Article Versions
Export Article
Cite this article
  • Normal Style
  • MLA Style
  • APA Style
  • Chicago Style
Research Article
Open Access Peer-reviewed

Comparison of Substituent Effects in Benzenes (XC5H5C), Pyridines (XC5H4N) and Phosphorines (XC5H4P) and their Protonated Species

R. Sanjeev, V. Jagannadham
World Journal of Chemical Education. 2020, 8(4), 155-162. DOI: 10.12691/wjce-8-4-3
Received August 15, 2020; Revised September 18, 2020; Accepted September 27, 2020

Abstract

Collection of interesting and stimulative data led us to construct Hammett plots for different properties like proton affinities, gas phase basicities, solvation free energies of free and protonated benzenes (I), pyridines (II) and phosphorines (III), and for pKa values of protonated pyridines and phosphorines. Trends in Hammett reaction constants (ρ) for all these processes were discussed.

1. Introduction

Acuity of work in chemical education and chemical research that took a shape from literature reported data on several chemical and physical aspects like phase transition temperatures, dipole moments, surface tensions, attenuation effect, associative and non-associative behavior of liquids, stability and lifetimes of reactive intermediates, LFER, effect of hybridization of carbon on Hammett (ρ) and Taft (ρ*) reaction constants, prediction of pKa values of unstable arenium ions and benzenes, from our group has been ever increasing in recent times 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63. In the present work to go a step ahead we have tried the comparison of substituent effects on pKa, proton affinities, gas phase basicities, solvation free energies in benzenes (C5H6C), pyridines (C5H5N) and phosphorines (C5H5P) and their protonated species.

2. Methods

All the linear correlations were done using the KaleidaGraph software, Reading, PA, USA. All chemical structures were drawn using chemdraw software. All Hammett σ values are from reference 64.

3. Discussion

Hammett reactions constants (ρ) and pKa data of arenium, pyridinium and phosphorinium ions are given in Table 1. The corresponding plots are shown in Figure 1, Figure 2 and Figure 3.

Since the Hammett ρ can not be determined for the dissociation equilibriums of arenium ions XC6H6+ ⇌ XC6H5 + H+ as they are highly unstable, an alternate and lucid method was adopted by us based on the attenuation effect 26. Figure 1 shows the determination of the Hammett ρ for the dissociation equilibriums of arenium ions XC6H6+ ⇌ XC6H5 + H+ from the study of attenuation effect of methylene group (-CH2-) on the dissociation equilibriums of anilinium ions, benzyl ammonium ions and 2-phenylethyl ammonium ions 26 and using the Andrew Williams’ empirical equation ρ = m1(2 – i) 65 where m1 is an arbitrary constant “i” is the number of atoms between ionizable proton and the ring carbon.

Figure 2 shows the determination of the Hammett ρ for the dissociation equilibriums of pyridinium ions XC5H5N+ ⇌ XC5H4N + H+ from the plot of pKa versus Hammett σ.

Figure 3 shows the determination of the Hammett ρ for the dissociation equilibriums of phosphorinium ions XC5H5P+ ⇌ XC5H4P + H+ from the plot of pKa versus Hammett σ. The pKa values of the equilibriums XC5H5N+ ⇌ XC5H4N + H+ and XC5H5P+ ⇌ XC5H4P + H+ are from reference 66.

The negative Hammett ρ values for the equilibriums XC5H5N+ ⇌ XC5H4N + H+ and XC5H5P+ ⇌ XC5H4P + H+ are from the plots of pKa versus Hammett σ to be taken as positive for the plots of log Ka (since -log Ka = pKa) versus Hammett σ. Therefore the three Hammett ρ values of the three equilibrium reactions are 14.3, 6.48 and 7.73 respectively. It is to be noted that there is a large difference of nearly 7.8 and 6.6 units between Hammett ρ of the equilibrium XC6H6+ ⇌ XC6H5 + H+ and of the equilibriums of XC5H5N+ ⇌ XC5H4N + H+ and XC5H5P+ ⇌ XC5H4P + H+. This is mainly due to the loss of energy of the highly unstable and energetic intermediate arenium ions to drive back to the highly stable and less energetic benzene molecule. And this involves the restoration of the aromaticity due to the relief of unit positive charge on the arenium ions. And the small difference of 1.25 units of Hammett ρ between the equilibriums of XC5H5N+ ⇌ XC5H4N + H+ and XC5H5P+ ⇌ XC5H4P + H+ is due to only the difference of the occupancy of the lone pairs of electrons of N and P. The lone pair of electrons of N is in the p orbital and that of P is in the d orbital. In spite of the fact that the p orbital is more electronegative than d orbital the tendency towards retention of aromaticity of both the molecules even on protonation is a prime reason. There are several arguments about the aromaticity of phosphorine based on many theoretical calculations. And it is believed to have the 88-96% of aromaticity of that of benzene 67. Such a high aromaticity of phosphorine is reflected from the well matched electronegativities of phosphorous (2.1) and carbon (2.5) 67.

Hammett reactions constants (ρ) and proton affinity data of benzenes, pyridines and phosphorines are given in Table 2. The corresponding Hammett plots are shown in Figure 4, Figure 5 and Figure 6.

Figure 4 shows the determination of the Hammett ρ for the proton affinities (PA) of benzenes from the plot of PAs versus Hammett σ.

Figure 5 shows the determination of the Hammett ρ for the proton affinities (PA) of pyridines from the plot of PAs versus Hammett σ.

Figure 6 shows the determination of the Hammett ρ for the proton affinities (PA) of phosphorines from the plot of PAs versus Hammett σ.

Figure 7 gives the Hammett ρ for the proton transfer reaction of protonated benzene to substituted benzenes.

Figure 8 gives the Hammett ρ for the gas phase basicities of pyridines.

Figure 9 gives the Hammett ρ for the gas phase basicities of phosphorines.

Figure 10 gives the Hammett ρ for the ΔGsolv versus Hammett σ of free benzenes.

Figure 11 gives the Hammett ρ for the ΔGsolv versus Hammett σ of protonated benzenes.

Figure 12 gives the Hammett ρ for the ΔGsolv versus Hammett σ of free pyridines.

Figure 13 gives the Hammett ρ for the ΔGsolv versus Hammett σ of protonated pyridines.

Figure 14 gives the Hammett ρ for the ΔGsolv versus Hammett σ of free phosphorines.

Figure 15 gives the Hammett ρ for the ΔGsolv versus Hammett σ of protonated phosphorines.

  • Table 5. Hammett reaction constants (ρ) on different properties of benzenes (XC5H5C), pyridines (XC5H4N) and phosphorines (XC5H4P) and their protonated species

The trends in the Hammett ρ values of the proton affinities (PA) and gas phase basicities (GB) of benzenes, pyridines and phosphorines are again in the same order of that observed for pKas (Table 5). At this point it is worth to discuss little about the proton affinities and gas phase basicities. Though they look same in brief but they differ thermodynamically. Proton affinity of a species A- is defined as the negative value of the enthalpy change (ΔH) of the process shown in the following reaction.

(1)

And gas phase basicity is defined as the negative value of the corresponding Gibbs free energy change (ΔG) of the same reaction 68, 69. It is known that ΔG = ΔH - TΔS. Therefore it is clear that both ΔG and ΔH differ by an amount of TΔS. And ΔH values are always higher by an amount of TΔS than the values of ΔG (Table 2 and Table 3). From the trends of Hammett ρ for PAs and GBs the same explanations offered hold good on Hammett ρ for pKas given on page 5.

Effect of substituents on the trends in the Hammett ρ values of ΔGsolv of the free and protonated benzenes, pyridines and phosphorines are rather complex. It is reported that there were two ways of approach of the addendum solvent molecule on to the benzene as shown below in A and B 70.

The solvation process is a result of a competition between π-electron interaction as shown in A and H-interaction of X-H bond (X = C or N or P) as shown in B with the approaching solvent molecule. From the negative Hammett ρ value of -3.75 (Table 5, Figure 10) of the correlation of ΔGsolv values with Hammett σ values in the present work for benzene clearly indicates that the interaction shown in A of scheme 1 may be predominant over the interaction shown in B. This is because the electron donating substituents are o,p-directing and they make the benzene molecule more electron rich at two ortho and at one para positions thus making the π-electron system of benzene more nucleophilic 71. This makes easy for the positive part of addendum molecule to be attracted more by the benzene molecule. In the case of protonated benzenes high negative value of Hammett ρ of -289 (Figure 11) is at present unexplainable. Probably one needs some more data of ΔGsolv for other substituents.

In the case of pyridines the Hammett ρ value is positive and it is 3.23 (Table 5, Figure 12). Here the solvation process is a result of a competition between H-interaction of N-H bond and π-electron interaction with the approaching solvent molecule. In this process from the positive Hammett ρ value of 3.23 suggests that the interaction of the type shown in B of scheme 1 is more favorable. This is because the electron withdrawing substituents at para position in pyridine moiety makes H of N-H bond more electrophilic hence the negative part of addendum molecule to be attracted more by the pyridine molecule.

In the case of protonated pyridines the whole process is just reversed as it can be seen from the negative Hammett ρ value of -10.3 (Table 5, Figure 13).

And the same observations hold well for free and protonated phosphorines (Table 5, Figure 14 and Figure 15).

4. Conclusions

Trends in Hammett reaction constants (ρ) on pKas, proton affinities (PA), gas phase basicities (GB) and free energy of solvation (ΔGsolv) of benzenes (XC5H5C), pyridines (XC5H4N) and phosphorines (XC5H4P) and their protonated species were discussed.

References

[1]  Sanjeev Rachuru, and Jagannadham Vandanapu, Journal of Molecular Liquids, 2020, vol. 302, page 112496.
In article      View Article
 
[2]  R. Sanjeev, V. Jagannadham and R. Ravi, Chemical Methodologies, 2020, vol. 4 page 106-114
In article      
 
[3]  Sanjeev. R , David Geelan and Jagannadham Vandanapu, Journal of Molecular Liquids, 2020, vol. 298, page 112138.
In article      View Article
 
[4]  R. Sanjeev, R. Ravi and V. Jagannadham, National Academy of Science Letters (Allahabad, India), 2020, Vol. 43, page 5-8.
In article      View Article
 
[5]  R. Sanjeev, David Geelan and V. Jagannadham, Education Quimica (The Mexican Journal of Chemical Education), 2019, Vol. 30, page 83.
In article      View Article
 
[6]  Sanjeev Rachuru, V. Jagannadham and Sreedhar Pandiri, Oriental J. Chemistry, 2019, Vol. 35, page 461-465.
In article      View Article
 
[7]  R. Sanjeev and V. Jagannadham, Oriental Journal of Physical Sciences, Bhopal, India (2018) vol. 3, page 58-61.
In article      View Article
 
[8]  R. Sanjeev, D. A. Padmavathi and V. Jagannadham, World Journal of Chemical Education (Science & Educational Publishing,USA), (2018), Vol. 6, No. 1, page 78-81.
In article      View Article
 
[9]  R. Sanjeev, D. A. Padmavathi and V. Jagannadham, Oriental J. Chemistry, 2018, Volume 34, Number 1, page no. 526-531.
In article      View Article
 
[10]  Sanjeev. R, V. Jagannadham, Veda Vrath . R, V. E. M. Mamatha Bethapudi and Adam. A. Skelton, Oriental J. Chemistry, 2017, Volume 33, Number 5, page no.2673-2675.
In article      View Article
 
[11]  R. Sanjeev, R. Ravi and V. Jagannadham, Journal of Applicable Chemistry, 2017, vol. 6, page 665-667
In article      
 
[12]  R. Sanjeev, V. Jagannadham, Adam A Skelton, Pandiri Sreedhar, V. E. M. Mamatha Bethapudi and R. Veda Vrath, Oriental J. Chemistry, 2017, Volume 33, Number 5, page no.2292-2296.
In article      View Article
 
[13]  R. Sanjeev and V. Jagannadham, Current Physical Chemistry published by Bentham Science publishers, USA 2017, vol. 7, page 1-6.
In article      View Article
 
[14]  R. Sanjeev, R. Ravi, V. Jagannadham and Adam A. Skelton, Australian Journal of Chemistry. Published online: 18 July 2016, in print 2017, vol. 70, page 90-100.
In article      View Article
 
[15]  Sanjeev Rachuru, V. Jagannadham, Adam A. Skelton, Journal of Molecular Liquids, 224 (2016) 43-46.
In article      View Article
 
[16]  G. Mallika Devi, D. A. Padmavathi, R. Sanjeev, V. Jagannadham, World Journal of Chemical Education, (2016), Vol. 4, No. 6, 117-123.
In article      
 
[17]  R. Sanjeev, V. Jagannadham, and R. Ravi, Journal of Applicable Chemistry, 2016, vol. 5, page 693.
In article      
 
[18]  R. Sanjeev, V. Jagannadham, Adam A. Skelton and R. Veda Vrath, Asian Journal of Chemistry; Vol. 27, No. 10 (2015), 3297.
In article      View Article
 
[19]  R. Ravi, R. Sanjeev, V. Jagannadham and Adam A Skelton, International Journal of Chemical Kinetics, (2015) Vol. 47, pages 36-41.
In article      View Article
 
[20]  Sanjeev R., Jagannadham V., Skelton Adam A. and Veda Vrath R, Research Journal of Chemistry & Environment, 2015, vol. 19(2), page 26-29.
In article      
 
[21]  R. Sanjeev, V. Jagannadham, Adam A Skelton and R. Veda Vrath, Research Journal of Chemistry & Environment, 2015, vol. 19, page 24.
In article      
 
[22]  R. Sanjeev, V. Jagannadham, Adam A Skelton and R. Veda Vrath, Australian Journal of Education in Chemistry, (2014), Vol. 74, page 41
In article      
 
[23]  Rachuru Sanjeev, V. Jagannadham, Adam A Skelton and Rachuru Veda Vrath, Chem. Educator 2014, 19, 327–329, (Published from University of Idaho, Idaho, USA
In article      
 
[24]  R. Sanjeev, V. Jagannadham, and R. Veda Vrath, Bull. Chem. Soc. Ethiopia, (2014), vol. 28, page 295-300.
In article      View Article
 
[25]  R. Sanjeev, V. Jagannadham, Adam A Skelton, R. Veda Vrath, World Journal Chemical Education, (2014), vol. 2, pages 4-7.
In article      
 
[26]  R. Sanjeev, V. Jagannadham, and R. Veda Vrath, Bulgarian Chem. Commns., (2014) vol. 46, page 375-377.
In article      
 
[27]  V. Jagannadham, and R. Sanjeev, Journal of Applicable Chemistry (2014) vol. 3, page 440-448.
In article      
 
[28]  V. Jagannadham, and R. Sanjeev, Journal of Applicable Chemistry (2014) vol. 3, page 1-5.
In article      
 
[29]  R. Sanjeev and V. Jagannadham, 20 April 2013 “Chemistry Views” of Wiley-VCH & Chem Pub Soc: Link: http://www.chemistryviews.org/view/0/ education.html.
In article      
 
[30]  R. Sanjeev, V. Jagannadham, R. Ravi, R. Veda Vrath, Arijit Das, Journal of Laboratory Chemical Education, Published by Scientific and Academic Publishing, USA 2013; 1(4): 59-64.
In article      
 
[31]  R. Sanjeev, V. Jagannadham, R. Veda Vrath and R. Ravi, QScience Connect, Bloomsbury Qatar Foundation Academic Journal (2013) Paper No. 36.
In article      View Article
 
[32]  V. Jagannadham, and R. Sanjeev, Advances in Analytical Chemistry, Published by Scientific and Academic Publishing, USA, (2013) Vol. 3, page 54-56.
In article      
 
[33]  R. Sanjeev, V. Jagannadham, and R. Veda Vrath, World Journal of Chemical Education, USA, 2013, Vol. 1. Page 1-5.
In article      
 
[34]  R. Sanjeev, and V. Jagannadham, ChemXpress, (2013) Vol. 2(2) page 59-64, http://www.globalpublication.org/globalwebsite/Journals/ChemXpress/volume_2 issue2.html.
In article      
 
[35]  R. Sanjeev, V. Jagannadham, and R. Veda Vrath, Chemical Education Journal (CEJ), Japan, Vol. 14, No. 2, The date of issue: February 19, 2013/Registration No. 14-8.
In article      
 
[36]  R. Ravi, R. Sanjeev and V. Jagannadham, International Journal of Chemical Kinetics, (2013), Vol. 45, pages 803-810.
In article      View Article
 
[37]  R. Sanjeev, V. Jagannadham & R. Veda Vrath, Journal of Applicable Chemistry, (India), 2012, 1 (4).
In article      
 
[38]  R. Sanjeev, V. Jagannadham, ChemXpress, (2012) Vol. 1, page 8, Published by Global Publications, India.
In article      
 
[39]  R. Sanjeev, V. Jagannadham, ChemXpress, (2012) Vol. 1, page 2, Published by Global Publications, India.
In article      View Article
 
[40]  V. Jagannadham, R. Sanjeev, Chem13News, published by Department of Chemistry, University of Waterloo, Canada, (2012). http://share.pdfonline.com/c42d0d5c91 ee4352b4e61e8803082ca2/The%20SignImpactFactoricance%20of %20Water%20 Neutrality. pdf.
In article      
 
[41]  R. Sanjeev, V. Jagannadham and R. Veda Vrath, ChemEdNZ (New Zeeland Journal of Chemical Education) (2012) November issue page 12.
In article      
 
[42]  R. Sanjeev, V. Jagannadham and R. Veda Vrath, Chemistry in New Zeeland (2012) October issue page 133.
In article      
 
[43]  R. Sanjeev, V. Jagannadham, R.Veda Vrath, American Journal of Physical Chemistry, published by Scientific and Academic Publishing, USA, (2012) Vol. 2 page 43-47.
In article      View Article
 
[44]  R. Sanjeev, V. Jagannadham and R. Veda Vrath, ChemEdNZ (New Zeeland Journal of Chemical Education) (2012) August issue page 7-9.
In article      
 
[45]  Jagannadham V and Sanjeev Rachuru, Advances in Physical Chemistry, published by Hindawi publishers, USA, Volume 2012 (2012), Article ID 598243, 1-4 pages.
In article      
 
[46]  V. Jagannadham, and R. Sanjeev, Chem13News, published by Department of Chemistry, University of Waterloo, Canada, February 2012, number 388, page 15.
In article      
 
[47]  V. Jagannadham, and R. Sanjeev, Creative Education, Published by Scientific Research Publishing Inc (USA) (2012) Vol. 3, No. 3, pages 380-382.
In article      View Article
 
[48]  R. Sanjeev, V. Jagannadham, International Journal of Chemistry, (Bombay, India) (2012), Vol. 1, page 97-99.
In article      
 
[49]  R. Sanjeev, V. Jagannadham and R. Veda Vrath, ChemEdNZ,(New Zeeland Journal of Chemical Education) (2012) May issue, pages 8-10.
In article      
 
[50]  V. Jagannadham, R. Sanjeev and R. Veda Vrath, ChemEdNZ, (New Zeeland Journal of Chemical Education) (2012) November issue page 14.
In article      
 
[51]  R. Sanjeev, V. Jagannadham, R. Veda Vrath, Khimiya/Chemistry (The Bulgarian Journal of Chemical Education), (2012) Vol. 21, page 71-77.
In article      
 
[52]  V. Jagannadham, American Journal of Chemistry, Published by Scientific and Academic Publishing, USA, (2012) Vol. 1, page 26-28.
In article      
 
[53]  R. Sanjeev, V. Jagannadham and R. Veda Vrath, Education Journal 2012; 1(1): 1-4. Published online December 30, 2012.
In article      
 
[54]  V. Jagannadham, American Journal of Physical Chemistry, Published by Scientific and Academic Publishing, USA, (2012) vol. 2. page 100-102.
In article      View Article
 
[55]  R. Sanjeev, V. Jagannadham, D. Dhiman, Bulgarian Chemical Communications, Vol. 43, (3), pp. 465-466, (2011).
In article      
 
[56]  V. Jagannadham, Bulgarian Chemical Communications, (2011) vol. 42, page 383-394.
In article      
 
[57]  V. Jagannadham, Khimiya/Chemistry (The Bulgarian Journal of Chemical Education), (2010) vol. 19, page 114.
In article      
 
[58]  V. Jagannadham, Creative Education Published by Scientific Research Publishing Inc (USA) (2010) Vol. 1, 128.
In article      View Article
 
[59]  V. Jagannadham, Chemical Education Journal, Japan, (2009), Vol. 12, No. 1. http://chem.sci.utsunomiya-u.ac.jp/cejrnlE.html.
In article      
 
[60]  V. Jagannadham, D. Annapurna Padmavathi, and R. Sanjeev, International Journal of Chemical Kinetics, (2009) vol. 41, page 554.
In article      View Article
 
[61]  V. Jagannadham. Bulgarian Chem. Commns., (2009) vol. 41, page 50.
In article      
 
[62]  V. Jagannadham Khimiya/Chemistry (The Bulgarian Journal of Chemical Education), Vol. 18, (2009) page 89.
In article      
 
[63]  V. Jagannadham. Resonance, (2009), Vol. 14, No. 11, page 1097.
In article      
 
[64]  Corwin Hansch, A. Leo, and R. W. Taft, Chem. Rev. 199l, 91, 165-195.
In article      View Article
 
[65]  A. Williams, Free Energy Relationships in Organic and Bioorganic Chemistry, Royal Society of Chemistry, Cambridge, 2003, p. 75.
In article      
 
[66]  Nguyen-Nguyen Pham-Tran, Guy Bouchoux, David Delaere, and Minh Tho Nguyen, J. Phys. Chem. A 2005, 109, 2957-2963.
In article      View Article  PubMed
 
[67]  Làszló Nyulàszi, Chem. Rev. 2001, 101, 1229-1246.
In article      View Article  PubMed
 
[68]  Adam Moser, Kevin Range, and Darrin M. York, J Phys Chem. B. 2010, 114(43): 13911-13921.
In article      View Article  PubMed
 
[69]  Kenzo Hiraoka, Can. J. Chem. 65, 1258 (1987).
In article      View Article
 
[70]  Takahashi H, Suzuoka D, Morita A, J Chem Theory Comput. 2015 Mar 10; 11(3): 1181-94.
In article      View Article  PubMed
 
[71]  Hunt, Ian. "Substituent Effects". University of Calgary Department of Chemistry. Retrieved 16 November 2012.
In article      
 

Published with license by Science and Education Publishing, Copyright © 2020 R. Sanjeev and V. Jagannadham

Creative CommonsThis work is licensed under a Creative Commons Attribution 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/

Cite this article:

Normal Style
R. Sanjeev, V. Jagannadham. Comparison of Substituent Effects in Benzenes (XC5H5C), Pyridines (XC5H4N) and Phosphorines (XC5H4P) and their Protonated Species. World Journal of Chemical Education. Vol. 8, No. 4, 2020, pp 155-162. http://pubs.sciepub.com/wjce/8/4/3
MLA Style
Sanjeev, R., and V. Jagannadham. "Comparison of Substituent Effects in Benzenes (XC5H5C), Pyridines (XC5H4N) and Phosphorines (XC5H4P) and their Protonated Species." World Journal of Chemical Education 8.4 (2020): 155-162.
APA Style
Sanjeev, R. , & Jagannadham, V. (2020). Comparison of Substituent Effects in Benzenes (XC5H5C), Pyridines (XC5H4N) and Phosphorines (XC5H4P) and their Protonated Species. World Journal of Chemical Education, 8(4), 155-162.
Chicago Style
Sanjeev, R., and V. Jagannadham. "Comparison of Substituent Effects in Benzenes (XC5H5C), Pyridines (XC5H4N) and Phosphorines (XC5H4P) and their Protonated Species." World Journal of Chemical Education 8, no. 4 (2020): 155-162.
Share
  • Table 1. pKa values of pyridinium and phosphorinium ions and Hammett ρ values for the three equilibriums
  • Table 2. Hammett reaction constants (ρ) and proton affinity data of benzenes, pyridines and phosphorines
  • Table 3. -ΔGo values of proton transfer to benzenes and gas phase basicities (GB) of pyridines and phosphorines
  • Table 4. Solvation free energies (ΔGsolv) of benzenes, pyridines, phosphorines (B) and their protonated species (BH+)
  • Table 5. Hammett reaction constants (ρ) on different properties of benzenes (XC5H5C), pyridines (XC5H4N) and phosphorines (XC5H4P) and their protonated species
[1]  Sanjeev Rachuru, and Jagannadham Vandanapu, Journal of Molecular Liquids, 2020, vol. 302, page 112496.
In article      View Article
 
[2]  R. Sanjeev, V. Jagannadham and R. Ravi, Chemical Methodologies, 2020, vol. 4 page 106-114
In article      
 
[3]  Sanjeev. R , David Geelan and Jagannadham Vandanapu, Journal of Molecular Liquids, 2020, vol. 298, page 112138.
In article      View Article
 
[4]  R. Sanjeev, R. Ravi and V. Jagannadham, National Academy of Science Letters (Allahabad, India), 2020, Vol. 43, page 5-8.
In article      View Article
 
[5]  R. Sanjeev, David Geelan and V. Jagannadham, Education Quimica (The Mexican Journal of Chemical Education), 2019, Vol. 30, page 83.
In article      View Article
 
[6]  Sanjeev Rachuru, V. Jagannadham and Sreedhar Pandiri, Oriental J. Chemistry, 2019, Vol. 35, page 461-465.
In article      View Article
 
[7]  R. Sanjeev and V. Jagannadham, Oriental Journal of Physical Sciences, Bhopal, India (2018) vol. 3, page 58-61.
In article      View Article
 
[8]  R. Sanjeev, D. A. Padmavathi and V. Jagannadham, World Journal of Chemical Education (Science & Educational Publishing,USA), (2018), Vol. 6, No. 1, page 78-81.
In article      View Article
 
[9]  R. Sanjeev, D. A. Padmavathi and V. Jagannadham, Oriental J. Chemistry, 2018, Volume 34, Number 1, page no. 526-531.
In article      View Article
 
[10]  Sanjeev. R, V. Jagannadham, Veda Vrath . R, V. E. M. Mamatha Bethapudi and Adam. A. Skelton, Oriental J. Chemistry, 2017, Volume 33, Number 5, page no.2673-2675.
In article      View Article
 
[11]  R. Sanjeev, R. Ravi and V. Jagannadham, Journal of Applicable Chemistry, 2017, vol. 6, page 665-667
In article      
 
[12]  R. Sanjeev, V. Jagannadham, Adam A Skelton, Pandiri Sreedhar, V. E. M. Mamatha Bethapudi and R. Veda Vrath, Oriental J. Chemistry, 2017, Volume 33, Number 5, page no.2292-2296.
In article      View Article
 
[13]  R. Sanjeev and V. Jagannadham, Current Physical Chemistry published by Bentham Science publishers, USA 2017, vol. 7, page 1-6.
In article      View Article
 
[14]  R. Sanjeev, R. Ravi, V. Jagannadham and Adam A. Skelton, Australian Journal of Chemistry. Published online: 18 July 2016, in print 2017, vol. 70, page 90-100.
In article      View Article
 
[15]  Sanjeev Rachuru, V. Jagannadham, Adam A. Skelton, Journal of Molecular Liquids, 224 (2016) 43-46.
In article      View Article
 
[16]  G. Mallika Devi, D. A. Padmavathi, R. Sanjeev, V. Jagannadham, World Journal of Chemical Education, (2016), Vol. 4, No. 6, 117-123.
In article      
 
[17]  R. Sanjeev, V. Jagannadham, and R. Ravi, Journal of Applicable Chemistry, 2016, vol. 5, page 693.
In article      
 
[18]  R. Sanjeev, V. Jagannadham, Adam A. Skelton and R. Veda Vrath, Asian Journal of Chemistry; Vol. 27, No. 10 (2015), 3297.
In article      View Article
 
[19]  R. Ravi, R. Sanjeev, V. Jagannadham and Adam A Skelton, International Journal of Chemical Kinetics, (2015) Vol. 47, pages 36-41.
In article      View Article
 
[20]  Sanjeev R., Jagannadham V., Skelton Adam A. and Veda Vrath R, Research Journal of Chemistry & Environment, 2015, vol. 19(2), page 26-29.
In article      
 
[21]  R. Sanjeev, V. Jagannadham, Adam A Skelton and R. Veda Vrath, Research Journal of Chemistry & Environment, 2015, vol. 19, page 24.
In article      
 
[22]  R. Sanjeev, V. Jagannadham, Adam A Skelton and R. Veda Vrath, Australian Journal of Education in Chemistry, (2014), Vol. 74, page 41
In article      
 
[23]  Rachuru Sanjeev, V. Jagannadham, Adam A Skelton and Rachuru Veda Vrath, Chem. Educator 2014, 19, 327–329, (Published from University of Idaho, Idaho, USA
In article      
 
[24]  R. Sanjeev, V. Jagannadham, and R. Veda Vrath, Bull. Chem. Soc. Ethiopia, (2014), vol. 28, page 295-300.
In article      View Article
 
[25]  R. Sanjeev, V. Jagannadham, Adam A Skelton, R. Veda Vrath, World Journal Chemical Education, (2014), vol. 2, pages 4-7.
In article      
 
[26]  R. Sanjeev, V. Jagannadham, and R. Veda Vrath, Bulgarian Chem. Commns., (2014) vol. 46, page 375-377.
In article      
 
[27]  V. Jagannadham, and R. Sanjeev, Journal of Applicable Chemistry (2014) vol. 3, page 440-448.
In article      
 
[28]  V. Jagannadham, and R. Sanjeev, Journal of Applicable Chemistry (2014) vol. 3, page 1-5.
In article      
 
[29]  R. Sanjeev and V. Jagannadham, 20 April 2013 “Chemistry Views” of Wiley-VCH & Chem Pub Soc: Link: http://www.chemistryviews.org/view/0/ education.html.
In article      
 
[30]  R. Sanjeev, V. Jagannadham, R. Ravi, R. Veda Vrath, Arijit Das, Journal of Laboratory Chemical Education, Published by Scientific and Academic Publishing, USA 2013; 1(4): 59-64.
In article      
 
[31]  R. Sanjeev, V. Jagannadham, R. Veda Vrath and R. Ravi, QScience Connect, Bloomsbury Qatar Foundation Academic Journal (2013) Paper No. 36.
In article      View Article
 
[32]  V. Jagannadham, and R. Sanjeev, Advances in Analytical Chemistry, Published by Scientific and Academic Publishing, USA, (2013) Vol. 3, page 54-56.
In article      
 
[33]  R. Sanjeev, V. Jagannadham, and R. Veda Vrath, World Journal of Chemical Education, USA, 2013, Vol. 1. Page 1-5.
In article      
 
[34]  R. Sanjeev, and V. Jagannadham, ChemXpress, (2013) Vol. 2(2) page 59-64, http://www.globalpublication.org/globalwebsite/Journals/ChemXpress/volume_2 issue2.html.
In article      
 
[35]  R. Sanjeev, V. Jagannadham, and R. Veda Vrath, Chemical Education Journal (CEJ), Japan, Vol. 14, No. 2, The date of issue: February 19, 2013/Registration No. 14-8.
In article      
 
[36]  R. Ravi, R. Sanjeev and V. Jagannadham, International Journal of Chemical Kinetics, (2013), Vol. 45, pages 803-810.
In article      View Article
 
[37]  R. Sanjeev, V. Jagannadham & R. Veda Vrath, Journal of Applicable Chemistry, (India), 2012, 1 (4).
In article      
 
[38]  R. Sanjeev, V. Jagannadham, ChemXpress, (2012) Vol. 1, page 8, Published by Global Publications, India.
In article      
 
[39]  R. Sanjeev, V. Jagannadham, ChemXpress, (2012) Vol. 1, page 2, Published by Global Publications, India.
In article      View Article
 
[40]  V. Jagannadham, R. Sanjeev, Chem13News, published by Department of Chemistry, University of Waterloo, Canada, (2012). http://share.pdfonline.com/c42d0d5c91 ee4352b4e61e8803082ca2/The%20SignImpactFactoricance%20of %20Water%20 Neutrality. pdf.
In article      
 
[41]  R. Sanjeev, V. Jagannadham and R. Veda Vrath, ChemEdNZ (New Zeeland Journal of Chemical Education) (2012) November issue page 12.
In article      
 
[42]  R. Sanjeev, V. Jagannadham and R. Veda Vrath, Chemistry in New Zeeland (2012) October issue page 133.
In article      
 
[43]  R. Sanjeev, V. Jagannadham, R.Veda Vrath, American Journal of Physical Chemistry, published by Scientific and Academic Publishing, USA, (2012) Vol. 2 page 43-47.
In article      View Article
 
[44]  R. Sanjeev, V. Jagannadham and R. Veda Vrath, ChemEdNZ (New Zeeland Journal of Chemical Education) (2012) August issue page 7-9.
In article      
 
[45]  Jagannadham V and Sanjeev Rachuru, Advances in Physical Chemistry, published by Hindawi publishers, USA, Volume 2012 (2012), Article ID 598243, 1-4 pages.
In article      
 
[46]  V. Jagannadham, and R. Sanjeev, Chem13News, published by Department of Chemistry, University of Waterloo, Canada, February 2012, number 388, page 15.
In article      
 
[47]  V. Jagannadham, and R. Sanjeev, Creative Education, Published by Scientific Research Publishing Inc (USA) (2012) Vol. 3, No. 3, pages 380-382.
In article      View Article
 
[48]  R. Sanjeev, V. Jagannadham, International Journal of Chemistry, (Bombay, India) (2012), Vol. 1, page 97-99.
In article      
 
[49]  R. Sanjeev, V. Jagannadham and R. Veda Vrath, ChemEdNZ,(New Zeeland Journal of Chemical Education) (2012) May issue, pages 8-10.
In article      
 
[50]  V. Jagannadham, R. Sanjeev and R. Veda Vrath, ChemEdNZ, (New Zeeland Journal of Chemical Education) (2012) November issue page 14.
In article      
 
[51]  R. Sanjeev, V. Jagannadham, R. Veda Vrath, Khimiya/Chemistry (The Bulgarian Journal of Chemical Education), (2012) Vol. 21, page 71-77.
In article      
 
[52]  V. Jagannadham, American Journal of Chemistry, Published by Scientific and Academic Publishing, USA, (2012) Vol. 1, page 26-28.
In article      
 
[53]  R. Sanjeev, V. Jagannadham and R. Veda Vrath, Education Journal 2012; 1(1): 1-4. Published online December 30, 2012.
In article      
 
[54]  V. Jagannadham, American Journal of Physical Chemistry, Published by Scientific and Academic Publishing, USA, (2012) vol. 2. page 100-102.
In article      View Article
 
[55]  R. Sanjeev, V. Jagannadham, D. Dhiman, Bulgarian Chemical Communications, Vol. 43, (3), pp. 465-466, (2011).
In article      
 
[56]  V. Jagannadham, Bulgarian Chemical Communications, (2011) vol. 42, page 383-394.
In article      
 
[57]  V. Jagannadham, Khimiya/Chemistry (The Bulgarian Journal of Chemical Education), (2010) vol. 19, page 114.
In article      
 
[58]  V. Jagannadham, Creative Education Published by Scientific Research Publishing Inc (USA) (2010) Vol. 1, 128.
In article      View Article
 
[59]  V. Jagannadham, Chemical Education Journal, Japan, (2009), Vol. 12, No. 1. http://chem.sci.utsunomiya-u.ac.jp/cejrnlE.html.
In article      
 
[60]  V. Jagannadham, D. Annapurna Padmavathi, and R. Sanjeev, International Journal of Chemical Kinetics, (2009) vol. 41, page 554.
In article      View Article
 
[61]  V. Jagannadham. Bulgarian Chem. Commns., (2009) vol. 41, page 50.
In article      
 
[62]  V. Jagannadham Khimiya/Chemistry (The Bulgarian Journal of Chemical Education), Vol. 18, (2009) page 89.
In article      
 
[63]  V. Jagannadham. Resonance, (2009), Vol. 14, No. 11, page 1097.
In article      
 
[64]  Corwin Hansch, A. Leo, and R. W. Taft, Chem. Rev. 199l, 91, 165-195.
In article      View Article
 
[65]  A. Williams, Free Energy Relationships in Organic and Bioorganic Chemistry, Royal Society of Chemistry, Cambridge, 2003, p. 75.
In article      
 
[66]  Nguyen-Nguyen Pham-Tran, Guy Bouchoux, David Delaere, and Minh Tho Nguyen, J. Phys. Chem. A 2005, 109, 2957-2963.
In article      View Article  PubMed
 
[67]  Làszló Nyulàszi, Chem. Rev. 2001, 101, 1229-1246.
In article      View Article  PubMed
 
[68]  Adam Moser, Kevin Range, and Darrin M. York, J Phys Chem. B. 2010, 114(43): 13911-13921.
In article      View Article  PubMed
 
[69]  Kenzo Hiraoka, Can. J. Chem. 65, 1258 (1987).
In article      View Article
 
[70]  Takahashi H, Suzuoka D, Morita A, J Chem Theory Comput. 2015 Mar 10; 11(3): 1181-94.
In article      View Article  PubMed
 
[71]  Hunt, Ian. "Substituent Effects". University of Calgary Department of Chemistry. Retrieved 16 November 2012.
In article