Fluorierungsreaktionen an 3,4‐Dichlor‐1,2,5‐thiadiazol

Geisel, M.; Mews, Rüdiger

doi:10.1002/cber.19821150610

Cited by 26 publications

(8 citation statements)

References 11 publications

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“…In this work, 3-chloro-4-fluoro-1,2,5-thiadiazole was successfully used for the preparation of 1 in an isolated yield of 58% (Scheme ), which gave the first example of chlorine substitution in a whole family of these types of reactions, both intra- and intermolecular . Preliminary substitution of Cl by F in the precursor requires very drastic reaction conditions …”

Section: Resultsmentioning

confidence: 98%

Heterospin π-Heterocyclic Radical-Anion Salt: Synthesis, Structure, and Magnetic Properties of Decamethylchromocenium [1,2,5]Thiadiazolo[3,4-c][1,2,5]thiadiazolidyl

Semenov¹,

Pushkarevsky

Lonchakov

et al. 2010

Inorg. Chem.

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Decamethylchromocene, Cr(II)(eta(5)-C(5)(CH(3))(5))(2) (2), readily reduced [1,2,5]thiadiazolo[3,4-c][1,2,5]thiadiazole (1) in a tetrahydrofuran solvent at ambient temperature with the formation of radical-anion salt [2](+)[1](-) (3) isolated in 97% yield. The heterospin salt 3 ([2](+), S = 3/2; [1](-), S = 1/2) was characterized by single-crystal X-ray diffraction as well as magnetic susceptibility measurements in the temperature range 2-300 K. The experimental data together with theoretical analysis of the salt's magnetic structure within the CASSCF and spin-unrestricted broken-symmetry (BS) density functional theory (DFT) approaches revealed antiferromagnetic (AF) interactions in the crystalline 3: significant between anions [1](-), weak between cations [2](+), and very weak between [1](-) and [2](+). Experimental temperature dependences of the magnetic susceptibility and the effective magnetic moment of 3 were very well reproduced in the assumption of the AF-coupled [1](-)...[1](-) (J(1) = -40 +/- 9 cm(-1)) and [2](+)...[2](+) (J(2) = -0.58 +/- 0.03 cm(-1)) pairs. The experimental J(1) value is in reasonable agreement with the value calculated using BS UB3LYP/6-31+G(d) (-61 cm(-1)) and CASSCF(10,10)/6-31+G(d) (-15.3 cm(-1)) approaches. The experimental J(2) value is also in agreement with that calculated using the BS DFT approach (-0.33 cm(-1)).

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Section: Resultsmentioning

confidence: 98%

Heterospin π-Heterocyclic Radical-Anion Salt: Synthesis, Structure, and Magnetic Properties of Decamethylchromocenium [1,2,5]Thiadiazolo[3,4-c][1,2,5]thiadiazolidyl

Semenov¹,

Pushkarevsky

Lonchakov

et al. 2010

Inorg. Chem.

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“…Synthesis of 1. Under argon, a solution of 3.66 g (0.03 mol) of 3,4-difluoro-1,2,5-thiadiazole and 6.18 g (0.03 mol) of (Me 3 SiN) 2 S 14b in 10 mL of absolute MeCN was added dropwise during 1 h to a refluxed and stirred suspension of 9.12 g (0.06 mol) of freshly calcinated CsF in 100 mL of the same solvent. After an additional 1 h, the reaction mixture was cooled to 20 °C, filtered, and the solvent was distilled off under reduced pressure.…”

Section: Methodsmentioning

confidence: 99%

[1,2,5]Thiadiazolo[3,4-c][1,2,5]thiadiazolidyl: A Long-Lived Radical Anion and Its Stable Salts

et al. 2005

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[1,2,5]Thiadiazolo[3,4-c][1,2,5]thiadiazole (1) is synthesized in 62% yield by fluoride ion-induced condensation of 3,4-difluoro-1,2,5-thiadiazole with (Me(3)SiN=)(2)S. The reversible electrochemical reduction of 1 leads to the long-lived [1,2,5]thiadiazolo[3,4-c][1,2,5]thiadiazolidyl radical anion (2) and further to the dianion (3). The radical anion 2 is also obtained by the chemical reduction of the precursor 1 with t-BuOK in MeCN. The radical anion 2 is characterized by ESR spectroscopy in solution and in the crystalline state. The stable salts [K(18-crown-6)][2] and [K(18-crown-6)][2].MeCN (8 and 9, respectively) are isolated from the spontaneous decomposition of the [K(18-crown-6)][PhXNSN] (6, X = S; 7, X = Se) salts in MeCN solution followed by XRD characterization. The radical anion 2 acts as a bridging ligand in 8 and as chelating ligand in 9. The structural changes observed by XRD in going from 1 to 2 are explained by means of DFT/(U)B3LYP/6-311+G calculations.

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“…3,4-Dichloro-1,2,5-thiadiazole ( 6 ) was a commercial product (Aldrich). All other thiadiazole derivatives were synthesized according to known literature methods: 3,4-difluoro-1,2,5-thiadiazole ( 7 ) was synthesized from the dichloro-derivative with potassium fluoride, 3,4-dicyano-1,2,5-thiadiazole ( 8 ) from diaminomaleonitrile with thionyl chloride, 1,2,5-thiadiazole ( 9 ), and 3,4-dimethyl-1,2,5-thiadiazole ( 10 ) from ethylenediamine dihydrochloride and dimethylglyoxime, respectively, with sulfur monochloride . 5-Methyl-1,3,4-oxathiazole-2-one ( 11 ) was synthesized from acetamide and ClC(O)SCl…”

Section: Methodsmentioning

confidence: 99%

Structure and Stability of Small Nitrile Sulfides and Their Attempted Generation from 1,2,5-Thiadiazoles

2001

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The gas-phase generation and spectroscopic identification of nitrile sulfides by thermolysis of 1,2,5-thiadiazole precursors was attempted, but in all cases the thiadiazoles were found to produce sulfur and the corresponding nitrile. This prompted an investigation by ab initio and density functional calculations for the equilibrium geometries, stabilities, and decomposition mechanisms of several nitrile sulfides (XCNS, where X = H, F, Cl, CN, CH3). Equilibrium geometries obtained from calculations at the B3LYP, MPn(n = 2−4), QCISD, QCISD(T), CCSD, and CCSD(T) levels with moderate to large basis sets indicate that the molecules have linear heavy atom geometries. The exception is the fluoro derivative, which is bent with a calculated barrier to linearity of 889 cm-1 (B3LYP/cc-pVTZ). The nitrile sulfides are predicted by the B3LYP method to be stable in the dilute gas phase, whereas in the condensed phase they are suggested to be very unstable due to bimolecular decomposition. The mechanism of this loss process is complicated by various sulfur transfer and cyclization reactions between decomposition intermediates, with the predicted stable products being sulfur, nitriles, and thiadiazoles. The first step of the bimolecular decomposition is either a cycloaddition to thiofuroxan or a sulfur transfer with simultaneous S2 loss to nitriles.

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Fluorierungsreaktionen an 3,4‐Dichlor‐1,2,5‐thiadiazol

Cited by 26 publications

References 11 publications

Heterospin π-Heterocyclic Radical-Anion Salt: Synthesis, Structure, and Magnetic Properties of Decamethylchromocenium [1,2,5]Thiadiazolo[3,4-c][1,2,5]thiadiazolidyl

Heterospin π-Heterocyclic Radical-Anion Salt: Synthesis, Structure, and Magnetic Properties of Decamethylchromocenium [1,2,5]Thiadiazolo[3,4-c][1,2,5]thiadiazolidyl

[1,2,5]Thiadiazolo[3,4-c][1,2,5]thiadiazolidyl: A Long-Lived Radical Anion and Its Stable Salts

Structure and Stability of Small Nitrile Sulfides and Their Attempted Generation from 1,2,5-Thiadiazoles

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