Theoretical evidence of metal-induced structural distortions in a series of bipyrimidine-based ligands

Abstract

Herein, we report theoretical evidence of the geometric changes occurring upon complexation, for a series of octupolar bipyrimidine-based ligands incorporating the NPh2 terminal donor group. It is shown that ligands 1 and 2 (4,4',6,6'-tetrakis(N,N-diphenylaminostyryl)-[2,2']bipyrimidine and 4,4',6,6'-tetrakis((N,N-diphenyl)-9,9'-dioctyl-9H-fluorene-2-amine)-2,2'-bipyrimidine) exhibit a non-planar geometry with a torsion angle between both pyrimidine moieties of ∼25° and 50° respectively. 1a (complex of 1) becomes planar upon addition of ZnCl2 to the bipyrimidine moiety whereas 2a remains distorted. Furthermore, an assignment of the absorption bands for all compounds is presented.

An Ab Initio QM/MM Study of the Electrostatic Contribution to Catalysis in the Active Site of Ketosteroid Isomerase

“…All MD simulations were performed with the AMBER12 program [ 30 ]. A previous work [ 41 ] by Latouche et al demonstrated that the Gaussian program is able to perform a QM/MM simulation with good accuracy, and thus the sander module with an interface to the Gaussian09 program [ 42 ] was used to carry out the QM/MM MD simulation.…”

Two-Photon-Triggered NO Release via a Ruthenium–Nitrosyl Complex with a Star-Shaped Architecture

“…However, the latter transition may become partially allowed upon relaxation to conformations with a lower symmetry. 23,24 Therefore, the interarm interaction energy can be estimated to have a value of ca. 0.31 eV for RuTX.…”

“…In this precise case, one should stress that for pure C 3 symmetry, the S 0 –S 1 transition is one-photon-allowed whereas the S 0 –S 2 one is theoretically one-photon-forbidden. However, the latter transition may become partially allowed upon relaxation to conformations with a lower symmetry. , Therefore, the interarm interaction energy can be estimated to have a value of ca. 0.31 eV for RuTX .…”

A Heptanuclear Copper Iodide Nanocluster

“…1 presents a large molecular structure with a great number of atoms (278). Calculations of both the ground and excited states on molecular compounds of such large size have rarely been conducted 48 and especially on polymetallic systems. 49 The geometries of the singlet ground state (S 0 ) and of the lowest excited triplet state (T 1 ) of 1 have thus been optimized.…”