1.
Entry a£ target molecule
ruse=
inputs underscored):
,
Total number of carbons 5 NYmber Carbons main Main FPI list ~0001111200000 > 2 FPI 00 side sbt U 8 M e d to 2 CX Ring CX Ring CX ) tw>
:
2.
computer m t w r
,)z
£01checking:
TARDET 1 20 1 3.
2 00 3
3 11 3
4 11 2
5 20 2
6 00 2
7 00 2
8 00 1
(carbons numbers1 (FPI lire) (sigma lint1
Study of a bandnet (C2-Cl and C3-C4I: (order $1) C-2 bond X 2 bond X 1 C-3
(order $21 bond X 2 C-3 band X 2 C-2
-, -,C-7 C-4
-, -,C-4 C-7
3022221121111100 + 11.3 2'1 2'2 1'12
3111200020111100 l"l2 1.2 + 2.1 EHl
3011211121111100 2.1 1*/2 + A.3 1 . 2
3011210020111100 1*/2 1*2 + 2.1 EH1
nb sequences
, 21
nb sequencer
, 18
Figure 4. Sample run of program SYNDES (HAGEMAN ESTER).
1000", and "Timex/Sinclair 1500". Worldwide distribution of the ZX81 computer is still handled by Sinclair Research, Ltd, Cambridge, England. Reported applications of this computer to chemistry instruction have been virtually nonexistent. This void is probably because of the limited availability of commercial software and the membrane keyboard that makes i t impractical to use the computer for text input. For use in a chemistry laboratory the membrane keyboard has the advantages that it is impervious to dust and liquid snills. Reported here is a simulation program I have developed for the ZX81 comDuter e a u i ~ ~ with e d 16K RAM1. The Drograms do not require a &ter, although a ~ i m e x l ~ i n c l a i r printer allows facile screen dumps of any graphics display for more permanent storage. I have used the ZX81 with the PMRSIM program described here in my organic and advanced organic chemistry courses for the last three years.2 The computer bas been placed in the laboratory for student use. Because of its low cost, many students are able t o afford their own ZX81 computer. The program simulates the Proton Magnetic Resonance (PMR) signals from a second-order AB spin-spin splitting of vicinal hvdroeens (19). The nroeram allows the user to observe both tce calculked n;m;ic values for the chemical shifts and the relative iutensitvof the sienals and a eranhical display of the results as the coipling changes from i n k ,to
'
This program automatically performs step 2, i.e., generates all chemically viable self-consistent syntheses for any user-supplied bondset of up to three disconnections. The tareet molecule mav be acvclic or cvclic and have UD to 22 skeletal carbons. he input of the target molecules A d the resulting output use the Hendrickson system for codification of structures and reactions (18). The preliminary selection and evaluation of the "best bondsets" to he examined by the program (step 1) is extremely useful to introduce students to some fundamental conceots in oreanic svnthesis nlannine such as the search for convergency, known building blocks, symmetry, or strategic bonds. Finally the translation of the "coded" reactions and structures to known chemical conversions (step 3) helps students to oreanize and memorize a friahtenina number of reactions under a few logical categories. k sampre run of the program is shown in Figure 4. This program can run on a Sharp PC-1500 or Radio Shack PC-2 computer. The main arithmetic and tree-search modules are written in assembly language. The input/output modules are in Basic, thus allowing the use of the standard CK150 prmter and cassette interface or of any peripherals \.ia the CE-15d communication interface. The program and its documentation are available unon sendine a-$10 check to the author for the cassette and pdstage expekes
-
-
NMR Simulation Program for the U(81 Computer
The PMRSiM program should also run on the following computers: TimexISinciair 2068, the Sinclair Spectrum, and the Memotech line. Since Sinclair Basic closely resembles TRS-80 Basic, a conversion to Radio Shack or IBM personal computers should be easy. Presented at the 17th Great Lakes Regional ACS Meeting. June 1983.
7 PMR D E L T O CHEMICOL
SIMULOTOR SHIFT
1 2 3 4
OCCURS OCCURS OCCURS OCCURS
-
CJ>
COUPLING CONSTINT LINE LINE LINE LINE
CF>
hT OT OT
37.882 41.802 58.198 62.198
I T
20
HZ
4
HZ HZ HZ HZ HZ
THE R I T I O OF T H E I N T E N S I T I E S 1.49 L I N E 2 TO L I N E i
=
THE R O T 1 0 OF F / J
PMRSIM SPECTRUM
Z
OF
5
F:20 HZ J: 4 HZ
2:i R O T 1 0
Ronald Starkey University of Wisconsin Green Bay, Wi 54302 The Sinclair ZX81 Computer is an extremely inexpensive and quite powerful Z8OA-based microcomputer. Equipped with 16K RAM its cost is about that of a programmable calculator. Although the Sinclair Basic in ROM is somewhat nonstandard, i t is avery usable language. As a matter of fact, the VAL function operation and the low-resolution graphics structure are better than those found in many popular versions of Basic. The computer was distributed in the United States by Timex Inc. under the names "Timex/Sinclair
Figwe 5. Representative spectrum for an AM system, program PMRSIM Volume 63 Number 7 July 1966
625
an AA' system. The intervening AM, AB, and AA' systems are easilv- disdaved . " bv the nroeram. . " Non-first-order snlitting generally is observed for two interacting protons when the ratio of the difference in chemical shift ( F i n Hz) to the coupling constant ( J in Hz) is less than 10 (FIJ < 1'0). The values for the chemical shifts and the relative intensity of the signals are calculated using a modified scheme described by J. Piper (20). The display centers the signals at 50 Hz in the NMR spectrum. The user inputs required are the difference in chemical shifts ( F in Hz) of the two interacting protons and the coupling constant ( J in Hz) of that interaction. A representative spectrum for an AB system is shown in Figure 5. A listing of the PMRSIM program and accompanying instructions are available from the author. Requests should include a stamped ($0.50), self-addressed, 9 X 12 in. envelope.
Jack Ryan
Southern Arkansas university El Dorado, AR 71730 Find-the-pairs, a game for the Commodore 64, can help students to avoid the drudgery of memorizing such essential items as elemental names and symbols or conversion factors. There are a number of things the beginning chemistry student must memorize that are crucial to success in chemistry: metriclmetric and metricEnglish (and perhaps even EnglishEnglish) conversion factors, or names and symbols of elements and of ions, for example. And although it is no fun to memorize these things, a game format can take some of the drudnerv out of this activitv. r in which pairs Some ye&n ago there was a ~ \ ; ~ a mshow of prizes u,ere hidden behind blocks of the enmr board. The contestants took turns selecting pairs of blocks to he removed, exposing the prizes. The object, of course, was to guess the locations of the pairs of prizes: the contestant who exposed a pair of washing machines won a washing machine. Find-the-Pairs is avariation on this type of game. In Find-the-Pairs the player(s) attempt to guess the location of pairs. In addition, they must also indicate that what they have is or is not a pair. In this version of the game, a pair does not necessarily consist of two of the same items, hut instead is a pair of equivalent items. For instance, "iron"and "Fe" are a pair of equivalent items-an element and its atomic symbol. Similarly, "4 X 9" and "36" are a pair. Correctly confirming a pair wins 20 points. Any incorrect answer loses 20 points. The aame mav he vlaved bv one or two. For two ~lavers. the game is won by thk piayer k t h the highest score when ali pairs have been exposed. The single player tries for a maximum score, and is penalized by one point for each minute of elapsed time required to confirm a pair-the contestant is playing against the clock. The game is fairly easy to play. After the players are asked for their names, playing instructions are provided if requested. The game hoard is drawn and one pair of letters, corres ~ o n d i n to a the boxes to be viewed. is entered for each turn. The hidien items are shown and the player is asked, "Is this a pair?" The daver enters v-or n. The comnuter affirms or deny8 the aniwei and updates the score. 1; the items were not pairs, or were not identified as such. thev are hidden again. Next turn. The game ends when all'pairs are exposed on the hoard. The final score(s) are shown and an o ~ t i o nto play again is offered. Find-the-Pairs was originally written to assist my freshman students learn the names and symbols of some common elements. But the program is written in a way that it could be used for any subject in which identification of pairs can he 626
Journal of Chemical Education
important. I t could even he used by preschoolers if graphics symbols were used instead of words to create pairs. Very few changes are needed to customize the program: The name should be changed and new strings representing the pairs must he typed into data statements. The screen blocks are 10 characters wide by four lines high. This limits single-line words to he used to 10 characters. Huwever, r here is no reason that cursor controls cannot be employed 10 create phrases or graphics patterns that till thc entire block. The routine that re-covers the blocks when apair is not found will cover the entire block, not just asingle line, so you can feel free to experiment. Find-the-Pairs is fun to play and has a very wide range of possible educational applications. Any reader who would like a disk or tape (specify which) for the Commodore 64 and complete documentation for a version with elemental names and symbols as the pairs can send a check for $10 made out to the author a t 300 S. West Avenue, El Dorado, AR 71730.
Information Storage and Retrieval Using a Microcomputer James A. Wood
The Polytechnic Queensgate,Huddersfield HD1 3DH, U.K. While there have been many publications dealing with the use of microcom~utersin interactive instruction.. exnerimen1 simulation, data manipulat~on,and instrument incerfacinp, much l e s ~ avvears to ha\,e been nuhlished (21.22) . . . on exercises in undergraduate chemical courses to illustrate their use as a means of storing and retrieving information. Yet this is a particularly imporiant application in education, industry, and elsewhere. The exercises described here have been developed for use in association with various undergraduate chemistry courses with the aims of introducing students to this application and impressing upon them the importance of computer information databases, of enabling the students to assess their advantages and disadvantages, and of giving them some experience of s i m ~ l evet t v ~ i c a annlication l .. in a chemical context. The couIsesthengo on to provide instruction in the use of nationallv and internationallv available databases for inl and examples formation rktrieva~(e.g., ~ h e m i i aAbstracts) of the use in industry of company databases, etc. The exercises are based around an Apple I1 microcomputer coupled with two disk drives and a printer. They rely on the commercially produced Data Factory.3 However, the idea and the topics can be adapted to other svstems and programs (com&ercially and/or personally deveioped). The Data Factory is a very versatile program that allows information (numerical and nonnumerical) to he stored in files of up to 88 fields of any length up to 239 characters. I t incomorates facilities for estahlishine new files. addine data to exl'sting files, inspecting andlor changing an; entry Fn any field in any file, transferring information hetween files. deleting entries, searching an; file for particular information, etc. Students are provided with instruction sheets that: 1) review this particular use of computers in general and in chemistry in particular; 2) describe the capabilities of the Data Factorv; 3) aive background information about each application to he h s t r a t e d ; and 4) explain what information they must obtain by using the data base disks orovided. An outline of three such exercises follows: Stock Control. A file of six searchable fields is used to simulate some of the information a large college department
.
The Data Factory by William Passauer, Microlab. 2310 Skokie Valley Road, Highland Park, IL 60035. :
