Ruthenophanes: Evaluating Cation−π Interactions in [Ru(η⁶-C₁₆H₁₂R₄)(NH₃)₃]^2+/3+ Complexes. A Computational Insight

Abstract

The nature of cation−π interactions in a set of [Ru(η6-C16H12R4)(NH3)3]2+3+ (R = F, CN, CH3, and others), complexes was investigated with Su–Li energy decomposition analysis and the natural orbitals for chemical valence and the extended transition state method EDA-NOCV. The long-distance effects of electron-donating and electron-withdrawing substituents as well as protonation of the ipso carbon on the nature of cation−π interactions were investigated. Both energy decomposition analyses, Su–Li EDA and EDA-NOCV, are in total agreement, showing that the presence of electron-donating substituents such as CH3, NH2, and H3CO tends to stabilize the ruthenium–arene interaction while electron-withdrawing substituents such as F, CN, and NO2 tend to weaken such interactions. The electrostatic component of the ruthenium–arene interaction is the most affected by the substitution, despite the fact that the covalent character is much more significant than the electrostatic character. EDA-NOCV reveals that the most important orbital stabilization comes from donation and back-donation between the interacting fragments, while the σ density deformations present a moderate contribution to total orbital stabilization energy in ruthenium–arene interactions of complexes 1–8.

Generalized Kohn‐Sham energy decomposition analysis and its applications

“…Understanding the physical origins of noncovalent interactions is an important task for EDA methods. GKS‐EDA and LMO‐EDA have been used to analyze various noncovalent interactions, including hydrogen bond, halogen bond, chalcogen bond, tetrel bond, pnicogen bond, π‐π stacking, cation⋯π, anion⋯π, XH⋯π (X = C, N, or O), and cooperative effects . Here we illustrate several representative applications for hydrogen bonds, halogen bonds and π‐π stacking, which show the diversity of physical origins in various noncovalent interactions.…”

In Silico Design of Cylindrophanes: The Role of Functional Groups in a Fluoride Selective Host

“…is considered a poor R group to host anions, [20] and s-triazine (TRZ) lies on the borderline between being able to interact with both cations and anions, [107][108][109] cyanuric acid (CA), on the other hand, is a very good anion receptor due to its π-acidic nature, and in fact has proved to be so. [20,23,40] Despite this fact, BZN and TRZ are known as good π-systems to form metal complexes, and such metal-R complexes have proved to be effective in tuning the aromatic system to become electron deficient, [24,60,61,110] hence BZN and TRZ should be considered good candidates to form novel π-metallated cylindrophane systems ideally including NH þ 2 groups in the bridges to coordinate anions. Figure 5, correlating H to HG in the H!…”

“…Attention has increasingly been given to receptors capable of selectively recognizing and coordinating fluoride, [58,59] highlighting the challenges intrinsic to anion coordination in aqueous systems, often involving the synthesis of metallated receptors that interact strongly with anions. [25,60,61]…”

“…Ultimately, numerous anion‐ π based studies have led to the development of novel supramolecular systems as well as advances in catalysis, medicinal chemistry, and biochemistry, all of which support the continued drive to gain insight into this specific NCI . Attention has increasingly been given to receptors capable of selectively recognizing and coordinating fluoride, highlighting the challenges intrinsic to anion coordination in aqueous systems, often involving the synthesis of metallated receptors that interact strongly with anions …”

Advances in bonding and properties of inorganic systems from relativistic calculations in Latin America

“…Furthermore, the cation‐π interaction can be modified by adjusting complementary ligands, as studied in the series of functionalized ruthenophanes of the type [Ru([2.2] paracyclophane)(NH 3 ) 3 ] 2+/3+. As a result, the use of electron‐withdrawing groups in the π‐ring, such as ‐F and ‐CN, leads to a significant increase in the total ruthenium‐arene bonding, while a decrease of the interaction is observed when the quantity of the electron‐donor group ‐CH 3 is diminished …”