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Abstract: The potential energy surface crossings for reaction between NO2(2A1) and CO(1∑+) catalyzed by Os+ have been investigated using the density functional theory (DFT). Minimum-energy crossing points (MECPs) between the potential energy surfaces and the possible spin inversion process are discussed by means of spin–orbit coupling (SOC) calculations. The latter is found to be the energetically favored channel. The energetic span (δE) model has been applied in this cycle to obtain some kinetic information. TDTS (TOF-determining transition state) and the TDI (TOF-determining intermediate) were confirmed, and TOF (E-representation) was calculated at different temperatures. [Copyright &y& Elsevier]

Abstract: A theoretical investigation at DFT (B3LYP) level on the cyclopropanation reactions catalyzed by nickel(0) and nickel(II) have been extensively investigated. The computation results show that the active catalytic species formed by a CH2 fragment and the Cl2Ni(PH3)2 is carbenoids (PH3)2Ni(CH2Cl)Cl (IMA) and (PH3)Ni(CH2PH3)Cl2 (IMB), but both the carbenes (Cl2NiCH2 (IMC), (PH3)3NiCH2 (IME) and (PH3)2NiCH2 (IMG)) and carbenoids (ClNiCH2Cl (IMD), Ni(CH2PH3)(PH3)2 (IMF) and Ni(CH2PH3)PH3 (IMH)) are active catalytic species obtained from NiCl2, Ni(PH3)3, Ni(PH3)2 and a CH2 fragment. The cyclopropanation reaction proceeds through either concerted or multistep reaction pathway. The most favor cyclopropanation reactions catalyzed by nickel(II) is multistep pathway for IMD with a barrier of 21.65kcalmol−1 but is endothermic 6.74kcalmol−1, and the most favor nickel(0) catalyzed cyclopropanation reactions is also multistep pathway for IME, IMH and IMG species all with barriers of 21.93kcalmol−1 but the downhill potential energy surface discloses that each step of the cyclopropanation reaction are all irreversible. Thus, nickel(0) catalyzed cyclopropanation reaction proceed easer than nickel(II). [Copyright &y& Elsevier]

Abstract: The mechanisms of the reaction between N2O and CO catalyzed by MO+ (M=Ru, Os) have been investigated using the density functional theory (DFT). The potential energy surfaces, the crossing points and the corresponding minimum energy crossing points have been explored. The probability of hopping in the vicinity of the crossing has been calculated by the Landau–Zener-type model. The results indicate the reactions are O-atom abstraction mechanism for the catalysts RuO+ and OsO+. The large probability value shows the intersystem crossing occurs efficiently, which makes the reaction access to a lower energy pathway and accelerate the reaction rate. [ABSTRACT FROM AUTHOR]