scholarly journals Theoretical study of the formation of a spiro-Sn-heterocyclic compound by cycloaddition reaction of Me2C=Sn: and ethene

2018 ◽  
Vol 24 (6) ◽  
pp. 311-315 ◽  
Author(s):  
Xiaojun Tan ◽  
Xiuhui Lu
Keyword(s):  
New Species ◽  
Intermediate Product ◽  
Theoretical Study ◽  
Cycloaddition Reaction ◽  
Heterocyclic Ring ◽  
Membered Ring ◽  
Energy Profile ◽  
Potential Energy Profile ◽  
Donor Acceptor ◽  
First Time

AbstractX2C=Sn: compounds (X=H, Me, F, Cl, Br, Ph, Ar) are new species. The cycloaddition reactions of X2C=Sn: are also a new study field of unsaturated stannylene chemistry. The mechanism of cycloaddition reaction between singlet Me2C=Sn: and ethene was investigated for the first time using the MP2/GENECP (C, H in 6-311++G**; Sn in LanL2dz) method. From the potential energy profile, it was predicted that the reaction has one dominant channel in which the 5p unoccupied orbital of Sn: in Me2C=Sn: and theπorbital of ethene form aπ→pdonor-acceptor bond in an intermediate product. Instability of the intermediate product results in its isomerization to a four-membered ring of stannylene. The four-membered stannylene further combines with ethene to form another intermediate product that further isomerizes to a spiro-Sn-heterocyclic ring compound.

scholarly journals Ab initio study of the mechanism of formation of a spiro-Sn-heterocyclic ring compound by the cycloaddition reaction of H2C=Sn: and ethylene

2019 ◽  
Vol 84 (3) ◽  
pp. 293-301
Author(s):  
Xiaojun Tan ◽  
Xiuhui Lu
Keyword(s):  
Cycloaddition Reaction ◽  
Heterocyclic Ring ◽  
Membered Ring ◽  
Ab Initio Study ◽  
Mechanism Of Formation ◽  
Potential Energy Profile ◽  
Unoccupied Orbital ◽  
Reaction Rule ◽  
Donor Acceptor ◽  
First Time

X2C=Sn: (X = H, Me, F, Cl, Br, Ph, Ar?) are new species of chemistry. The cycloaddition reactions of X2C=Sn: is a new study field of stannylene chemistry. The mechanism of cycloaddition reaction of singlet H2C=Sn: with ethylene is studied for the first time using the MP2/GENECP (C, H in 6-311++G**; Sn in LanL2dz) method in this paper. From the potential energy profile, it could be predicted that the reaction has one dominant reaction channel. The reaction rule presented is that the 5p unoccupied orbital of tin in H2C=Sn: sidewise overlaps with the bonding ? orbital of ethylene resulting in the formation of an intermediate. The instability of the intermediate makes it isomerise to a four-membered ring stannylene. As the 5p unoccupied orbital of the Sn atom in the four-membered ring stannylene and the ? orbital of ethylene form a ??p donor?acceptor bond, the four-membered ring stannylene further combines with ethylene to form another intermediate, and this intermediate further isomerises to a spiro-Sn-heterocyclic ring compound. The Sn in the spiro-Sn-heterocyclic ring compound is combined with adjacent atoms by sp3 hybridization. The results of this study reveal the mechanism of cycloaddition reaction of X2C=Sn: with symmetric ?-bond compounds.

scholarly journals Ab initio study of the mechanism of forming a spiro-Si-heterocyclic ring compound involving Ge from H2Ge=Si: and acetaldehyde

2016 ◽  
Vol 81 (6) ◽  
pp. 633-643
Author(s):  
Xiuhui Lu ◽  
Jingjing Ming
Keyword(s):  
New Species ◽  
Reaction Pathway ◽  
Cycloaddition Reaction ◽  
Heterocyclic Ring ◽  
Energy Profile ◽  
Ab Initio Study ◽  
Potential Energy Profile ◽  
Reaction Rule ◽  
Donor Acceptor ◽  
A New Species

The H2Ge=Si: and its derivatives(X2Ge=Si:, X = H, Me, F, Cl, Br, Ph, Ar??) is a new species. Its cycloaddition reactions is a new area for the study of silylene chemistry. The mechanism of the cycloaddition reaction between singlet H2Ge=Si: and acetaldehyde has been investigated with MP2/6-311++G** method, From the potential energy profile, it can be predicted that the reaction has a dominant reaction pathway. The reaction rule presented is that the two reactants firstly form a four-membered Ge-heterocyclic ring silylene through the [2+2] cycloaddition reaction. Because of the 3p unoccupied orbital of Si: atom in the four-membered Ge-heterocyclic ring silylene and the ? orbital of acetaldehyde form a ??p donor-acceptor bond, the four-membered Ge-heterocyclic ring silylene further combines with acetaldehyde to form an intermediate. Then the intermediate isomerizes to a spiro-Si-heterocyclic ring compound involving Ge via a transition state.

scholarly journals Ab initio study of mechanism of forming a Si-heterocyclic spiro-Sn-heterocyclic ring compound by cycloaddition reaction of Me2Si=Sn: and ethene

2019 ◽  
Vol 44 (2) ◽  
pp. 114-121
Author(s):  
Xiaojun Tan ◽  
Xiuhui Lu
Keyword(s):  
Singlet State ◽  
Cycloaddition Reaction ◽  
Chemical Species ◽  
Heterocyclic Ring ◽  
Basis Set ◽  
Cycloaddition Reactions ◽  
Unoccupied Orbital ◽  
Donor Acceptor ◽  
Moller Plesset ◽  
First Time

X2Si=Sn: (X = H, Me, F, Cl, Br, Ph, Ar, etc.) are a new chemical species. The cycloaddition reactions of X2Si=Sn: are a new field of stannylene chemistry. The mechanism of the cycloaddition reaction between singlet state Me2Si=Sn: and ethene has been investigated for the first time here using second-order Møller-Plesset perturbation theory together with the 6-311++G** basis set for C, H and Si atoms and the LanL2dz basis set for Sn atoms. From the potential energy profile, it could be predicted that the reaction has one dominant reaction channel. The reaction process presented is that the 5p unoccupied orbital of Sn in Me2Si=Sn: and the π orbital of ethene form a π → p donor–acceptor bond resulting in the formation of an intermediate. The instability of this intermediate makes it isomerize to a four-membered Si-heterocyclic ring stannylene. Because the 5p unoccupied orbital of the Sn atom in the four-membered Si-heterocyclic ring stannylene and the π orbital of ethene form a π → p donor–acceptor bond, the four-membered Si-heterocyclic ring stannylene further combines with ethene to form another intermediate. Because the Sn atom in this intermediate assumes sp3 hybridization after the transition state, the intermediate isomerizes to a Si-heterocyclic spiro-Sn-heterocyclic ring compound. This result indicates the modes of cycloaddition reactions between X2Si=Sn: and symmetric π-bonded compounds, i.e. this study opens up a new field for stannylene chemistry.

scholarly journals An ab initio study of the mechanism of formation of a silicic bis-heterocyclic compound from silylenesilylene (H2Si=Si:) and ethene

2012 ◽  
Vol 77 (1) ◽  
pp. 75-81
Author(s):  
Xiuhui Lu ◽  
Leyi Shi ◽  
Yongqing Li ◽  
Zhina Wang
Keyword(s):  
Potential Energy ◽  
Heterocyclic Compound ◽  
Singlet State ◽  
Reaction Pathway ◽  
Cycloaddition Reaction ◽  
Membered Ring ◽  
Energy Profile ◽  
Ab Initio Study ◽  
Mechanism Of Formation ◽  
Potential Energy Profile

The mechanism of the cycloaddition reaction of the formation of a silicic bis-heterocyclic compound between singlet state silylenesilylene (H2Si=Si:) and ethene wasi investigated by the CCSD(T)//MP2/6-31G* method. From the potential energy profile, it can be predicted that the reaction has one dominant reaction pathway. The presented rule of the dominant reaction pathway is that the [2+2] cycloaddition effect of the two reactants leads to the formation of a four-membered ring silylene (INT1). When the four-membered ring silylene (INT1) interacts with ethene, due to sp3 hybridization of the Si: atom in four-membered ring silylene (INT1), the four-membered ring silylene (INT1) further combines with ethene to form a silicic bis-heterocyclic compound (P2).

The preparation of 1,2,3,5-dithiadiazolium chlorides from the reaction of nitrile sulphides with thiazyl chloride

1994 ◽  
Vol 72 (4) ◽  
pp. 1143-1153 ◽  
Author(s):  
John N. Bridson ◽  
Steven B. Copp ◽  
Melbourne J. Schriver ◽  
Shuguang Zhu ◽  
Michael J. Zaworotko
Keyword(s):  
Crystal Structure ◽  
Cycloaddition Reaction ◽  
Heterocyclic Ring ◽  
Monoclinic Space Group ◽  
Crystal Data ◽  
Space Group ◽  
X Ray ◽  
Alkyl Derivatives ◽  
First Time

Adamantyl-1,3,4-oxathiazol-2-one has been prepared for the first time and from it 1-adamantyl nitrile sulphide has been generated. Characterisation data are presented, including the X-Ray crystal structure of the oxathiazolone. (Crystal data for C12H15NO2S: monoclinic, space group P21/c, a = 11.334(2) Å,b = 7.344(1) Å, c = 14.373(2) Å,β = 107.74(1)°, V = 1139.5(3) Å3, Z = 4, R = 0.042). The planar heterocyclic ring is similar to structures observed in the gas phase for other oxathiazolone derivatives. The nitrile sulphide was reacted with dimethyl-acetylene dicarboxylate in situ to give an isothiazole derivative. The X-Ray crystal structure of 3-adamantyl-4,5-bis(methoxycarbonyl)-isothiazole has been obtained. (Crystal data for C17H21NO4S: monoclinic, space group P21/n, a = 7.305(4) Å, b = 7.339(4) Å, c = 31.552(4) Å, β = 92.75(3)°, V = 1690(1) Å3, Z = 4, R = 0.079). A general cycloaddition reaction was discovered between the nitrile sulphides and thiazyl chloride to give 1,2,3,5-dithiadiazolium chlorides. The structure of the new 4-adamantyl-1,2,3,5-dithiadiazolium chloride was confirmed by reduction to the 4-adamantyl-1,2,3,5-dithiadiazolyl for which the X-Ray crystal structure has been determined. (Crystal data for C11H15N2S2: monoclinic, space group C2, a = 10.284(4) Å, b = 8.651(2) Å, c = 13.669(2) Å, β = 112.83(1)°, V = 1120.9(4) Å3, Z = 4, R = 0.042). The radical adopts a twisted dimer structure in the solid state which is similar to the structures observed for other alkyl derivatives.

Theoretical Study of the Potential Energy Profile of the HBr+ + CO2 → HOCO+ + Br· Reaction

2019 ◽  
Vol 123 (45) ◽  
pp. 9791-9799 ◽  
Author(s):  
Alyson Shoji ◽  
David Schanzenbach ◽  
Ron Merrill ◽  
Jiaxu Zhang ◽  
Li Yang ◽  
...  
Keyword(s):  
Potential Energy ◽  
Theoretical Study ◽  
Energy Profile ◽  
Potential Energy Profile

Diatoms of the genus Navicula of Lake Teletskoye (Altai) and some rivers of its basin

2019 ◽  
Vol 53 (2) ◽  
pp. 255-278
Author(s):  
D. A. Chudaev
Keyword(s):  
New Species ◽  
Diatom Species ◽  
Lake Teletskoye ◽  
First Time ◽  
One New Species

As a result of study of 18 samples, collected in Lake Teletskoye and inflowing rivers in 1992–1995, 34 diatom species of the genus Navicula Bory were found. Among them 21 taxa are new for the studied region, 7 species (Navicula arkona, N. hangaica, N. cf. pseudoreinhardtii, N. ricardae, N. scaniae, N. schweigeri, N. suecicarum) are recorded for the first time in Russia. One new species (N. pseudoharmoniae sp. nov.) is described. It is compared with N. harmoniae and N. digitoconvergens.

Alkaliphilic species Euastrum lacustre (Charophyta, Zygnematophyceae), first record from Russia

2020 ◽  
Vol 54 (2) ◽  
pp. 313-320
Author(s):  
O. V. Anissimova
Keyword(s):  
Cell Wall ◽  
New Species ◽  
First Record ◽  
European Russia ◽  
Similar Species ◽  
Morphological Differences ◽  
First Time ◽  
Kursk Region

Euastrum lacustre is reported for Russia for the first time. This alcaliphilic species was found in the periphyton and plankton of three lakes in the Kursk Region (European Russia). A description of morphology, including the relief of cell wall, and habitats where this taxon is found are represented. LM and SEM microphotographs are provided. Morphological differences of E. lacustre from similar species are discussed. New species for region, namely Closterium aciculare, Cosmarium formosulum, C. granatum, C. pseudoinsigne, C. reniforme and Staurastrum pingue, are found in the samples together with E. lacustre.

To the moss flora of the highlands of the Northern Elbrus region (Central Caucasus)

2013 ◽  
Vol 47 ◽  
pp. 310-317 ◽  
Author(s):  
G. Ya. Doroshina
Keyword(s):  
New Species ◽  
Rare Species ◽  
The Caucasus ◽  
Central Caucasus ◽  
First Time

The list of 89 taxa of mosses from the northern slopes of Elbrus Mount is provided. New species for the region and rare species for the Caucasus are marked. Conostomum tetragonum (Hedw.) Lindb. was collected in the Caucasus for the first time.

The genus Tolmerinus Bernhauer in Borneo (Coleoptera: Staphylinidae, Staphylininae)

2018 ◽  
Vol 154 (1) ◽  
pp. 9-15
Author(s):  
Guillaume De Rougemont
Keyword(s):  
New Species ◽  
Three New Species ◽  
First Time

The genus Tolmerinus Bernhauer is recorded from Borneo for the first time with the descriptions of three new species: T. brunneus sp.n., T. sharpi sp.n.and T. tutus sp.n.

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