12597-33-0Relevant articles and documents
Theoretical and Experimental Studies of Six-Membered Selenium-Sulfur Nitrides SexS4-xN2 (x = 0-4). Preparation of S4N2 and SeS3N2 by the Reaction of Bis[bis(trimethylsilyl)amino]sulfane with Chalcogen Chlorides
Maaninen, Arto,Siivari, Jari,Suontamo, Reijo J.,Konu, Jari,Laitinen, Risto S.,Chivers, Tristram
, p. 2170 - 2177 (1997)
The reaction of [(Me3Si)2N]2S with equimolar amounts of SCl2 and S2Cl2 produces S4N2 in a good yield. The reaction of [(Me3Si)2N]2S with a 3:1:1 mixture of S2Cl2, Se2Cl2, and SeCl4 yields a dark brown-red insoluble material that was inferred to be mainly SSeSNSN on the basis of the elemental analysis, mass spectroscopy, vibrational analysis, and NMR spectroscopy. Attempts to prepare selenium-rich species resulted in the formation of elemental selenium or Se3N2Cl2. The experimental work was supported by ab initio MO calculations which establish the structural and stability relationships of the different members of the series 1,3-SexS4-xN2 (x = 0-4). Full geometry optimization was carried out for each molecular species using the polarized split-valence MIDI-4* basis sets. The effects of electron correlation were taken into account involving the second-order M?1er-Plessett perturbation theory. Each molecule was found to lie in an approximate half-chair conformation that is well established for 1,3-S4N2 (i.e., interacting planar NEN and EEE fragments; E = S, Se). The bond parameters agree well with experimental information where available. Whereas the lengths of the bonds in the NEEEN fragment approach those of the single bonds, the bonds in the NEN fragment show marked double bond character. The stabilities of the molecules decrease expectedly with increasing selenium content as judged by the total binding energy at the MP2 level of theory. Within a given chemical composition, isomers containing a N=Se=N unit lie higher in energy than those containing a N=S=N unit. These results may explain why selenium-rich SexS4-xN2 molecules have not been isolated.
Crystal Structure of γ-Monoclinic Selenium
Foss, Olav,Janickis, Vitalijus
, p. 624 - 627 (1980)
The crystallization of a new allotrope of cyclo-octaselenium, named γ-monoclinic selenium, from a solution of dipiperidinotetraselane in carbon disulphide is described.The allotrope γ-Se8 crystallizes in space group P21/c (no. 14) with a=15.018(1), b=14.713(1), c=8.789(1) Angstroem, β=93.61(1) deg, and Z=64 (atoms).The crystal structure has been determined by X-ray diffraction from Mo-Kα diffractometer data and refined to R 0.047 for 2 525 observed reflections.There are two crown-shaped Se8 rings in the asymmetric unit, with bond lengths, bond angles , and dihedral angles in the ranges 2.326(3)-2.344(3) Angstroem, 103.3(1)-109.1(1) deg, and 96.5-107.2 deg respectively.The overall averages, 2.334+/-0.005 Angstroem, 105.8+/-1.4 deg, and 101.1+/-2.2 deg, are the same, within error limits, as in α- and β-monoclinic selenium.There are more short contacts between the rings than in the α and β forms, the shortest ones being 3.346(3) and 3.404(3) Angstroem.
Raman band of matrix isolated NaMSeN clusters
Herwig,Schnell,Becker
, p. 462 - 466 (2004)
Selenium clusters are doped with sodium atoms in the reaction zone of a dual laser vaporization source. Product clusters SeN and Na 2SeN with N=4-8 are deposited in a nitrogen matrix and investigated by Raman spectroscopy. Beside the Raman band of pure Se N clusters, a new intense band between 165 and 225 cm-1 is observed. Within a simple model of dynamical charge transfer the new band is attributed to certain vibrational modes with considerable changes of Na-Se bond lengths. The assignment is confirmed by density functional calculations. A bonding model for the Na2SeN clusters containing horseshoe shaped polyanionic selenium chains is developed.
Heteroleptic Samarium(III) Chalcogenide Complexes: Opportunities for Giant Exchange Coupling in Bridging σ- And π-Radical Lanthanide Dichalcogenides
Dimucci, Ida M.,Giansiracusa, Marcus J.,Goodwin, Conrad A. P.,Kragskow, Jon G. C.,Lancaster, Kyle M.,Mills, David P.,Réant, Benjamin L. L.,Sproules, Stephen,Vettese, Gianni F.
, (2020)
The introduction of (N2)3-? radicals into multinuclear lanthanide molecular magnets raised hysteresis temperatures by stimulating strong exchange coupling between spin centers. Radical ligands with larger donor atoms could promote more efficient magnetic coupling between lanthanides to provide superior magnetic properties. Here, we show that heavy chalcogens (S, Se, Te) are primed to fulfill these criteria. The moderately reducing Sm(II) complex, [Sm(N??)2], where N?? is the bulky bis(triisopropylsilyl)amide ligand, can be oxidized (i) by diphenyldichalcogenides E2Ph2 (E = S, Se, Te) to form the mononuclear series [Sm(N??)2(EPh)] (E = S, 1-S; Se, 1-Se, Te, 1-Te); (ii) S8 or Se8 to give dinuclear [{Sm(N??)2}2(μ-η2:η2-E2)] (E = S, 2-S2; Se, 2-Se2); or (iii) with Te=PEt3 to yield [{Sm(N??)2}(μ-Te)] (3). These complexes have been characterized by single crystal X-ray diffraction, multinuclear NMR, FTIR, and electronic spectroscopy; the steric bulk of N?? dictates the formation of mononuclear complexes with chalcogenate ligands and dinuclear species with the chalcogenides. The Lα1 fluorescence-detected X-ray absorption spectra at the Sm L3-edge yielded resolved pre-edge and white-line peaks for 1-S and 2-E2, which served to calibrate our computational protocol in the successful reproduction of the spectral features. This method was employed to elucidate the ground state electronic structures for proposed oxidized and reduced variants of 2-E2. Reactivity is ligand-based, forming species with bridging superchalcogenide (E2)-? and subchalcogenide (E2)3-? radical ligands. The extraordinarily large exchange couplings provided by these dichalcogenide radicals reveal their suitability as potential successors to the benchmark (N2)3-? complexes in molecular magnets.
Sandmeyer-Type Trifluoromethylthiolation and Trifluoromethylselenolation of (Hetero)Aromatic Amines Catalyzed by Copper
Matheis, Christian,Wagner, Victoria,Goossen, Lukas J.
supporting information, p. 79 - 82 (2016/01/25)
Aromatic and heteroaromatic diazonium salts were efficiently converted into the corresponding trifluoromethylthio- or selenoethers by reaction with Me4NSCF3 or Me4NSeCF3, respectively, in the presence of catalytic amounts of copper thiocyanate. These Sandmeyer-type reactions proceed within one hour at room temperature, are applicable to a wide range of functionalized molecules, and can optionally be combined with the diazotizations into one-pot protocols.
Syntheses of THF solutions of SeX2 (X = Cl, Br) and a new route to selenium sulfides SenS8-n (n = 1-5): X-ray Crystal Structures of SeCl2(tht)2 and SeCl2·tmtu
Maaninen, Arto,Chivers, Tristram,Parvez, Masood,Pietikaeinen, Jarkko,Laitinen, Risto S.
, p. 4093 - 4097 (2008/10/08)
A simple and efficient synthesis of solutions of pure SeCl2 in THF or dioxane (ca. 0.4 M) at 23 °C was achieved by treatment of elemental selenium with an equimolar amount of SO2Cl2. SeCl2 was characterized by 77Se NMR and Raman spectra. SeCl2 forms 1:1 or 1:2 adducts with tetramethylthiourea (tmtu) or tetrahydrothiophene (tht), respectively. The crystal structure of SeCl2·tmtu (1) reveals a T-shaped geometry [d(Se-Cl) = 2.443(4) A] with weak intramolecular Se-Cl interactions [d(Se-Cl) = 3.276(4) A]. Crystals of 1 are triclinic, space group P1, with a = 8.473(3) A, b = 9.236(3) A, c = 7.709(4) A, α = 109.90(3)°, β= 92.26(4)°, γ = 107.89(3)°, V = 532.9(4) A 3, and Z =2. The complex SeCl2(tht)2 (2) adopts a square planar geometry with d(Se-Cl) = 2.4149-(8) A. Crystals of 2 are monoclinic, space group C2/c, with a - 15.6784(8) A, b = 9.1678(4) A, c = 9.1246(4) A, β= 110.892(2)°, V = 1225.3(1) A,3 and Z = 4. The reaction of Ph3PS with SeCl2 gives Ph3PCl2 and a complex mixture of selenium Sulfides SenS8-n (n = 1-5), which were identified by 77Se NMR. Halogen exchange between SeCl2 and Me3SiBr in THF yields thermally unstable SeBr2 (ca. 0.4 M) characterized by 77Se NMR and Raman spectra.
Preparation, X-ray Structure, and Spectroscopic Characterization of 1,5-Se2S2N4
Maaninen, Arto,Laitinen, Risto S.,Chivers, Tristram,Pakkanen, Tapani A.
, p. 3450 - 3454 (2008/10/08)
The reaction of [(Me3Si)2N]2S with equimolar amounts of SCl2 and SO2Cl2 produces S4N4 in a good yield. The new chalcogen nitride 1,5-Se2S2N4 hasbeen prepared in high yield by two different reactions: (a) from [(Me3S i)2N]2S and SeCl4 and (b) from [(Me3Si)2N]2Se with equimolar amounts of SCl2 and SO2Cl2. 1,5-Se2S2N4 has a cage structure similar to those of S4N4 and Se4N4. The crystal structure is disordered with site occupation factors ca. 50% for selenium in each chalcogen atom position. The 12 eV EI mass spectrum shows Se2SN2(+) as the fragment with highest mass. Both the (14)N and (77)Se NMR spectra show a single resonance (-238 and 1418 ppm, respectively). These data rule out the possibility that the crystalline sample is a solid solution of S4N4 and Se4N4 and imply the presenceof 1,5-Se2S2N4. This deduction was further verified by Raman spectrosco py and vibrational analysis.
Synthetic studies on the CpRu-PPh3-(Se2) system: Redox interconversions of Ru2(Se2)2 cores
Amarasekera, Jayantha,Houser, Eric J.,Rauchfuss, Thomas B.,Stern, Charlotte L.
, p. 1614 - 1620 (2008/10/08)
The reaction of NaSeH and CpRu(PPh3)2Cl gave CpRu(PPh3)2SeH, while the synthesis of (MeCp)Ru(PPh3)2SeH required the use of NMe4SeH. The corresponding H2Se complexes could not be prepared, as CpRu(PPh3)2OTf failed to add H2Se and protonation of (MeCp)Ru(PPh3)2SeH gave (MeCp)Ru(PPh3)2H2+. The reaction of CpRu(PPh3)2OTf with elemental selenium gave [CpRu(PPh3)2]2(μ-η 1,η1-Se2)(OTf)2 (1). The compound 1·PhMe·CH2Cl2 crystallized in the monoclinic space group P21, with a = 15.965 (3) A?, b = 15.898 (5) A?, c = 18.406 (4) A?, α = γ = 90°, β = 111.28 (2)°, V = 4353 (3) A?3, and Z = 2. The structure was refined to R = 0.054 (Rw = 0.061). The crystallographic studies provide evidence for Ru-Se multiple bonding but show that the Ru2Se2 core is not planar, unlike the core of the analogous persulfido complex. Solutions of 1 reacted further with selenium to give primarily [CpRu(PPh3)]2(μ-η1,η 2-Se2)2(OTf)2. The analogous MeCp complex (2) was characterized by X-ray crystallography. It crystallizes in the triclinic space group P1, with a = 10.909 (5) A?, b = 13.530 (5) A?, c = 10.064 (4) A?, α = 110.13 (3)°, β = 112.18 (3)°, γ = 79.62 (3)°, V = 1289 (2) A3, and Z = 1. The structure was refined to R = 0.050 (Rw = 0.058). Compound 2 was reduced by Cp2Co to give the unstable compound [(MeCp)Ru(PPh3)]2(μ-η1,η 1-Se2)2, which could be reoxidized to give 2 and which in turn thermally eliminated SePPh3 to give (MeCp)4Ru4Se4.
77Se NMR spectroscopic study of the molecular composition of sulfur-selenium melts
Chivers, Tristram,Laitinen, Risto S.,Schmidt, Kenneth J.
, p. 719 - 725 (2007/10/02)
A series of six sulfur-selenium mixtures containing 0.4, 5, 15, 25, 35, and 45 molpercent of selenium were heated in evacuated ampoules at 430 deg C for 4 h and, keeping the material molten at 135 deg C, their natural-abundance 77Se NMR spectra were recorded.The equilibrium melt in each case was found to contain both heterocyclic SenS8-n species and polymeric material.The most abundant eight-membered selenium sulfide rings were SeS7, which was the main cyclic component in all melts studied in this work, and 1,2-Se2S6, the quantity of which increased with increasing selenium content of the melt.In addition the melts contained smaller amounts of 1,3, 1,4, and 1,5 isomers of Se2S6, 1,2,3, 1,2,4, and 1,2,5 isomers of Se3S5, 1,2,3,4, 1,2,3,5, and 1,2,5,6 isomers of Se4S4, 1,2,3,4,5-Se5S3, 1,2,3,4,5,6-Se6S2, and Se8.The relative distribution of the cyclic products as a function of the selenium content in the melt was virtually identical with that obtained earlier in the CS2 solutions of the quenched melts, implying that the extracted quenched melts actually represent the original melt composition as far as the SenS8-n species are concerned.The resonances due to the polymeric material in the melts could best be interpreted by the statistical random distribution of selenium and sulfur in the polymeric chains, the probability of occurrence of the different fragments being governed by the overall composition of the melt.As the selenium content increases, the relative amount of selenium bound in the polymer seems to increase at the expense of heterocyclic selenium sulfides.Key words: selenium sulfides; sulfur-selenium melt, 77Se NMR spectroscopy.
Synthesis, multinuclear magnetic resonance spectra, and chemistry of some complexes (2-) (R = alkyl; M = Zn or Cd; X = Cl, Br, or I) and the X-ray structural analysis of (Et4N)2i)6(CdBr)4>
Dean, Philip A. W.,Vittal, Jagadese J.,Wu, Yuyang
, p. 779 - 791 (2007/10/02)
The self-assembly method has been used to prepare a wide range of new adamantane-like anions of the type (2-) (M = Zn or Cd; R = alkyl or benzyl; X = Cl, Br, or I) as their Et4N(1+) salts.Metal (111or113Cd) NMR data have been measured for the cadmium complexes, and also for many of the possible mixed-metal complexes 4-n>(2-).In the complexes with mixed metals, the effects of Zn substitution on the metal chemical shifts are generally larger for the alkyl- and benzyl-thiolate complexes than for related benzenethiolate complexes.However, for i)6(CdX)n(CdX')4-n>(2-) (X/X'= Cl/Br, Cl/I, or Br/I), substituent effects are no larger than found in some PhS(1-)-bridged complexes.The reaction of i)6(CdX)4>(2-) (X = Cl, Br, or I) with E'8 (E' = S or Se) in CH2Cl2 gives i)12(CdX)4>(2-) as the major species detectable by metal, 13C, and, where applicable, 77Se NMR.However, the reaction does not occur stoichiometrically.The compound (Et4N)2i)6(CdBr)4> crystallizes in the monoclinic space group P 21/c with cell dimensions a = 24.079(3) Angstroem, b = 11.365(2) Angstroem, c = 22.561(3) Angstroem, β = 113.89(1), and Z = 4.The structure was refined to R(Rw) = 0.0663(0.0703) with the use of 2669 unique data with I > 2.5 ?(I).The anion contains an adamantane-type (μ2-S)6Cd4 cage composed of a nearly regular Cd4 tetrahedron and a distorted S6 octahedron, the irregularity of which is caused by 1,3-interactions of the substituent groups on the sulfur atoms.The axial or equatorial dispositions of the six alkyl groups in the four fused M3S3 rings are .For the zinc-group elements, this is the first example of an adamantane-like (μ-Salkyl)6M4 cage that has been characterized crystallographically.Key words: cadmium complex, cadmium-111/113 NMR, thiolate complex, X-ray analysis, zinc complex.
