Abstract
The characteristic of π electrons has a crucial role in determining various properties of chemical systems, such as reactivity, aromaticity and spectroscopy. There are a large number of methods could be used for investigating π electronic structure, for example, the well-known electron localization function and multicenter bond order. For completely planar systems, the π molecular orbitals can be unambiguously identified and thus studying their π electronic structure is easy. However, for non-planar systems, identification of π orbitals and then analysis of π electrons are often not trivial. In this work, based on localized molecular orbitals (LMOs), we propose a conceptually simple and easy way to automatically identify π orbitals for any kind of systems, which makes subsequent analyses of π electrons straightforward. In addition, we show that the identified π LMOs can also be used to reliably estimate π component of molecular orbitals or other kinds of orbitals. The method proposed in this work has been implemented into our wavefunction analysis code Multiwfn as a key ingredient of standard analysis protocol for π electrons. Application examples given in this article illustrated that this protocol makes analysis of π electronic structure for a wide variety of chemical systems unprecedentedly convenient and reliable.
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References
Yu D, Rong C, Lu T, Chattaraj PK, De Proft F, Liu S (2017) Aromaticity and antiaromaticity of substituted fulvene derivatives: perspectives from the information-theoretic approach in density functional reactivity theory. Phys Chem Chem Phys 19:18635
Yu D, Rong C, Lu T, Proft FD, Liu S (2018) Aromaticity study of benzene-fused fulvene derivatives using the information-theoretic approach in density functional reactivity theory. Acta Phys Chim Sin 34:639
Yu D, Stuyver T, Rong C, Alonso M, Lu T, De Proft F, Geerlings P, Liu S (2019) Global and local aromaticity of acenes from the information-theoretic approach in density functional reactivity theory. Phys Chem Chem Phys 21:18195
Klessinger M, Michl J (1994) Excited states and photochemistry of organic molecules. VCH Publishers Inc, New York
Grimme S (2008) Do special noncovalent π–π stacking interactions really exist? Angew Chem Int Ed 47:3430
Yang Y-F, Liang Y, Liu F, Houk KN (2016) Diels-Alder reactivities of benzene, pyridine, and di-, tri-, and tetrazines: the roles of geometrical distortions and orbital interactions. J Am Chem Soc 138:1660
Liu Z, Lu T, Hua S, Yu Y (2019) Aromaticity of Hückel and Möbius topologies involved in conformation conversion of macrocyclic [32]Octaphyrin(1.0.1.0.1.0.1.0): refined evidence from multiple visual criteria. J Phys Chem C 123:18593
Lu T, Manzetti S (2014) Wavefunction and reactivity study of benzo[a]pyrene diol epoxide and its enantiomeric forms. Struct Chem 25:1521
Geuenich D, Hess K, Köhler F, Herges R (2005) Anisotropy of the induced current density (ACID), a general method to quantify and visualize electronic delocalization. Chem Rev 105:3758
Hirshfeld FL (1977) Bonded-atom fragments for describing molecular charge densities. Theor Chem Acc 44:129
Lu T, Chen F (2012) Atomic dipole moment corrected Hirshfeld population method. J Theor Comput Chem 11:163
Lu T, Chen F (2012) Comparison of computational methods for atomic charges. Acta Phys Chim Sin 28:1
Lu T, Chen F (2013) Bond order analysis based on the Laplacian of electron density in fuzzy overlap space. J Phys Chem A 117:3100
Bader FW (1994) Atoms in molecules: a quantum theory. Oxford University Press, New York
Rong C, Lu T, Liu S (2014) Dissecting molecular descriptors into atomic contributions in density functional reactivity theory. J Chem Phys 140:024109
Mulliken RS (1955) Electronic population analysis on LCAO-MO molecular wave functions. II. Overlap populations, bond orders, and covalent bond energies. J Chem Phys 23:1841
Becke AD, Edgecombe KE (1990) A simple measure of electron localization in atomic and molecular systems. J Chem Phys 92:5397
Fuentealba P, Chamorro E, Santos JC (2007) Understanding and using the electron localization function. In: Toro-Labbé A (ed) Theoretical aspects of chemical reactivity. Elsevier, Amsterdam, p 57
Lu T, Chen F (2011) Meaning and functional form of the electron localization function. Acta Phys Chim Sin 27:2786
Lu T, Chen Q (2018) Revealing molecular electronic structure via analysis of valence electron density. Acta Phys Chim Sin 34:503
Manzetti S, Lu T (2013) Alternant conjugated oligomers with tunable and narrow HOMO-LUMO gaps as sustainable nanowires. RSC Adv 3:25881
Manzetti S, Lu T, Behzadi H, Estrafili MD, Thi Le H-L, Vach H (2015) Intriguing properties of unusual silicon nanocrystals. RSC Adv 5:78192
Savin A, Jepsen O, Flad J, Andersen OK, Preuss H, von Schnering HG (1992) Electron localization in solid-state structures of the elements: the diamond structure. Angew Chem Int Ed Engl 31:187
Santos JC, Andres J, Aizman A, Fuentealba P (2004) An aromaticity scale based on the topological analysis of the electron localization function including σ and π contributions. J Chem Theory Comput 1:83
Santos JC, Tiznado W, Contreras R, Fuentealba P (2004) Sigma-Pi separation of the electron localization function and aromaticity. J Chem Phys 120:1670
Liu S, Rong C, Lu T, Hu H (2018) Identifying strong covalent interactions with pauli energy. J Phys Chem A 122:3087
Astakhov AA, Tsirelson VG (2014) Spatial localization of electron pairs in molecules using the fisher information density. Chem Phys 435:49
Schmider HL, Becke AD (2000) Chemical content of the kinetic energy density. J Mol Struct (THEOCHEM) 527:51
Tsirelson V, Stash A (2002) Analyzing experimental electron density with the localized-orbital locator. Acta Crystallogr Sect B Struct Sci 58:780
Jacobsen H (2013) Bond descriptors based on kinetic energy densities reveal regions of slow electrons—another look at aromaticity. Chem Phys Lett 582:144
Giambiagi M, de Giambiagi M, Mundim K (1990) Definition of a multicenter bond index. Struct Chem 1:423
Kar T, Sánchez Marcos E (1992) Three-center four-electron bonds and their indices. Chem Phys Lett 192:14
Ponec R, Mayer I (1997) Investigation of some properties of multicenter bond indices. J Phys Chem A 101:1738
Yu D, Rong C, Lu T, De Proft F, Liu S (2018) Baird’s rule in substituted fulvene derivatives: an information-theoretic study on triplet-state aromaticity and antiaromaticity. ACS Omega 3:18370
Matito E (2016) An electronic aromaticity index for large rings. Phys Chem Chem Phys 18:11839
Mayer I (1983) Charge, bond order and valence in the AB initio SCF theory. Chem Phys Lett 97:270
Matito E, Poater J, Solà M, Duran M, Salvador P (2005) Comparison of the AIM delocalization index and the mayer and fuzzy atom bond orders. J Phys Chem A 109:9904
Lu T, Chen F (2012) Multiwfn: a multifunctional wavefunction analyzer. J Comput Chem 33:580
Lu T, Chen F (2011) Calculation of molecular orbital composition. Acta Chim Sin 69:2393
Ros P, Schuit GCA (1966) Molecular orbital calculations on copper chloride complexes. Theor Chem Acc 4:1
Szabo A, Ostlund NS (1989) Modern quantum chemistry. Dover Publications, New York
Pipek J, Mezey PG (1989) A fast intrinsic localization procedure applicable for ab initio and semiempirical linear combination of atomic orbital wave functions. J Chem Phys 90:4916
Edmiston C, Ruedenberg K (1963) Localized atomic and molecular orbitals. Rev Mod Phys 35:457
Reed AE, Schleyer PVR (1990) Chemical bonding in hypervalent molecules the dominance of ionic bonding and negative hyperconjugation over d-orbital participation. J Am Chem Soc 112:1434
Jensen F (2007) Introduction to computational chemistry. Wiley, West Sussex
Foster JM, Boys SF (1960) Canonical configurational interaction procedure. Rev Mod Phys 32:300
Martin RL (2003) Natural transition orbitals. J Chem Phys 118:4775
Weinhold F (1998) Natural bond orbital methods. In: Schleyer PVR (ed) Encyclopedia of computational chemistry, vol 2. Wiley, West Sussex, p 1792
Frisch MJ, Trucks GW, Schlegel HB, Scuseria GE, Robb MA, Cheeseman JR, Scalmani G, Barone V, Petersson GA, Nakatsuji H, Li X, Caricato M, Marenich AV, Bloino J, Janesko BG, Gomperts R, Mennucci B, Hratchian HP, Ortiz JV, Izmaylov AF, Sonnenberg JL, Ding WF, Lipparini F, Egidi F, Goings J, Peng B, Petrone A, Henderson T, Ranasinghe D, Zakrzewski VG, Gao J, Rega N, Zheng G, Liang W, Hada M, Ehara M, Toyota K, Fukuda R, Hasegawa J, Ishida M, Nakajima T, Honda Y, Kitao O, Nakai H, Vreven T, Throssell K, Montgomery JA Jr, Peralta JE, Ogliaro F, Bearpark MJ, Heyd JJ, Brothers EN, Kudin KN, Staroverov VN, Keith TA, Kobayashi R, Normand J, Raghavachari K, Rendell AP, Burant JC, Iyengar SS, Tomasi J, Cossi M, Millam JM, Klene M, Adamo C, Cammi R, Ochterski JW, Martin RL, Morokuma K, Farkas O, Foresman JB, Fox DJ (2016) Gaussian 16. Wallingford, CT
Hariharan PC, Pople JA (1973) The influence of polarization functions on molecular orbital hydrogenation energies. Theor Chem Acc 28:213
Stephens PJ, Devlin FJ, Chabalowski CF, Frisch MJ (1994) Ab initio calculation of vibrational absorption and circular dichroism spectra using density functional force fields. J Phys Chem 98:11623
Humphrey W, Dalke A, Schulten K (1996) VMD: visual molecular dynamics. J Mol Graph 14:33
Deng Y, Yu D, Cao X, Liu L, Rong C, Lu T, Liu S (2018) Structure, aromaticity and reactivity of corannulene and its analogues: a conceptual density functional theory and density functional reactivity theory study. Mol Phys 116:956
Perdew JP (1986) Density-functional approximation for the correlation energy of the inhomogeneous electron gas. Phys Rev B 33:8822
Becke AD (1988) Density-functional exchange-energy approximation with correct asymptotic behavior. Phys Rev A 38:3098
Andrae D, Häußermann U, Dolg M, Stoll H, Preuß H (1990) Energy-adjustedab initio pseudopotentials for the second and third row transition elements. Theor Chim Acta 77:123
Sedlak R, Janowski T, Pitoňák M, Řezáč J, Pulay P, Hobza P (2013) Accuracy of quantum chemical methods for large noncovalent complexes. J Chem Theory Comput 9:3364
Johnson ER, Keinan S, Mori-Sánchez P, Contreras-García J, Cohen AJ, Yang W (2010) Revealing noncovalent interactions. J Am Chem Soc 132:6498
For manual corresponding to Multiwfn Version 3.7, see section 4.100.22 on how to perform analyses similar to this work. The steps of realizing topology analysis of ELF-π is illustrated in section 4.5.3. The way of rendering isosurface maps by VMD program based on the data calculated by Multiwfn is introduced in section 4.A.14. The manual is freely available at http://sobereva.com/multiwfn Accessed on 30 Sep 2019
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Lu, T., Chen, Q. A simple method of identifying π orbitals for non-planar systems and a protocol of studying π electronic structure. Theor Chem Acc 139, 25 (2020). https://doi.org/10.1007/s00214-019-2541-z
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DOI: https://doi.org/10.1007/s00214-019-2541-z
Keywords
- Orbital localization
- Electron structure
- Electron localization function
- Multiwfn
- Localized orbital locator
- Electron density
- π electron
- Bond order