Ion‐Pairing in Organometallic Chemistry: Structure and Influence on Proton Transfer from a Computational Perspective

Abstract

Keywords: Ion pairs / Density functional calculations / Anions / Cations / Proton transferThe development of NMR spectroscopic techniques such as the nuclear Overhauser effect (NOE) and pulsed gradient spin echo (PGSE) method to study ion-pairing phenomena has increased the understanding of anion-cation interactions in organometallic chemistry and its influence on reactivity in homogeneous catalysis. These developments have greatly benefited from computational studies carried out in synergy with experimental observations. A good description of the preferred sites for anion interaction is obtained with charge analysis on the cation itself. However, depending on the na-

Revisiting the Stereochemistry of Propylene Isotactic Polymerization Reaction Mechanism on C2 Symmetric [SiH2(Ind)2ZrCH3]+ and [SiH2(Ind)2ZrCH3]+[CH3B(C6F5)3]−

“…This clearly indicates that orientation of CA can alter the activation barrier. 74 We also believe that there are many other possible orientations of CA with which the reaction could proceed in the most favorable way. Note that the first insertion in the A approach of this alternative mechanism is more exergonic by 72.57 to 23.08 kcal mol ¹1 compared to that of the C approach.…”

Formation of Chiral Heteronuclear LnIII Assemblies by Ion Pair Formation

“…The DFT theory that has become a standard computation level for molecular complexes is also useful to investigate ion-pairing. [26] We have chosen DFT level theory with the hybrid functional of Truhlar and Zhao M062X [27] with split valance effective core potential effective for the lanthanides by Stevens, Basch and Krauss (CEP-31G). [28][29][30] All calculations have been performed with Gaussian 09 [31] computer code.…”

Outer‐Sphere Redox Reactions Leading to the Formation of Discrete CoIII/FeII Pyrazine‐Bridged Mixed‐Valence Compounds

“…[6][7][8] In circumstances in which the final Co II complex is sufficiently kinetically stable (i.e., due to its encapsulation by a macrocyclic ligand), a substitution process by the formed [Fe III -(CN) 6 ] 3-species (Oxd 2 in Scheme 1) has been observed, [9,10] especially for cases in which the outer-sphere complex-formation equilibrium constant is much larger than that expected from simple Fuoss equation electrostatic considerations. [8,11] These systems are a clear example of the importance of nonelectrostatic interactions in outer-sphere complex formation; they appear even between species with high charges of the same sign [12] that are able to tune the reactivity of {Oxd 1 ;Red 2 } species. [13][14][15] We have been involved in the kinetic and mechanistic study of the outer-sphere redox processes between [Fe II -(CN) 6 ] 4-(Scheme 1, Red 2 ) and Co III or Cr III complexes of pentadentate macrocyclic (N) 5 ligands (Scheme 1, Oxd 1 ).…”