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MARM 2003 36 th Middle Atlantic Regional Meeting American Chemical Society Princeton University, June 8-11 2003. McDonnell Hall. Chlorine Rule for Br m Cl n Compounds. Ray A. Gross, Jr. Prince George’s Community College. Acknowledgements. - PowerPoint PPT Presentation
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1
MARM 200336th Middle Atlantic Regional Meeting
American Chemical SocietyPrinceton University, June 8-11 2003
2
McDonnell Hall
3
Chlorine Rule
forBrmCln Compounds
Ray A. Gross, Jr.Prince George’s Community College
4
Acknowledgements
• Junhua Yan’s Isotope Pattern Calculator http://www.geocities.com/junhuayan/pattern.htm (accessed May 2003).
• Instutute of Advanced Industrial Science and Technology; Tsukuba, Ibaraki, Japan
SDBSWeb: http://www.aist.go.jp/RIODB/SDBS/ (accessed May 2003).
• NSF Grant: DUE-0202431
• Submitted to JCE
5
Outline
• Compare molecular-ion clusters of real and ideal BrmCln compounds
• Discover a chlorine rule for BrmCln
compounds
• Apply the chlorine rule to three spectra
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1:1
1:2:1
(1:1)m
1:3:3:1
(3:1)n
3:1
9:6:1
Br1
Br2
Br3
Cl1
Cl2
Brm Cln
ideal compounds
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Ideal Model = Binomials
(a + b)m(3a + b)n
Br1Cl1
(1:1)1(3:1)1 = 3:4:1
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Br1Cl1Br Br
Br
Cl
Br
Cl
Br
Cl
Br
Cl
Br
Cl
Br
Cl
Br
Cl
Br
Cl
Chem. Educ. 2003, 8, 182-186
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Ideal Br1Cl2
(1:1)1(3:1)2 = 9:15:7:1
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Real = Calculated
Mass 288 289 290 291 292 293 294 295
% 61.8 6.8 100 11 45.3 5 6.4 0.7
Mass % Normalized 288 61.8 10 289 6.8 290 100.0 16 291 11.0 292 45.3 7 293 5.0 294 6.4 1 295 0.7
C10H19Br1Cl2
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Chlorine Constant
M +2 +4 +6 +8
3 10 12 6 13 11 13 6 1
Br3Cl1
M +2 +4 +6
3 7 5 13 7 5 1
M +2 +4
Br2Cl1
3 4 13 4 1
Br1Cl1
12
M +2 +4 M +2 +4 +6 M +2 +4 +6 +8
3 4 13 4 1
9 15 7 110 16 7 1
27 54 36 10 130 59 38 10 1
Br1Cl1 Br1Cl2 Br1Cl3
Bromine Constant
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Chlorine Rule for Ideal Compounds
IM = 3n
When IM = 1, 3, 9, 27 or 81;
then
n = 0, 1, 2, 3, or 4, resp.
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240220
M = 224
220200 180170
Normal PatternEven M
m/z
M = 203
m/z
Normal PatternOdd M, contains N
Abnormal Pattern Strong M-1, M +1 peaks, etc. Contains aldehyde, etc.
M = 174
m/z
Cl
Br
Cl
NHCCH3
O
Cl
Cl CHO
Cl
Cl
15
NH2
Cl
BrBr
3.3
283
283207 = Br2Cl1N1 76
16 224
Br
Cl
Cl9.9
224149 = Br1Cl2 75
17 174145
M - 29
9.6
CHO
Cl
Cl
174 99 = Cl2 + CHO 75
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Summary
• Find n in BrmCln from molecular-ion cluster
• Find m from number of cluster peaks
• Chlorine rule: a new tool for use in structure determinations