide ions with the [Co (NH ₃ ) ₅ X] 2+ complex, leading to [Co (NH ₃ ) ₅ OH] ²⁺ , occurs either by associative ( S _N 2 ) or dissociative ( S _N 1 _CB ) mechanism. The second was proven in the course of research.

Another work was devoted to the hydrolysis and the formation of peptides with the participation of esters of amino acids and amides under the action of cobalt. It was found that the bis-ethylenediamine (NH ₂ CH ₂ CH ₂ NH ₂ ) complex containing glycine methyl ester quickly reacts in a dry polar aprotic solvent with amino acid and peptide ethers to form new peptide bonds . Thus, they demonstrated that the cobalt ion can act as a protective group for the amino group, and can also act as an activating agent ( Lewis acid ) for the carbonyl center of the chelated amino acid ester. In similar works, they showed that the [Co (NH ₃ ) ₅ NH ₂ CH ₂ (O) OC ₂ H ₅ ] ³⁺ complex in an alkaline aqueous solution quickly gives the [Co (NH ₃ ) ₄ NH ₂ CH ₂ C amide complex (O) NH] ²⁺ with bidentate glycine, with the intermediate formation of the amide [Co (NH ₃ ) ₄ (NH ₂ ) NH ₂ CH ₂ C (O) C ₂ H ₅ ] ²⁺ . Although the proposed amide intermediate has a very short lifetime, it is capable of entering into a very fast reaction with the ether group, presumably due to the anchimeric effect — an increase in speed due to the forced convergence of the reactants. A similar transformation was observed in the reaction with [Co (en) ₂ Br (NH ₂ CH ₂ C (O) NH ₂ )] ²⁺ . Substitution of the ligand with Br ^- hydroxide with an ion followed by rapid intramolecular formation of a coordinated amino acid . It was found that, as a rule, these intramolecular reactions occur more than 400 times faster than the corresponding intermolecular reactions.

In 1967, ANU completed the creation of a chemistry research school. Alan and his group were supposed to move there. He left medical school with some regret, because he had previously collaborated with biologists, but the chemical school provided unique advantages, in particular, a more flexible administrative structure. In the new school, the collaboration between Sargesson and Buckingham continued for a few more years, but it became increasingly clear that this could not continue any longer, since progress required a clear distinction between individual contributions. Soon, Alan hired two employees, Jack Harrofield and Greg Jackson. Both later became professors at Australian universities.

It was well known that ions such as Zn ²⁺ and Mg ²⁺ are able to accelerate the hydrolysis of polyphosphates and esters of phosphoric acid ^[9] . Due to the lability of these metal-phosphate bonds (the complexes are kinetically unstable), it was difficult to trace the steps of the hydrolysis mechanism. Co ³⁺ ions form thermodynamically stable (non-labile) cobalt-phosphate bonds, which makes them suitable for studying phosphorus-oxygen bond cleavage mechanisms. Also, it was found that in an alkaline aqueous solution [Co (NH ₃ ) ₅ OP (O) ₂ OC ₆ H ₄ NO ₂ ] ⁺ , containing a monodentate p-nitrophenol phosphate ligand, forms a cyclic phosphoamide ligand and this is accompanied by the release of p-nitrophenolate (NPO). It was found that the rates for intramolecular NPO substitution are about 10 ⁶ times higher than for the corresponding intermolecular reaction.

Similar intramolecular cyclization, but with the participation of a hydroxyl ligand bound to cobalt, was studied on cis - [Co (En) ₂ (OH) (OP (O) ₂ OC ₆ H ₄ NO ₂ ] ⁺ . Although the coordinated hydroxide is an ion, at least 10–7 times less basic than a free hydroxide ion, is an intramolecular process, at least 10 ⁵ times faster than the corresponding intermolecular replacement of a NPO group with free hydroxide ions.

Alan continued to work on classical substitution reactions in Co ³⁺ complexes. The most notable of these was the complete study, with Jackson, of the stereochemical behavior of cis- [Co (En) ₂ XY] ^{n +} ions, which undergo spontaneous hydration reactions.

Perhaps the most notable achievement of Alan was the synthesis with a high yield of molecular cells into which a metal ion was placed ^{[10] [11]} . The synthetic concept emerged from previous observations of the group related to the fact that in an alkaline aqueous solution formaldehyde is able to interact with amines coordinated with cobalt, giving in one of the cases a macrocyclic ligand in which the adjacent nitrogen atoms of two ethylenediamines are bound by bis-methylenoxy groups. An interesting reaction occurs with the slow introduction of formaldehyde and ammonia into an alkaline aqueous solution of [Co (En) ₃ ] ³⁺ . There was a high yield of [Co (sep)] ³⁺ . The polycyclic cell is called the sepulchrate (SEP). The [Co (sep)] ³⁺ cell complex is indefinitely stable in neutral aqueous solutions and in 3 M HCl. The reduced analogue [Co (sep)] ²⁺ is stable in neutral and weakly alkaline solutions; in such solutions, it is easily oxidized by oxygen to the starting complex, [Co (sep)] ³⁺ . The ion [Co (sep)] ²⁺ decomposes in acidic solutions by a mechanism that involves the protonation of apical (cap) amines. The stability of the [Co (sep)] ³⁺ complex with a higher degree of oxidation of cobalt is associated with a much lower basicity of the apical amines. Homochiral ( optically active ) cell forms [Co (sep)] ³⁺ were isolated, and it was found that, when [Co (sep)] ^{2+ was} reduced and then re-oxidized, the chirality was fully preserved. This result shows that the Co ^{2+ ion} does not exit the cell; this result was confirmed using the tag exchange method ( ⁶⁰ Co ²⁺ ). The inherent volatility with respect to acids of divalent complexes sep was bypassed by preparing [Co (sar)] ³⁺ (sar is short for sarcophagin (sarcophagine)), a similar cell complex in which the nitrogen atoms of the caps are replaced by methylene groups. This complex was obtained with a high yield in the reaction of [Co (En) ₃ ] ³⁺ with formaldehyde and nitromethane in cold alkaline aqueous solution ^[12] . In the initially formed cell complex, the apical carbon atoms of the caps are associated with nitro groups. The substitution of these groups by hydrogen atoms was achieved using standard methods of organic chemistry. As expected, the [Co (sar)] ³⁺ complex was stable in strongly acidic solutions; its other chemical properties were the same as those of the [Co (sep)] ³⁺ analogue. Several methods of removal have been developed, the most useful is the reaction of cyanide ions with the Co ²⁺ complex in boiling water. Almost all of the first transition metal ions, some in two oxidation states, were placed in the sar cell. All these complexes have demonstrated high thermodynamic and kinetic stability, and some - unusual physical properties.

Alan Sargeson will be remembered for his charm and wit. He was always accessible and as calm with others as he was with himself. He was condescending to mistakes and attentive to his staff. It should be noted that almost all his colleagues continued to cooperate with Alan personally or professionally after they moved to other places. Towards the end of his life, he became especially close to his family, in particular, his youngest daughter, Bente.

Almost everyone who was asked about Alan remembers with enthusiasm his stories on various topics, as a rule, after dinner. It seemed that there were only four stories in his repertoire that he could tell again and again. The number of stories he told at a time depended on the endurance of the audience. Not the content of the stories amused the audience, but the way he told them. The stories were characterized by the continuous laughter of Alan, who was clearly in awe of what he was going to say next, deviations that have a mysterious connection with the theme of the story, the audience’s calls for help or other investments.

Although Alan never fully recognizes this, his perception of the chemistry that he studied was a funny side. Co ³⁺ complexes are intensely stained; their color varies from purple to green and can be anything between them. He could detect a change in color during the reaction, but what he saw was different from normal vision ; who could testify, that when Alan spoke about the connection, that it was blue, in fact it was pink.

Alan knew what he was good at, and what he didn’t. He was not afraid to admit the lack of competence, and developed extensive cooperation in Australia and in other countries. Many of his colleagues remember trips to visit various experts to either clarify the interpretation, or to get advice on how to conduct an experiment. He was always meticulous in providing his colleagues with the proper understanding.

Like many scientists who have reached the peak of their professionalism, Alan expected from others that they would conduct their research with the same prudence, completeness and integrity that he imposed on himself. He was particularly dismissive of scholars, in whom he saw that they used their publications only as a method for promotion. It was his complete loyalty to the integrity of science - perhaps the defining personality trait of Alan.

Alan was organized in his scientific work, but less responsive to administrative matters. He will actually serve one term of three years as the dean (chairman) of the chemistry research school without incident. He created the impression that, although he was ready to do administrative work as a debt to his colleagues, his research took over. As a result, he was rarely asked to do routine committee work or offered to take a post that included administrative work. He was an adequate lecturer, but not one whose performances captured the audience. At the chemistry research school, research support was distributed according to past activity, and not as a result of the development of proposals that required external funding. As a result, Alan has always been well funded so that he does his job without being distracted by writing proposals and reports. In addition, he had access to generous travel expenses, which allowed him to visit other laboratories.

He retired at age 65. He said he was happy to do it, because he gave the opportunity to the “young guys” to make a name for themselves. As an honorary professor, he continued to come to the faculty and participate as much as possible in his activities. Shortly after his retirement, his health declined, slowly at first, but rather quickly in the last few years of his life. In recent years, he suffered from various diseases that made him fragile. Shortly after he celebrated Christmas at home with his family, he died.

Alan was awarded numerous honors and awards. Although he appreciated getting them, he treated them easily.

• 1975 Australian Chemical Institute for Inorganic Chemistry and Burrows Lecture
• 1978 HG Smith Medal, Royal Australian Chemical Institute
• 1980 American Chemical Society Award for Inorganic Chemistry Bailar Medal, University of Illinois, Urbana
• 1983 Nyholm Medal, The Royal Society of Chemistry, UK
• 1985 Dwyer Medal, University of New South Wales.
• 1990 Doctor of Science Honoris causa, University of Sydney
• 1992 Centenary Medal, The Royal Society of Chemistry, UK
• 1995 Rolf Sammet Award, Johann Wolfgang Goethe Universität, Frankfurt am Main
• 1996 Honoris causa, University of Copenhagen
• 1997 International Izatt-Christensen Award in Macrocyclic Chemistry, Brigham Young University of Honoris, University of Bordeaux, France
• 2000 Leighton Medal, Royal Australian Chemical Institute
• 2002 Matthew Flinders Medal, Australian Academy of Science

• 1972 Fellow of the Royal Australian Chemical Institute
• 1976 member of the Australian Academy of Sciences ^[13]
• 1976 Foreign Member of the Royal Danish Academy of Arts and Science
• 1983 member of the Royal Society of London ^[14]
• 1996 Foreign Associate National Academy of Sciences ^[15]
• 1998 Foreign Honorary Member of the American Academy of Arts and Sciences
• 2002 Member of the Royal Physiographic Society in Lund, Sweden

• Bosnich, B. (2011). “Alan McLeod Sargeson FAA. 13 October 1930 - 29 December 2008 ”. Biographical Memoirs of Fellows of the Royal Society . doi: 10.1098 / rsbm.2011.0017.
• Leonard F. Lindoy "Celebration of inorganic lives: Interview with Alan M. Sargeson" Coordination Chemistry Reviews 2005, volume 249, pp. 2731-2739. doi: 10.1016 / j.ccr.2005.04.015