Simulation of the molecular and electronic structure of heterofullerenes C55Y5 (YSi, Ge, Sn, B, Al, N, P, SiH, GeH, SnH) and their η5-π-complexes with Li by the MNDO method

Chistyakov, A. L.; Станкевич, И. В.

doi:10.1016/s0020-1693(98)00210-2

Cited by 13 publications

(3 citation statements)

References 23 publications

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“…116 Apart from the extensive experimental work, theoretical investigations into the monodoped C 59 B/ C 59 N, 117 C 59 O, 118 C 59 S, 118d C 59 Be, 118c C 59 Si, 118c,119 C 59 P, 120 C 59 M (M ) Fe, Co, Ni, Rh), 114,121 C 69 M (M ) Co, Rh, Ir), 122 C 58 (BN), 123 and C 59 B/C 59 N dimer 124 have been performed. Some multiply substituted heterofullerenes, such as C 55 X 5 (X ) Si, Ge, Sn, B, Al, N, P, SiH, GeH, SnH) and their η 5 -π-complexes with Li 125 and C 54 N 6 126 , have also been studied. The isomerism, aromaticity, and electronic properties of C 48 X 12 (X ) B, N, Si, P), especially C 48 N 12 , have probably been the most active area for computational studies on heterofullerenes in the last 3 years (see section 3.4.5 for details).…”

Section: Aromaticity Of Heterofullerenesmentioning

confidence: 99%

Spherical Aromaticity: Recent Work on Fullerenes, Polyhedral Boranes, and Related Structures

2005

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Section: Aromaticity Of Heterofullerenesmentioning

confidence: 99%

Spherical Aromaticity: Recent Work on Fullerenes, Polyhedral Boranes, and Related Structures

2005

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“…Therefore for all practical purposes, 3PH may be considered to have a planar skeleton. For 3PH , another minima with C s symmetry is obtained but it is virtually identical in energy compared to the bowl (see also ref ), since we are interested in bowl shaped molecules, only the C 3 v structure is considered.…”

Section: Referencesmentioning

confidence: 99%

“…The discovery of fullerenes stimulated contemporary chemistry researchers to investigate and unravel the unique structural, electronic, optical, biological, magnetic, and other properties of this potentially promising class of compounds. , Although the attempts to achieve the synthesis of C 60 by rational means are yet to be successful, these attempts have opened an exciting area in the synthetic organic chemistry, in the form of buckybowl chemistry. − A large number of interesting bowl-like moieties, which form a part of C 60 , have been synthesized and were shown to exhibit novel structural, chemical, and physical properties. − Computations played a pivotal role in understanding and modeling the novel properties of buckybowls. − In fullerene chemistry, heterohedral fullerenes, where one or more skeletal C atoms are replaced by heteroatoms, such as B, Si, and N, have attracted considerable attention, and these dopyballs are considered to modulate the superconducting, electrical, and redox properties of fullerenes. , …”

Section: Introductionmentioning

confidence: 99%

Heterobuckybowls: A Theoretical Study on the Structure, Bowl-to-Bowl Inversion Barrier, Bond Length Alternation, Structure-Inversion Barrier Relationship, Stability, and Synthetic Feasibility

and

Sastry

2001

J. Org. Chem.

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Hybrid density functional theory (DFT) calculations at the B3LYP/cc-pVDZ level have been performed on a series of heterobuckybowls, 3X, C(18)X(3)H(6) (X = O, NH, CH(2), BH, S, PH, PH(3), Si, SiH(2), and AlH). The minimum energy conformations and the transition states for bowl-to-bowl inversion, where the geometry is bowl shaped, are computed and characterized by frequency calculations. The geometries of heterotrindenes, 2X, C(12)X(3)H(6) (X = O, NH, CH(2), BH, S, PH, PH(3), Si, SiH(2), and AlH), were obtained, and the bond length alternation (Delta) in the central benzenoid ring shows remarkable sensitivity as a function of substituent with a wide range of fluctuations (-0.014 to +0.092 A). The Delta computed in 2BH was found to be comparable with the highest bond alternation reported to date in benzenoid frameworks. The inversion dynamics of these heterobowls and their bowl depths were fit to a mixed quartic/quadratic function. The size of the heteroatom seems to exclusively control the bowl depth and rigidity as well as the synthetic feasibility. In contrast, the bond length alternation seems to be controlled by electronic factors and not by the size of the substituted atom either in trindenes or in heterosumanenes. The thermodynamic stability of this class of compounds is very much comparable with trithiasumanene (3S), which has been synthesized recently. The chemical hardness (eta) was measured to assess the stability of the heterosumanenes. The strain energy buildup in a sequential ring closure strategy along two synthetic routes, namely a triphenylene route and a trindene route, were explored, and the trindene route was found to be highly favorable for making such compounds compared to the triphenylene route. However, in both routes the ease of the synthetic feasibility increases as the size of the heteroatom increases.

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Simulation of molecular and electronic structure of η5-π-complexes of fullereneI h -C 60 with half-sandwich XCp species (X=Si, Ge, Sn)

Chistyakov

Станкевич

1998

Russ Chem Bull

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The molecular and electronic structure of hypothetical complexes of unsubstituted fullerene C6o with I h symmetry and its cyclopentadienyl type derivatives were simulated by the MNDO/PM3 method taking the C60(XCp) ~ molecules (n = 1, 2, 10, 12; X = Si, Ge, Sn) and qS-rc-C60HsXCp (X ---Ge, Sn), respectively, as example. The complexes 12qS-Tt-C60(XCP)12 and rls-n-Cts0HsXCp with lh and Csv symmetry, respectively, were found to be the most stable compounds. The energies of the X--C60 bonds in these complexes are close ~o those of X--Cp bonds in bis(cyclopentadienyl) complexes XCp2 and are substantially higher than the energies of similar bonds in complexes of unsubstituted fullerene q t-C60XC p" al~ rl5--x-C60XCp +. Geometric parameters and spin densities in radicals C60XC p" and biradicals C60(XCp) 2 and C60Hl0 were calculated.Key words: fullerenes, re-complexes, radicals; silicon, germanium, tin; quantum-chemical calculation, M N DO/PM3 method.The carbon framework of the polyhedral cluster C60 with I h symmetry (lh-C60) (as well as the polyhedra of many other fullerenes) consists of five-and sixmembered cycles, each of them containing 5 and 6 =-electrons, respectively. Because of this, there is a possibility for the cluster lh-C60 to form rlS-,'t -and rl6-Tc-complexes. However, no stable compounds of this type have been synthesized to date, though the fuUerene chemistry is progressing very intensively (see, e.g., Ref. 1).Theoretical estimates of the possibility for 35-and rl6-complexes of C60 to exist z-8 have been carried out first of all taking exohedral and endohedral C60 complexes with the Li + cation as examples (see Ref. 2). It has been shown by the MNDO method that the rl6-coordination of Li + to unsubstituted fullerene is more preferable than the rlS-coordination; however, the Li--C60 bond energy (taking into account the fact that this method overestimates the Li--C bond energy) 9 is low.The estimates of the stability of hypothetical complexes rl'l-C60MCp (M = Fe, Ru, Os) and rln-C60CrBz (n = 5, 6) obtained from EHT calculations with no geometry optimization show that the M--C60 bonds in such coml~lexes, if they exist, must be very weak as compared to the M--Cp bonds in the same complexes and in corresponding classical sandwich compounds MCp~ and MBz 2 with the same metals. 4`s Strong delocalization of ~-electrons in rl 5-and rl6-complexes of unsubstituted fullerenes C m (m > 60) is likely to be the main reason for the relatively low stability of these systems. 5 Previously, we have proposed three procedures for increasing the stability of rlS-complexes with polyhedral carbon framework. This procedure was first demonstrated taking bowl-shaped fullerene fragments as an example 6 and then applied to complexes C60R 5 (R = H, CI, Br) with SiCp" species (see Ref. 7) and Li atom (see Ref. 8). In this case the ~-el.ectron system of the radical C60R 5" (1) formed is divided into two parts consisting of 5 and 50 r~-electrons.The electron density on the atoms of the isolated pent* fragment increases and the net effe...

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Simulation of the molecular and electronic structure of heterofullerenes C55Y5 (YSi, Ge, Sn, B, Al, N, P, SiH, GeH, SnH) and their η5-π-complexes with Li by the MNDO method

Cited by 13 publications

References 23 publications

Spherical Aromaticity: Recent Work on Fullerenes, Polyhedral Boranes, and Related Structures

Spherical Aromaticity: Recent Work on Fullerenes, Polyhedral Boranes, and Related Structures

Heterobuckybowls: A Theoretical Study on the Structure, Bowl-to-Bowl Inversion Barrier, Bond Length Alternation, Structure-Inversion Barrier Relationship, Stability, and Synthetic Feasibility

Simulation of molecular and electronic structure of η5-π-complexes of fullereneI h -C 60 with half-sandwich XCp species (X=Si, Ge, Sn)

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