Editorial. Paul Von Ragué Schleyer ( ) Gernot Frenking and Peter R. Schreiner.. 9. Published online 31 October 2015.

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1 Editorial Paul Von Ragué Schleyer ( ) Gernot Frenking and Peter R. Schreiner.. 9 Published online 31 October 2015 From Small Fullerenes to the Graphene Limit: A Harmonic Force-Field Method for Fullerenes and a Comparison to Density Functional Calculations for Goldberg Coxeter Fullerenes up to C 980 Lukas N. Wirz, Ralf Tonner, Andreas Hermann, Rebecca Sure, and Peter Schwerdtfeger...10 A general force field is introduced which works for all fullerene isomers. It leads to structures and zero-point vibrational energy contributions in very good agreement to more expensive quantum theoretical calculations. The graphene limit is well represented by the growth of Goldberg- Coxeter transforms of C 20. Published online 26 March 2015 Theoretical and Experimental Investigation of Crown/Ammonium Complexes in Solution Andreas J. Achazi, Larissa K. S. von Krbek, Christoph A. Schalley, and Beate Paulus...18 Published online 13 April 2015 Gibbs energies of association DG T sol of monovalent crown/ammonium complexes in solution are calculated with DFT-D3(BJ) and the continuum solvation model COSMO-RS. For comparison, experimental data are obtained by isothermal titration calorimetry. Calculated and measured Gibbs energies of association DG T sol in solution agree well. Inter- and Intramolecular CFC¼O Interactions on Aliphatic and Cyclohexane Carbonyl Derivatives Rodrigo A. Cormanich, Roberto Rittner, David O Hagan, and Michael Bühl Published online 23 April 2015 Prototypical inter- and intramolecular CFC¼O interactions are assessed computationally at the B3LYP-D3 level. The interactions are noticeable in intermolecular complexes, where they can amount to stabilizations around 1 kcal/mol. However, they are not strong enough to dominate conformational preferences in organofluorine derivatives.

2 The block-localized wavefunction method, which can derive hypothetical structures without the charge transfer effect and conduct intermolecular energy decomposition analysis, is used to probe the origins of the directionality of weak noncovalent bonds. While the overall steric energy exhibits certain angular dependency, in all cases the charge transfer exhibits the strongest directionality, suggesting that the linearity or near linearity of noncovalent bonds is largely governed by the charge-transfer interaction whose magnitude determines the bond covalency. The occupancy of the a 2u MOs of (CO) 4, (CS) 4, and (CSe) 4 control the NICS(1) values that are computed for these compounds. The Origins of the Directionality of Noncovalent Intermolecular Interactions Changwei Wang, Liangyu Guan, David Danovich, Sason Shaik, and Yirong Mo...34 Published online 25 May 2015 Nucleus-Independent Chemical Shift Analysis of the Electronic States of the (CO) 4, (CS) 4, and (CSe) 4 Molecules Yunfei Zhou, Xiaoguang Bao, and Weston Thatcher Borden...46 Published online 8 June 2015 This work determines total atomization energies and heats of formation for platonic and prismatic polycyclic hydrocarbon cages by means of the W1-F12 and W2- F12 thermochemical protocols. Using these accurate reference data, the performance of computationally economical theoretical methods (e.g., density functional theory and composite ab initio methods) was evaluated via atomization and bond separation reactions for the calculation of these challenging thermochemical quantities. Hydrogen bonding interactions can polarize the p-systems of 4-pyridones to increase cyclic (4n+2) p-electron delocalization. The resulting H-bonded six-membered rings exhibit enhanced p-aromaticity and the corresponding N HO¼C interactions are strengthened. Extended H- bonded 4-pyridone chains exhibit high degrees of such cooperativity, even when each of the neighboring 4-pyridone rings are twisted to preclude direct p-overlap between the H-bonded units. Heats of Formation of Platonic Hydrocarbon Cages by Means of High-Level Thermochemical Procedures Amir Karton, Peter R. Schreiner, and JanM.L.Martin...49 Published online 12 June 2015 Hydrogen Bond Aromaticity Cooperativity in Self-Assembling 4-Pyridone Chains Megha Anand, Israel Fernández, and Henry F. Schaefer III, Judy I-Chia Wu Published online 23 June 2015 VC 2016 Wiley Periodicals, Inc. Journal of Computational Chemistry 2016, 37, 1 154

3 Molybdatricarbaboranes as Examples of Isocloso Metallaborane Deltahedra with Three Carbon Vertices Alexandru Lupan and R. Bruce King...64 Published online 16 July 2015 The lowest energy CpMoC 3 B n 4 H n 1 (n 5 8, 9, 10, 11) structures are based on isocloso or similar MoC 3 B n 4 deltahedra with the molybdenum atom at the unique degree 6 vertex, the carbon atoms at the lowest degree vertices (typically degree 4 vertices), no pairs of adjacent carbon atoms (i.e., no C-C edges), and the maximum number of Mo-C edges. Ab Initio/GIAO-CCSD(T) 13 C NMR Study of the Rearrangement and Dynamic Aspects of Rapidly Equilibrating Tertiary Carbocations, C 6 H þ 13 and C 7H þ 15 The rearrangement pathways of the equilibrating tertiary carbocations such as 2,3- dimethyl-2-butyl cation were calculated by the ab initio/giao-ccsd(t) method. George A. Olah, G. K. Surya Prakash, and Golam Rasul...70 Published online 20 July 2015 Aromaticity, Quantum Multimolecular Polyhedra, and Quantum QSPR Fundamental Equation Ramon Carbó-Dorca...78 Published online 18 August 2015 Beyond Static Structures: Putting Forth REMD as a Tool to Solve Problems in Computational Organic Chemistry Riccardo Petraglia, Adrien Nicolaï, Matthew D. Wodrich, Michele Ceriotti, and Clemence Corminboeuf Published online 31 July 2015 A concise description of Kekulé s historical origin of aromaticity and the current state of the field is given. Still, space is left for a discussion about the existence of aromaticity s quantum mechanical foundation. Quantum multimolecular polyhedra (QMP), based on density functions sets attached to QMP vertices, collective QMP distances, QSPR fundamental equation, and aromaticity descriptors are proposed as a way to construct an equation able to estimate aromaticity via expectation values of Hermitian operators. Replica-exchange molecular dynamics (REMD) is combined with density functional tight binding (DFTB) and applied to organic chemical problems. REMD@DFTB permits thorough exploration of the potential energy surface and reveals new insights and chemistry that likely would be missed using static electronic structure computations.

4 Electron transfer through the p-stacked faces of paracyclophane bridge units in bis-triarylamine mixed-valence systems has been studied using a previously established quantum-chemical protocol. Pseudo-meta and pseudo-para connected systems exhibit very similar electronic couplings and thermal electron-transfer barriers, explained by resonant hole transfer. Through-space electron transfer through the p-stack dominates over through-bond transfer through the linkers. Electron Transfer Pathways in Mixed- Valence Paracyclophane-Bridged Bis-Triarylamine Radical Cations Martin Kaupp, Simon Gückel, Manuel Renz, Sascha Klawohn, Kolja Theilacker, Matthias Parthey, and Christoph Lambert Published online 12 August 2015 A highly stable bare Ce 6 O 8 cluster of a spherical shape is predicted using evolutionary algorithm and DFT + U calculations. Natural bond orbital analysis, adaptive natural density partitioning algorithm, electron localization function, and partial charge plots demonstrate that the bare Ce 6 O 8 cluster exhibits a unique 6c 2e chemical bonding, thus, explaining its exotic geometry and stability. Very recently, the isolation of 1,2-azaborine was achieved in a cryogenic matrix. The possible isomerization, ring opening, and fragmentation pathways of 1,2-azaborine are investigated computationally and compared with available experimental and theoretical results for the all-carbon system. d-ao Spherical Aromaticity in Ce 6 O 8 Xiaohu Yu, Artem R. Oganov, Ivan A. Popov, and Alexander I. Boldyrev Published online 18 August 2015 Isomerization and Fragmentation Pathways of 1,2-Azaborine Klara Edel, Reinhold F. Fink, and Holger F. Bettinger Published online 29 September 2015 Quantum chemical calculations are used to investigate the effect of substituents at the 5-position of cyclopentadiene on the stabilities and the activation energies (E a ) for the Diels Alder reactions. Acceptors induce antiaromatic character by Schleyer s negative hyperconjugative aromaticity; donors have the opposite effect. The interaction energies (red) are nearly constant, and the differences in E a arise mainly through changes in the distortion energies of the diene (blue) and dienophile (green). (Values reported in kcal/mol.) Schleyer Hyperconjugative Aromaticity and Diels Alder Reactivity of 5-Substituted Cyclopentadienes Brian J. Levandowski, Lufeng Zou, and K. N. Houk Published online 7 October 2015 VC 2016 Wiley Periodicals, Inc. Journal of Computational Chemistry 2016, 37, 1 154

5 Catenanes: A Molecular Mechanics Analysis of the (C 13 H 26 ) 2 Structure D2 Jenn-Huei Lii, Norman L. Allinger, Ching-Han Hu, and Henry F. Schaefer III Published online 29 October 2015 Catenanes have become important molecular units for the design of new materials for 21 st century technology. The origins of strain in the simplest viable saturated hydrocarbon knots is investigated here. The combination of quantum chemistry with molecular mechanics provides many new insights. Re-evaluation of the Bond Length Bond Strength Rule: The Stronger Bond Is not Always the Shorter Bond Elfi Kraka, Dani Setiawan, and Dieter Cremer Published online 29 October 2015 Reverse bond length/bond strength relations have been reported in the literature, in particular for chemical bonds between electron rich atoms, e.g. N F or O F bonds. In this work, a comprehensive rational is derived covering all electronic and electrostatic factors that may lead to shorter but weaker bonds. A key feature is the use of a qualified bond strength measure based on vibrational spectroscopy. The Barrier to the Methyl Rotation in Cis- 2-Butene and its Isomerization Energy to Trans-2-Butene, Revisited Chérif F. Matta, Seyed Abdolreza Sadjadi, Dale A. Braden, and Gernot Frenking Atomic origin of the locally stabilizing H_H contact in cis-2-butene from virial QTAIM atomic energies along the potential energy surface of methyl rotation, i.e., in terms of atomic sub-potential energy surfaces. Published online 18 November 2015