The 1,2,5-Thiadiazoles

Weinstock, Leonard M.; Pollak, Peter

doi:10.1016/s0065-2725(08)60372-4

Cited by 35 publications

(13 citation statements)

References 64 publications

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“…(iv) Assignments for the X-Sensitive Fundamental Vibrations of Chlorobenzene Since 1 has been shown to have aromatic character (2,8), it is reasonable to expect that the effect on the vibrational frequencies of replacing H by C1 might be similar to that in benzene. Therefore.…”

Section: Methodsmentioning

confidence: 99%

The Infrared and Raman Spectra of 3-Chloro-1,2,5-thiadiazole

Richardson¹

1972

Can. J. Chem.

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Section: Methodsmentioning

confidence: 99%

The Infrared and Raman Spectra of 3-Chloro-1,2,5-thiadiazole

Richardson¹

1972

Can. J. Chem.

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“…This implies cleavage of the selenodiazole rings, release of the Se atoms and formation of external 1,2-diamino groups, in the line of well-identified parallel reduction reactions which transform thiadiazoles or selenodiazoles into similar 1,2-diamino compounds in the presence of reducing agents (Na/ ethanol, Zn/mineral acids, Raney nickel/ethanol, aqueous KHSO 3 , etc.) [31][32][33]. The formation of the octaminoporphyrazine macrocycle (OAPzMg) can be easily followed by observing the colour change of the solution from green to violet, with associated significant UV-vis spectral changes.…”

Section: Transition and Non-transition Metal Derivativesmentioning

confidence: 99%

“…The available information indicates that 1,2,5-thiadiazole is a planar molecule with considerable double bond character over the entire ring, similar to thiophene, pyrazine and even to benzene, sharing with these molecules the same number of p electrons [31], so that the following appear the most adequate representations of 3,4-dicyano-1,2,5-thiadiazole and also of the Se analogue:…”

Section: Structural Information and Further Observationsmentioning

confidence: 99%

New classes of porphyrazine macrocycles with annulated heterocyclic rings

Angeloni

Ercolani

2000

J. Porphyrins Phthalocyanines

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The present contribution summarizes the most recent results on the synthesis and chemical physical characterization of the new classes of porphyrazine macrocycles having annulated five- and seven-membered heterocyclic rings, i.e. tetrakis(thiadizole)porphyrazine, TTDPzH 2, tetrakis(selenodiazole)porphyrazine, TSeDPzH 2, tetrakis-2,3-(5,7dipheny-6H-1,4-diazepino)porphyrazine, Ph 8 DzPzH 2, and a number of their metal derivatives, prepared by using, respectively, 3,4-dicyano-1,2,5-thiadiazole, 3,4-dicyano-1,2,5-selenodiazole, and 5,7-diphenyl-2,3-dicyano-6H-1,4-diazepine as monomeric precursors. The available information indicates that, owing to the presence of electron rich and soft atoms ( S , Se ) inserted in the proximity of the porphyrazine core, the TTDPz and TSeDPz macrocycles, closely resembling their phthalocyanine analogues in terms of structural and electronic features and physical behaviour (solubility, thermal stability, vaporizability, etc.), might be promising new materials for applicative properties. Particularly interesting is the operated peripheral ring opening of the TSeDPz macroxycle leading to the formation of octaaminoporphyrazine, followed by its conversion to a tetrakis(pyrazino)porphyrazine. The macrocycles containing the Ph 8 DzPz skeleton, due to the presence of the external non planar diphenyldiazepine units, appear to exhibit a distinct physical behaviour, which can be probably modulated by appropriate alternative substitutions in the 5, 6, and 7 positions of the diazepine rings.

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“…This ring system is rare in nature [9], but recently amino acid derivatives of 1,2,5-thiadiazol-3-yl-piperazine have been shown to be important in mood control [10] as examples of non-benzodiazepine anxiolytics; other uses are in possible treatment of Alzheimer's disease [11], and as antibacterial and anti-fungal agents (sulphametrole) [12].…”

Section: Introductionmentioning

confidence: 99%

The electronic states of 1,2,5-thiadiazole studied by VUV absorption spectroscopy and ab initio configuration interaction methods

Palmer

2008

Chemical Physics

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The 1,2,5-thiadiazole VUV absorption spectrum over the range 5-12 eV has been obtained for the first time. It shows broad bands centred near 5. 0, 7.2, 7.7, 8.7, 9.6 and 10.6 eV; several of these show well resolved vibrational structure. A number of valence states and Rydberg states relating to the first and second ionisation energies have been identified. The doubling of some bands in the 4.7 eV region (previously reported) is confirmed; a 3s Rydberg state shows a similar phenomenon, which we also attribute to a non-planar upper state; a study of the (planar) equilibrium geometry of the corresponding triplet Rydberg state shows it is a saddle point. Electronic excitation energies for valence (singlet and triplet) and Rydberg-type states have been computed using ab initio multi-reference multi-root CI methods. These studies used a triple-zeta + double polarisation basis set, augmented by diffuse (Rydberg) orbitals. The theoretical study shows the nature of the more intense Rydberg state types, and positions of the main valence and Rydberg bands. There is generally a good correlation between the theoretical intensities and the experimental envelope. Reconsideration of the order of cationic states in the UV-photoelectron spectrum, crucial to the Rydberg state interpretation, has led to the sequence: 2 B 1 < 2 B 2 < 2 A 2 < 2 A 1 . Study of the excitation energies to specific upper states, also supports this order. The value of IE 1 is refined to 10.111 eV. Equilibrium structures show the p-and r-cations are planar, in contrast to the lowest triplet state.

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The 1,2,5-Thiadiazoles

Cited by 35 publications

References 64 publications

The Infrared and Raman Spectra of 3-Chloro-1,2,5-thiadiazole

The Infrared and Raman Spectra of 3-Chloro-1,2,5-thiadiazole

New classes of porphyrazine macrocycles with annulated heterocyclic rings

The electronic states of 1,2,5-thiadiazole studied by VUV absorption spectroscopy and ab initio configuration interaction methods

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