A combined QM/MM study of ligand substitution enthalpies in the L2Fe(CO)3, RuCpL2Cl, and RuCp*L2Cl systems

1998 ◽  
Vol 76 (10) ◽  
pp. 1457-1466 ◽  
Author(s):  
Luigi Cavallo ◽  
Tom K Woo ◽  
Tom Ziegler
Keyword(s):  
Experimental Data ◽  
Key Words ◽  
Molecular Mechanics ◽  
Density Functional ◽  
Ligand Substitution ◽  
Organometallic Complexes ◽  
Molecular Structures ◽  
Substitution Reactions ◽  
Good Accord ◽  
Steric Influence

A combined density functional and molecular mechanics approach (QM/MM) has been validated in a study of the substitution reactions: (i) (PH3)2Fe(CO)3 + 2ER3 ⇆ (ER3)2Fe(CO)3 + 2PH3(ER3 = PMe3, PEt3, PMePh2, PPh3, PCyPh2, PiPr3, PBz3, PCy3, AsEt3, AsPh3); and (ii) Cp'Ru(PH3)2Cl + 2ER3 ⇆ Cp'Ru(ER3)2Cl + 2PH3 (Cp' = C5H5, C5(CH3)5; ER3 = PMe3, PEt3, PnBu3, PMe2Ph, PMePh2, PPh3, AsEt3, P(OMe)3, P(OPh)3, P(OCH2)3CEt). The steric influence of the R substituents on the substitution enthalpies correlates well with experimental data. The combined QM/MM approach is also able to afford molecular structures in good accord with experimental estimates. Key words: combined QM/MM, ligand substitutions, organometallic complexes.

scholarly journals Controlling ligand substitution reactions of organometallic complexes: Tuning cancer cell cytotoxicity

2005 ◽  
Vol 102 (51) ◽  
pp. 18269-18274 ◽  
Author(s):  
F. Wang ◽  
A. Habtemariam ◽  
E. P. L. van der Geer ◽  
R. Fernandez ◽  
M. Melchart ◽  
...  
Keyword(s):  
Cancer Cell ◽  
Ligand Substitution ◽  
Organometallic Complexes ◽  
Cell Cytotoxicity ◽  
Substitution Reactions ◽  
Ligand Substitution Reactions

Ab Initio Hartree-Fock and Density Functional Theory Study on Molecular Structures, Energies, and Vibrational Frequencies of 2-Amino-3-, 4-, and 5-Nitropyridine

2010 ◽  
Vol 65 (1-2) ◽  
pp. 107-112 ◽  
Author(s):  
Yusuf Sert ◽  
Fatih Ucun ◽  
Mustafa Böyükata
Keyword(s):  
Experimental Data ◽  
Density Functional Theory ◽  
Ab Initio ◽  
Density Functional ◽  
Vibrational Frequencies ◽  
Geometric Parameters ◽  
Molecular Structures ◽  
Basis Set ◽  
Functional Theory ◽  
Hartree Fock

AbstractThe molecular structures, vibrational frequencies, and corresponding vibrational assignments of 2-amino-3-, 4-, and 5-nitropyridine have been calculated by using ab initio Hartree-Fock (HF) and density functional theory (B3LYP) methods with 6-311++G(d,p) basis set level. The calculated vibrational frequencies and optimized geometric parameters (bond lengths and bond angles) were found to be in well agreement with the experimental data. The comparison of the observed and the calculated results showed that the scaled B3LYP method is superior to the scaled HF method for both the vibrational frequencies and the geometric parameters. For well fitting the calculated and the experimental frequencies we used scale factors obtained from the ratio of the frequency values of the strongest peaks in the calculated and the experimental spectra. These obtained scales seem to cause the better agreement of the gained vibrations to the experimental data.

scholarly journals Supported and inserted monomeric niobium oxide species on/in silica: a molecular picture

2015 ◽  
Vol 17 (34) ◽  
pp. 22402-22411 ◽  
Author(s):  
Diana C. Tranca ◽  
Anna Wojtaszek-Gurdak ◽  
Maria Ziolek ◽  
Frederik Tielens
Keyword(s):  
Experimental Data ◽  
Density Functional Calculations ◽  
Density Functional ◽  
Niobium Oxide ◽  
Spectroscopic Properties ◽  
Oxide Catalysts ◽  
Molecular Structures ◽  
Molecular Picture

The geometry, energetic, and spectroscopic properties of molecular structures of silica-supported niobium oxide catalysts are studied using periodic density functional calculations (DFT) and compared with experimental data.

Computational Investigation of the Asymmetry in Photosynthetic Reaction Center Models from First Principles

2020 ◽  
Author(s):  
Denis Artiukhin ◽  
Patrick Eschenbach ◽  
Johannes Neugebauer
Keyword(s):  
Spin Density ◽  
Reaction Center ◽  
Density Functional ◽  
Photosynthetic Reaction Center ◽  
Chem Phys ◽  
Molecular Structures ◽  
Error Characteristic ◽  
Molecular Systems ◽  
Density Distributions ◽  
The Asymmetry

We present a computational analysis of the asymmetry in reaction center models of photosystem I, photosystem II, and bacteria from <i>Synechococcus elongatus</i>, <i>Thermococcus vulcanus</i>, and <i>Rhodobacter sphaeroides</i>, respectively. The recently developed FDE-diab methodology [J. Chem. Phys., 148 (2018), 214104] allowed us to effectively avoid the spin-density overdelocalization error characteristic for standard Kohn–Sham Density Functional Theory and to reliably calculate spin-density distributions and electronic couplings for a number of molecular systems ranging from dimeric models in vacuum to large protein including up to about 2000 atoms. The calculated spin densities showed a good agreement with available experimental results and were used to validate reaction center models reported in the literature. We demonstrated that the applied theoretical approach is very sensitive to changes in molecular structures and relative orientation of molecules. This makes FDE-diab a valuable tool for electronic structure calculations of large photosynthetic models effectively complementing the existing experimental techniques.

scholarly journals 1,3,5-Triaza-7-Phosphaadamantane (PTA) as a 31P NMR Probe for Organometallic Transition Metal Complexes in Solution

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1390 ◽  
Author(s):  
Ilya G. Shenderovich
Keyword(s):  
Chemical Shift ◽  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Density Functional ◽  
Molecular Structures ◽  
Basis Sets ◽  
Functional Theory ◽  
Non Covalent Interactions ◽  
Covalent Interactions

Due to the rigid structure of 1,3,5-triaza-7-phosphaadamantane (PTA), its 31P chemical shift solely depends on non-covalent interactions in which the molecule is involved. The maximum range of change caused by the most common of these, hydrogen bonding, is only 6 ppm, because the active site is one of the PTA nitrogen atoms. In contrast, when the PTA phosphorus atom is coordinated to a metal, the range of change exceeds 100 ppm. This feature can be used to support or reject specific structural models of organometallic transition metal complexes in solution by comparing the experimental and Density Functional Theory (DFT) calculated values of this 31P chemical shift. This approach has been tested on a variety of the metals of groups 8–12 and molecular structures. General recommendations for appropriate basis sets are reported.

Sign in / Sign up

Export Citation Format

Share Document