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The binary freezing-point diagrams of SeCl4AlCl3 and TeCl4AlCl3 were determined. Both systems show a dissociating compound in a molecular ratio 1: 1 with melting points of 163.8° C resp. 149.3° C. In the case of the binary system SeCl4AlCl3 only one half of the system, with AlCl3 in excess, could be determined because of the decomposition of SeCl4 at higher temperatures. The compound TeCl4 · AlCl3 could be distilled in high-vacuum without decomposition. An approximate value for the heat of fusion of both addition compounds was calculated.

Die Titelverbindungen wurden durch Reaktionen von Selen und Selentetrachlorid mit PPh4Cl, NEt4Cl, NMe3PhCl oder (K-18-Krone-6)Cl in Dichlormethan oder Acetonitril hergestellt. (PPh4)2Se3Cl8 · CH2Cl2 entstand auch aus GeSe, PPh4Cl und Chlor in Acetonitril. Die 77Se-NMR-Spektren der Losungen zeigen das Vorliegen von dynamischen Gleichgewichten, bei denen je nach Zusammensetzung vor allem die Spezies SeCl2, SeCl4, Se2Cl2, SeCl62–, Se2Cl62– und/oder Se2Cl102– vorherrschen. Aus Losungen von AsCl3 und (PPh4)2Se4 in Acetonitril wurde (PPh4)2Se2Cl6 durch Chlorierung mit Cl2 oder PPh4AsCl6 erhalten, bei Chlorierung mit SOCl2 war das Produkt (PPh4)2As2Se4Cl12. Nach den Kristallstrukturanalysen haben die Ionen SeCl62–, Se2Cl9– und Se2Cl102– die bekannten Strukturen mit oktaedrischer Koordination der Se-Atome. Das Se3Cl82–-Ion ist wie das Se3Br82–-Ion aufgebaut, d. h. drei SeCl2-Molekule, die uber zwei Cl–-Ionen assoziiert sind. (PPh4)2Se4Cl12 · CH2Cl2 ist isotyp zum gleichartigen Bromoselenat und enthalt Anionen, in denen drei SeCl2-Molekule an ein SeCl62–-Ion angelagert sind, wobei eine eigenartige Se–Se-Wechselwirkung auftritt. Chloroselenates with Di- and Tetravalent Selenium: 77Se-NMR-Spectra, Syntheses, and Crystal Structures of (PPh4)2SeCl6 · 2 CH2Cl2, (NMe3Ph)2SeCl6, (K-18-crown-6)2SeCl6 · 2 CH3CN, PPh4Se2Cl9, (NEt4)2Se2Cl10, (PPh4)2Se3Cl8 · CH2Cl2, and (PPh4)2Se4Cl12 · CH2Cl2 The title compounds were obtained from reactions of selenium and selenium tetrachloride with PPh4Cl, NEt4Cl, NMe3PhCl, or (K-18-crown-6)Cl in dichloromethane or acetonitrile. (PPh4)2Se3Cl8 · CH2Cl2 was also formed from GeSe, PPh4Cl and chlorine in acetonitrile. The 77Se-NMR spectra of the solutions show the presence of dynamical equilibria which, depending on composition, mainly contain SeCl2, SeCl4, Se2Cl2, SeCl62–, Se2Cl62–, and/or Se2Cl102–. Solutions of AsCl3 and (PPh4)2Se4 in acetonitrile upon chlorination with Cl2 or PPh4AsCl6 yielded (PPh4)2Se2Cl6, while (PPh4)2As2Se4Cl12 was the product after chlorination with SOCl2. According to the X-ray crystal structure analyses the ions SeCl62–, Se2Cl9–, and Se2Cl102– have the known structures with octahedral coordination of the Se atoms. The structure of the Se3Cl82– ion corresponds to that of Se3Br82– consisting of three SeCl2 molecules associated via two Cl– ions. (PPh4)2Se4Cl12 · CH2Cl2 is isotypic with the corresponding bromoselenate and contains anions in which three SeCl2 molecules are attached to a SeCl62– ion; there is a peculiar Se–Se interaction.

Electrophilic reactions of sulfur dichloride with unsaturated systems underlie one of the most general methods for the synthesis of bis(2-chloroalkyl) sulfides [1]. Reactions of analogous unsaturated compounds with selenium tetrachloride yield the corresponding bis-adducts containing a four-coordinate selenium atom (>SeCl2) [2]. In recent years we performed systematic studies on reactions of SeCl2 with alkenes and their oxygenand sulfur-containing derivatives [3, 4]. Reactions with chlorinated ethylenes, such as chloroethene, 1,1and 1,2-dichloroethenes, and trichloroethene were reported only for SCl2, and they required the presence of Lewis acids as catalyst [5]. Garratt et al. [6] showed that SeCl4 failed to react with 1,2-dichloroethene in the presence of AlCl3 as catalyst. Nevertheless, we succeeded in adding SeCl2 to bis(2-chlorovinyl) selenide (a selenium-containing derivative of 1,2-dichloroethene) in the absence of a catalyst [7]. Sulfur and selenium dichlorides are known to act as chlorinating agents toward alkylsulfanyl derivatives of polychloroethenes, e.g., alkyl 2,2-dichlorovinyl sulfides [8].

The electrophilic addition of SCl2 or SeCl4 to diallylsilane (I) proceeds strictly according to the Markovnikoff rule furnishing previously unknown thiasilacyclooctane (II) or selenasilaoctane (III), respectively.

Selenium dichloride and dibromide were not isolated as individual substances. It is known that selenium dichloride in solution exists in equilibrium with selenium tetrachloride and Se2Cl2, whereas the equilibrium of selenium dibromide in solution involves Se2Br2 and bromine [1, 2]. We were the first to reveal that freshly prepared selenium dichloride and selenium dibromide can be used in selective synthesis of organic selenides [3, 4]. Reactions of selenium dichloride and dibromide with divinyl chalcogenides and their derivatives opened a synthetic route to new heterocyclic compounds [5–10]. In continuation of our systematic studies on the chemical properties of selenium dihalides [3–10], we examined previously unknown addition of selenium dichloride to divinyl sulfone. It was found that the reaction occurs with high regioselectivity and leads to the formation of a new four-membered heterocyclic compound, 2,4-bis(chloromethyl)-1,3-thiaselenetane 1,1-dioxide (I). The yield of compound I was 85%, calculated on the reacted divinyl sulfone, the conversion of the latter being 58%. sional correlation techniques, as well as by mass spectrometry and elemental analysis. According to the NMR data, compound I was isolated as a mixture of two diastereoisomers at a ratio of 2.5 : 1. 2,4-Bis(chloromethyl)-1,3-thiaselenetane 1,1-dioxide (I). mp 76–77°C. Major diastereoisomer: H NMR spectrum, δ, ppm: 3.91 d.d (2H, CH2Cl, J = 11.8, J = 7.1 Hz), 4.27 d.d (2H, CH2Cl, J = 11.8, J = 7.1 Hz), 5.52 d.d (2H, CHSe, J = 7.1, 7.1 Hz). C NMR spectrum, δC, ppm: 41.39 (CH2Cl), 69.36 (CHSe). Se NMR spectrum: δSe 193 ppm. Minor diastereoisomer: H NMR spectrum, δ, ppm: 3.93 d.d (2H, CH2Cl, J = 11.9, J = 7.7 Hz), 4.31 d.d (2H, CH2Cl, J = 11.9, J = 7.9 Hz), 5.54 d.d (2H, CHSe, J = 7.7, 7.9 Hz). C NMR spectrum, δC, ppm: 41.63 (CH2Cl) , 70.03 (CHSe) . Se NMR spectrum: δSe 200 ppm. Mass spectrum, m/z (Irel, %): 268 (29) [M], 204 (12), 169 (100), 142 (56), 133 (34), 107 (82), 93 (24), 81 (13), 61 (19), 53 (21). Found, %: C 17.69; H 2.21; Cl 26.30. C4H6O2Cl2SSe. Calculated, %: C 17.93; H 2.26; Cl 26.46. The NMR spectra were recorded from solutions in CDCl3 on a Bruker DPX-400 instrument at 400.13 (H, HMDS), 100.61 (C, HMDS), and 76.30 MHz (Se, Me2Se). The mass spectrum (electron impact, 70 eV) was obtained on a Shimadzu GCMS-QP5050A instrument. This study was performed in the framework of the Basic Research Program of the Russian Academy of Sciences (project no. 5.1.8).

The reaction of selenium tetrachloride with the dichlorothiophene diselenolate 3,4-C4Cl2S(SeLi)2 gives triselenole (I) in 38% yield. Purification of I is difficult due to the occurrence of a facile decomposition on attempted dissolution in a variety of solvents.

The cyclocondensation of R 2 PN 2 (SiMe 3 ) 3 (R=Me, Et, Ph) with a mixture of selenium monochloride and selenium tetrachloride that gives a Se:Cl ratio of 1:3 in acetonitrile at 23 o C produces 1,5-Ph 4 P 2 N 4 Se 2 , 2a, in 85% yield by mixtures of 1,5- and 1,3-R 4 P 2 N 4 Se 2 in combined isolated yields of 79% (R=Me) or 96% (R=Et). The heterocycles 1,3-Me 4 P 2 N 4 Se 2 , 4b, and 1,5-Et 4 P 2 N 4 Se 2 , 2c, were separated from these mixtures by fractional crystallization and gel permeation chromatography, respectively.

Selenium dichloride is a promising reagent for organic synthesis. However, prior to our studies [1, 2], it was not used for the preparation of organoselenium compounds. It is known that selenium dichloride in solution exists in equilibrium with selenium tetrachloride and Se2Cl2 [3]. No examples of aromatic electrophilic substitution with participation of selenium dihalides have been reported so far. While continuing our systematic studies on reactions of selenium dihalides [1, 2, 4–10], we examined the reaction of selenium dichloride with methoxybenzene. The reaction occurred as aromatic replacement of hydrogen by the electrophile Se and afforded bis(4-methoxyphenyl) selenide (I) in high yield (91%). Thus selenium dichloride may be used as source of electrophilic Se species in aromatic electrophilic substitution reactions. The possibility of using selenium dihalides for performing analogous reactions with other aromatic systems is now under study. Bis(4-methoxyphenyl) selenide (I). mp 54–55°C; published data [11]: mp 54°C. H NMR spectrum, δ, ppm: 7.28 d (4H, CH, J = 7.4 Hz), 6.69 d (4H, CH, J = 7.4 Hz), 3.72 s (6H, CH3O). C NMR spectrum, δC, ppm: 158.85 (C), 135.24 (C), 122.04 (C), 114.53 (C), 54.49 (CH3O). Mass spectrum, m/z (Irel, %): 294 [M] (75), 214 (100), 199 (96), 187 (14), 171 (28), 144 (12), 128 (25), 107 (77), 92 (13), 77 (14), 63 (47), 39 (18). The H and C NMR spectra were recorded on a Bruker DPX-400 spectrometer at 400.13 and 100.61 MHz, respectively, from a solution in carbon tetrachloride; the chemical shifts were determined relative to hexamethyldisiloxane. The mass spectrum (electron impact, 70 eV) was obtained on a Shimadzu GCMS-QP5050A instrument.

The chemical vapour transport (CVT) of NiTiO3 with SeCl4 is reported. In addition to small NiTiO3 crystals a more or less quantity of solid NiCl2 is deposited in the deposition zone. At higher temperature gradients the solid which is deposited besides NiCl2 is NiO. The transport behaviour is satisfactory explained using two thermodynamical models: the model of connected equilibrium states and the four-stage model. Beim chemischen Transport (CVT) von NiTiO3 mit SeCl4 wird neben kleinen NiTiO3-Kristallen ein Teil des Transportmittels in Form von festem NiCl2 in der Abscheidungszone abgeschieden. Bei groseren Temperaturgradienten wird neben NiCl2 das NiO transportiert. Das Transportverhalten wird sowohl mit dem Modell der gekoppelten Gleichgewichtsraume als auch mit dem Vier-Stufen-Modell befriedigend erklart.

The title compounds 5 were obtained from the reaction of 3,3′,4,4′-tetramethoxybiphenyl (6) or its 2,2′-dilithio derivative 8 with various chalcogen electrophiles (sulfur dichloride, selenium tetrachloride, selenium oxychloride and tellurium tetrachloride).

Raman spectra were obtained for SeCl4 in the solid and for TeCl4 in the solid and the liquid state. Polarization measurements were performed for the stronger Raman lines of liquid TeCl4. The four stronger Raman lines of SeCl4 are very close in frequency to those of pyramidal AsCl3; there is also a close analogy between the frequencies of the stronger Raman lines of TeCl4 (both in the solid and in the liquid state) and those of antimony trichloride. These findings favour the assumption that solid SeCl4 and TeCl4 have to be written as SeCl3+Cl− and TeCl2+Cl− respectively, SeCl3+ being isosteric with AsCl3 and TeCl2+ with SbCl3. Force constant and frequency calculations have been effected for the hypothetical SeCl3+ and TeCl3+ ions. The results support the above assumption.

Durch Reaktion von Tellurtetrachlorid mit Trimethylsilylazid konnten Tellur-trichlorid-azid und Tellur-dichlorid-diazid dargestellt werden. Tellur-trichlorid-azid, das mit Triphenylphosphin unter Stickstoffentwicklung zu (Ph3PNPPh3)2TeCl6 und Te reagiert, ist monomer. Im Unterschied zu Tellurtetrachlorid werden Schwefel- und Selentetrachlorid von Trimethylsilylazid reduziert. Tellurium Trichloride Azide and Tellurium Dichloride Diazide. (Reaction of Trimethylsilyl Azide with Chalkogen Halides) The reaction of tellurium tetrachloride with trimethylsilyl azide leads to the formation of tellurium trichloride azide and tellurium dichloride diazide. The monomeric tellurium trichloride azide reacts with triphenylphosphine under elimination of nitrogen to give (Ph3PNPPh3)2TeCl6 and Te. Unlike tellurium tetrachloride, sulfur tetrachloride and selenium tetrachloride are reduced by trimethylsilyl azide.

Results are discussed which have been obtained in the last few years by the application of Raman spectroscopy to the unravelling of structures of complex compounds, e.g. addition compounds of aluminium chloride with nitrosyl chloride, selenium tetrachloride, and tellurium tetrachloride. Arguments are brought forward for considering NOCl. AlCl3 as a compound intermediate in structure between NO+AlCl4− and NOCl…. AlCl3. Compounds such as SeCl4. AlCl3 and TeCl4. AlCl3 clearly show features of the ionic structures SeCl3+AlCl4− and TeCl3+AlCl4− respectively. In Cl3Al. NH3, on the contrary, a covalent bond between Al and N is present. Preliminary results for compounds SeCl4. SO3 and TeCl4. SO3 argue the presence in these compounds of SeCl3+ and TeCl3+ ions respectively as well.

Selenium tetrachloride(SeCl4) reacts smoothly with alcohols in various nonpolar solvents to give the corresponding alkyl chlorides in 44–97% yield. Similar reaction also proceeds with tellurium tetrachloride (TeCl4), while the treatment of benzyl, 1-phenylethyl, and t-butyl alcohols with TeCl4 in aromatic solvents results in a high yield formation of alkylated aromatics instead of alkyl chlorides. Such Friedel-Crafts aromatic alkylation hardly occurs in the SeCl4 case. The chlorinating species is not chlorine which might be evolved by dissociation of SeCl4 or TeCl4, but the metal chloride itself. The conversion of optically active (R)-(+)-1-phenylethanol to 1-phenylethyl chloride proceeds with nearly complete racemization.