A computational study on heterodimerization of charged porphyrins

2001 ◽  
Vol 05 (06) ◽  
pp. 512-522 ◽  
Author(s):  
SAFİYE SAǦ ERDEM
Keyword(s):  
Computational Methods ◽  
Ground State ◽  
Computational Study ◽  
Electrostatic Attraction ◽  
Quantum Mechanical ◽  
Quantum Mechanical Calculations ◽  
Face To Face ◽  
Ground State Structures ◽  
Semi Empirical ◽  
Porphyrin Rings

The structures of the charged porphyrins and their dimers have been investigated with computational methods. Dimers have been formed based on electrostatic attraction of the opposite charges on two different porphyrin monomers, tetra ammonium porphyrin (TAP) and tetra carboxy porphyrin (TCP). Semi-empirical quantum mechanical calculations have been employed to explore the most stable ground-state structures of TCP, TAP and their hetero-dimers. Dimeric structures analyzed are all in face-to-face fashion indicating the strong electrostatic attraction between the two porphyrin rings. Calculations have also predicted that the protons transfer from [Formula: see text]; groups to -COO- groups when the interplanar separation is shorter than 3.7 Å.

STRUCTURE, STABILITY, AND ELECTRONIC PROPERTIES OF LARGE FULLERENES

1993 ◽  
Vol 07 (26) ◽  
pp. 4305-4329 ◽  
Author(s):  
C.Z. WANG ◽  
B.L. ZHANG ◽  
K.M. HO ◽  
X.Q. WANG
Keyword(s):  
Total Energy ◽  
Electronic Properties ◽  
Ground State ◽  
Relative Stability ◽  
Chemical Reactivity ◽  
Structure Stability ◽  
Quantum Mechanical ◽  
Efficient Scheme ◽  
Ground State Structures ◽  
Fullerene Clusters

The recent development in understanding the structures, relative stability, and electronic properties of large fullerenes is reviewed. We describe an efficient scheme to generate the ground-state networks for fullerene clusters. Combining this scheme with quantum-mechanical total-energy calculations, the ground-state structures of fullerenes ranging from C 20 to C 100 have been studied. Fullerenes of sizes 60, 70, and 84 are found to be energetically more stable than their neighbors. In addition to the energies, the fragmentation stability and the chemical reactivity of the clusters are shown to be important in determining the abundance of fullerene isomers.

Crystal Structure and Tautomerism of 1-[N-(4-Iodophenyl)]aminomethylidene-2(1H)naphthalenone

2001 ◽  
Vol 56 (10) ◽  
pp. 1003-1008 ◽  
Author(s):  
H. Ünver ◽  
M. Kabak ◽  
D. M. Zengin ◽  
T. N. Durlu
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Quantum Mechanical ◽  
Monoclinic Space Group ◽  
Quantum Mechanical Calculations ◽  
X Ray ◽  
H Nmr ◽  
Mechanical Methods ◽  
Intramolecular Hydrogen ◽  
Semi Empirical

1-[N-(4-Iodophenyl)]aminomethylidene-2(1H)naphthalenone (1) (C17H12NOI) has been studied by X-ray analysis, IR, 1H NMR, UV and AM1 semi-empirical quantum mechanical methods. It crystallises in the monoclinic space group P21/n with a = 4.844(3), b = 21.428(2), c = 13.726(2) Å, ß = 93.07(2)° (R1 =0.032 for 4132 reflections [I > 2σ(I)]). The title compound is not planar and an intramolecular hydrogen bond connects O1 and N1 [2.530(4) Å]. Complementary IR, 1H NMR and UV measurements out. Tautomerism and conformations of the title semi-empirical quantum mechanical calculations and the results are compared with the X-ray data.

scholarly journals Computational Study of some Double Headed Acyclo-C-Nucleosides

2015 ◽  
Vol 61 ◽  
pp. 1-11
Author(s):  
Sarah Amara ◽  
Noureddine Tchouar ◽  
Salah Belaidi
Keyword(s):  
Electronic Properties ◽  
Ground State ◽  
Density Functional ◽  
Computational Study ◽  
Experimental Studies ◽  
Functional Theory ◽  
Hartree Fock ◽  
Structural And Electronic Properties ◽  
Semi Empirical

In the present paper we have a focus in a study of theoretical characterization of three double headed acyclo-C-nucleosides, which are a recent target of experimental studies. The structural and electronic properties of double headed acyclo-C-nucleosides, 1,4-bis (3-mercapto-1H-1,2,4-triazol-5-yl) butane-1,2,3,4-tetrol, 1,4-bis (4-amino-5-mercapto-4H-1,2,4-triazol-3-yl) butane-1,2,3,4-tetrol and 5,5'-(1,2,3,4-tetrahydroxybutane-1,4-diyl) bis (1,3,4-oxadiazole-2(3H)-thione), have been investigated theoretically by performing semi-empirical molecular orbital, ab initio Hartree-Fock (HF) and Density Functional Theory (DFT) calculations. Geometries of the three molecules are optimized at the level of Austin Model 1 (AM1). The electronic properties and relative energies of the molecules have been calculated by HF and DFT in the ground state.

scholarly journals Application of super cells for quantum-mechanical calculations of the mixing enthalpy of the BCC-phase of the Fe-V system for the basic state

2021 ◽  
Vol 2052 (1) ◽  
pp. 012049
Author(s):  
A L Udovsky ◽  
M V Kupavtsev
Keyword(s):  
Total Energy ◽  
Ground State ◽  
Ferromagnetic State ◽  
Mixing Enthalpy ◽  
Quantum Mechanical ◽  
Quantum Mechanical Calculations ◽  
Bcc Phase

Abstract In this work, the super-cells were used for quantum mechanical calculations of the mixing enthalpia of the BCC phase of the Fe-V system for the ground state. The values of total energy were calculated using 16 -th and 54- atomic super-cells for both clean components and alloys. The mixing enthalpy (ΔH) for the BCC phase was calculated on four 16- and 54- atomic super-cells in the vicinity of pure components, on the basis of which the dependence of the concentration ΔH for BCC alloys in the ferromagnetic state of the Fe-V system of the ground state was built.

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