The Chlorine Rule: An Analysis of Isotope Patterns of Compounds Containing Multiple Bromine and Chlorine Atoms. Ray A. Gross, Jr. With an Introduction to the Isotope-Pattern Analyzer. My Reasons for this Presentation. Present results obtained at PGCC
The Chlorine Rule: An Analysis of Isotope Patterns of Compounds Containing Multiple Bromine and Chlorine Atoms
Ray A. Gross, Jr.
With an Introduction to the Isotope-Pattern Analyzer
Isotopes of Br and Cl
Schematic diagram of a mass spectrometer
Why Br and Cl?
Molecular-ion peaks of C10H20Br1Cl1, C10H19Br2Cl1 and C10H18Br3Cl1.
In lieu of pattern matching,it should be possible to determine the number of Br and Cl atoms in a molecular formula of a compound by analyzing the molecular-ion cluster (i.e., by cluster analysis).
with BH3 (CHM 201)
Reduction with NaBH4
IM = 3n
Br (a:b) = 1:1
Cl (a:b) = 3:1
13C and 2H negligible
Ideal Model = Binomial Pair
(1a + 1b)m(3a + 1b)n
3a2 + 4ab + 1b2 = 3:4:1
(1a + 1b)m(3a + 1b)n = 1m3na(m+ n) + …. + 1m1nb(m+ n)
I(L/R) = 1m3n/1m1n
IM = 3n
Chlorine Rule:When I equals 1, 3, 9, 27 or 81; n is 0, 1, 2, 3, or 4, respectively, where n = number of chlorine atoms.
The number of bromine atoms m equals A – n.
J.Chem.Educ. 2004, 81, 1161-1168 (article available at front desk)
Conservation of orbital symmetry
“Oxygen” Priestley vs Sheele
Gross giving lecture with Hoffmann, Djerassi and
Woodward looking on.
N = 2m4n
N = 2m2n2n
N = 2A2n
Chem. Educ. 2003, 8, 182-186
Summary Part I for BrmClnCompounds
J. Chem. Educ., in press
The Excel program returns the A + 2 (Cl, Br, S) composition of the molecular formula