Keywords: open chain and cycloalkynes, π and σbond, triple and single bond, number of carbon, hydrogen atoms
World Journal of Chemical Education, 2014 2 (1),
pp 13.
DOI: 10.12691/wjce211
Received September 20, 2013; Revised December 15, 2013; Accepted December 30, 2013
Copyright © 2014 Science and Education Publishing. All Rights Reserved.
1. Introduction
The number and types of bonds in open chain and cycloalkynes having complex molecular formula is a Herculean_{ }task. Keeping this in view, a rapid method has been proposed for the calculation of number of πbonds, σbonds, single and triple bonds with the help of following 08 (eight) completely new formulae for certain aliphatic unsaturated open chain and cycloalkynes.
Earlier eight new innovative methods including sixteen new formulae have been introduced on the easy prediction of ‘BondOrder of mono and diatomic homo and heteronuclear molecules or ions’, ‘Bondorder of oxide based acid radicals’, ‘Hybridization’, ‘IUPAC nomenclature of spiro and bicyclo compounds, ‘spin multiplicity value calculation and prediction of magnetic properties of diatomic hetero nuclear molecules and ions, ‘Aromaticity’ and ‘magnetic properties of homo and hetero nuclear diatomic molecules and ions [17]^{[1]}.
The present study involves eight formulae by just manipulating the number of carbon and hydrogen atoms by using some factors.
We think it would go a long way to help the students of organic chemistry and applied chemistry also who would choose the subject as their carrier. Experiment in vitro on 100 students show that by using these new methods strike rate is 1Q/30secs.
On the basis of this, we can strongly recommend that by using these new formulae the students can calculate number of πbonds, σbonds, single and triple bonds for aliphatic unsaturated open chain and cycloalkynes.
2. Result and Discussion
2.1. Open Chain Aliphatic Alkynes2.1.1. Calculation of πbonds (P)In the first case, we have to count the number of carbon atoms (X) and the number of hydrogen atoms (Y) in a given unsaturated hydrocarbon containing triple bonds. The formula to calculate the number of π bonds for an aliphatic open chain alkyne, where there is one or more than one triple bonds is
Where, X = number of carbon atoms; Y = number of hydrogen atoms and P = number of π bonds.
E.g.: In C_{16}H_{30}, X = 16, Y = 30, therefore P = [{(2XY)/2} + 1] = [{(2 x 16 – 30)/2} +1] = 1 + 1 = 2 number of π bonds.
2.1.2. Calculation of σbonds (S)In the first case, we have to count the number of carbon atoms (X) and the number of hydrogen atoms (Y) in a given unsaturated hydrocarbon containing triple bonds. The formula to calculate the number of σ bonds for an aliphatic open chain alkyne, where there is one or more than one triple bonds is
Where, X = number of carbon atoms; Y = number of hydrogen atoms and S = number of σ bonds.
E.g.: In C_{16}H_{30}, X = 16, Y = 30, therefore, S= [X+Y1] = [16+301] = 45 numbers of σ bonds.
2.1.3. Calculation of Single bonds (A)The total number of single bond for an aliphatic open chain alkyne, where there is one or more than one triple bonds is A = [{(2X+5Y)/2}  3]/2
Where, A = number of single bonds, X = number of carbon atoms and Y = number of hydrogen atoms.
E.g.: In C_{16}H_{30}, X = 16, Y = 30, therefore, A = [{(2X+5Y) / 2}  3]/2 = [{(2x16+5x30)/2}3]/2=[913]/2 = 44 numbers of single bonds.
2.1.4. Calculation of Triple Bonds (T)In the first case, we have to count the number of carbon atoms (X) and the number of hydrogen atoms (Y) in a given unsaturated hydrocarbon containing triple bonds. The formula to calculate the number of triple bonds for an aliphatic open chain alkyne, where there is one or more than one triple bonds is
Where, X = number of carbon atoms; Y = number of hydrogen atoms and T = number of triple bonds.
E.g.: In C_{16}H_{30}, X = 16, Y = 30, therefore, T = [{(2XY)/2} + 1]/2 = [{(2 x 16 – 30)/2} +1]/2 = 2/2 = 1 triple bond.
2.2. Cycloalkynes2.2.1. Calculation of πbonds (P_{c})In the first case, we have to count the number of carbon atoms (X) and the number of hydrogen atoms (Y) in the given unsaturated cycloalkyne. The formula to calculate the number of π bonds for an aliphatic cycloalkyne is
Where, X = number of carbon atoms; Y = number of hydrogen atoms and P_{c} = number of π bonds in the cycloalkyne system.
E.g.: In Cycloheptyne (C_{7}H_{10}), X =7, Y = 10, therefore P_{c} = (2x710)/2 = 2 number of π bonds.
2.2.2. Calculation of σbonds (S_{c})In the first case, we have to count the number of carbon atoms (X) and the number of hydrogen atoms (Y) in the given unsaturated cycloalkyne. The formula to calculate the number of σ bonds for an aliphatic cycloalkyne is
Where, X = number of carbon atoms; Y = number of hydrogen atoms and S_{c} = number of sigma bonds (σbonds) in cyclo alkyne system.
E.g.: In Cycloheptyne (C_{7}H_{10}), X =7, Y = 10, therefore S_{c} = (7+10) = 17 number of σ bonds.
2.2.3. Calculation of Single bonds (A_{c})The total number of single bond for an aliphatic cyclo alkyne is
Where, A_{c} = number of single bonds in cycloalkyne, X = number of carbon atoms and Y = number of hydrogen atoms.
E.g.: In Cycloheptyne (C_{7}H_{10}), X = 7, Y = 10, therefore, A_{c} = [{(2X+5Y)/2}]/2 = [{(2x7+5x10)/2}]/2=32/2 = 16 numbers of single bonds.
2.2.4. Calculation of Triple bonds (T)In the first case, we have to count the number of carbon atoms (X) and the number of hydrogen atoms (Y) in a given unsaturated cyclo system containing triple bond. The formula to calculate the number of triple bond is
Where, X = number of carbon atoms; Y = number of hydrogen atoms and T_{c} = number of triple bond.
E.g.: In Cycloheptyne (C_{7}H_{10}), X =7, Y = 10, therefore, T_{c} = [{(2XY)/2}]/2 = [{(2 x 7 – 10)/2}]/2 = 2/2 = 1 triple bond.
3. Conclusions
In conclusion here we approach a new rapid innovative method on easier calculation of number of πbonds, σbonds, single and triple bonds for aliphatic unsaturated open chain and cycloalkynes. This new method is very helpful to undergraduate and graduate level students of chemistry. By using these methods we can easily predict nature of bonds in alkyne system in a very simple and metabolic way.
Acknowledgement
The corresponding author, Dr. Arijit Das, would be grateful to Dr. S. Rakshit, Principal, Govt. Degree College, Dharmanagar, Tripura (N), Tripura, India, for giving the opportunity to carry out the research work.
References
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