Synthesis, Optical Properties, Structures and Molecular Orbital Calculations of Subazaporphyrins, Subphthalocyanines, Subnaphthalocyanines and Related Compounds

Author(s):  
NAGAO KOBAYASHI

The synthesis of and spectroscopic data on subazaporphyrins, subphthalocyanines, subnaphthalocyanines and their related compounds reported to date are summarized, together with the results of molecular orbital (MO) calculations from our laboratory. Thus the problems and key points in the synthesis of these subazamacrocycles and their electronic absorption and magnetic circular dichroism (MCD) spectra are discussed, together with those of the monosubstituted-type low-symmetrical phthalocyanines obtained by their ring expansion reaction. The Q bands of these subazamacrocycles are orbitally doubly degenerate, and in the Soret band region, three transitions to the orbitally degenerate state are found. The MO calculations suggest that the HOMO levels destabilize considerably while the LUMO levels change slightly with increasing size of the π system. In addition, the electronic adsorption data are reproduced by the calculation only when the two pyrrole hydrogens in the monosubstituted-type phthalocyanines are assumed to be linked to the two pyrrole nitrogens along the short axis.

2006 ◽  
Vol 59 (1) ◽  
pp. 59 ◽  
Author(s):  
Craig J. Roxburgh ◽  
Lee Banting

We have found that the hydrochloride of 2-phenyl-2-[2-(2-piperidyl)ethyl]-4,5,6,7-tetrahydroindan-1,3-dione 1 possesses marked analgesic activity (100% inhibition referenced to codeine) and report, as part of an extensive synthetic program, the synthesis of 38 new and structurally related compounds. Selective catalytic hydrogenation of the pyridine ring of 2-phenyl-2-[2-(2-pyridyl)ethyl]-indan-1,3-dione 2 yields the nine-membered nitrogen-containing heterocycle 6 by a novel ring cyclization–expansion reaction. The structural and functional group parameters required for this novel ring-expansion reaction have been extensively and thoroughly investigated through the synthesis of a series of structurally related compounds; principally by modification, substitution, and replacement of the various functionality contained within 2. In addition, we report the synthesis of a series of new 2-methyl-2-(ω-N-phthalimidoalkyl)-indan-1,3-diones 41, 45, and 53, two of which, like the parent 2-phenyl substituted indan-1,3-dione 2, also undergo a novel ring cyclization–expansion reaction to yield eight- and nine-membered nitrogen-containing rings. However, in these cases, further transannular reactions occur to produce the new 5,5- and 5,6-ring-fused nitrogen-containing heterocycles 44, 48 and 51, 52. Hydrazinolysis of the third, 2-methyl-2-(4-N-phthalimidobutyl)-indan-1,3-dione yields the new azepine-containing ring structure 56 by direct cyclization. Furthermore, some interesting and unexpected chemical properties of the final compounds, which include selective and non-selective pyridine-ring hydrogenations and a few unexpected side reactions, are described.


1962 ◽  
Vol 40 (5) ◽  
pp. 864-869 ◽  
Author(s):  
R. A. Abramovitch ◽  
K. A. H. Adams

δ-Carboline, together with β-carboline, has been synthesized in reasonably good yield by the Fischer cyclization of cyclohexanone 3-pyridylhydrazone followed by dehydrogenation of the separated tetrahydro derivatives. The isomer ratios of products formed in this and similar reactions are discussed. Nitration of δ-carboline gives a mixture of the 6- and 8-nitro derivatives, the latter being the predominant product. The magnitude of the dipole moment of δ-carboline is appreciably higher than that predicted from molecular orbital calculations (15).


1985 ◽  
Vol 63 (1) ◽  
pp. 71-76 ◽  
Author(s):  
N. Colin Baird

Abinitio MO calculations for Si2H2 are reviewed and discussed in qualitative terms. New calculations are reported, by MNDO for Si2H2 and Si2H4, and using both MNDO and abinitio methods (including electron correlation at the MP2 level) for various possible structures for Al2H2 (3). As with the analogous silicon dihydride, a dibridged structure 3a is found to be superior to classical structures 3b, 3c, and 3d. MNDO calculations for derivatives of Al2H2 are reported. Finally, some implications of the calculations for the surface structures of partially-hydrogenated elemental aluminum and silicon are discussed.


1981 ◽  
Vol 36 (10) ◽  
pp. 1092-1094
Author(s):  
H. Itoh ◽  
G. Ertl

Ab initio MO calculations for PN predict a pronounced electron transfer from the P to the N atom. Only very weak interactions result for M-PN (M = Ni, Cu) configurations whereas bond formation is predicted if the N atom couples to the metal. The bond strength for Ni (10.5 kcal/mole) is about twice as large as for the Cu-NP complex (4.6 kcal/mole). Coupling occurs mainly with the 7 σ-level (HOMO) of the ligand whose energy is lowered below that of the 2 π-level.


2019 ◽  
Author(s):  
Yuji Mochizuki ◽  
Koji Okuwaki ◽  
Takumi Kato ◽  
Yuichiro Minato

Recently, the molecular orbital (MO) calculations with quantum computations (QCs) have attracted considerable interest. The cost of QCs highly depends on the number of qubits even on quantum simulators. The reduction of MO space can thus be a crucial issue for the practical applicability of MO-QC. Besides the frozen-core restriction for the occupied MO space, we have used the pseudo-natural orbital derived from the second-order M{\o}ller-Plesset perturbation (MP2) theory for the virtual MO space. A preliminary test on the LiH molecule (STO-3G basis) showed acceleration by a factor larger than 500 for MO-QC with the Blueqat simulator, where the required time was 72 s per solution. Simulations of MO-QC may be used as practical teaching materials in classes.


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