The role of Cr, Mo and W in the electronic delocalization and the metal–ring interaction in metallocene complexes

2018 ◽  
Vol 42 (7) ◽  
pp. 5334-5344 ◽  
Author(s):  
David Arias-Olivares ◽  
Dayán Páez-Hernández ◽  
Rafael Islas

Metal influence over triple-decker, sandwich-like and pyramidal structured benzenes was studied by means of energy decomposition analysis (Morokuma–Ziegler), combined with extended transition state natural orbitals for chemical valence, and Nucleus Independent Chemical Shift descriptors.

2018 ◽  
Vol 14 ◽  
pp. 1537-1545 ◽  
Author(s):  
Eric Detmar ◽  
Valentin Müller ◽  
Daniel Zell ◽  
Lutz Ackermann ◽  
Martin Breugst

Carboxylate-assisted cobalt(III)-catalyzed C–H cyanations are highly efficient processes for the synthesis of (hetero)aromatic nitriles. We have now analyzed the cyanation of differently substituted 2-phenylpyridines in detail computationally by density functional theory and also experimentally. Based on our investigations, we propose a plausible reaction mechanism for this transformation that is in line with the experimental observations. Additional calculations, including NCIPLOT, dispersion interaction densities, and local energy decomposition analysis, for the model cyanation of 2-phenylpyridine furthermore highlight that London dispersion is an important factor that enables this challenging C–H transformation. Nonbonding interactions between the Cp* ligand and aromatic and C–H-rich fragments of other ligands at the cobalt center significantly contribute to a stabilization of cobalt intermediates and transition states.


Molecules ◽  
2020 ◽  
Vol 25 (24) ◽  
pp. 5860
Author(s):  
Tímea R. Kégl ◽  
László Kollár ◽  
Tamás Kégl

The mechanism of the carbonylation of diazomethane in the presence of iron–carbonyl–phosphine catalysts has been investigated by means of DFT calculations at the M06/def-TZVP//B97D3/def2-TZVP level of theory, in combination with the SMD solvation method. The reaction rate is determined by the formation of the coordinatively unsaturated doublet-state Fe(CO)3(P) precursor followed by the diazoalkane coordination and the N2 extrusion. The free energy of activation is predicted to be 18.5 and 28.2 kcal/mol for the PF3 and PPh3 containing systems, respectively. Thus, in the presence of less basic P-donor ligands with stronger π-acceptor properties, a significant increase in the reaction rate can be expected. According to energy decomposition analysis combined with natural orbitals of chemical valence (EDA–NOCV) calculations, diazomethane in the Fe(CO)3(phosphine)(η1-CH2N2) adduct reveals a π-donor–π-acceptor type of coordination.


2015 ◽  
Vol 11 ◽  
pp. 2727-2736 ◽  
Author(s):  
Diego M Andrada ◽  
Nicole Holzmann ◽  
Thomas Hamadi ◽  
Gernot Frenking

Fifteen cyclic and acylic carbenes have been calculated with density functional theory at the BP86/def2-TZVPP level. The strength of the internal X→p(π) π-donation of heteroatoms and carbon which are bonded to the C(II) atom is estimated with the help of NBO calculations and with an energy decomposition analysis. The investigated molecules include N-heterocyclic carbenes (NHCs), the cyclic alkyl(amino)carbene (cAAC), mesoionic carbenes and ylide-stabilized carbenes. The bonding analysis suggests that the carbene centre in cAAC and in diamidocarbene have the weakest X→p(π) π-donation while mesoionic carbenes possess the strongest π-donation.


2021 ◽  
Vol 23 (36) ◽  
pp. 20533-20540
Author(s):  
Gustavo Cárdenas ◽  
Álvaro Pérez-Barcia ◽  
Marcos Mandado ◽  
Juan J. Nogueira

The interactions that control the permeation of cisplatin through a DOPC bilayer are unveiled by a QM/MM EDA scheme.


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