cilitates the construction of actual three-dimensional models of complex structures. Any structure can he converted to a erauhic reoresentation of a suace-filling h atomic radius and the color mobel. ~ 0 t the in a hich aMma are plutted on thewreen are determined by the typeot atam indicated hy the label given to that atom a t the time the coordinates are entered. Up t o 20 different data files can be drawn on the screen simultaneously, and the most recently added structure can be manipulated independently of the previously added ones. This permits a "docking" function, where, for example, a substrate can be moved into position a t the active site of an enzyme. While manipulating structures, users can simultaneously monitor the interatomic distances between as many as three pairs of atoms. The stereochemistry of a molecule on disolav also can he inverted. When comhinedkith the ability of the program tomanipulatr two structures indeprndently, it hecmws possiblp t,, draw a molecule next to its mirror image and test for superimposahility and therefore chirality. Color can he used t o denote either depth from the viewer or atom type. Although valuable, this feature is fundamentallv,limited bv the choice of onlv three foreground cdc,rs'in HASICA. C& is put to wry nod use by one ieature u hich pluts m e structure (rotated by 5 degrees about the yaxis) on top of a second. If the first is plotted in red, and the second in green, the use of red-green glasses converts the image into a three-dimensional representation of the molecule. In practice, this feature is disappointing with a medium resolution screen. The manual suggests much better images will be obtained with a high resolution (RGB) monitor. Without access to such a monitor, I was unable t o verify this statement. Printer listings of coordinates, connectivities, and interatomic distances are readily available. A screen dump of the graphics image also can be obtained on a graphics printer, provided the user has the necessary utility software (GRAPHICS.COM in DOS 2.10). ~
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Student Reactlon This program was used as an option for several first-year general chemistry students and for aspecific assignment withsecond-year organic chemistry students. It was used both on IBM PC and PCjr microcomputers. I found it necessary to prepare a supplemental sheet giving several examples t o help the organic students perform superimpasability studies on simple chiral molecules. Students generally did not feel a pragram such as this could replace molecular models, but they thought i t would augment their use, and might actually assist them in makine models of comolex structures from X-my crystal darn R'ithuut rxception, btur l ~ n t s~njm.rdthe pnl,gram, and were reasonshly n ~ n v m a n w t t h the main menu options in one to twa hours. They particularly appreciated the dynamic motion and spacefilling model features of the program. SeverA88
Journal
of Chemical Education
al students criticized the organization of material in the manual that accompanies the program. Students also suggested adding several examples of the manipulation of molecules, particularly relating to the inversion, orientation, and superimposability features of the program t o help them become familiar with the available options. Overall Assessment Molecular Grauhics is one of the first versatile entries into the aoolicetion of microcomputer graphics ior purpose, of risualiz. ing three-dimensional structure. The pn,gram is innovative and offers a considerable range of options once the Cartesian coordinates have been generated for a structure. I believe that the program may even have applications to nonchemical systems, allowing data which can he entered in the form of Cartesian coordinates to be readily visualized and manipulated in space. The limitation of three foreground colors will be restrictive for many applications. Furthermore, unless a user has access to a color graphin printer, most vivid three-dimensional images will he left in the mind of the viewer. Molecular Graphics will probably prove most useful t o students in organic and biochemistry courses. Some obvious educational applications are for the visualization of crystal structure data for large molecules, where building a molecular model would be tedious, examination of structnre-reactivity relationshins in biaoreanic chemistrv. .. and carrying o;t superimp&ahility studies. Given the great deal of attention paid t o the development and refinement of the pmgram, i t is disappointing that a similar effort was not paid to the accompanying manual. I t was originally well conceived, but when the program was revised and enhanced, the changes in documentation simply were added to the end of the manual that had already been published. This leads to considerable confusion for first time users who must often go to a t least two places to find information on a single feature. For a t least one feature (three-dimensional representation using redlgreen structures), important information is contained in the original reference and then not repeated in the new section that describes that option. Clarity in documentation is particularly important if the program is t o be used successfully in introductory and lower level courses. Peter G. Mahaffy The King's College 10766-97th Street Edmonton. Alberta, Canada TSH ZM1 ~~~~~
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Molecular Animator, IBM PC Verslon J. Jeffrey Howbert, COMPress, A Division of Wadsworth. Inc. P.O. Box 102, Wentworth, NH 03282 Hardware: IBM PC Components: 1 disk with backup, User's Manual Level and Sublect: Any chemistry course in which molecular structure is discussed. cost: $95.00
Review I The Molecular Animator is s modeline prugram that alloxs thr user to display and umitrurt ball-and-stir< mudels uf organlc and inorganic molecules. Thi, sotruarc package provides a unique opportunity for teacher and student alike to explore graphically a variety of geometric forms associated with molecular structure. Primarily intended for students with some exposure in the fundamentals of chemical hondine. this m o gram raanexcelltnt vehicle i n \\ hich to view the depth in all threp dimensions, ln a convmring fashion,oisurh nvtaolrs as thechair and boat conformations of cyclohexane, the planarity of aromatics like hennent. ur the octahedral arrangcrnrnr of driulfurdccafluoride. 1 found m e o i its attributrs to he the mare than 20 typical molecular structures. ~. includine those listed above. that can be displayd in front of n large lrrture revtion on aaorren thruughaprqection dpwrc. This latter vharacrerisr~cha\ many advantages over the omnipresent overheadprojector with two-dimensional transparencies, or attempts, futile as they are, to build a model of a molecule from a kit large enough to be seen well by all in the class, or worse yet, the practice still common with t h e artists among us t o draw structures on the chalkboard, a practice that baffles our colleagues in business and industry. While one molecule is displayed on the screen, or monitor, the user can manipulate, by a single stroke of the function keys, the structure to rotate about its center of mass in either direction along an x,y, or z axis, a t slow or fast speeds. It can also be made to stop in any position, he enlarged, or reduced in size, and, as a ball-and-stick model, it can be displayed or rotated as just a stick (wire frame) or as just atoms in the full model. Students in my second-semester General Chemistry class used the program individually and found it to be far more helpful in understanding the full picture of molecular geometry thanjust relying on textbook illustrations and one's imagination. Though I did not have such a class a t the time, I believe from past experience that introductory organic chemistry students would benefit greatly not only from the ready display models, hut also from the flexibility to construct their own models from the various editors and menus that are accessed easily, and from the ample instructions given in the User's Manual. Their newly constructed models can then be saved and stored on a second formatted disk. Most of my students seemed to feel a t ease with the utilization of the main menu and the displaying of the stored figures from the files, but they were more tentative about the construction of models. They seemed also to marvel a t their ability to manipulate the rotation, size, and direction in which the structure moved by use of the function keys. Yet I also detected that they tended totire after an hour or so of working with the shapes stored on the main disk, which is why, I believe, their overall evaluation tended toward good rather than excellent. But this is not unusual for any chemistry student today considering that most of them are not chemistry majors and view the subject matter with some amount of reproach and scepticism as to its reievance for their chosen vocations. Because of its ease of use and pedagogical value, the Molecular animator ranks as a significant
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This monograph brings together new findines and innovative oraoosals in the user. If i t were written far the structural novice. then there is not enoueh " information in the oroeram tomakeiteasv to usennd the ~~-~ process of molecule construction is complicated. If it is for the professional chemist, then the program is too limited. The design doesnot seem to satisfy the requirements of either group, and the intellectual rewards of the program are limited in comparison t o the effort required for its use. Buildingplastic models is easier and as informative. This progrom would hrncfit greatly through rhr enhanced nuw of color, a ~ c e s d , l e~ ~ P C I I I R I infwnarron, nnd a discussion of inorgnnlr applications in the text as well as more examples of structures in the program. An interesting addition would be t o include VSEPR theory by having the user input data about atom types, bonding pairs, lone oairs. and have the oroeram .. draw the moleh , drfine nand angles. and animate it for the user. There rnhancemtnL~would provirk n more u~efuland complete package. Richard E. Palmer Department of Genetics University of Wisconsin Madison. Wi 53706
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E~IIOT'S Note: The Apple I1 family version of this SOnWare was reviewed in the November 1987 issue of this Journal.
Titles of Interest -1986-
Metal Complexes in Solution Everen A. Jenne and Enrio Rizzarelli, et al., Editors. Piccin Nuova Libraria, Padova, Italy, 1986.viii 317 pp. Figs. and tables. 17.2 X 24 cm. 540.00.
ing author presents the general principles behind a specific chemical process, then explores the results and implications of recent &arch. Interactions a& explained from a mechanistic and dynamic point of view rather than a descriptive one.
Catalyst Design: Progress and Perspectives L. Louis Hegedus, Editor. Wiley: New York. NY. 1987. xi 288 pp. Figs. and tables. 15.4 X 23.6 cm. $47.50.
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Contemporary Themes in Biochemistry. Volume Vi, ICSU Short Reports 0.L. Kon, M. C.-M. Chung, et aL, Editors. Cambridge University: New York, NY. 1987. xxxvii 715 pp. Figs. and tables. 15.8 X 23.6 cm. $49.50.
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Binding Constants: The Measurement of Molecular Complex Stability Kenneth A. Connors. Wiley: New York, NY, 1987.xiv 411 pp. Figs. and tables. 15.9X 23.5 cm. $69.95.
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This volume describes methods for the measurement of bindine" constants for comd e x formation in solution-alone with discuaiionr of prrtinrnt thermodynnmici. modeling stntirtics, and regression analyiii. I t also covers all of the experimental methods useful far measuring these equilibrium constants. An attempt is made toward a systematic compilation of information on binding constants from the literature of studies as diverse as acid-base chemistrv. . . metal ion coordinoriun compound^, hydrogpn bunding. chnrgr transfer complrxation, nydrophnhw intrmction,and protrm binding. Nen marrrial introduced here includes more modern approaches to random association (contact complexes), methods of selection of standard sites, and com~arisonof results. The treatment of nonlinear least squares regression is more detailed than usual.
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Proceedings of the 4th Federation of Asian and Oceanian Biochemists Congress, Novemher 30-December 5,1986.
Diagnostic Enzymology David Hawcroff Arthur M. James. Editor. Wiley: New York, NY, 1987.xxi 280 pp. Figs. and tables. 15.1 X 22.8cm. $21.95.
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This book, another in the ACOL series, describes the nature of enzymes, the techniqars usrd tor measuring en7yme a r t ~ \ i t y and the problems assuriated with obtaining rroroducihle and mranineiul results. The final section discusses the importance of enzyme assays in the diagnosis of human illness and the monitoring of treatment and recovery to put the methods and interpretation previously described into context. References are included so that the basic introduction supplied here can he extended by those interested in reading further.
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Proceedings of the International School in Metal Complexes in Solution held a t Portieello, Palermo, Italy, October 3-8,1983.
Carbohydrates P. M. Collins, Editor. Chapman and Hall: New York. NY. 1987.xi 720 pp. 21.4 X 28.2 cm. 5175.00.
Handbook of Separation Process Technology Ronald Rousseau, Editor. Wiley: New York. NY. 1987.xiv 1010 pp. Figs. and tables. 16.6 X 24 cm. $69.95.
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Applied Geothermics Michael J. Economides and Plene 0.UR gemach, Editors. Wiley: New York. NY, 1987. xiii 238 pp. Figs. 17 X 25 cm. $69.95.
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The aim of the editors of this hook is to provide a state-of-the-art report of current research in geothermal energy.
Aquatic Surface Chemistry: Chemical Processes at the Particle-Water Interface Werner Stumm. Editor. Wilev: New York. NY. 1987.xix 520 pp. ~ i & . and tables. 16.8 X 24.3 cm. $69.95.
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A90
Journal
of Chemical Education
This latest volume in the series Chapman and Hall Chemistry Soumebooks, the aim of which is t o provide carefully tailored information to individual workers in particular arens of rherniirr) and biorhemicrry. The ~ n f ~ r n a a t iinmrhiq vulumr is parrialI S ~ C I I V from P ~ the Fitlh Icditiun ofthe TJlrtionary of Organic Compounds, published in 1982, and its annual supplements. Each individual entry has been reviewed and updated and a large number of totally new entries have been added. In addition, many hundreds ofadditionel synonyms and derivative molecular formulas have been added to the existing entries, thus enhancing the utility of the Name and Molecular Formula Indexes.
High Performance Liquid Chromatography in Enzymatic Analysis EdwardF. Rossomando. Wiley: New York, NY. 1987.xv 253 pp. Figs. and tables. 15.7 X 23.5 cm. $39.95.
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This small book describes the HPLC method and explains and illustrates its use. Eachchapter deals withadifferent aspect of the method, beginning with an overview and ending with a detailed summary. Throughout, an attempt is made to focus on questions related to the assay of the activity of an enzyme rather than its purification.
