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1.
Ionic Structures of 4- and 5-coordinated Silicon. Novel Ionic Crystal Structures of 4- and 5-coordinated Silicon: [Me3Si(NMI)]+ Cl?, [Me2HSi(NMI)2]+ Cl?, [Me2Si(NMI)3]2+ 2 Cl?. NMI Me3SiCl forms with N-Methylimidazole (NMI) a crystalline 1:1-compound which is stable at room temperature. The X-ray single crystal investigation proves the ionic structure [Me3Si(NMI)]+Cl? 1 which is the result of the cleavage of the Si? Cl bond and the addition of an NMI-ring. The reaction of Me2HSiCl with NMI (in the molar ratio of 1:2), under cleavage of the Si? Cl bond and co-ordination of two NMI rings, yields the compound [Me2HSi(NMI)2]+Cl? 2 . The analogous reaction of Me2SiCl2 with NMI (molar ratio 2:1) leads to a compound which consists of Me2SiCl2 and NMI in the molar ratio of 1:2. During the sublimation single crystals of the compound [Me2Si(NMI)3]2+ 2 Cl?. NMI 3 are formed.  相似文献   

2.
Alternative Ligands. XVII. Reaction of the Lewis Base [Mn(CO)5]? with Donor/Acceptor Ligands Me2PCH2CH2SiX3 (X = Cl, F, OMe) Reactions [eqn. (1) and (2)] for the preparation of intramolecular adducts between the base [Mn(CO)4PMe2R]? and the Lewis acidic terminal group SiX3 of the ligands Me2PCH2CH2SiX3 (X = Cl, F, OMe) have been studied. Cleavage of the MnSi bond with Cl? [equ.(2)] in the chelate complex to form the complex salt [Ph4As][Mn(CO)4PMe2 CH2CH2SiCl3] proves unsuccessful because of the surprising stability of this bond. The alternative route [equ. (1)] yields the anionic species [Mn(CO)4PMe2CH2CH2SiX3]? in the first step, but reaction conditions favour the formation of with decreasing tendency Cl> F> OMe. The complex salts, therefore, cannot be isolated as pure compounds.  相似文献   

3.
Contributions to the Chemistry of Halogenosilane Adducts. VII. 2,2′-Bipyridine-mono-N-oxide Complexes of Halogenosilanes The new adducts SiF4 · bipyO, SiCl4 · bipyO, SiCl4 · 2 bipyO, SiBr4 · 2 bipyO, SiI4 · 2 bipyO and SiI4 · 3 bipyO have been prepared by the reaction of SiF4, SiCl4, SiBr4 and SiI4 with bipyO in the appropriate molar ratio. The 1:1 reaction of Si2Cl6 and bipyO yields the adduct Cl3SiOSiCl3 · bipy (reduction of the amineoxide), in a 1:2 molar ratio Cl3SiOSiCl3 · bipy and Cl3SiOSiCl3 · 2 bipyO are obtained. The latter compound is formed in the reaction of Cl3SiOSiCl3 · bipy and bipyO and also in the reaction of Cl3SiOSiCl3 and bipyO. The results show that bipyO is a stronger base than bipy with reference to the silanes investigated. Some properties of the compounds and structural investigations are reported. bipyO is chelating and silicon is hexacoordinated in all adducts. The following structures are suggested: SiX4 · bipyO (molecular), [SiX2 · 2 bipyO]X2 (ionic), [Si · 3 bipyO]I4 (ionic). In Cl3SiOSiCl3 · 2 bipyO both ligands are coordinated to one Si atom.  相似文献   

4.
Preparation and Vibrational Spectra of Dichloro and Dibromodithiophosphate. Crystal Structures of [PPh3Me][PS2Cl2] and [PPh4][PS2Br2] Dichloro and dibromodithiophosphates [Cat+][PS2X2?] with a large organic cation can be obtained from P4S10, CatX and HX in CH2Cl2 (Cat+ = PPh4+, PPh3Me+; X = Cl, Br). The vibrational spectra (i.r. and Raman) of the [PS2X2]? ions are reported and discussed; force constants were calculated. The crystal structures of [PPh3Me][PS2Cl2] and [PPh4][PS2Br2] were determined and refined with X-ray diffraction data. In both cases, simple anions [PS2X2]? are present. [PPh3Me][PS2Cl2]: orthorhombic, space group P212121, a = 1089, b = 1334, c = 1476 pm, Z = 4, refinement to a residual index R = 0.046 for 1116 reflexions; the structure is isotopic with [PPh3Me][VO2Cl2]. [PPh4][PS2Br2]: tetragonal space group I4 , a = 1301, c = 721 pm, Z = 2, refinement to R = 0.065 for 357 reflexions; the structure is isotypic with [AsPh4][FeCl4] with [PS2Br2]? ions occupying positions of 4 -symmetry with statistical orientation (statistical superposition of Br and S positions).  相似文献   

5.
Preparation and vibrational spectra of the complexes [MBr6]?, [Br5MN3]? and [Br5MNPPh3]? of niobium and tantalum. Cyrstal structure of PPh4[NbBr6] The compounds PPh4[MBr6] and PPh4[MBr5N3] are obtained by reaction of MBr5 with PPh4Br or PPh4N3, respectively, in CH2Cl2 solution (M ? Nb, Ta). The azido complexes PPh4[MBr5N3] can also be obtained by reactions of the hexabromo complexes with iodine azide. According to its i.r. spectrum the symmetry of the [MBr6]? ion is lower than Oh in the solide state. This is corfirmed for PPh4[NbBr6] by a crystal structure analysis; it crystallizes in the monoclinic space group B2/b with four formula units in the unit cell and with the lattice constants a = 2301, b = 1777, c = 686 pm and γ = 96,6°. The structure was determined with X-ray diffraction data and was refined to a residual index of R = 0.055. The [NbBr6]? ion has the symmetry Ci, the deviations from Oh being small. In the azido complexes [MBr5N3]? the azido groups are covalently linked with the metal. From [NbBr5N3]? and PPh3 the complex [Br5Nb?N?PPh3]?, is obtained; for the analogous formation of the corresponding Ta complex photochemical activation is necessary. In this way the complex [Cl5Nb?N?AsPh3]? can also be obtained. I.r. spectra of all the compounds are reported and assigned.  相似文献   

6.
Three Oxidation Paths of [Ta6Cl12]2+ ([Ta6Br12]2+ and [Nb6Cl12]2+) [Ta6Cl12]2+ is oxidized autocatalytically to [Ta6Cl12]4+ by HNO3. The titration of [Ta6Cl12]2+ with KBrO3 (in HBr-containing solutions) or with Ce4+ or K2Cr2O7 (in HNO3-containing solutions) leads to a clear [Ta6Cl12]3+ step. The further titration leads beside [Ta6Cl12]4+ to the formation of Ta2O5(· xH2O). [Ta6Cl12]2+ behaves with KBrO3(+ HBr) equally, but the formation of [Ta2O5](· xH2O) is only small. [Nb6Cl12]2+ (22°C) titrated with Ce(ClO4)4 in 2n HClO4 gives the first potential step nearby exact ([Nb6Cl12]3+) and at a very slow titration in a second step a precipitation of Nb2O5(· xH2O) occurs, which adsorbed Ce4+ additionally. At ?15°C with Ce(ClO4)4 the first potential step was exactly at [Nb6Cl12]2+→3+, while the second step needs a distinct additional consumption of titer. (Formation of [Nb6Cl12]4+ and beside it [Nb2O5](· xH2O)). From the titration curves and sections of its normal progress in all cases we get the normal potentials 2+/3+ and 3+/4+ with an accuracy of ± 0.01 volt. In alkaline solution the complexes are oxidized with air-oxygen to [M6X12](OH)62?, while the Br-containing complexes suffer hydrolysis afterwards.  相似文献   

7.
For decades the chemistry of polyhalides was dominated by polyiodides and more recently also by an increasing number of polybromides. However, apart from a few structures containing trichloride anions and a single report on an octachloride dianion, [Cl8]2?, polychlorine compounds such as polychloride anions are unknown. Herein, we report on the synthesis and investigation of large polychloride monoanions such as [Cl11]? found in [AsPh4][Cl11], [PPh4][Cl11], and [PNP][Cl11]?Cl2, and [Cl13]? obtained in [PNP][Cl13]. The polychloride dianion [Cl12]2? has been obtained in [NMe3Ph]2[Cl12]. The novel compounds have been thoroughly characterized by NMR spectroscopy, single‐crystal Raman spectroscopy, and single‐crystal X‐ray diffraction. The assignment of their spectra is supported by molecular and periodic solid‐state quantum‐chemical calculations.  相似文献   

8.
Alternative Ligands. XXII. Rhodium(I) complexes with Donor/Acceptor Ligands of the Typs Me2PCH2CH2SiXnMe3?n(X = F, Cl, OMe) Donor/acceptor ligand of the type Me2PCH2SiXnMe3?n react with [Rh(CO)2Cl]2 ( 1 ) to give the mononuclear complexes RhCl(CO)(PMe2CH2CH2SiXnMe3?n)2 ( 2-6 , Table 1) with planar geometry of the donor atoms, one exception being Me2PCH2CH2CH2SiCl3, yielding the crystalline RhIII-complex RhCl2(CO)(PMe2CH2CH2SiCl2)(PMe2CH2CH2SiCl3) ( 7 ) by oxidative addition of one of the SiCl bonds to the Rh1 precursor. Structures with Rh → Si interaction between the basic central atoms and the acceptor group SiXnMe3?n could be detected in the isolated products neither spectroscopically nor by X-ray diffraction of the two representatives RhCl(CO)(PMe2CH2CH2SiF3)2 ( 2 ) and RhCl(CO)[PMe2CH2CH2siF3]2 ( 2 ) and RhCl(CO) [PMe2CH2CH2Si(OMe3]2 ( 6 ). The presence of such acid/base adducts in the reaction mixture is indicated for the more acidic acceptor groups SiXnMe3?n byvco values near 1990cm?1, (see Table 3). The complex RhCl(CO)PMe3)(PMe2CH2CH2SiF3 ( 8 ) is obtained by the reaction of RhCl(CO)(PMe3)2 ( 9 ) with Me2PCH2SiF3 and has been identified spectroscopically in a mixture with 2 and 9 .  相似文献   

9.
Syntheses, Properties and Crystal Structures of the Cluster Salts Bi6[PtBi6Cl12] and Bi2/3[PtBi6Cl12] Melting reactions of Bi with Pt and BiCl3 yield shiny black, air insensitive crystals of the subchlorides Bi6[PtBi6Cl12] and Bi2/3[PtBi6Cl12]. Despite the substantial difference in the bismuth content the two compounds have almost the same pseudo‐cubic unit cell and follow the structural principle of a CsCl type cluster salt. Bi6[PtBi6Cl12] consists of cuboctahedral [PtBi6Cl12]2? clusters and Bi62+ polycations (a = 9.052(2) Å, α = 89.88(2)°, space group P 1, multiple twins). In the electron precise cluster anion, the Pt atom (18 electron count) centers an octahedron of Bi atoms whose edges are bridged by chlorine atoms. The Bi62+ cation, a nido cluster with 16 skeletal electrons, has the shape of a distorted octahedron with an opened edge. In Bi2/3[PtBi6Cl12] the anion charge is compensated by weakly coordinating Bi3+ cations which are distributed statistically over two crystallographic positions (a = 9.048(2) Å, α = 90.44(3)°, space group ). Bi6[PtBi6Cl12] is a semiconductor with a band gap of about 0.1 eV. The compound is diamagnetic at room temperature though a small paramagnetic contribution appears towards lower temperature.  相似文献   

10.
Chalcogenohalogenogallates(III) and -indates(III): A New Class of Compounds for Elements of the Third Main Group. Preparation and Structure of [Ph4P]2[In2SX6], [Et4N]3[In3E3Cl6] · MeCN and [Et4N]3[Ga3S3Cl6] · THF (X = Cl, Br; E = S, Se) [In2SCl6]2?, [In2SBr6]2?, [In3S3Cl6]3?, [In3Se3Cl6]3?, and [Ga3S3Cl6]3? were synthesised as the first known chalcogenohalogeno anions of main group 3 elements. [Ph4P]2[In2SCl6] ( 1 ) (P1 ; a = 10.876(4) Å, b = 12.711(6) Å, c = 19.634(7) Å, α = 107.21(3)°, β = 96.80(3)°, γ = 109.78(3)°; Z = 2) and [Ph4P]2[In2SBr6] ( 2 ) (C2/c; a = 48.290(9) Å, b = 11.974(4) Å, c = 17.188(5) Å, β = 93.57(3)°, Z = 8) were prepared by reaction of InX3, (CH3)3SiSSi(CH3)3 and Ph4PX (X = Cl, Br) in acetonitrile. The reaction of MCl3 (M = Ga, In) with Et4NSH/Et4NSeH in acetonitrile gave [Et4N]3[In3S3Cl6] · MeCN ( 3 ) (P21/c; a = 17.328(4) Å, b = 12.694(3) Å, c = 21.409(4) Å, β = 112.18(1)°, Z = 4), [Et4N]3[In3Se3Cl6] · MeCN ( 4 ) (P21/c; a = 17.460(4) Å, b = 12.816(2) Å, c = 21.513(4) Å, β = 112.16(2)°, Z = 4), and [Et4N]3[Ga3S3Cl6] · THF ( 5 ) (P21/n; a = 11.967(3) Å, b = 23.404(9) Å, c = 16.260(3) Å, β = 90.75(2)°, Z = 4). The [In2SX6]2? anions (X = Cl, Br) in 1 and 2 consist of two InSX3 tetrahedra sharing a common sulfur atom. The frameworks of 3, 4 and 5 each contain a six-membered ring of alternating metal and chalcogen atoms. Two terminal chlorine atoms complete a distorted tetrahedral coordination sphere around each metal atom.  相似文献   

11.
Compounds of Silicon. 140. Sterical Overloaded Compounds of Silicon. 24. Disupersilylsilanes R*2SiX2, Disupersilyldisilanes R*2XSi–SiX3, and Tetrasupersilyltetrasilanes R*2XSi–SiX2–SiX2–SiXR*2 Supersilylsilanes R*2SiX2, disupersilyldisilanes R*2XSi–SiX3 and tetrasupersilyltetrasilanes R*2XSi–SiX2–SiX2–SiXR*2 (R* = supersilyl = SitBu3; X = H, Me, Ph, Hal, OH, OTf) are prepared in organic solvents (i) by reactions of supersilylhalosilanes R*X2SiHal with supersilyl sodium NaR* (Hal/R* exchange), (ii) by reactions of halosilanes X3SiHal with silanides NaSiXR*2 (Hal/SiXR*2 exchange), (iii) by dehalogenations of disupersilylhalodisilanes R*2XSi–SiX2Hal with Na, (iv) by insertions of supersilylsilylenes R*XSi into the NaSi‐bond of supersilylsodium NaR*, (v) by reactions of disupersilylated halosilanes and ‐disilanes R*2XSiHal and R*2XSi–SiX2Hal with H (Hal/H exchange), (vi) by reactions of the title silanes (X = H) with halogens Hal2 (H/Hal exchange), (vii) by reactions of the title silanes (X = Hal) first with Na (Hal/Na exchange), then with agents for protonation (Na/H exchange) or halogenation (Na/Hal exchange), (viii) by reactions of the title silanes (X = Hal) with nucleophiles like F, H2O (Hal/F or Hal/OH exchange) or (ix) by reactions of the title silanes (X = H) with strong acids like HOTf (H/OTf exchange). The colorless compounds are characterized by IR, NMR and X‐ray structure analyses (structures of R*2SiX2 with X = H, F, Cl and R*2HSi–SiHX–SiHX–SiHR*2 with X = H, Br). They may thermolize under formation of silylenes (e. g. R*2SiX2 → R*X + R*SiX) and are normally stable for hydrolysis. For other reactions confer preparation of the title silanes (i–ix).  相似文献   

12.
Transition Metal Complexes Containing the Ligands Pyrazine-2, 6-dicarboxylate and Pyridine-2, 6-dicarboxylate: Syntheses and Electrochemistry. Crystal Structure of NH4[RuCl2(dipicH)2] The coordination chemistry of the tridentate ligand pyrazine-2, 6-dicarboxylate (pyraz-2,6 = L) with transition metals in aqueous solution has been investigated. The reaction of the ligand with metal aqua ions (1:1) affords insoluble precipitates [MIIL(OH2)2] (M = Mn, Fe, Co, Ni, Cu, Zn, Cd). [TiOL(OH2)2], [VOL(H2O)2] and [UO2L(H2O)] were also prepared. [MIIIL2]? complexes (MIII ? FeIII, CoIII) were isolated as NH4+ and P(C6H5)4+ salts; they are strong one electron oxidants (E1/2 = +0.602 V and +0.795 V vs. NHE, respectively). Redox potentials of analogous complexes containing pyridine- 2, 6-dicarboxylate (L′) ligands have been determined by cyclic voltammetry: [ML′2]1-/2?: M = VIII: -0.591 V; CrIII: -0.712 V. It is shown that pymzine-2,6-dicarboxylate as compared to pyridine-2,6-dicarboxylate stabilizes metal complexes in low oxidation states (+II). The reaction of RuCl3 · nH2O with pyridine-2,6-dicarboxylic acid in aqueous solution affords the yellow-green anion [RuCl2(L′H)2]?. The crystal structure of NH4[RuCl2(L′H)2] has been determined. It crystallizes in the monoclinic space group P21/c with a = 8.812(2) Å b = 10.551(2) Å, c = 10.068(2) Å, β = 110.03(6)°, Z = 2; 2507 independent reflections; R = 0.032. The ruthenium centers are in an octahedral environment of two Cl? ligands (trans) and two bidentate pyridine-2, 6-hydrogendicarboxylate ligands which possess each one protonated, uncoordinated carboxylic group.  相似文献   

13.
Crystal Structures of [Ph3PMe]Cl·CH2Cl2, [Ph4P]NO3·CH2Cl2, and [Ph4P]2[SiF6]·CH2Cl2 The crystal structures of the title compounds are determined by X‐ray diffraction. In all cases, the included dichloromethane molecules as well as the phosphonium cations are involved to form hydrogen bridges with the anions. [Ph3PMe]Cl·CH2Cl2 ( 1 ): Space group , Z = 2, lattice dimensions at 100 K: a = 890.3(1), b = 988.0(1), c = 1162.5(1) pm, α = 106.57(1)°, β = 91.79(1)°, γ = 92.60(1)°, R1 = 0.0253. [Ph4P]NO3·CH2Cl2 ( 2 ): Space group P21/n, Z = 4, lattice dimensions at 193 K: a = 1057.0(1), b = 1666.0(1), c = 1358.9(1) pm, β = 100.10(1)°, R1 = 0.0359. [Ph4P]2[SiF6]·CH2Cl2 ( 3 ): Space group , Z = 2, lattice dimensions at 193 K: a = 1063.9(1), b = 1233.1(1), c = 1782.5(2) pm, α = 76.88(1)°, β = 83.46(1)°, γ = 72.29(1)°, R1 = 0.0332.  相似文献   

14.
Preparation and spectroscopic characterization of the decahalogenodirhenates(IV), [Re2X10]2?, X = Cl, Br On heating of [ReX6]2? with trifluoroacetic acid/trifluoroacetic anhydride (1 : 1), the edge-sharing bioctahedral anions [Re2X10]2?, X = Cl, Br are formed, which IR and Raman spectra are assigned according to point group D2h. The bands are found in three characteristic regions; at high wavenumbers stretching vibrations with terminal ligands v(ReClt): 367–321, v(ReBrt): 242–195; in an intermediate region with bridging ligands v(ReClb): 278–250, v(ReBrb): 201–167 cm?1, and at distinct lower frequencies the deformation modes. The absorption spectra of the dirhenates are distinguished in the region 600–1400 nm by eight intraconfigurational transitions with a slight bathochromic shift and higher intensities in comparison to the monomeric complexes. Due to a stronger bonding of the terminal ligands the energy of the charge transfer bands is lowered by about 4 000 cm?1, too. The magnetic moments are 3.32 and 3.81 B.M./ReIV for [Re2Cl10]2? and [Re2Br10]2?, respectively.  相似文献   

15.
《Chemical physics letters》1986,123(3):182-186
EPR studies have been carried out in Mn2+-doped paramagnetic single crystals of [Co(H2O)6]SiF6, [Co(H2O)6]SnF6 and [Co(H2O)6]PtCl6 at different temperatures using X-band microwave frequency. Reasonably sharp resonance lines of Mn2+ have been obtained at room temperature and analysed using the spin Hamiltonian for trigonal symmetry. From the observed linewidths of Mn2 + in single-crystal [Co(H2O)6]SiF6 the T1 of Co2 + has been estimated to be = 3.3 × 10−11 s. A st phase transition in [Co(H2O)6]SiF6 was observed and the low-temperature phase studied.  相似文献   

16.
Zusammenfassung Folgende Koordinationsformen entstehen aus [Co(HMPT)4]2+ bei Zusatz von Halogenidionen in Hexamethylphosphorsäuretriamid (HMPT): [Co(HMPT)3Cl]+, [Co(HMPT)2Cl2], [Co(HMPT)Cl3], [CoCl4]2–, [Co(HMPT)3Br]+, [Co(HMPT)2Br2] und [Co(HMPT)3J]+.
Hexamethylphosphoric triamide as a ligand II: Reactions of Co(HMPT)4 2+ with chloride, bromide, and iodide ions
The following coordination species are formed from [Co(HMPT)4]2+, by addition of halide ions in hexamethylphosphoric triamide (HMPT): [Co(HMPT)3Cl]+, [Co(HMPT)2Cl2], [Co(HMPT)Cl3], [CoCl4]2–, [Co(HMPT)3Br]+, [Co(HMPT)2Br2] and [Co(HMPT)3J]+.


Mit 7 Abbildungen

V. Gutmann, A. Weisz undW. Kerber, 1. Mitt., Mh. Chem.100, 2096 (1969).  相似文献   

17.
TAS Indolide and TAS Carbazolide: Structures of [TAS]+[IndHInd]? and [TAS]+[Carb]?·½CarbH From the reaction of TAS‐fluoride [(Me2N)3S]+[Me3SiF2]? with trimethylsilyl‐indole and trimethylsilyl‐carbazole TAS‐indolide and TAS‐carbazolide are formed. During crystallisation partially protonation to indole and carbazole occurs, resulting in the formation of [TAS]+[IndHInd]? ( 3a ) and [TAS]+[Carb]?·½CarbH ( 5a ) according to X‐ray analysis.  相似文献   

18.
[Be(OH2)4]Cl2 – Preparation, IR spectrum, and Crystal Structure Single crystals of [Be(OH2)4]Cl2 were prepared by the reaction of thionyl chloride at 20 °C with samples which result from evaporated, HCl containing, aqueous solutions of BeCl2. With excess of boiling thionyl chloride BeCl2 is formed. [Be(OH2)4]Cl2 is characterized by IR spectroscopy and by X‐ray crystal structure determination: Space group P21/c, Z = 4, lattice dimensions at 193 K: a = 653.53(5), b = 1298.15(14), c = 789.52(6) pm, β = 103.005(9)°, R1 = 0.027. The structure consists of slightly distorted tetrahedral [Be(OH2)2]2+ ions, which are connected with the chloride ions via nearly linear O–H···Cl hydrogen bonds to give a 3D network.  相似文献   

19.
The thermal dissociation of the [Co(NH3)6]X3 (X = Cl?, Br?, I?, and NO?3), [Co(en)3]X3 (X = Cl?, Br?, I?, NO?3, HSO?4 and 12 C2O2?4), cis- [Co(en)2Cl2]Cl, and trans-[Co(en)2ClBr]NO3 complexes was investigated by an electrical conductivity (EC) technique. During the thermal dissociation reactions, liquid or semi-liquid phases are formed which cause large increases in the EC of the compound. The effect of concentration of the complex in a matrix medium as well as the composition of the matrix material on the EC curves were also determined.  相似文献   

20.
Chloro- and Polyselenoselenates(II): Synthesis, Structure, and Properties of [Ph3(C2H4OH)P]2[SeCl4] · MeCN, [Ph4P]2[Se2Cl6], and [Ph4P]2[Se(Se5)2] By symproportionation of elemental selenium and SeCl4 in polar protic solvents the novel chloroselenates(+II), [SeCl4]2? and [Se2Cl6]2?, could be stabilized; they were crystallized with voluminous organic cations. They were characterized from complete X-ray structure analysis. Yellow-orange [Ph3(C2H4OH)P]2[SeCl4] · MeCN (space group P1 , a = 10.535(4), b = 12.204(5), c = 16.845(6) Å, α = 77.09(3)°, β = 76.40(3)°, γ = 82.75(3)° at 140 K) contains in its crystal structure monomeric [SeCl4]2? anions with square-planar coordination of Se(+II). The mean Se? Cl bond length is 2.441 Å. In yellow [Ph4P]2[Se2Cl6] (space group P1 , a = 10.269(3), b = 10.836(4), c = 10.872(3) Å, α = 80.26(3)°, β = 79.84(2)°, γ = 72.21(3)° at 140 K) a dinuclear centrosymmetric [Se2Cl6]2? anion, also with square-planar coordinated Se(+II), is observed. The average terminal and bridging Se? Cl bond distances are 2.273 and 2.680 Å, respectively. From redox reactions of elemental Se with boranate/thiolate in ethanol/DMF the bis(pentaselenido)selenate(+II) anion [Se(Se5)2]2? was prepared as a novel type of a mixed-valent chalcogenide. In dark-red-brown [Ph4P]2[Se(Se5)2] (space group P21/n, a = 12.748(4), b = 14.659(5), c = 14.036(5) Å, β = 108.53(3)° at 140 K) centrosymmetric molecular [Se(Se5)2]2? anions with square-planar coordination of the central Se(+II) by two bidentate pentaselenide ligands is observed (mean Se? Se bond lengths: 2.658 Å at Se(+II), 2.322 Å in [Se5]2?). The resulting six-membered chelate rings with chair conformation are spirocyclically linked through the central Se(+II). The vibrational spectra of the new anions are reported.  相似文献   

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