Vital Statistics

Design and Analysis in ChemicalResearch. Edited by Roy L. Tranter.Sheffield Academic Press, Sheffield2000. xviii�558 pp., hardcover£ 95.00.ÐISBN 1-85075-994-4

It can be said right at the start that thisbook is a pleasure to read. Instead of aformal and dry description of the funda-mentals, variants, and applications ofstatistical methods, the emphasis here ison ªstatistical thinkingº. In fact, that isthe subject of Chapter 1, which attemptsto answer questions of the ªwhat shouldI do when ...?º kind that are commonlyasked by beginners in statistics or bythose with no relevant knowledge at all.Statistics is the application of a widevariety of methods to tasks such asplanning experiments, analyzing data,and establishing quantitative models.Statistical thinking, on the other hand,is much more than that: it includes notonly the methods but, most importantly,the thought processes whereby we de-velop an understanding of a problem,and decide which approach to adopt andwhich method to use for analyzing theresulting data. It includes a recognitionof the capabilities and limitations of thevarious methods, and rests on the gen-eral philosophy of analyzing and inter-preting data in the most effective way.

This introduction is followed by chap-ters dealing with the collection anddescription of data, the selection ofsamples and of data, and the interpreta-tion of experimental results based onstatistical criteria, although still withoutusing mathematical models. The section

on robust nonparametric methods dis-cusses error distributions, spread of data,and variance. Two chapters are thendevoted to the statistical planning ofexperiments, which is important forensuring that the analysis of the datayields meaningful information. Theseare followed by a chapter on the analysisof variance. The section on optimizationand control is mainly concerned withgraphical methods. There is then a largesection on model development, which issubdivided into chapters on cluster anal-ysis and pattern recognition, linear re-gression, and regression methods withlatent variables (PCA, PCR, and PLSmethods, etc.). The last chapter, onprocessing and transforming experimen-tal data, seems rather unconnected withthe rest.

The book leads the reader gently bythe hand. Each chapter begins with atable listing important terms, with refer-ences to the relevant subsections. Thisexcellent aid makes the book very clearand easy to use. The many carefullychosen examples illustrate the versatilityof the individual methods. The text isenlivened by pithy phrases which guidethe user onto the right path. For exam-ple, on the ªoutlierº problem we read:ªA [data] point is never to be excludedon statistical grounds onlyº, or onANOVA (analysis of variance) tables:ªMuch of this table can and should beignored.º A remarkable wealth of sub-ject matter is presented and discussed.Naturally one should not expect individ-ual methods to be treated in great depthhere, and therefore a more or less de-tailed list of references to specializedliterature is provided at the end of eachchapter, in some cases arranged undersubject headings, sometimes also num-bered and referred to in the text.

Mistakes in the text are rare. Forexample, on page 422 there is a cross-reference to ªSection 11.4.3º, which doesnot exist. Unfortunately Section 10.6.5contains a statement that is completely

wrong; the purpose of transforming bio-logical data to a logarithmic scale is notto obtain a normal distribution curve,but to make the experimental errorsconform approximately to a normaldistribution (as correctly pointed out atthe top of page 436). Also, regrettably,the subject index contains many faults,with keywords missing or in the wrongplace. The authors have listed theirkeywords under general subject head-ings, and unfortunately these packageshave not been subsequently brokendown further. Thus, for example, thesubject ªD-optimal designº cannot befound under either D or O, but insteadunder ªExperimental designº and ªRe-sponse surface modellingº, which are therelevant chapter headings. UnderªNoiseº one finds 29 different pageslisted, which is not very helpful. Theacronym ANOVA (analysis of variance,a commonly used method) appears fre-quently in the book, but is not in theindex. It first appears on page 58, with-out explaining the acronym, and againlater on page 175; that explanation isonly to be found on page 142. There is nosuch explanation in Chapter 8 (pages 279ff.), which is entirely devoted to varianceanalysis and where the term ANOVAappears often. All these are typicalweaknesses of a multiauthor work inwhich the editor has not ensured thenecessary consistency.

Despite that, the book is enthusiasti-cally recommended for all analysts,planners of experiments, and buddingstatisticians. Also chemists, physicists,biologists, and other interested scientistsshould find the contents useful. Powerfulsuites of statistical programs are nowavailable for non-statisticians to apply totheir experimental planning and dataanalysis, and this book is a unique sourceof help in such work. To read andunderstand the discussions about thebreadth of application of the methodsand their limitations will in itself be animportant and valuable experience. The

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This section contains book reviews and a list ofnew books received by the editor. Book reviewsare written by invitation from the editor. Sug-gestions for books to be reviewed and for bookreviewers are welcome. Publishers should sendbrochures or (better) books to the RedaktionAngewandte Chemie, Postfach 10 1161, 69451Weinheim, Germany. The editor reserves theright of selecting which books will be reviewed.Uninvited books not chosen for reviews will notbe returned.

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editor�s recommendation that oneshould become competent in the use ofjust a few of the methods, rather thantrying to cover all the many variants, issensible. This book will not make thereader into a statistician, but will givehim or her the knowledge to use themethods effectively. Statistical thinkingand action, initially in planning experi-ments and later in analyzing the data anddeveloping models, will enable one toreduce the number of experiments need-ed, while at the same time improving thequality and reliability of the results. Thatis the purpose for which the book waswritten, and it achieves it fully.

Hugo KubinyiBASF AG

Ludwigshafen (Germany)

Chemical Topology. Applicationsand Techniques. (MathematicalChemistry Series, Vol. 6.) Editedby Daniel Bonchev and Dennis H.Rouvray. Gordon and Breach Sci-ence Publishers, Amsterdam 2000.350 pp., hardcover $ 125.00.ÐISBN90-5699-240-6

Chemists are usually reluctant to learnabstract new mathematics, or in extremecases, any mathematics at all, and thetheories of knots, links, and non-Eucli-dean geometry as featured in ChemicalTopology may seem far from the realitiesof the laboratory. Nevertheless, familiar-ity with the Lewis Carroll world offlypes, writhes, tangles, and reticulationsmay soon be a required skill for theresearcher in supramolecular, solid-state, or biological chemistry. As thereview articles in this collection argue,the mathematical objects of topologyhave a surprisingly close correspondenceto molecules and materials of currentinterest such as catenanes, artificial andnatural DNA, zeolites, liquid crystals,and the new forms of carbon.

The latest in a series devoted tomathematical chemistry, and the secondon chemical topology itself, this volumespans a variety of topics and approaches,from an austere discussion of topologicalchirality (Cerf), a beautifully illustrated150-page survey of ªhyperbolic crystal-lographyº (Hyde and Ramsden), a more

specialized treatment of the connectionsbetween symmetry groups, knots, andDNA topologies (Qiu), a review oftopological and physical aspects of pro-tein folding (Bohr and Bohr), to amodeling study of topological coding ofpolymer and protein structure (Karasevet al.). Overlaps between the articles dooccur but they are mostly helpful. Math-ematical prerequisites vary, but on thewhole the authors begin at the beginningand make appropriately extensive use ofillustration to introduce the more trickyconcepts.

Although this volume contains a hugeamount of specific information, its last-ing value probably lies more in theconvincing case that it makes for theoverall relevance of topology to struc-ture and dynamics in chemistry andbiology. This is good for topology aswell as for chemistry; given the incentiveof applicability, chemists and biologistsmay soon be making the sort of contri-bution to this area of mathematics thatchemists and physicists of the last cen-tury made to group theory and graphtheory. Professional topologists watchout!

Patrick FowlerSchool of Chemistry

University of Exeter (Great Britain)

Stereoselective Biocatalysis. Editedby Ramesh N. Patel. Marcel Dekker,New York 1999. xiii�932 pp.,hardcover $ 250.00.ÐISBN 0-8247-8282-8

To be very straightforward: this is nota book that would immediately qualifyfor the category ªlove at first sightº. Thereader has to be very active, take notes,work through the material, flip the pagesback and forth, in order to see thebenefits of digging through 900 pages.Stereoselective Biocatalysis does not set

out to be a text-book or dictionaryon the topic; it isless structured asto the chemistry atwhich the enzymesare targeted. Oneshould understandthe book more as areference for bio-

catalysis, in which experts in the fieldshare their views with the readers.

It is the need for small chiral mole-cules in a wide range of industrialapplications that drives the search fornew chemistry to reach such targets. Theorganic branch of that discipline hasbeen one of the most successful develop-ments in the last 150 years, and it hascome up with brilliant solutions to theproblem of making chemical entities atwill. In parallel with synthetic chemistry(often referred to as ªclassicalº), biocat-alytic transformations have been devel-oped since the beginning of the lastcentury. However, it has taken almost ahundred years to write concise accountsof that topic of a standard equal to thatexisting for organic transformations.

The 30 main chapters are equallybalanced between enzyme classes andcompound classes, with a short appendixof two chapters on enzyme technology(immobilization and new reaction me-dia). The enzymes discussed here spanalmost all technically interesting classesof biocatalysts: a) hydrolytic enzymescleaving the C ± heteroatom bond toarrive at asymmetric compounds byresolving racemic mixtures; b) the for-mation of C ± O bonds by mono- anddioxygenases and Baeyer ± Villiger oxi-dations for the synthesis of chiral diols,epoxides, and esters. Chapters on aldo-lases and hydroxynitrile lyases coverC ± C bond forming reactions.

Those chapters focusing on targetcompounds place more emphasis onthe specific generation of functionalgroups in different chemical contexts.Central themes are the generation ofenantiopure building blocks for drugsynthesis, enzyme-mediated protectinggroup techniques, the synthesis of b-hydroxy acids and steroids, and terpenefunctionalization, to mention just a few.

It might be perceived as a drawbackthat some topics appear scatteredthroughout the book, with similar targetsor enzymes being mentioned by severalauthors in their individual contributions.However, if one takes time to go throughthese different presentations, the advan-tages of having the topic illuminatedfrom several angles become clear, as thereader gains a more ªintegratedº view ofthe subject.

It might be a very personal view thatlipases and esterases, although industri-

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ally very important, seem overempha-sized here, with the theme of chiralresolution almost beaten to death,whereas glycosidases, glycosyl transfer-ases, and phosphatases (to name just afew) could have received more atten-tion. The chapter on yeast appearsunexpectedly out of the blue; it seemsanomalous since it could qualify as anaccount of the topic by itself. It is a bit ofa drawback that the contributions on thelarger scale applications are limited, andthe main focus is on academic examples.Therefore, it could be a good idea to fillthis need by a second volume on techni-cal enzymatic transformations.

Much of the material presented herehas been reviewed earlier; however,having it here in one book with a moreor less consistent layout has its advan-tages. It can serve as one referencesource for the organic chemist in indus-try or academia who wants to make useof enantioselective reaction steps or whoseeks a cheap and ªgreenº synthetic step.This book is a welcome addition to thelibrary of anyone who is working in thefield or wishes to take an in-depth lookat the very exciting new developments inthis area.

Werner KlaffkeOrganisch-Chemisches Institut

Universität Münster (Germany)

Semiconducting Polymers. Chemis-try, Physics and Engineering. Editedby Georges Hadziioannou andPaul F. van Hutten. WILEY-VCH,Weinheim 2000. xxvi� 631 pp.,hardcover DM 398.00.ÐISBN3-527-29507-0

The rapidly developing field of semi-conducting polymers is attracting theinterest of increasing numbers of physics,chemistry, and engineering researchgroups. Many postgraduate students arelooking for a good book that can providea quick and comprehensive introductionto the fundamentals of the subject, tohelp them begin research in this area.Such a book has now at last appeared.The 16 chapters of Semiconducting Poly-mers, edited by Georges Hadziioannouand Paul van Hutten, cover all theimportant aspects of the technology ofthis new class of materials. All the

chapters have been written by well-recognized experts in their special areas,so that the list of authors reads like aªWho�s Whoº of the work groups thatare active in the field.

The book treats the important classesof semiconducting polymers, namely thepolyphenylenevinylenes, the polyphenyl-enes, their heteroatom analogues, andpolyacetylene. Chapters 1, 2, and 16cover the synthesis of the materials,excluding that of polyacetylene. Chap-ters 3 and 4 are devoted to the theory ofconjugated polymers; of these Chapter3, by J. Knoester and M. Mostovny,concentrates particularly on the solitonmodel for trans-polyacetylene. Nextcomes a chapter by M. Lögdlund andW. Salaneck on the electronic structuresat metal ± polymer interfaces. The fol-lowing four chapters (Chaps. 6 ± 9) areconcerned with spectroscopic details andthe related photophysics. Chapter 12discusses charge transport in conjugatedpolymers. The rest of the chapters de-scribe the many different applications ofsemiconducting polymers: organic light-emitting diodes (Chaps. 11 and 13),optically pumped polymer lasers (Chap.10, by U. Lemmer et al.), organic field-effect transistors (Chap. 14, by G. Horo-witz), and solar cells (Chap. 15, by C.Brabec and S. Sariciftci).

The book provides an excellent intro-duction to conjugated polymers and anextremely useful compilation of the sortof data that one is often looking for,although these tend to be somewhathidden in some cases. Examples of thistendency include the table of structuralformulas in Chapter 13 (J. C. Scott andG. Malliaras), which also contains somesmall-molecule compounds, and the sur-vey in Chapter 11 (I. H. Campbell andD. L. Smith) of the types of metalelectrodes used. Commonly used exper-imental techniques, such as photoelec-tron spectroscopy, arrangements for la-ser spectroscopy, and time-of-flightmeasurements, are described in shortintroductions within the individual chap-ters. Also, Chapter 14 contains an ex-cellent and easily readable introductionto the theory of field-effect transistors.

In their preface the editors explainthat they asked the authors to write onlywhat they felt certain about, and to omitresults that still belonged to the realm ofspeculation. It is pleasing to find that,

thanks to that policy, the book is not justa collection of specialist articles but hasalmost the character of a monograph.However, one�s pleasure is slightly di-minished on noting that there has evi-dently been no proper coordinationbetween the individual contributions.There is much redundant material, andoften topics are touched on and ex-plained only briefly, whereas elsewherein the book they are treated in muchmore detail. For example, the charge-transport mechanism in organic semi-conductors is discussed in detail by H.Bässler in Chapter 12, but is thenexplained again in Chapter 14. Or again,the field-effect transistor is described inChapter 1, whereas all that was neededwas a cross-reference to Chapter 14.Although this redundancy means thatthe individual chapters can be readindependently without difficulty, the ab-sence of any interconnections betweenthe chapters becomes very obvious. Alittle coordination work by the editorswould have greatly improved the clarityof the book and reduced the number ofpages. That would perhaps have pre-vented situations such as the presenta-tion and discussion of exactly the samefigure (!) in two different places (Figs.8 ± 5 and 9 ± 11). Another source oftrouble for the user is that the indexhas not been carefully checked, with theresult that an index entry often fails tolist all the relevant text pages. Althoughit is praiseworthy to have provided asubject index, there is a duty to ensurethat it is usable.

Despite this shortcoming with regardto the guidance of the user, the book iswell on the way to becoming a standardwork for everyone active in this field.Chemists using this book will probablyhave a formidable task in understandingthe physical chapters, and physicists willhave trouble with the chemical parts, butnevertheless this work has significantlyreduced the gulf between the two dis-ciplines. Therefore I can recommend thebook, although I fear that the price ofalmost DM 400 may be an obstacle to itsreaching its proper place, namely on thebookshelves of postgraduate students.

Thomas FuhrmannFachgebiet Elektrochemie undOptoelektronische Materialien

Universität Duisburg (Germany)

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Solid-Phase Synthesis. A PracticalGuide. Edited by Steven A. Katesand Fernando Albericio. MarcelDekker, New York 2000. 848 pp.,hardcover $ 250.00.ÐISBN 0-8247-0359-6

In accordance with the authors� scien-tific background, this book is mainlyconcerned with individual disciplines inthe area of the solid-phase chemistry of

peptides. Readerswho, on the basisof the title, expectto find in it also adetailed treatmentof ªclassicalº or-ganic chemistry inthe solid phasewill unfortunatelybe disappointed,as that complexof topics receivesonly marginal at-

tention. Regrettably, therefore, the titleis misleading to that extent. Neverthe-less, everyone involved in work on thesynthesis of peptides, peptide mimetics,etc., will find here a comprehensivereference source, spanning the rangefrom R. B. Merrifield�s ground-breakingsolid-phase synthesis of peptides to thelatest advances in this broad field.

The various aspects of the subject arecovered in 20 chapters, but the editorshave not entirely succeeded in arrangingthe material in an orderly way. Also, asthe chapters have all been written bydifferent authors with different stylesand layouts, the book has the disadvan-tage of not presenting a consistent ap-pearance, and this may displease readerswho are concerned with more than theactual content. Furthermore, it wouldhave been helpful to provide a glossaryof abbreviations, especially as there areso many in this area of chemistry.

Chapter 1 deals with solid supports(resins), and even includes laboratoryprocedures for preparing various typesof polymeric supports, such as thosebased on polystyrene or polyacrylamide.I read this chapter with interest, butnevertheless I intend to continue usingonly commercially available resins, asthe range of these with a wide choice ofsubstituents has improved greatly in thelast few years, so that it is now hardlyever necessary to consider preparingone�s own.

Building on the above foundation, thefollowing chapters deal with the varioustools of solid-phase synthesis in detail,including linkers (Chap. 5), couplingreagents (Chap. 6), and protecting groupstrategies (Chaps. 2, 3, and 4). In theUSA the Boc strategy is still preferredover the Fmoc strategy, so it comes as nosurprise to European readers that theformer receives so much attention in thisbook. The extensive lists of literaturereferences in these chapters, as also inthe later ones, are as detailed andcomprehensive as one could wish.

Advances in the capabilities of solid-phase synthesis for peptides haveopened up possibilities for more com-plex synthetic strategies. Therefore sev-eral chapters are devoted to syntheses ofother structures derived from peptides,including cyclopeptides (Chaps. 7 and 8),and pseudopeptides or peptide mimetics(Chap. 16). Compared with normal lin-ear peptides, these structures offer im-proved pharmacokinetic properties, andtherefore are of great interest for phar-maceutical chemistry. Another chapter(Chap. 10) is devoted to phospho- andsulfopeptides.

The two-stage process in peptidechemistry (detachment of protectinggroups followed by a coupling reaction)is gaining ground, and can be used forefficient syntheses of peptides with up to

30 amino acids. If one wishes to gobeyond that, then, as in natural productsynthesis, the fragment synthesis methodcan be effective. Chapter 9 discusses theprinciples of such syntheses in detail, andillustrates the strategy by discussingthree representative highlights from theliterature.

Chapters 11 ± 13 review in turn devel-opments in the synthesis of oligonucleo-tides, oligonucleotide ± peptide conju-gates, and peptide nucleic acids (PNAs),which are the analogues of (deoxy)-ribonucleic acids.

Chapter 14 contains an excellent re-view of the third main group of biopoly-mers, the oligosaccharides. As well asgiving a general overview of the topic,the authors discuss in detail the keyresearch projects of the last five years,which will very probably form the basisfor new syntheses now being planned.

Chapter 15 is concerned with thesolid-phase synthesis of heterocyclesstarting from amino acids and linearpeptides. Considering the peptide back-ground of the authors of this book, onecan easily guess the origin of the exam-ples chosen. However, in view of themany solid-phase heterocyclic synthesesthat have been published in the last tenyears, the choice of material seemsrather arbitrary, and thus hardly servesto cover this broad field of research.

The book is completed by a look atprogress in the automation of solid-phase syntheses, which includes a list ofcommercially available automated sys-tems (Chap. 17), and by Chapters 18 ± 20,which deal with the purification andanalysis of peptides.

Wolfgang K. StähleMerck KGaA

Darmstadt (Germany)