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71:
atoms are summed up to give the total pi- occupation. From this value the sum of pi-occupation for unsubstituted benzene (value close to 6 in accord to
503:
Ozimiński, Wojciech P.; Dobrowolski, Jan C. (2009-08-01). "σ- and π-electron contributions to the substituent effect: natural population analysis".
130:
63:
is performed. The molecule have to be oriented in such a way that the aromatic benzene ring is perpendicular to the z-axis. Then, the 2p
59:. First the geometry should be optimized at a suitable model of theory, then the natural population analysis within the framework of
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Sums of pi-electron occupations and pEDA parameter for substituents of various character are gathered in the following table:
37:
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112:
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The pEDA scale linearly correlates with experimental substituent constants like Taft-Topsom σR parameter.
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60:
547:
75:) is subtracted resulting in original pEDA parameter. For pi-electron donating substituents like
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87:
33:
225:
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90:
the pEDA parameter is positive, and for pi-electron withdrawing substituents like
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For easy calculation of pEDA the free of charge for academic purposes written in
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The pEDA parameter for a given substituent is calculated by means of
91:
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44:
is a substituent. The more negative pEDA, the more pi-electron
126:
40:. The more positive is the value of pEDA the more pi-electron
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and the details are available in the original paper.
55:methods. The model molecule is the monosubstituted
8:
28:substituent effect scale, described also as
48:is the substituent (see the table below).
556:) CS1 maint: location missing publisher (
138:
36:. There is also a complementary scale -
495:
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129:program with Graphical User Interface
505:Journal of Physical Organic Chemistry
7:
14:
538:R. W. Taft, R. D. Topsom (1987).
111:The pEDA scale was invented by
1:
67:orbital occupations of ring
61:Natural Bond Orbital theory
604:
22:pi electron donor-acceptor
578:Chemical bond properties
552:: CS1 maint: location (
108:the pEDA is negative.
540:Prog. Phys. Org. Chem
113:Wojciech P. Oziminski
542:. 16. pp. 1–83.
117:Jan Cz. Dobrowolski
588:Quantum chemistry
583:Organic chemistry
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53:quantum chemistry
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73:Huckel rule
46:withdrawing
26:pi-electron
20:parameter (
572:Categories
490:References
548:cite book
525:1099-1395
30:mesomeric
145:π-total
131:AromaTcl
42:donating
483:-0.611
469:-0.227
455:-0.142
441:-0.129
430:-0.117
419:-0.087
408:-0.081
397:-0.077
383:-0.069
369:-0.068
358:-0.052
347:-0.044
333:-0.035
322:-0.024
308:-0.020
297:-0.017
283:-0.007
57:benzene
24:) is a
523:
480:5.380
466:5.764
452:5.849
438:5.861
427:5.874
424:-COCN
416:5.903
405:5.910
394:5.914
380:5.922
366:5.923
363:-COOH
355:5.938
344:5.947
330:5.955
319:5.967
305:5.971
294:5.974
280:5.984
269:0.000
266:5.991
258:0.014
255:6.005
244:0.057
241:6.047
233:0.062
230:6.053
220:0.078
217:6.069
209:0.121
206:6.112
198:0.145
195:6.136
184:0.397
181:6.387
173:0.491
170:6.481
162:0.571
159:6.562
69:carbon
413:-CHO
402:-CFO
352:-BeH
338:-CONH
148:pEDA
558:link
554:link
521:ISSN
435:-NO
327:-CN
302:-Li
288:-SiH
238:-Br
203:-OH
167:-NH
115:and
38:sEDA
18:pEDA
16:The
513:doi
474:-CH
446:-BH
388:-BF
374:-NO
313:-CF
274:-NH
263:-H
249:-CH
226:-Cl
214:-F
189:-NH
178:-O
153:-CH
127:Tcl
106:-CN
104:or
99:-BH
92:-NO
86:or
77:-NH
32:or
574::
550:}}
546:{{
519:.
509:22
507:.
460:-N
142:R
97:,
88:-F
84:OH
82:,
560:)
527:.
515::
476:2
462:2
448:2
390:2
376:2
340:2
315:3
290:3
276:3
251:3
191:2
155:2
101:2
94:2
79:2
65:z
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