Zur Reaktion von Trifluorhalomethanen mit Phosphanen

On the Reaction of Trifluorohalomethanes with Phosphanes The reactions of trifluorohalomethanes CF₃X (X = Cl, Br, I) with Ph₃P, Bu₃P, (Me₂N)₃P, and (Et₂N)₃P were investigated. CClF₃ does not react. In the reactions of CBrF₃ and CF₃I with Bu₃P in acetonitrile trifluorophosphonium salts, [Bu₃PCF₃]X (X = Br, I), are formed, whereas gaseous CF₃I and Bu₃P yield Bu₂PCF₃. Depending on the reaction conditions the aminophosphanes form either [(R₂N)₃PX]X (R = Me, Et; X = Br, I) and CF₃H or [(R₂N)₃PCF₃]X.     

tBu2P?PP(X)tBu2-Ylide (X = Cl,Br, I) durch Halogenierung von [tBu2P]2P?SiMe3

tBu₂P? P?P(X)tBu₂ Ylides (X = Cl, Br, I) by Halogenation of [tBu₂P]₂P? SiMe₃ [tBu₂P]₂P? SiMe₃ 1 with halogenating agents as Br₂, I₂, Br-succinimide, CCl₄, CBr₄, CI₄ or C₂Cl₆ via cleavage of the Si? P bond in 1 produces the ylides tBu₂P? P?P(X)tBu₂ (X = Cl, Br, I). This proceeds independent from the formerly known pathway – [tBu₂P]₂PLi + 1,2-dibromoethane – and shows that the Li-phosphide must not be present as a necessary requirement for the formation of ylides.     

Polymerization of phenylacetylene catalysed by RhTp(cod) and RhBp(cod) in ionic liquids: effect of alcohols and of tetraammonium halides

RhTp(cod) ( 1 ) and RhBp(cod) ( 2 ), almost inactive in CH₂Cl₂, became good catalysts of phenylacetylene polymerization in ionic liquids ([bmim]Cl, [bmim]BF₄: bmim = 1‐butyl‐3‐methylimidazolium, [mokt]BF₄: mokt = 1‐methyl‐3‐oktylimidazolium, [bumepy]BF₄: 1‐butyl‐4‐methylpyridinium) and in CH₂Cl₂ in the presence of tetraammonium halides ([R₄N]X, R = Bu, Et; X = Cl, Br). The highest yields of polyphenylacetylene with catalyst 1 were obtained in [bmim]Cl at 65°C (64% after 2 h) and in [mokt]BF₄ at 20°C (56% after 24 h). In alcohols (CH₃OH, (CH₃)₂CHOH, (CH₃)₃COH) as solvents, up to 100% of the polymer was produced. When a mixture of an ionic liquid and CH₃OH was used as the reaction medium, the polymer yield was similar to the yield achieved in an ionic liquid only, but the molecular weight increased remarkably. Tetraammonium salts, [R₄N]X, are co‐catalysts for 1 , and the yield of the polymer increased in the order [Et₄N]Br < [Bu₄N]Br < [Et₄N]Cl < [Bu₄N]Cl. Polymers with molecular weights from 6900 to 38 800 Da were obtained with catalyst 2 in [R₄N]Br or [R₄N]Cl, whereas in ionic liquids ([bmim]Cl, [bmim]BF₄) the corresponding molecular weights were higher, from 51 300 to 60 300 Da. Copyright © 2004 John Wiley & Sons, Ltd.     

Ruthenium(II)-Phthalocyaninate(2–): Darstellung und Eigenschaften von Acido(carbonyl)phthalocyaninato(2–)ruthenat(II), [Ru(X)(CO)Pc2−]− (X = Cl,Br, I,NCO, NCS,N3)

Ruthenium(II) Phthalocyaninates(2–): Synthesis and Properties of (Acido)(carbonyl)phthalocyaninato(2–)ruthenate(II), [Ru(X)(CO)Pc^2?]^? (X = Cl, Br, I, NCO, NCS, N₃) (ⁿBu₄N)[Ru(OH)₂Pc^2?] is reduced in acetone with carbonmonoxid to blue-violet [Ru(H₂O)(CO)Pc^2?], which yields in tetrahydrofurane with excess (ⁿBu₄N)X acido(carbonyl)phthalocyaninato(2–)ruthenate(II), [Ru(X)(CO)Pc^2?]^? (X = Cl, Br, I, NCO, NCS, N₃) isolated as red-violet, diamagnetic (ⁿBu₄N) complex salt. The UV-Vis spectra are dominated by the typical π-π* transitions of the Pc^2? ligand at approximately 15100 (B), 28300 (Q₁) und 33500 cm^?1 (Q₂), only fairly dependent of the axial ligands. v(C? O) is observed at 1927 (X = I), 1930 (Cl, Br), 1936 (N₃, NCO) 1948 cm^?1 (NCS), v(C? N) at 2208 cm^?1 (NCO), 2093 cm^?1 (NCS) and v(N? N) at 2030 cm^?1 only in the MIR spectrum. v(Ru? C) coincides in the FIR spectrum with a deformation vibration of the Pc ligand, but is detected in the resonance Raman(RR) spectrum at 516 (X = Cl), 512 (Br), 510 (N₃), 504 (I), 499 (NCO), 498 cm^?1 (NCS). v(Ru? X) is observed in the FIR spectrum at 257 (X = Cl), 191 (Br), 166 (I), 349 (N₃), 336 (NCO) and 224 cm^?1 (NCS). Only v(Ru? I) is RR-enhanced.     

Indium-based liquid clathrates. III. Inclusion compounds derived from [Bu4N][InCl3X] salts and their suitability as a catalysis medium

Tetrabutylammonium salts of the mixed haloindates, [Bu₄N][InCl₃X], X=Cl, Br, I, interact with aromatic solvents forming liquid inclusion compounds. The aromatic/cation ratio (A/C), a measure of the amount of guest aromatic, has been determined for a variety of simple aromatics. The values range from 2.6 to 0.4, substantially lower than the A/A of similar [Bu₄N][Al₂R₆X] liquid clathrates. The ability of these liquid clathrates to function as catalysis media has been explored. The solubility of (Ph₃P)₂Rh(CO)Cl and (Ph₃P)₃RhCl in the various clathrates was determined. It was found that significant leaching of the catalyst into the bulk aromatic solvent occurred, ranging from 13 to 94%. A related liquid clathrate, [Li·12-crown-4][InCl₄]·(C₆H₅CH₃)₂, had <1% of the dissolved catalyst leached.     

Strukturen von neuen Bis(pentafluorophenyl)halogenomercuraten [{Hg(C6F5)2}3(μ‐X)]— (X = Cl,Br, I)

Structures of New Bis(pentafluorophenyl)halogeno Mercurates [{Hg(C₆F₅)₂}₃(μ‐X)]^— (X = Cl, Br, I) From the reactions of [PNP]Cl or [PPh₄]Y (Y = Br, I) with Hg(C₆F₅)₂ crystals of the composition [Cat][{Hg(C₆F₅)₂}₃X] (Cat = PNP, X = Cl ( 1 ); Cat = PPh₄, X = Br ( 2 ), I ( 3 )) are formed. 1 crystallizes in the triclinic space group P1¯, 2 and 3 crystallize isotypically in the monoclinic space group C2/c. In the crystals the halide anions are surrounded by three Hg(C₆F₅)₂ molecules. The reaction of [PPh₄]Br with Hg(C₆F₅)₂ under slightly changed conditions gives the compound [PPh₄]₂[{Hg(C₆F₅)₂}₃(μ‐Br)][{Hg(C₆F₅)₂}₂(μ‐Br)] ( 4 ).     

PSEUDOTETRAHEDRAL METAL (II) COMPLEXES OF TRIS- (t-BUTYL) PHOSPHINE

Abstract

The synthesis of divalent metal complexes of the type [Bu^t ₃PH] [(Bu^t ₃P)MX₃] (M = Ni; X = Cl, Br, I; M = Co; X = Br; M = Zn; X = Cl) is reported. Characterization of the solids by conductivity, magnetic susceptibility, electronic and vibrational spectral measurements indicate that the structures are similar and unchanged in solution from the solid state. On the basis of an earlier X-ray single crystal analysis of [Bu^t ₃PH] [(Bu^t ₃P)NiBr₃] and a comparison of the physical measurements for the series of complexes, the inner coordination geometry of the anions can be represented as pseudotetrahedral with C_3v local symmetry. The unexpected formation of these ionic complexes is attributed to the bulkiness of tris-(t-butyl) phosphine. The isolation and probable geometry of the anion are also discussed for an orange-brown [Bu^t ₃PH] [Ni(NCS)₃] complex.     

Synthese,Struktur und Eigenschaften von [nacnac]MX3‐Verbindungen (M = Ge,Sn; X = Cl,Br, I)

Synthesis, Structure, and Properties of [nacnac]MX₃ Compounds (M = Ge, Sn; X = Cl, Br, I) Reactions of [nacnac]Li [(2,6‐ⁱPr₂C₆H₃)NC(Me)C(H)C(Me)N(2,6‐ⁱPr₂C₆H₃)]Li ( 1 ) with SnX₄ (X = Cl, Br, I) and GeCl₄ in Et₂O resulted in metallacyclic compounds with different structural moieties. In the [nacnac]SnX₃ compounds (X = Cl 2 , Br 3 , I 4 ) the tin atom is five coordinated and part of a six‐membered ring. The Sn–N‐bond length of 3 is 2.163(4) Å and 2.176(5) Å of 4 . The five coordinated germanium of the [nacnac]GeCl₃ compound 5 shows in addition to the three chlorine atoms further bonds to a carbon and to a nitrogen atom. In contrast to the known compounds with the [nacnac] ligand the afore mentioned reaction creates a carbon–metal‐bond (1.971(3) Å) forming a four‐membered ring. The Ge–N bond length (2.419(2) Å) indicates the formation of a weakly coordinating bond.     

Phosphoniumsalze mit Hydrogendihalogenidanionen HCl2−, HBr2− Hl2− oder HBrCl−

Phosphonium Salts with Hydrogen Dihalide Anions HCl₂^?, HBr₂^?, HI₂^?, or HBrCl^? Phosphonium hydrogen dihalides [R₃PR′][XHY] (X = Y = Cl, Br, I; X = Br, Y = Cl) resp. [R₃PH]HBr₂ are obtained as extremely hydrolyzable crystals by reaction of phosphonium halides or tertiary phosphanes with hydrogen halide. According to IR spectroscopic results the solid compounds mostly contain anions [XHX]^? with symmetric hydrogen bonds. In solution ¹H NMR measurements show a slight (X = Cl, Br) or considerable (X = I) dissociation according to HX₂^? ? X^? + HX. On heating the solid compounds decompose with formation of hydrogen halide and [R₃PR′]X or [R₃PH]X. In this process the hydrogen bromidechlorides [R₃PR′][BrHCl] exclusively eliminate HCl. NMR studies (¹H und ³¹P) with solutions containing [R₃PH]HBr₂ (R = phenyl, 1-naphtyl) or HBr and Ph₃P in varying molar ratios show that a fast proton exchange between the competing Lewis bases R₃P and Br^? exists.     

A Mechanistic Study on Reactions of Group 13 Diyls LM with Cp*SbX2: From Stibanyl Radicals to Antimony Hydrides

Oxidative addition of Cp*SbX₂ (X=Cl, Br, I; Cp*=C₅Me₅) to group 13 diyls LM (M=Al, Ga, In; L=HC[C(Me)N (Dip)]₂, Dip=2,6-iPr₂C₆H₃) yields elemental antimony (M=Al) or the corresponding stibanylgallanes [L(X)Ga]Sb(X)Cp* (X=Br 1 , I 2 ) and -indanes [L(X)In]Sb(X)Cp* (X=Cl 5 , Br 6 , I 7 ). 1 and 2 react with a second equivalent of LGa to eliminate decamethyl-1,1’-dihydrofulvalene (Cp*₂) and form stibanyl radicals [L(X)Ga]₂Sb ^. (X=Br 3 , I 4 ), whereas analogous reactions of 5 and 6 with LIn selectively yield stibanes [L(X)In]₂SbH (X=Cl 8 , Br 9 ) by elimination of 1,2,3,4-tetramethylfulvene. The reactions are proposed to proceed via formation of [L(X)M]₂SbCp* as reaction intermediate, which is supported by the isolation of [L(Cl)Ga]₂SbCp ( 11 , Cp=C₅H₅). The reaction mechanism was further studied by computational calculations using two different models. The energy values for the Ga- and the In-substituted model systems showing methyl groups instead of the very bulky Dip units are very similar, and in both cases the same products are expected. Homolytic Sb−C bond cleavage yields van der Waals complexes from the as-formed radicals ([L(Cl)M]₂Sb ^. and Cp* ^. ), which can be stabilized by hydrogen atom abstraction to give the corresponding hydrides, whereas the direct formation of Sb hydrides starting from [L(Cl)M]₂SbCp* via concerted β-H elimination is unlikely. The consideration of the bulky Dip units reveals that the amount of the steric overload in the intermediate I determines the product formation (radical vs. hydride).     

Gold(I) complexes of thioamides

Summary Gold(I) forms linear [AuL₂]X complexes (X = Cl, Br, I or CIO₄) with thioacetamide and thiobenzamide, AuLX compounds with thiobenzamide (X = CI or Br),N, N-dimethylthioformamide (X = Cl, Br or 1) andN-dimethylthioacetamide (X = CI, Br or 1). Thev(AuS) vibrations are assigned in the 320-260 cm^–1 range. The i.r. spectra further suggest hydrogen bonding between the ligands and the anions. The conductivity measurements indicate dissociation of the [AuL₂]X complexes (X = halide) and coordination of X in solution.Presented in part at the XIX ICCC, Prague, 1978.     

Zum Ligandenaustausch an TcNX4−-Komplexen (X = Cl,Br)

Ligand-Exchange Reactions on TcNX₄^? Complexes (X = Cl, Br) Ligand exchange reactions on the nitridotechnetium(VI) compounds (Bu₄N)TcNCl₄ and (Bu₄N)TcNBr₄ are reported. The use of various organic ligands having different donor atom sets produces Tc^V nitrido complexes. The reaction of (Bu₄N)TcNCl₄ with (Bu₄N)TcNBr₄ is characterized by the formation of Tc^VI complex species with mixed Cl/Br coordination spheres. EPR detection of the mixed-ligand complexes results in a well-defined dependence of the EPR parameters on the composition of the first coordination sphere of the complexes.     

Alkoxy,amido and thiolato complexes of tris (3, 5-dimethylpyrazolyl)borato(nitrosyl) molybdenum fluoride,chloride and bromide

The complexes Mo{HB(Me₂pyz)₃}(NO)XY {HB(Me₂pyz)₃  HB(3, 5-Me₂C₃HN₂)₃; X=Y=F, Cl or Br; X=F, Y=OEt, NHMe or SBuⁿ; X=Cl, Y=NHR (R=Me Et, Buⁿ, Ph, p-MeC₆H₄), NMe₂ and SR (R=Buⁿ, C₆H₁₁, CH₂Ph, Ph); X=Br, Y=NHMe, NMe₂ and SBuⁿ} have been prepared and characterised spectroscopically. Their properties are generally similar to those of their iodo-analogues.     

Synthese von methyldihalogenarsinen CH3AsXY mit verschiedenen halogenen XY

The reactions of the methylhalogenodimethylaminoarsines CH₃As-[N(CH₃)₂]X (X  F, Cl, Br, I) with HY (Y = Cl, Br) yield the methyldihalogenoarsines CH₃AsXY. The compounds CH₃As[N(CH₃)₂]X are prepared by the reactions of CH₃AsCl₂ with HN(CH₃)₂, CH₃As[N(CH₃)₂]₂ with HX (X = Cl, Br) and by exchange reactions between CH₃As[N(CH₃)₂]₂ and CH₃AsX₂ (X = F, Cl, Br, I).     

Magnesiumphthalocyanine: Darstellung und Eigenschaften von Halogenophthalocyaninatomagnesat, [Mg(X)Pc2−]− (X = F,Cl, Br); Kristallstruktur von Bis(triphenylphosphin)iminiumchloro(phthalocyaninato)magnesat-Aceton-Solvat

Magnesium Phthalocyanines: Synthesis and Properties of Halophthalocyaninatomagnesate, [Mg(X)Pc^2?]^? (X = F, Cl, Br); Crystal Structure of Bis(triphenylphosphine)iminiumchloro-(phthalocyaninato)magnesate Acetone Solvate Magnesium phthalocyanine reacts with excess tetra(n-butyl)ammonium- or bis(triphenylphosphine)iminiumhalide ((ⁿBu₄N)X or (PNP)X; X = F, Cl, Br) yielding halophthalocyaninatomagnesate ([Mg(X)Pc^2?]^?; X = F, Cl, Br), which crystallizes in part as a scarcely soluble (ⁿBu₄N) or (PNP) complex-salt. Single-crystal X-ray diffraction analysis of ^b(PNP)[Mg(Cl)Pc^2?] · CH₃COCH₃ reveals that the Mg atom has a tetragonal pyramidal coordination geometry with the Mg atom displaced out of the center (Ct) of the inner nitrogen atoms (N_iso) of the nonplanar Pc ligand toward the Cl atom (d(Mg? Ct) = 0.572(3) Å; d(Mg? Cl) = 2.367(2) Å). The average Mg? N_iso distance is 2.058 Å. Pairs of partially overlapping anions are present. The cation adopts a bent conformation (^b(PNP)⁺: d(P1? N(K)) = 1.568(3) Å; d(P2? N(K)) = 1.587(3) Å; ?(P1? N(K)? P2) = 141.3(2)°). Electrochemical and spectroscopic properties are discussed.     

Osmium(II)-Phthalocyanine: Darstellung und Eigenschaften von Di(acido)phthalocyaninatoosmaten(II)

Osmium(II) Phthalocyanines: Preparation and Properties of Di(acido)phthalocyaninatoosmates(II) “H[Os(X)₂Pc^2?]” (X = Br, Cl) reacts in basic medium or in the melt with (ⁿBu₄N)X forming less stable, diamagnetic, darkgreen (ⁿBu₄N)₂[Os(X)₂Pc^2?]. Similar dicyano and diimidazolido(Im) complexes are formed by the reaction of “H[Os(Cl)₂Pc^2?]” with excess ligand in the presence of [BH₄]^?. The cyclic voltammograms show up to three quasireversible redoxprocesses: E_1/2(I) = 0.13 V (X = CN), ?0.03 V (Im), ?0.13 V (Br) resp. ?0.18 V (Cl) is metal directed (Os^II/III), E_1/2(II) = 0.69 V (Cl), 0.71 V (Br), 0.83 V (CN), 1.02 V (Im) is ligand directed (Pc^2?/?) and E_1/2(III) = 1.17 V (Cl) resp. 1.23 V (Br) is again metal directed (Os^III/IV). Between the typical “B” (～16.2 kK) and “Q” (～29.4 kK), “N regions” (～34.1 kK) up to seven strong “extra bands” of the phthalocyanine dianion (Pc^2?) are observed in the uv-vis spectrum. Within the row CN > Im > Br > Cl, most of the bands are shifted slightly, the “extra bands” considerably more to lower energy in correlation with E_1/2(I). The vibrational spectra are typical for the Pc^2? ligand with D_4h symmetry. M.i.r. bands at 514, 909, 1 173 and 1 331 cm^?1 are specific for hexa-coordinated low spin Os^II phthalocyanines. In the resonance Raman (r.r.) spectra polarized, depolarized or anomalously polarized deformation and stretching vibrations of the Pc^2? ligand will be selectively enhanced, if the excitation frequency coincides with “extra bands”. With excitation at ～19.5 kK the intensity of the symmetrical Os? X stretching vibration at 295 cm^?1 (X = Cl), 252 cm^?1 (X = Im) and 181 cm^?1 (X = Br) is r.r. enhanced, too. The asymmetrical Os? X stretching vibration is observed in the f.i.r. spectrum at 345 cm^?1 (X = CN), 274 cm^?1 (X = Cl), 261 cm^?1 (X = Im) and 200 cm^?1 (X = Br).     

OsII-Phthalocyaninate(2−): Darstellung und Eigenschaften von (Halogeno)-(carbonyl)phthalocyaninato(2−)osmat(II)

Os^II Phthalocyaninates(2?): Synthesis and Properties of (Halo)(carbonyl)phthalocyaninato-(2?)osmate(II) Soluble, blue tetra(n-butyl)ammonium (halo)(carbonyl)phthalocyaninato(2?)osmate(II), (ⁿBu₄N)[Os(X)(CO)Pc^2?] (X = Cl, Br, I) is obtained by the reaction of [Os(THF)(CO)Pc^2?] (THF: tetrahydrofurane) with (ⁿBu₄N)X in THF. In the cyclovoltammograms there are three reversible electrode processes at ?1.21 ± 0.01, 0.18 ± 0.04 and 0.65 ± 0.01 V assigned to the three redox pairs Pc^2?/Pc^3?, Os^II/Os^III and Pc^2?/Pc^3?. In the electronic absorption spectra only the intense B and Q regions are observed at ～ 15800 resp. 27500, 33000 cm^?1. The infrared and resonance Raman spectra closely resemble those of other phthalocyaninates(2?) of low valent osmium. In the infrared spectrum v(C? O) is detected at 1896 ± 4 cm^?1 and v(Os? X) at 260 (X = Cl), 175 (X = Br) or 143 cm^?1 (X = I).     

Ruthenium(II)-Phthalocyanine: Darstellung und Eigenschaften von Di(halogeno)phthalocyaninatoruthenat(II)

Ruthenium(II) Phthalocyanines: Preparation and Properties of Di(halo)phthalocyaninatoruthenate(II) [Ru(Py)₂Pc^2?] reacts with molten (ⁿBu₄N)X forming stable, green (ⁿBu₄N)₂[Ru(X)₂Pc^2?] (X = Cl, Br). The cyclovoltammogram shows a quasireversible redoxprocess for the metal oxidation at E_1/2(I) = ?0.02 V (X = Cl) resp. 0.05 V (X = Br) and for the first ringoxidation at E_1/2(II) = 0.70 V. The typical π-π*-transitions (B < Q < N) of the phthalocyanine dianion (Pc^2?) are observed in the uv-vis spectrum. With respect to Ru^III phthalocyanines B is shifted significantly to higher, Q, N to lower energy. The strong extra-band at 24.2 kK is diagnostic for these Ru^II phthalocyanines. The vibrational spectra are typical for the Pc^2? ligand with D_4h symmetry, too, and bands at 513, 909, 1 171 und 1 329 cm^?1 in the m.i.r. spectrum are specific for hexa-coordinated low spin Ru^II. In the Raman spectrum with excitation at ～480 nm the intensity of the totally symmetrical Ru? X stretching vibration at 266 cm^?1 (X = Cl) resp. 168 cm^?1 (X = Br) together with a progression of up to three overtones is selectively resonance Raman enhanced. The asymmetrical Ru? X stretching vibration is observed in the f.i.r. spectrum at 272 cm^?1 (X = Cl) resp. 215 cm^?1 (X = Br).     

Zn(II) Heteroleptic Halide Complexes with 2-Halopyridines: Features of Halogen Bonding in Solid State

Reactions between Zn(II) dihalides and 2-halogen-substituted pyridines 2-XPy result in a series of heteroleptic molecular complexes [(2-XPy)₂ZnY₂] (Y = Cl, X = Cl (1), Br (2), I (3); Y = Br, X = Cl (4), Br (5), I (6), Y = I, X = Cl (7), Br (8), and I (9)). Moreover, 1–7 are isostructural (triclinic), while 8 and 9 are monoclinic. In all cases, halogen bonding plays an important role in formation of crystal packing. Moreover, 1–9 demonstrate luminescence in asolid state; for the best emitting complexes, quantum yield (QY) exceeds 21%.     

Darstellung und spektroskopische Charakterisierung von Di(halogeno)phthalocyaninato(1–)rhodium(III), [RhX2Pc1−] (X = Cl,Br, I)

Synthesis and Spectroscopical Characterization of Di(halo)phthalocyaninato(1–)rhodium(III), [RhX₂Pc^1?] (X = Cl, Br, I) Bronze-coloured di(halo)phthalocyaninato(1–)-rhodium(III), [RhX₂Pc^1?] (X = Cl, Br) and [RhI₂Pc^1?] · I₂ is prepared by oxidation of (ⁿBu₄N)[RhX₂Pc^2?] with the corresponding halogene. Irrespective of the halo ligands, two irreversible electrode reactions due to the first ringreduction (E_R = ?0,90 V) and ringoxidation (E_O = 0,82 V) are present in the cyclovoltammogram of (ⁿBu₄N)[RhX₂Pc^2?]. The optical spectra show typical absorptions of the Pc^1?-ligand at 14.0 kK and 19.1 kK. Characteristic vibrational bands are at 1 366/1 449 cm^?1 (i. r.) and 569/1 132/1 180/1 600 cm^?1 (resonance Raman (r. r.)). The antisym. (Rh? X)-stretching vibration is observed at 294 cm^?1 (X = Cl), 240 cm^?4 (Br) and 200 cm^?1 (I). Only the sym. (Rh? I)-stretching vibration at 133 cm^?1 is r. r. enhanced together with a strong line at 170 cm^?1, which is assigned to the (I? I)-stretching vibration of the incorporated iodine molecule. Both modes show overtones and combinationbands.