The inability of quantum based methods to provide an exact representation for complex chemical systems is well documented. Thus quantum based methods are prone to inaccurate predictions of the underlying mechanisms due to the use of approximations, assumptions, the diversity of factors involved, intractable calculations, computational limitations, indeterminacy and chaos. Santilli's hadronic chemistry provides a further potential source of inaccuracy due to the fact that it proposes that the present quantum chemical theories require the addition of a small correction factor for molecules with 2 or more electrons. These factors become even more pronounced and inhibitive as the complexity of the system increases. Randell Mills' hydrino species raises questions over the validity of quantum mechanics itself (The hydrogen atom revisited R.L. Mills International Journal of Hydrogen Energy,2000,25,1171-1183).

It is in the area of pericyclic chemistry and aromaticity/antiaromaticity that quantum mechanics has seen it greatest growth within chemistry. Nobel prizes have been awarded for these methods; namely the Woodward Hoffmann Conservation of Orbital Symmetry, Fukui's Frontier Molecular Orbital Theory in 1981 and the ab initio and DFT methods in 1998.

Based on the above limitations of quantum based methods a new theory of pericyclic chemistry and aromaticity/antiaromaticity was developed and published in 2006 in the International Journal of Hydrogen Energy. This new chemical theory is called the Cplex-isoelectronic theory. It is based on the chemical level of the reductional hierarchy and is in line with the Robinson/Ingold electronic theory of organic chemistry. As it is not based on the physics and quantum level less factors are involved and thus there is a lower probability of making inaccurate predictions compared to quantum based methods.

A new electronic theory of pericyclic chemistry and aromaticity is proposed: The Cplex-isoelectronic theory. Consistent with Santilli's hadronic chemistry.
Cloonan MO. Int J Hydrogen Energy 2007, 32, 159-171.

Application of the Cplex-isoelectronic theory to electrocyclisations, sigmatropic rearrangements, cheletropic reactions and antiaromaticity: Consistent with Santilli's hadronic chemistry.
Cloonan MO. Int J Hydrogen Energy 2007, 32 , 3026-3039.

Origins of the Endo selectivity Observed in Pericyclic Reactions based on the Cplex-isoelectronic theory
Cloonan MO. Hadronic Journal 2009, 32(2), 125-158.

The assumptions of the Cplex-isoelectronic theory (ADEP, SDEP, SDSE) were deduced from nucleophilic, radical addition, SN2 and SN2' reactions and the anomeric effect. These assumptions were applied to pericyclic reactions and aromaticity in line with Complexity theory and is backed up by direct empirical evidence from 1,3-dipolar cycloaddition reactions involving nitronates and by its ability to predict the experimental data. The Cplex-isoelectronic theory makes different predictions from the present quantum chemical methods in some cases and the available empirical evidence is consistent with these new predictions.

The ADEP, SDEP and SDSE assumptions of the Cplex-isoelectronic theory represent an expansion of the Robinson Electronic (Electrochemical) Theory of Organic Chemistry (J. Chem. Soc. 1947, 1288-1301; Chem. Rev. 1934;15(2):225-74; Natural Product Reports 1987;4:53-60; J. Soc. Dyers and Colourists 1934;(Jubilee Issue):65-76; J. Chem. Soc. 1926;401-411; J. Chem. Soc. 1922;427-440; Natural Product Reports 1987;4:61-66; J. Chem. Ed. 1980;57(7):484-488; Robinson R. Memoirs of a Minor Prophet. Amsterdam-Oxford-New York: Elsevier; 1976). This expansion explains why it was not possible to explain pericyclic reactions and aromaticity (in full) using the Robinson theory and why quantum chemistry became the major theoretical force in chemistry. However the Robinson theory is still used by chemists including researchers especially when dealing with complex reactions. The Robinson theory explains a phenomenal degree of chemistry and has great predictive powers (see Foreword by J.E. Baldwin in Deslongchamps P, Stereoelectronic Effects in Organic Chemistry; Pergamon: Elmsford New York, 1983). The Robinson electronic theory is at present clothed in the terminology used by Ingold (Chem. Rev. 1934, 15, 225-273) and many chemists know the Robinson theory as “electron pushing”, curved arrows and the electron flow concept. Electron flow is strongly embedded in Coulomb’s law. The cplex-isoelectronic theory is based on making qualitative connections between systems. This method of making connections or noting patterns is at the heart of science and cognition and is in line with regularity theories and is also recognised within Complexity theory. The Robinson theory itself is based on making a qualitative connection between organic molecules/reactions and electrical/charge/magnetism phenomena. This connection was also held strongly by Michael Faraday, the discoverer of electromagnetic induction, diamagnetism, laws of electrolysis and benzene. Other researchers who influenced Robinson’s theory include Joseph Thomson, Volta, Davy, Berzelius, Ramsay, Stark, Lewis, Langmuir, Lapworth and Werner. Experimental evidence for Robinson's connection was found in dipole moment measurements among other experiments. The cplex-isoelectronic theory recognises the limitations of quantitative methods in general to complex chemical systems.

The Cplex-isoelectronic is currently been developed for all areas of pericyclic reactions and aromaticity/antiaromaticity. Obtaining a link with hadronic chemistry and quantum mechanics is for future study