RESUMEN
Through an use of three functionals (B3PW91, B3LYP and BP86) associated to a generic basis set LanL2DZ for transition metals (as well as halogen atoms) and 6-311+G (d,p) for others atoms, an examination of the bonding properties of a series of mononuclear half-sandwich nd7 transition metal (anticancer) complexes based on Nâ©N dendritic scaffolds (L) has been done. Collectively, complexes studied have adopted the piano-stool environment. An examination of the performance of each functional has shown that for the most reliable geometrical analysis of Metal-Nitrogen and Metal-Halogen bonds, the B3LYP and B3PW91 functionalities are suitable respectively. Regardless of the halogen ligand adopted, the B3LYP metal-nitrogen bond lengths are the most widely overestimated. A correlation has been built between the retained charge on each divalent transition metal cation and its metal ion affinity (MIA). Topological examinations reveal the higher instability of metal-N bonds compared to metal-X ones (X = Cl and Br). By the mean of the energy decomposition analysis, a predominant electrostatic character of metal halogen and [LCP]- [MX]+ interaction has been demonstrated. The transition metal atom (hydrophobic) surface (Cp*) interaction is most pronounced for the chloride rhodium complexes of rhodium (combined with (E)-N-(pyridin-2-ylmethylene) Propan-1-amine and 2,2'- dipyridylketone ligands and iridium combined with 2,2'- dipyridylketone ligand. The charge decomposition analysis displays the weakening of the [Formula: see text] bonds in the studied complexes.
Asunto(s)
Rodio , Elementos de Transición , Modelos Moleculares , Ligandos , Elementos de Transición/química , NitrógenoRESUMEN
We investigated the flow of electron density along the cyclocondensation reaction between ethyl acetate 2-oxo-2-(4-oxo-4H-pyrido[1.2-a]pyrimidin-3-yl) polyazaheterocycle (1) and ethylenediamine (2) at the ωB97XD/6-311++G(d,p)computational method within of bond evolution theory (BET). The exploration of potential energy surface shows that this reaction has three channels (1-3) with the formation of product 3 via channel-2 (the most favorable one) as the main product and this is in good agreement with experimental observations. The BET analysis allows identifying unambiguously the main chemical events happening along channel-2. The mechanism along first step (TS2-a) is described by a series of four structural stability domains (SSDs), while five SSDs for the last two steps (TS2-b and TS2-c). The first and third steps can be summarized as follows, the formation of N1-C6 bond (SSD-II), then, the restoration of the nitrogen N1 lone pair (SSD-III), and finally, the formation of the last O1-H1 bond (SSD-IV). For the second step, the formation of hydroxide ion is noted, as a result of the disappearance of V(C6,O7) basin and the transformation of C6-N1 single bond into double one (SSD-IV). Finally, the appearance of V(O7,H2) basin lead to the elimination of water molecule within the last domain is observed.
Asunto(s)
Etilenodiaminas , Nitrógeno , AguaRESUMEN
This work lays out the flow of electron density taking place along four reaction pathways of 32CA reaction of acetonitrile oxide between 7-bromo-oxanorborn-5-en-2-one which has been examined in detail and in accordance with the bonding evolution theory (BET). The BET study makes apparent the non-concerted bond breaking/forming processes along each reaction pathway. The number (seven) of stability structural domains (SSD) found along the different reaction pathway through the syn and anti-approach is identical. For the both reaction pathway, the N-C triple and C-C double bonds are the main electron flux and responsible for the appearance of the fold-type catastrophe on N and C atoms. Finally, the C-C sigma bond formation corresponding to cusp catastrophe starts first and follows by the O-C one along the four different reaction pathways.