Darstellung und spektroskopische Charakterisierung von bindungsisomeren Halogenoselenocyanato-Osmaten(IV) und -Rhenaten(IV)

Preparation and Spectroscopic Characterization of Bond Isomeric Halogenoselenocyanato-Osmates(IV) and -Rhenates(IV) By oxidative ligand exchange of appropriate chloro-iodo complexes of Os^IV or Re^IV with (SeCN)₂ in CH₂Cl₂ or by heterogeneous reaction with Pb(SeCN)₂ or AgSeCN in CH₂Cl₂ the new complexes cis-[OsCl₄(NCSe)(SeCN)]^2?, tr.-[OsCl₄Br(NCSe)]^2?, tr.-[OsCl₄Br(SeCN)]^2?, [ReCl₅(NCSe)]^2?, [ReCl₅(SeCN)]^2?, tr.-[ReCl₄I(NCSe)]^2?, tr.?[ReCl₄(NCSe)(SeCN)]^2? and tr.?[ReCl₄(NCSe)₂]^2? are formed and isolated as pure compounds by ion exchange chromatography on DEAE-cellulose. The bond isomers are significantly distinguished by the frequencies of innerligand vibrations: n?_CN(Se) > n?_CN(N); n?_CSe(N) > n?_CSe(Se); δ_NCSe > δ_SeCN. The electronic spectra (10 K) of the solid salts reveal a bathochromic shift for the charge transfer bands of the Se isomers as compared with the corresponding N isomers. The intra-configurational transitions are observed for the Os^IV complexes at 600 to 2400 and for the Re^IV complexes at 500 to 1600 nm. The ⁷⁷Se nmr signals of the Os^IV bond isomers are registrated for Se binding in the region 970 to 1040 ppm, for N coordination downfield at 1540 to 1640 ppm.     

Darstellung und spektroskopische Charakterisierung von Bindungsisomeren Halogenoselenocyanatoosmaten(IV)

Preparation and Spectroscopic Characterization of Bondisomeric Halogenoselenocyanatoosmates (IV) The new compounds [OsCl₅(NCSe)]^2?, [OsCl₅(SeCN)]^2?, tr.-[OsCl₄(NCSe)(SeCN)]^2?, tr.-[OsCl₄I(NCSe)]^2? and tr.-[OsCl₄I(SeCN)]^2? are prepared from [OsCl₅I]^2? and tr.-[OsCl₄I₂]^2? by oxidative ligand exchange with (SeCN)₂ or by reaction with suspended Pb(SeCN)₂ in CH₂Cl₂ and isolated by ion exchange chromatography on DEAE cellulose. The bondisomers are significantly distinguished by the frequencies of innerligand vibrations: ν_CN(Se), ν_CN(N), ν_CSe(N) > ν_CSe(Se), δ_NCSe >, δ_SeCN. The electronic spectra measured at 10 K on the solid salts exhibit in the region 450–650 nm intensive Se → Os and N → Os charge transfer bands. Essentially weaker intraconfigurational transitions (t) are observed near to 2000 and 1000 nm, splitted by lowered symmetry (C_4v) and spin orbit coupling. Only some of the 0–0-transitions may be assigned by measuring electronic Raman bands with the same frequencies.     

Darstellung und spektroskopische Charakterisierung von Fluoro-Chloro-Iridaten(V)

Preparation and Spectroscopic Characterization of Fluoro-Chloro-Iridates(V) By careful oxidation of the pure fluoro-chloro iridates(IV) with BrF₃ in dichloromethane the corresponding pentavalent complexes [IrF₅Cl]^?, cis-[IrF₄Cl₂]^?, and fac-[IrF₃Cl₃]^? are formed without replacements of Cl ligands. The vibrational spectra of these mixed ligand complexes are assigned according to point groups C_4v, C_2v, and C_3v. The increased bond strength compared with the corresponding Ir^IV compounds is indicated by a significant shift to higher energy by about 5–15%. The anomalous intensities of some of the Raman active fundamentals are attributed to the resonance Raman effect. The electronic absorption spectra are measured on the solid tetraethylammonium salts of the fluoro-chloro iridates(V) at 10 K. The strong bands in the UV/VIS region are assigned to charge transfer transitions from π(t_1u, t_2u) and σ(t_1u) Cl orbitals into the π(t)Ir^V level. The intraconfigurational transitions within the t configuration of Ir^V are split by spin orbit coupling and lowered symmetry, observed in the ranges 3000, 5100–6400, 10900–13000, and 18200 cm^?1. The O? O transitions are deduced from the vibrational fine structure; in some cases they are confirmed by electronic Raman bands. With increasing number of F ligands all absorption bands are shifted systematically to higher energies.     

Darstellung und spektroskopische Charakterisierung von Carboxylatododecaboraten

Preparation and Spectroscopic Characterization of Carboxylatododecaborates The tetrabutylammonium salt (TBA)₂[B₁₂H₁₂]^2? reacts with formic, acetic, cyanoacetic, phenylacetic, propionic, butyric, and thioacetic acid at temperatures between 80 and 150°C forming the carboxylatododecaborates [(RC(O)O)_n? B₁₂H_{12? n}]^2?, n = 1, 2, [CH₃C(O)S? B₁₂H₁₁]^2?. The isolation of the pure compounds is achieved by ion exchange chromatography on diethylaminoethyl cellulose. In case of the dicarboxylatododecaborates beside the 1,7-isomer predominantly the 1,2-isomer, while 1,2-[(OH)C₆H₅CH₂C(O)O? B₁₂H₁₀]^2? is formed exclusively. The alcaline hydrolysis of [RC(O)O? B₁₂H₁₁]^2? and 1,2-[(OH)C₆H₅CH₂C(O)O? B₁₂H₁₀]^2? results in [(OH)? B₁₂H₁₁]^2? and 1,2-[(OH)₂? B₁₂H₁₀]^2?. All compounds are characterized by their ¹¹B-nmr, ¹³C-nmr and IR spectra. The ¹¹B-nmr signals are assigned by a sheme allowing to establish expected spectra.     

Darstellung und spektroskopische Charakterisierung von Di(acido)phthalocyaninatorhodaten(III)

Preparation and Spectroscopical Characterization of Di(acido)phthalocyaninatorhodates(III) Triethylendiaminorhodiumiodide reacts quickly and completely with boiling phthalodinitrile precipitating ?rhodiumphthalocyanine”?, which is purified and dissolved in alkaline media as di(hydroxo)phthalocyaninatorhodate(III). Acidification in the presence of halides or pseudohalides yields less soluble acidophthalocyaninatorhodium reacting with tetra-n-butyl-ammonium(pseudo)halide to give (blue)green tetra-n-butyl-ammoniumdi(acido)phthalocyaninatorhodate(III), (ⁿBu₄N)[Rh(X)₂Pc^2?] (X = Cl, Br, I, N₃, CN, NCO, SCN, SeCN). The asym. Rh? X-stretching vibration (v_as(RhX)) is observed in the f.i.r. at 290 (X = Cl), 233 (Br), 205 (I), 366 (N₃), 347 (CN), 351 (NCO), 257 (SCN) and 214 cm^?1 (SeCN). v_s(RhI) is the only sym. Rh? X-stretching vibration excited at 131 cm^?1 in the Raman spectrum. The m.i.r. and resonance Raman spectra are typical for hexacoordinated phthalocyaninatometalates(III). The influence of the axial ligands is very small. The frequency of the stretching vibrations of the pseudohalo-ligands are as expected (in the case of the ambident ligands the bonding atom is named first): v_as(NN) at 2006 and v_s(NN) at 1270 cm^?1 (N₃); v_as(CN) at 2126 (CN), 2153 (NCO), 2110 (SCN) and 2116 cm^?1 (SeCN). The characteristic π–π*-transitions of the Pc^2?-ligand dominate the UV-vis spectra. The splitting of the Q and N region is discussed and the weak absorbance at ca. 22 kK is assigned to a n–π*-transition.     

Darstellung,Kristallstrukturen und Schwingungsspektren von bindungsisomeren Pentabromorhodanoosmaten(IV)

Synthesis, Crystal Structures and Vibrational Spectra of Linkage Isomeric Pentabromorhodanoosmates(IV) By treatment of (n‐Bu₄N)₂[OsBr₅I] with (SCN)₂ in dichloromethane the linkage isomers (n‐Bu₄N)₂[OsBr₅(NCS)] and (n‐Bu₄N)₂[OsBr₅(SCN)] are formed which have been separated by ion exchange chromatography on diethylaminoethyl cellulose. X‐ray structure determinations on single crystals of (n‐Bu₄N)₂[OsBr₅(NCS)] (monoclinic, space group P2₁/n, a = 10.955(5), b = 11.649(5), c = 35.478(5) Å, β = 91.92(1)°, Z = 4) and (CH₂Py₂)[OsBr₅(SCN)] (monoclinic, space group P2₁/n, a = 12.244(2), b = 10.134(3), c = 15.882(4) Å, β = 107.91(2)°, Z = 4) have been performed. The thiocyanate group is coordinated with the Os–N–C angle of 168° for N bonding and the Os–S–C angle of 110° for S bonding. Based on the molecular parameters of the X‐ray determinations the IR and Raman spectra of both linkage isomers are assigned by normal coordinate analysis. The valence force constants are f_d(OsN) = 1,81 and f_d(OsS) = 1,42 mdyn/Å.     

Darstellung und Charakterisierung von Bindungsisomeren Bromorhodanorhenaten(IV)

Preparation and characterization of bondisomeric bromorhodanorhenates(IV) The new compounds [ReBr₅(SCN)]^2?, [ReBr₅(NCS)]^2?, cis/tr.-[ReBr₄(NCS)(SCN)]^2?, cis-[ReBr₄(NCS)₂]^2?, mer-[ReBr₃(NCS)₃]^2? are prepared from [ReBr₆]^2? by ligand exchange with NaSCN, KSCN, or (SCN)₂ in organic solvents and isolated by ion exchange chromatography on DEAE cellulose. The bondisomers are significantly distinguished by the frequencies of inner ligand vibrations: v_CN(S) > v_CN(N), v_CS(N) > v_CS(S), δ_NCS δ_SCN. The electronic absorption spectra measured at 10 K exhibit in the region 5700 to 15300 cm^?1 all intraconfigurational transitions (t_2g³) splitted into 8 Kramers doublets by lowered symmetry (C_4v, C_2v, C_s) and spin orbit coupling. The O–O-transitions are deduced form vibrational fine structure and confirmed by electronic Raman bands in some cases. The magnetic moments are in the range of 3.0 to 3.9 B.M.     

Darstellung,spektroskopische Charakterisierung und Normalkoordinatenanalyse der bindungsisomeren Tetrachloroiodoselenocyanatoosmate(IV). Kristallstruktur von trans‐(PPh4)2[OsCl4I(NCSe)]

Preparation, Crystal Structure, and Normal Coordinate Analysis of Linkage Isomeric Pentachloroiodoselenocyanatoosmates(IV). Crystal Structure of trans‐(PPh₄)₂[OsCl₄I(NCSe)] By treatment of the solution of (n‐Bu₄N)₂[OsCl₅I] in dichloromethane with suspended Pb(SeCN)₂ the linkage isomers trans‐(n‐Bu₄N)₂[OsCl₄I(NCSe)] ( 1 ) and trans‐(n‐Bu₄N)₂[OsCl₄I(SeCN)] ( 2 ) are formed, which have been separated by ion exchange chromatography on diethylaminoethyl cellulose. The X‐Ray structure determination on a single crystal of trans‐(PPh₄)₂[OsCl₄I(NCSe)] (triclinic, space group P1¯, a = 10.8950(13), b = 11.076(2), c = 20.980(2)Å, α = 96.940(10), β = 98.747(9), γ = 104.419(11)°, Z = 2) reveals, that the nearly linear selenocyanate group in trans position to the iodine atom is coordinated with the Os‐N‐C angle of 171.1°. Based on the molecular parameters of the X‐ray determination ( 1 ) and estimated data ( 2 ) the IR and Raman spectra of both linkage isomers are assigned by normal coordinate analysis. The valence force constants are f_d(OsN) = 1.70 und f_d(OsSe) = 1.15 mdyn/Å.     

Darstellung und Charakterisierung von Tetrakis(Chloro-Bromo)-Oxalato-Osmaten(IV)

Preparation and Characterization of Tetrakis(chloro-bromo) Oxalatoosmates(IV) On treatment of [OsBr₄ox]^2? with Cl^? the yellow to orange coloured complexes [OsCl_nBr_4?nox]^2?, n = 1, 2, 3, are formed. The separation of geometric isomers is difficult but possible by ion exchange chromatography on diethylaminoethyl cellulose. The 10 K absorption spectra show in the UV/VIS region intensive Br←Os and Cl←Os charge transfer bands and in the NIR weak intraconfigurational transitions splitted by spin-orbit coupling and lowered symmetry into 5 components. A very weak spin-forbidden d—d-transition at about 600 nm is improved as a luminescence absorption band in the Raman spectrum.     

Darstellung,Kristallstrukturen, Schwingungsspektren und Normalkoordinatenanalyse von vier bindungsisomeren Tetrachlorodirhodanoosmaten(IV)

Preparation, Crystal Structures, Vibrational Spectra, and Normal Coordinate Analysis of Four Linkage Isomeric Tetrachlorodirhodanoosmates(IV) By treatment of cis- or trans-[OsCl₄I₂]^2? with (SCN)₂ in dichloromethane the linkage isomers cis-[OsCl₄(NCS)₂]^2? ( 1 ), trans-[OsCl₄(NCS)(SCN)]^2? ( 2 ), cis-[OsCl₄(NCS)(SCN)]^2? ( 3 ) and trans-[OsCl₄(SCN)₂]^2? ( 4 ) are formed which have been separated by ion exchange chromatography on diethylaminoethyl cellulose. The X-Ray structure determinations on single crystals of cis-(Ph₄As)₂[OsCl₄(NCS)₂] (triclinic, space group P1 , a = 10.019(5), b = 11.702(5), c = 21.922(5) Å, α = 83.602(5)°, β = 85.718(5)°, γ = 73.300(5)°, Z = 2), trans-(Ph₄As)₂[OsCl₄ · (NCS)(SCN)] (monoclinic, space group P2₁/c, a = 18.025(5), b = 11.445(5), c = 23.437(5) Å, β = 94.208(5)°, Z = 4), cis-(Ph₄As)₂[OsCl₄(NCS)(SCN)] (triclinic, space group P1 , a = 10.579(5), b = 11.682(5), c = 22.557(5) Å, α = 81.073(5)°, β = 85.807(5)°, γ = 87.677(5)°, Z = 2) and trans-(Ph₄As)₂ · [OsCl₄(SCN)₂] (triclinic, space group P1 , a = 10.615(5), b = 11.691(5), c = 11.907(5) Å, α = 111.314(5)°, β = 96.718(5)°, γ = 91.446(5)°, Z = 1) reveal the complete ordering of the complex anions. The via N or S coordinated thiocyanate groups are located nearly direct above one of the cis-positioned Cl ligands with Os? N? C angles of 171.2° and 174.3° ( 1 ), 162.3° ( 2 ), 172° ( 3 ) and Os? S? C angles of 108.3° ( 2 ), 105.7° ( 3 ) and 105.5° ( 4 ). Using the molecular parameters of the X-Ray determinations the low temperature (10 K) IR and Raman spectra of the (n-Bu₄N) salts of all four linkage isomers are assigned by normal coordinate analyses based on a modified valence force field. The valence force constants are f_d(OsN) = 1.59 ( 1 ), 1.67 ( 2 ), 1.60 ( 3 ) and f_d(OsS) = 1.27 ( 2 ), 1.31 ( 3 ) and 1.32 mdyn Å^?1 ( 4 ). Taking into account increments of the trans influence a good agreement between observed and calculated frequencies is achieved.     

Darstellung und Charakterisierung von bindungsisomeren Hexakis(thiocyanato-isothiocyanato)-iridaten(III) und einiger Chloro-, Cyano-pentarhodanoiridate(III)

Preparation and Characterization of Bond-Isomeric Hexakis(thiocyanato-isothiocyanato)-iridates(III) and Some Chloro-, Cyano-pentarhodanoiridates(III) The evaporated ethanolic extract of the reaction product of K₃[IrCl₆] and HNO₃, refluxed with an aqueous KSCN solution yields a mixture of the bond isomers [Ir(NCS)_n(SCN)_6?n]^3?, n = 0–2 and small amounts of bond isomeric chloropentrahodanoiridates(III). By heating the tetrabutylammonium salts, N coordination of the ambident SCN^? is favoured forming compounds with n = 2–5 beside chloro- and cyanopentarhodanoiridates(III). With n = 2, 3 pairs of geometric isomers can be detected. The pure compounds are separated by ion exchange chromatography on diethylaminoethylcellulose. The trans/mer-complexes migrate 1.9 times faster than the cis/fac-isomers. Depending on S- or N-bonding the IR and Raman spectra show typical vibrations: ν_CN(N) and ν_CN(S): 2100–2175, ν_CS(N): 810–855, ν_CS(S): 690–710, δ_NCS: 470–480, δ_SCN: 420–470, ν_IrN: 300–325, ν_IrS: 255–313 cm^?1. Except the inner ligand vibrations the Rh? N and Rh? S valence frequencies are assigned according to the supposed point symmetries. By interaction of the trans-positioned ligands characteristic shifts are caused.     

Darstellung,Kristallstrukturen, Schwingungsspektren und Normalkoordinatenanalyse von vier bindungsisomeren Trichlorotrirhodanoosmaten(IV)

Preparation, Crystal Structures, Vibrational Spectra, and Normal Coordinate Analysis of four Linkage Isomeric Trichlorotrirhodanoosmates(IV) By treatment of fac-[OsCl₃I₃]^2? with (SCN)₂ in dichloromethane the linkage isomers fac-[OsCl₃(NCS)₃]^2? ( 1 ), mer-[OsCl₃(NCS)₂^c(SCN)]^2? ( 2 ), mer-[OsCl₃(NCS)(SCN)₂^t]^2? ( 3 ), and mer-[OsCl₃(NCS)(SCN)₂^c]^2? ( 4 ) are formed which have been separated by ion exchange chromatography on diethylaminoethyl cellulose. X-Ray structure determinations have been performed on single crystals of fac-(Ph₄As)₂[OsCl₃(NCS)₃] (triclinic, space group P1 , a = 12.142(5), b = 13.233(5), c = 19.300(5) Å, α = 98.642(5)º, β = 100.509(5)º, γ = 112.514(5)º, Z = 2), mer-(Ph₄As)₂[OsCl₃(NCS)₂^c (SCN)] · acetone (triclinic, space group P1 , a = 11.707(5), b = 13.238(5), c = 19.048(5) Å, α = 75.960(5)º, β = 88.981(5)º, γ = 69.999(5)º, Z = 2), mer-(Ph₄As)₂[OsCl₃(NCS)(SCN)₂ ^t] (triclinic, space group P1, a = 10.6861(12), b = 11.6587(5), c = 12.5232(5) Å, α = 112.069(8)º, β = 95.052(8)º, γ = 92.559(7)º, Z = 1) and mer-(Ph₄As)₂[OsCl₃(NCS)(SCN)₂ ^c] · 2acetone (triclinic, space group P1 , a = 11.444(5), b = 14.661(5), c = 15.830(5) Å, α = 75.790(5)º, β = 80.273(5)º, γ = 75.205(5)º, Z = 2). The complex anions are completely ordered. The via N or S coordinated thiocyanate groups are located nearly direct above one of the cis-positioned Cl ligands with Os? N? C angles of 169.1º, 171.5º, 175.7º ( 1 ), 175.6º, 178.6º ( 2 ), 172º ( 3 ), and 173.1º ( 4 ) and Os? S? C angles of 106.2º ( 2 ), 106.1º, 106.6º ( 3 ), 105.1º, and 108.2º ( 4 ). Using the molecular parameters of the X-Ray determinations the low temperature (10 K) IR and Raman spectra of the (n-Bu₄N) salts of all four linkage isomers have been assigned by normal coordinate analyses based on a modified valence force field. The valence force constants are f_d(OsN) = 1.71 ( 1 ), 1.46 and 1.62 ( 2 ), 1.69 ( 3 ), and 1.61 ( 4 ), f_d(OsS) = 1.27 ( 2 ), 1.36 ( 3 ), 1.32, and 1.49 mdyn/Å ( 4 ). Taking into account increments of the trans influence a good agreement between observed and calculated frequencies is achieved.     

Darstellung,Kristallstruktur und Normalkoordinatenanalyse der bindungsisomeren Pentachlororhodanoosmate(IV)

Preparation, Crystal Structure and Normal Coordinate Analysis of Linkage Isomeric Pentachlororhodanoosmates(IV) By treatment of [OsCl₅I]^2? with (SCN)₂ in dichloromethane the linkage isomers [OsCl₅(NCS)]^2? and [OsCl₅(SCN)]^2? are formed which have been separated by ion exchange chromatography on diethylaminoethyl cellulose. The X-ray structure determination on single crystals of (Ph₄As)₂[OsCl₅(NCS)] (monoclinic, space group P2₁/a, a = 18.872(2), b = 11.6024(2), c = 22.786(1), β = 109.057(1)°, Z = 4) and (Ph₄As)₂[OsCl₅(SCN)] (monoclinic, space group P2₁/a, a = 19.057(2), b = 11.306(2), c = 22.612(1), β = 106.64(2)°, Z = 4) reveals the complete ordering of the complex anions. The thiocyanate group is located above one of the Cl ligands of the equatorial plane with the Os? N? C angle of 166.1° for N bonding and the Os? S? C angle of 109.9° for S bonding. The IR and Raman spectra of both linkage isomers known from literature are assigned by normal coordinate analysis based on the general valence force field using the molecular parameters of the X-ray determination. The valence force constants are f_d(OsN) = 1,81 and f_d(OsS) = 1,32 mdyn/Å. Taking into account increments of the trans influence a good adjustment between observed and calculated frequencies is achieved.     

Darstellung und spektroskopische Eigenschaften von Nitridophthalocyaninatorhenium(V)

Preparation and Spectroscopical Properties of Nitridophthalocyaninatorhenium(V) Nitridophthalocyaninatorhenium(V) ([ReNPc^2?]) is prepared by the reaction of dirheniumheptoxide with ammoniumiodide in molten 1,2-dicyano-benzene. The diamagnetic complex is chemically und thermically extremely stable. In the Uv-vis spectra the typical π-π*-transitions of the Pc^2? ligand are observed. Extra bands in the solid state spectrum are due to strong excitonic coupling of ca. 2.8 kK. In the resonance Raman spectra the intensity of the Re≡N stretching vibration (v(Re≡N)) at 969 cm^?1 is selectively enhanced by laser excitations above 19.0 kK. v(Re≡N) is a dominant m.i.r. absorption at 976 cm^?1.     

Darstellung und Charakterisierung von bindungsisomeren Hexakis-(thiocyanato-isothiocyanato)-rhodaten(III) und Di-μ-thiocyanato-N,S-octathiocyanatodirhodat(III)

Preparation and Characterization of Bond-Isomeric Hexakis-(thiocyanato-isothiocyanato)rhodates(III) and Di-μ-thiocyanato-N, S-octathiocyanatodirhodate (III) The reaction of RhCl₃ with an aqueous solution of KSCN does not yield pure [Rh(SCN)₆]^3? as is supposed until now but a mixture of the bond isomers [Rh(NCS)_n(SCN)_6?n]^3?, n = 0–3. By heating the tetrabutylammonium salts N coordination of the ambident SCN^? is favoured forming mixtures with n = 0–4. The pure bond isomers are separated by ion exchange chromatography on diethylaminoethyl cellulose. Extracting the mixture (n = 0–3) with triphenylphosphiniminiumchloride from water into CH₂Cl₂ [Rh₂(SCN)₁₀]^4? is formed, containing two Rh? SCN? Rh bridges and exclusively S-coordinated terminal ligands. Depending on S or N bonding the IR and Raman spectra show typical vibrations: ν_CN(N) and ν_CN(S): 2095–2170, ν_CS(N): 810–835, ν_CS(S): 695–710, δ_NCS: 460–470, δ_SCN: 425–465, ν_RhN: 300–340, ν_RhS: 265–306 cm^?1. The application of group theory indicates that for n = 2 and 4 the cis-, for n = 3 the mer-compound exists. Except the inner ligand vibrations the Rh? N and Rh? S valence vibrations are assigned according to the supposed point symmetries. By interaction of trans-positioned ligands characteristic shifts are caused. The isolated complexes may also be distinguished and identified by their electronic spectra.     

Darstellung,Kristallstruktur und spektroskopische Charakterisierung von P4O6Se3

Synthesis, Crystal Structure, and Spectroscopic Characterization of P₄O₆Se₃ P₄O₆Se₃ has been prepared for the first time as a pure substance by photochemical selenation of P₄O₆ with red selenium. The compound crystallizes in a monoclinic system with space group P2₁/a (a = 973.6(2); b = 846.9(2); c = 1277.7(3) pm; β = 90.56(2)°; Z = 4; 1358 diffractometer data; R₁ = 0.044; wR² = 0.099). Bond lengths and angles within the molecule as well as the arrangement of the molecules within the crystal are discussed; vibrational (IR and Raman) and ³¹P-n.m.r. (solution) data are given.     

Darstellung,spektroskopische Charakterisierung und Normalkoordinatenanalyse von Nonabromoditechnetat(IV), [Tc2Br9]−

Preparation, Spectroscopic Characterization and Normal Coordinate Analysis of Nonabromoditechnetate(IV), [Tc₂Br₉]^? . On heating the tetraethylammonium salt (TEA)₂[Tc₂Br₆] with trifluoroacetic acid the face-sharing bioctahedral anion [Tc₂Br₉]^? is formed, which vibronic spectrum is assigned according to point group D_3h. Normal coordinate analysis, based on a general valence force field has been performed, resulting in a good agreement of calculated frequencies with the observed IR and Raman bands. Due to stronger bonding of the terminal as compared to the bridging ligands, the valence force constant f_d(TcBr_t) = 1.045 is significantly higher than f_d(TcBr_b) = 0.80 mdyn/Å.     

Darstellung von Fluorjodsilanen (über Halogenaustauschreaktionen) und ihre spektroskopische Charakterisierung. Spektren von SiBrCl2F und SiBr2ClF

Zusammenfassung Durch Br/J-Austauschreaktionen entstehen aus den entsprechenden Bromfluorsilanen und HSiJ₃ die bisher unbekannten Fluorjodsilane SiFCl₂J, SiFClJ₂, SiFBr₂J SiFBrJ₂ und SiF₂BrJ sowie auch SiFJ₃ und SiF₂J₂. Die¹⁹F-NMR-Parameter und die zugeordneten Schwingungsspektren dieser Verbindungen sowie von SiFCl₂Br und SiFClBr₂ werden angegeben und diskutiert.

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Synthesis of fluoroiodosilanes by halogen exchange reactions and their spectroscopic characterization. spectra of SiBrCl₂F and SiBr₂ClF

Br/I-exchange reactions between some bromofluorosilanes and HSiI₃ lead to the hitherto unknown fluoroiodosilanes SiFCl₂I, SiFClI₂, SiFBr₂I SiFBrI₂, and SiF₂BrI as well as SiFI₃ and SiF₂I₂. The¹⁹F-NMR data and vibrational spectra (including assignments) of these compounds and of SiFCl₂Br and SiFClBr₂ are reported and discussed.

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Herrn Prof. Dr.Harald Schäfer zum 60. Geburtstag gewidmet.     

Darstellung und spektroskopische charakterisierung von mer-trihalogeno-carbonyl-oxalato-osmaten(III)

Upon treatment of trans-[OsX₄(CO)₂]^? or [OsX₅(CO)]^2? with oxalate in aqueous solution new complexes of the type mer-[OsX₃(CO)ox]^2? (X  Cl, Br, I) are formed. The IR and Ra spectra are assigned according to point group C_s. In the UV/VIS spectra, recorded at 10 K, charge transfer transitions from ligand levels, splitted by spin-orbit coupling, (π + σ)t_1u(X) and πt_2u(X) to t_2g(Os³⁺) are observed. Two weak bands with vibrational fine structure in the NIR region are assigned to intraconfigurational transitions within the ground term of osmium(III). The assignment is confirmed by bands of the same frequency observed in the electronic Raman spectrum.