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Reviews
"You are thinking in a great combination of frontier orbital – of course I like that – and chemical ways. I like it."
A personal communication from Prof. Roald Hoffmann, upon receipt of a copy of the Lewis Acid/Base Reaction Chemistry book + poster.
Prof. Hoffmann received the 1981 Nobel prize for his work on the orbital symmetry interpretation of chemical reactions
"I've never seen such a comprehensive and lucid explanation of the emergent nature of chemistry in all it's forms before... Great chemistry stuff in here!"
Stumbleupon"While the treatment of the subject of chemistry on this site has nothing to do with any [current] academic syllabus, the Chemogenesis site is nevertheless a useful tool that can help students understand reaction chemistry and its causes (and effects) in a more complete or holistic manner."
PoisonLinks"A well planned, well laid out site, which deals with chemical reactions and chemical reactivity. I found it fascinating."
PSER, Nov 2004The Chemical Thesaurus Reaction Chemistry Database
"The Chemical Thesaurus is a reaction chemistry information system that extends traditional references by providing hyperlinks between related information. This program goes a long way toward meeting its ambitious goal of creating a nonlinear reference for reaction information. With its built-in connections, organizing themes, and multiple ways to sort and view data, The Chemical Thesaurus is much greater than the sum of the data in its database. The program does an excellent job of removing the artificial barriers between different subdisciplinary areas of chemistry by presenting a unified vision of inorganic and organic reaction chemistry."
K.R. Cousins, JACS, 123, 35, pp 8645-6 (2001)"Good tutorial about chemistry."
"Excellent, just what I was looking for."
"Love chemistry so this is fantastic!"
StumbleuponThe Lewis Acid/Base Reaction Chemistry Package (book + poster + CD-ROM)
"Intriguing, stimulating and of much interest and at £30 it is an absolute bargain."
The Alchemist on ChemWeb"I do not know of any other textbook or other work in which the many different combination possibilities of Lewis acids and Lewis bases are treated so thoroughly and systematically as they are here."
Angewandte Chemie"... a broad holistic approach is used to present a very large accumulation of reductionist data and information. Details become only details, and yet precision is maintained throughout."
Chemistry & Industry"Overall, Leach's writing is crisp, and, although dense with facts and information, this book is simple enough for secondary school students."
Chemistry & Industry"...undergraduates, post graduates, teachers and professional chemists will all find much in this package to interest them."
The Alchemist on ChemWeb"This all leads me to recommend the work to anyone teaching in this area..."
Chemistry in Britain"As someone who does/did well in organic chemistry (up to stereoselectivity), it makes me sad to say that? I never really understood the fundamentals of it. As a result, everytime I did an Organic course, it felt new to me, because I would have to 'remember' how things work. You make this very simple, concise and you answer why things this works. Understanding the basics will make it very easy to come up with answers as oppose to remembering them."
"Explaining chem like a BOSS! Thank you so much!"
Reviews In Full
A well planned, well laid out site, which deals with chemical reactions and chemical reactivity. Meta-synthesis is a publishing house, which aims to produce material that deals with the 'over' or 'meta' view of science. To this end, they have published a free web book entitled: "Chemogenesis" by Mark R Leach.
Their approach to patterns in reaction chemistry aims to separate the wood from the trees; to separate the large scale structure of reaction chemistry from the details of individual chemical species, their interactions and reactions.
The site has a good introduction page that introduces how chemical structure and reactivity 'emerge from the periodic table of the elements and develop into the rich science we experience'. The site then goes on to look at the main group elemental hydrides and five hydrogen probe experiments, which feed into a page that defines congeneric series and planars. Further pages look at how to quantify congeneric behaviour and the emergence of organic chemistry. The web-book then goes on to look at five reaction chemistries, unit and compound mechanisms, STAD, mechanism matrix and so on with more pages than could be effectively described in this review. There is also an excellent chemical thesaurus page and further reading list.
The site is continuing to evolve however, in that there are several pages under construction, for example a section on Linear behaviour and Chaos in Chemistry and Controlling reactions.
Although the site content is not suitable for the majority of my access or first year students, there are occasionally diagrams that explain things so well I could easily use them on the Higher Chemistry course. For example the Segre chart is particularly good, as are the periodic tables. Any advanced students that would like to investigate reaction chemistry further should have no problems navigating this site with minimal lecturer support. The vast majority of chemistry lecturers and teachers should also find something of interest here.
According to the site, "Chemogenesis" was designed for academic chemists, teachers of chemistry and students. The material was designed to be understood by a 'first year university chemistry major, a bright and interested school student, or a scientifically literate lay person'. However, I feel that students and lay people would get more from this web-book if the language used was simpler and perhaps if the diagrams were explained further in the text. If this were altered I feel this web book would be accessible to a wider range of users, although I acknowledge that this 'dumbing down' may put off the academic chemists. Another minor criticism would be that the intro page is very bland and most students would probably be put off by the page titles. A 'map of ideas' would probably pull lay people into the text more quickly, although then I suppose it would be less of a book and more of a website.
Overall I found it to be a fascinating site though. It is possible to navigate around it quickly enough and all the pictures downloaded with minimal effort.
Elizabeth Barron, Physical Sciences Educational Reviews, vol 5, issue 2, pp2, Nov. 2004
The Lewis Acid/Base Reaction Chemistry package
As a graduate student, I was somewhat confused. My thesis was designated as being in the area of inorganic chemistry. However, when pressed to be more precise, I could never decide whether what I was doing was better described as coordination or organometallic chemistry. I was synthesising palladium and platinum compounds of sterically demanding tertiary phosphines, and then allowing, or forcing, these bound ligands to undergo cyclometallation, thereby forming direct metal-carbon bonds. That confusion of mine has been alleviated, finally, after about 15 years.
I always had a sneaky suspicion that I was entangling myself in mounds of split hair. Is the distinction between coordination and organometallic chemistry important? On an even broader canvas, should we be so over-concerned with distinguishing inorganic from organic chemistry? In the foreword to this book, it is stated: 'The division of reaction chemistry into organic and inorganic is anachronistic and confusing.' Thus, a broad holistic approach is used to present a very large accumulation of reductionist data and information. Details become only details, and yet precision is maintained throughout. For example, the hydroxide ion is always represented with the negative charge on the oxygen atom, -OH or HO-, and never on the hydrogen.
After introducing the background concepts, Leach presents his material schematically–with a visual organising system that maps chemical species and their behaviours. He begins with the premise that Lewis acids, bases and acid/base complexes are ubiquitous, occurring throughout inorganic, organic and organometallic chemistry. He has mapped all this onto a generalised interaction matrix, reproduced on a wall chart, for which this book essentially becomes a guide, or instruction manual. Lewis acids and bases are classified by their frontier molecular orbital topology and are placed in a grid, such that 24 different types of bonding interaction can be immediately recognised. For example, ionic bond formation is seen as one type of Lewis acid-base interaction. Complexation due to hydrogen bonding, van der Waals attractions, anion bridge bonding and/or molecular shape recognition do not fit within the body of the matrix, but they are included at the foot of the grid.
Overall, Leach's writing is crisp, and, although dense with facts and information, this book is simple enough for secondary school students. All terms are defined along the way, and are further delineated in an excellent glossary of terms and symbols. The book is quite comprehensive and fully referenced, with suggestions for further reading; and thus should be as useful to graduate students. The package (book and chart) also includes a CDROM containing [tutorials and chemical thesaurus] software.
Finally, this is only the first volume of a projected five-volume series called 'Patterns in reaction chemistry'. The next four will address redox chemistry, photochemistry, and radical and diradical chemistry. I am already freeing up some more wall space.
John Malito is at the department of chemistry, Cork Institute of Chemistry, Rossa Avenue, Bishopstown, Cork, Ireland.
John Malito is at the department of chemistry, Cook Institute of Chemistry, Ireland.
© Chemistry and Industry 21/8/2000
Lewis Acid/Base Reaction Chemistry is the first package in a series entitled Patterns in Reaction Chemistry. It consists of a slim paperback book, a large A1 summary colour poster, a CD-ROM containing a series of tutorials, and a reaction chemistry database. This is an ambitious project aimed at providing a uniform approach to the study of organic, inorganic and physical chemistry. Without doubt the complexity of the chemistry summarised on the poster on Lewis Acid/Base Reaction Chemistry is awesome and the author is wise to acknowledge this and assure the reader that the classifications and ideas will be covered step by step in the CD-ROM tutorials. Thus you are asked to take an hour or so at the start to work through the (introductory) tutorials.
The software, which is cross platform requiring 16MB memory, auto ran from the CD-ROM without any problems using NT and Windows 95. Selection of the Tutorials pad on the opening screen takes you to a menu offering 10 tutorials each consisting of a series of gradually progressing slides. These include an Introduction and Overview of the poster; two revision tutorials – one introduces Reaction Chemistry and the other revises electronic theory; five tutorials cover redox, photochemistry, Lewis acids and bases, radicals and diradicals; a brief explanation of the paradigm nature of these five reaction classes; and a 'clickable' matrix of the 24 types of Lewis acid-base and related interactions each leading to appropriate explanatory text. Selection of the Database tab takes you to a menu allowing access to a short overview of the database, a periodic table with elemental properties, and an extensive list of different chemical species and reactions.
The tutorial which introduces the poster consists of 76 slides. It begins with definitions of the five reaction types before focusing on Lewis acid base complexation. The four types of Lewis base and six types of Lewis acid are defined and the ways in which these can combine to form 24 types of acid-base complex are demonstrated one by one. The division of the matrix into organic, organometallic, inorganic, main group and H-redox areas, called signposting, is demonstrated before finishing with explanations of hydrogen bonding, anion bridge bonding, VDW attraction and guest/host recognition.
The 98 slide revision tutorial entitled "What is Reaction Chemistry" gives examples of chemical species (both real and genera), components of chemical reactions, reaction types/mechanisms, physical theory (classical, wave and quantum), analytical methodology and the literature.
There is a very good revision tutorial on electronic theory. It consists of 136 slides and explains Lewis octet theory, valency and balancing equations, electronegativity (including calculations of dipoles and ionic character), atomic structure, filling of shells and frontier MO's.
There is a tutorial on each of the five main reaction classes. The first, which concerns the basic process of redox reactions for both organic and inorganic reactions, is covered quite well on 55 slides. Photochemistry is likewise covered using 67 slides. As expected there is extra emphasis (114 slides) on Lewis acid/base complexation. The tutorial on radicals introduces homolysis, the singlet and triplet structures of radicals, and some examples of reactions including the chlorination of methane. In the last tutorial on diradicals, 39 slides are used to demonstrate some carbene chemistry with a mention of nitrenes and oxygen.
The possibility of paradigms across the five classes is pointed out briefly giving the basic and reducing properties of the hydride ion as an example.
The 'clickable' matrix on Lewis acid/base complexes gives the user access to explanatory text on each of the 24 combinations. The text is basically the same as that in the text book but reworded to some extent for this purpose.
The database is divided into three main parts – a list of 2000 chemical species, a list of 1500 reactions and the periodic table. The species database can be sorted into 21 fields including name, formula, reagents, reactivity types e.g. acids, bases, redox properties etc. The reactions database can be sorted into 19 fields e.g. reactants or products, bond formation possibilities, functional group modifications, mechanisms, HASAB properties etc. as well as into examples of biosynthesis. There is also a complexation field which gives several examples for each of the 28 Lewis acid/base complex types. The elements in the periodic table can also be sorted into 10 fields. These include mass number, name, m.p., b.p., radii. A complete list of isotopic abundancies is available. There is a short overview of the database which includes a chemical thesaurus and a glossary of terms.
The 96 page text book begins with acid-base theory including the Hard Soft Acid Base Principle moving on to symbiosis, congeneric series and planars. Most of the text deals with definitions and explanations of the various Lewis Acid-Base interactions etc. The text concludes with sections on multi-step reaction mechanisms, ambidentate reactivity using HOMO LUMO explanations, a glossary of terms, bibliography and further reading.
The poster is very well produced. It has good diagrams and is packed with information of the five classes of interaction, the 24 types of acid/base interactions and other types of complexation. It is a useful student's wall chart. There is a lot of small print which would make is less suitable for class room teaching.
Chemists and lecturers, whose approach to chemistry is physical and mechanistic, will find this package intriguing, stimulating and of much interest and at £30 it is an absolute bargain. Many parts of it could be pulled out to enhance current course materials. However, using it as a central theme for a teaching scheme will require much thought, planning and reorganisation of the teaching programme including how to interface it with the rest of the chemistry syllabus. Many students would find the approach quite daunting if faced with the objective to understand the full pattern of possible interactions too early and too quickly. Certainly students with find immediate use for the database information on chemical species and organic reactions and for much of the text as alternative explanations for key concepts. Ultimately, for graduates and chemists to be familiar with an overarching explanation of all types of chemical reaction must be very beneficial and undergraduates, post graduates, teachers and professional chemists will all find much in this package to interest them.
Reviewed by Prof. John C. Tebby who teaches chemistry in the Division of Natural Sciences at Staffordshire University.
© The Alchemist on Chemweb.com, 5th May 2000
"Chemistry is in crisis" screams the blurb on the back page. "Thirty pounds for 96 pages and a CD?!" screams the reviewer. But appearances can be deceptive and once the shock has died down you realise that there's more to this work than initially meets the eye. Its stated aim is to map Lewis acid-base bonding diversity and behavioural variety by means of an interaction matrix acting as a visual organising system or schema. If that all sounds a bit off-putting, rest assured that once you get the hang of what the author is aiming at, it mostly works very well.
A worthwhile and generally readable introduction leads into the grandly titled 'Lewis acid-base interaction matrix', which is in fact simply a correlation table of the interaction between six classes of Lewis acid - including onium ions, pi LUMO acids and heavy metal acids - with four types of Lewis base. This leads to 24 varieties of acid-base interaction, each of which then receives a page or two of detailed notes. The same format is used for each case - including general chemistry and a list of congeneric series - allowing comparisons to be made effectively. The final part of the book consists of a quick look at a number of associated topics.
Its brief means that a book such as this lives or dies by the quality of its layout and artwork and here this is almost universally excellent (being only rarely let down by the compact - and occasionally somewhat florid - nature of the text). The accompanying CD includes a large searchable database of reagents and reactions pertinent to the work together with a very useful reference Periodic Table and tutorials (though alas the latter appear to be only presentational in form with no capacity for answer input).
This all leads me to recommend the work to anyone teaching in this area, for the students on the other hand the price is likely to be a definite turn-off. Chemistry will continue to be in crisis until innovative and informative works such as this come at an affordable price.
Reviewed by Paul Kelly, Department of Chemistry, Loughborough University of Technology.
© Chemistry in Britain, May 2000
This multimedia teaching pack consists of a paperback text, a CD-ROM, and a poster. It begins with a roll of thunder: "Chemistry is in a crisis. Textbooks become thicker every year, but they fail to address the central problem of what chemical reactivity really means. The division of reaction chemistry into organic chemistry and inorganic chemistry is anachronistic and misleading. There is no general or coherent scheme that is suitable for describing the behavior of chemical species. Patterns in Reaction Chemistry recognizes this problem and offers solutions." The solutions referred to, which are arrived at by a "meta-analysis", are to be published as an ongoing series, of which this is the first volume. If, instead of having to work slowly and laboriously through thousands of pages (organic and inorganic), one relies on a little book in one's hand, a poster on the wall, and a CD in the disc drive, will that be sufficient? That is too good to be true; however, the author's attempted solution deserves to be discussed and its merits recognized.
Although the expression "meta-analysis" is not defined or explained, the reader soon discovers what it means: it is the long familiar heuristic approach in chemistry, which is used repeatedly in classical textbooks and by many university teachers. It means collecting together many different chemical phenomena and properties and summarizing the observations in concepts of general validity, though sometimes these are no more than rules of thumb. Some examples of such concepts are those of Lewis acids and Lewis bases, redox reactions, the HSAB principle, HOMO/LUMO interactions, the Aufbau Prinzip (which, incidentally, is repeatedly written wrongly in the CD-ROM), and many more. Of course, such ordering schemes make the classification into organic and inorganic reactions unnecessary, but in all cases we are concerned again and again with the one underlying theme of chemistry: the formation and breaking of bonds. So, is the book just a slightly different way of packaging and presenting the eternal truths of chemistry? I do not know of any other textbook or other work in which the many different combination possibilities of Lewis acids and Lewis bases are treated so thoroughly and systematically as they are here. The author considers altogether 24 reaction "types", which result from the combinations of four types of Lewis bases and six types of Lewis acids–these range from the simple reaction of a hydride ion with a proton, to the combination of Fe2+, a heavy metal Lewis acid, with the cyclopentadienyl anion, a Õ-HOMO Lewis base, to give ferrocene. This way of viewing things is very useful for the student, emphasizing common features as opposed to those that distinguish different chemical transformations. Nevertheless, I doubt whether beginners will benefit greatly from studying this learning program. Every experienced teacher knows that nothing causes more difficulty for the beginner than recognizing and applying general principles. The beginner who is in the process of learning the vocabulary of a new language clings to the new words acquired, but cannot yet speak fluently. The book Lewis Acid/Base Reaction Chemistry is a compendium of the key phrases of chemistry. One can learn the statements by rote, but one is then still a long way from a deeper understanding. Therefore the book may be of real value for students in the later stages of their degree course, who already have a reasonably broad factual knowledge, and may help them to an appreciation of more far-reaching relationships. The condensed information in the textual part can only be digested in small morsels if it is to stick in the mind, and the author appears to have realized this–what other explanation can there be for the relatively large mass of chemical facts (mainly without discussion) that are provided on the CDROM, partly in the form of data banks of reactions and compounds. This is followed in the poster by a final compressed form of the knowledge; it is more suitable for recapitulation and revising for examinations, rather than for conveying a deeper understanding.
However, transmitting knowledge in a highly concentrated form such as this takes no account of an experience that is familiar to both students and teachers: namely that learning is a slow process and takes time. This fact is better recognized in a book than in the inevitably faster method of study using electronic media. For example, whereas one can mouse-click through the 76 diagrams of Tutorial 1 on the CD-ROM in quite a short time, during the (slow) process of reading the same information in a book one would learn and understand more. Notwithstanding that, for revision (examination preparation) this form of presentation has some clear advantages over the printed text.
On the whole this is an imaginative addition to the textbook literature, and we can look forward with keen anticipation to the volumes that will follow.
Henning Hopf, Institut fur Organische Chemie, Technische Universitat Braunschweig (Germany)
© Angewandte Chemie International Edition
2957-2958, 2000, 39, No. 16
The Chemical Thesaurus v2The question I am wrestling with in reviewing this software is: what is it for? Its title, "Chemical Thesaurus 2" suggests a systemised treasury of chemical information, a title it lives up to. But who is it aimed at and for what purpose?
The press release suggests that the target audience includes chemistry undergraduates, postgraduates and HE teachers and implies that it aims to supersede reaction textbooks. In my view it succeeds in part in fulfilling these aims.
Chemical Thesaurus 2 is a database of reaction chemistry including 2600 reactions, along with other data. It is a self-contained product, powered by FileMakerPro, and ran at a satisfactory speed on my iBook direct from the CDROM with no crashes. The CDROM is accompanied by negligible documentation, but following the Overview's advice to "just click around" I was soon able to get a good feel for the package.
The user interface feels like a web page with 12 buttons on the main index screen. The biggest and most significant buttons allow one to browse or search the chemical species and reactions contained in the database. The search options operate by the selection of various prescribed options (e.g. by element or class of reaction) without the user inputting text or structures, this system works well but was occasionally rather slow.
The data one retrieves is generally presented graphically with some supporting text but without references to the literature. Reaction mechanisms are discussed, using curly arrows or molecular orbitals in some cases. So, for example, a species search for boron gives 48 boron containing species which may be re-ordered by various criteria, a further click on triethylborane takes one to a screen describing the reagent as "real, long lived, electronically neutral", with a curly arrow scheme displaying its action as a Lewis acid, some physical data and a link to the reactions featuring it in the database (one in this case, its synthesis from borane and ethene). Similarly a reaction search of the pericyclic reaction category provides links to 7 classes of reaction and selecting the Claisen rearrangement provides two examples and a brief mechanistic description. The species and reactions may also be browsed with the former ordered by name and with the option to order the latter by substrate, reagent, or products (as warned re-ordering is slow).
The smaller buttons on the main index screen allow one to navigate around the database using other criteria: through an attractive "Lewis acid/base interaction matrix" that depicts the HOMO - LUMO interactions; or using a periodic table, which also provides information and data on the elements. The other smaller buttons provide congeneric series, a glossary of terms, and a user definable aromatic substitution reaction predictor (though limited and without rationales).
The data entry and editing facility was not active on the review copy I received. Overall I enjoyed clicking around this database and found it easy to use. But I am still vexed by the question of what it is for. It certainly is not where I would search for a reaction I wished to perform as no literature references are provided and there are better and much more comprehensive on-line databases to which I would turn, thus I consider its research applications to be limited. It seems to me to be comparable with an introductory undergraduate textbook, though with less actual text. The abilities to browse, search and interconnect in a non-linear manner are the great strengths of Chemical Thesaurus 2, as is its portability; these facilities may prove to be useful to HE teachers and students. To chemistry students (undergraduate and postgraduate) I would recommend Chemical Thesaurus 2 only as a (useful, user-friendly, affordable and possibly unique) supplement to one of the standard textbooks. HE teachers are also likely to enjoy browsing around this database and may find its approach to ordering material useful and challenging.
Mathew Fletcher University of Wales, Bangor. Physical Science Educational Reviews, Nov. 2001.