[(C6F5)2IF2][BF4], the First Salt with the Electrophilic Cation [(C6F5)2IF2]+: Synthesis,Reactivity, and Structure

The substitution of hypervalently bonded fluorine atoms in C₆F₅IF₄ was performed with C₆F₅BF₂ and resulted in the new salt [(C₆F₅)₂IF₂][BF₄]. The iodonium(V) salt was characterized by multi‐NMR and Raman spectroscopy and X‐ray crystal structure analysis. The fluorinating ability of the new electrophilic cation [(C₆F₅)₂IF₂]⁺ was exemplified in reactions with monovalent iodine compounds (C₆F₅I, p‐FC₆H₄I, and I₂) and with electron‐poor tri(organyl)pnictanes ER₃ (E = P, As, Sb, Bi; R = C₆F₅). In a heterogeneous reaction with CsF in MeCN the [(C₆F₅)₂IF₂]⁺ cation forms the dinuclear [{(C₆F₅)₂IF₂}₂F]⁺ cation.     

Pentafluorphenylioddifluorid: alternative Darstellungsmethoden,Molekülstruktur und Eigenschaften

Pentafluorophenyliodine(III) Compounds. 3 Pentafluorophenyliodinedifluoride: Alternative Preparations, Molecular Structure, and Properties The formation of C₆F₅IF₂ ( 1 ) by oxidative fluorination of C₆F₅I ( 2 ) using ClF, CF₃OCl, BrF₅, C₆F₅BrF₂, and C₆F₅BrF₄ is described. Highest purity and yield of 1 was achieved by a modified low temperature fluorination with F₂. Thermolysis of 1 delivered perfluoroiodocyclohexadiene‐1,4 and perfluoroiodocyclohexene besides 2 . X‐ray structural analysis of 1 exhibits the fluoride donor and acceptor ability. 1 is spectroscopically characterized by NMR (¹⁹F, ¹³C), IR and Ra. The influence of the change in the oxidation number of iodine in 2 , 1 and C₆F₅IF₄ ( 3 ) on spectroscopic and structural results will be discussed. Minimum energy geometries and charge distributions are calculated (RHF, LANL2DZ) for 1 , 2 and related compounds.     

Aryl(pentafluorphenyl)iodoniumtetrafluoroborate: allgemeine Synthesemethode,typische Eigenschaften und strukturelle Gemeinsamkeiten

Pentafluorophenyliodine(III) Compounds. 4 [1] Aryl(pentafluorophenyl)iodoniumtetrafluoroborates: General Method of Synthesis, Typical Properties, and Structural Features Aryl(pentafluorophenyl)iodoniumtetrafluoroborates [Ar′Ar″I][BF₄] (Ar′ = C₆F₅, Ar″ = C₆H₅, o‐C₆H₄F, m‐C₆H₄F, p‐C₆H₄F, 2,6‐C₆H₃F₂, 3,5‐C₆H₃F₂, 2,4,6‐C₆H₂F₃, 3,4,5‐C₆H₂F₃, C₆F₅) are prepared in good yields and high purity by the reaction of C₆F₅IF₂ with Ar″BF₂ in CH₂Cl₂. This convenient method can be applied generally to many iodonium compounds. Thermal and spectroscopic properties (¹H, ¹³C, ¹⁹F NMR, IR, Raman) are reported and discussed. The solid state structures of six iodonium compounds show significant cation‐anion interactions which result in two different arrangements: a dimer with a 8‐membered ring or polymers with infinite zigzag chains. Ab initio calculations on prototypes of aryliodonium cations show relations between the kind of the aryl group (C₆H₅ vs. C₆F₅) and structural parameters as well as charges. By means of ¹⁹F NMR the σ_I‐ and σ_R‐constants of the [C₆F₅I]⁺‐substituent are determined.     

Neue Synthesen und Kristallstrukturen von Bis(fluorphenyl)quecksilber,Hg(Rf)2 (Rf = C6F5, 2, 3, 4, 6‐F4C6H, 2, 3, 5, 6‐F4C6H, 2, 4, 6‐F3C6H2, 2, 6‐F2C6H3)

New Syntheses and Crystal Structures of Bis(fluorophenyl) Mercury, Hg(R_f)₂ (R_f = C₆F₅, 2, 3, 4, 6‐F₄C₆H, 2, 3, 5, 6‐F₄C₆H, 2, 4, 6‐F₃C₆H₂, 2, 6‐F₂C₆H₃) Bis(fluorophenyl) mercury compounds, Hg(R_f)₂ (R_f = C₆F₅, C₆HF₄, C₆H₂F₃, C₆H₃F₂), are prepared in good yields by the reactions of HgF₂ with Me₃SiR_f. The crystal structures of Hg(2, 3, 4, 6‐F₄C₆H)₂ (monoclinic, P2₁/n), Hg(2, 3, 5, 6‐F₄C₆H)₂ (monoclinic, C2/m), Hg(2, 4, 6‐F₃C₆H₂)₂ (monoclinic, P2₁/c) and Hg(2, 6‐F₂C₆H₃)₂ (triclinic, P1) are described.     

Long‐Lived Radical Cation Salts Obtained by Interaction of Monocyclic Arenes with Niobium and Tantalum Pentahalides at Room Temperature: EPR and DFT Studies

The 1:3 reactions of the alkoxy arenes 1,4‐(MeO)₂C₆H₄ and 1,4‐F₂‐2,5‐(MeO)₂C₆H₂ with TaF₅ in chloroform at 40–50 °C resulted in formation in about 35 % yield of the long‐lived radical cation salts [1,4‐(MeO)₂C₆H₄][Ta₂F₁₁] ( 2 a ) and [1,4‐F₂‐2,5‐(MeO)₂C₆H₂][Ta₂F₁₁] ( 2 b ), respectively. The non‐alkoxy‐substituted [arene][M₂X₁₁] [M=Ta, X=F: arene=C₆H₅Me ( 2 c ), 1,4‐C₆H₄Me₂ ( 2 d ), C₆H₅F ( 2 e ), C₆H₅NO₂ ( 2 f ); M=Nb, X=F: arene=C₆H₅Me ( 4 a ), 1,4‐C₆H₄Me₂ ( 4 b ), C₆H₅F ( 4 c ), C₆H₅NO₂ ( 4 d ); M=Ta, X=Cl: arene=1,4‐C₆H₄Me₂ ( 5 )] were obtained from the 3:1 reactions of MX₅ with the appropriate arene in chloroform at temperatures in the range 40–90 °C. Compounds 2 – 5 were detected by EPR spectroscopy (in CHCl₃) at room temperature, and their gas‐phase structures were optimized by DFT calculations. Formation of the M^IV species [MX₄(NCMe)₂] [M=Ta, X=F ( 3 a ); M=Nb, X=F ( 3 b ); M=Ta, X=Cl ( 3 c )] was ascertained by EPR spectroscopy on solutions obtained by treatment of the reaction mixtures with acetonitrile. Non‐selective reactions occurred upon combination of 1,4‐F₂‐2,5‐(MeO)₂C₆H₂ with AgNbF₆ (in CH₂Cl₂) and 1,4‐(MeO)₂C₆H₄ with SbF₅.     

Explored routes to unknown polyfluoroorganyliodine hexafluorides, RFIF6

Two routes to R_FIF₆ compounds were investigated: (a) the substitution of F by R_F in IF₇ and (b) the fluorine addition to iodine in R_FIF₄ precursors. For route (a) the reagents C₆F₅SiMe₃, C₆F₅SiF₃, [NMe₄][C₆F₅SiF₄], C₆F₅BF₂, and 1,4-C₆F₄(BF₂)₂ were tested. C₆F₅IF₄ and CF₃CH₂IF₄ were used in route (b) and treated with the fluoro-oxidizers IF₇, [O₂][SbF₆]/KF, and K₂[NiF₆]/KF. The observed sidestep reactions in case of routes (a) and (b) are discussed. Interaction of C₆F₅SiX₃ (X = Me, F), C₆F₅BF₂, 1,4-C₆F₄(BF₂)₂ with IF₇ gave exclusively the corresponding ring fluorination products, perfluorinated cyclohexadiene and cyclohexene derivatives, whereas [NMe₄][C₆F₅SiF₄] and IF₇ formed mixtures of C₆F_nIF₄ and C₆F_nH compounds (n = 7 and 9). CF₃CH₂IF₄ was not reactive towards the fluoro-oxidizer IF₇, whereas C₆F₅IF₄ formed C₆F_nIF₄ compounds (n = 7 and 9). C₆F₅IF₄ and CF₃CH₂IF₄ were inert towards [O₂][SbF₆] in anhydrous HF. CF₃CH₂IF₄ underwent C-H fluorination and C-I bond cleavage when treated with K₂[NiF₆]/KF in HF. The fluorine addition property of IF₇ was independently demonstrated in case of perfluorohexenes. C₄F₉CFCF₂ and IF₇ underwent oxidative fluorine addition at −30 °C, and the isomers (CF₃)₂CFCFCFCF₃ (cis and trans) formed very slowly perfluoroisohexanes even at 25 °C. The compatibility of IF₇ and selected organic solvents was investigated. The polyfluoroalkanes CF₃CH₂CHF₂ (PFP), CF₃CH₂CF₂CH₃ (PFB), and C₄F₉Br are inert towards iodine heptafluoride at 25 °C while CF₃CH₂Br was slowly converted to CF₃CH₂F. Especially PFP and PFB are new suitable organic solvents for IF₇.     

Halogenid‐Ionen als Katalysator: Metallzentrierte C–C‐Bindungsknüpfung ausgehend von Acetontril

Halide Ions as Catalyst: Metalcentered C–C Bond Formation Proceeded from Acetonitril AlMe₃ reacts at 20 ?C in acetonitrile to the complex [Me₃Al(NCMe)] ( 1 ). By addition of cesium halides (X^– = F^–, Cl^–, Br^–) a trimerisation to the heterocycle [Me₂Al{HNC(Me)}₂C(CN)] ( 2 ) has been observed. The reaction might be carried out under catalytic conditions (1–2 mol% CsX). The gallium complex [Me₂Ga{HNC(Me)}₂ · C(CN)] ( 3 ), generated under similar reaction conditions, can be converted to the silylated compound [Me₂Ga{Me₃SiNC(Me)}₂C(CN)] ( 4 ) by successive treatment with two equivalents n‐butyllithium and Me₃SiCl. 3 reacts under hydrolysis conditions (1 M hydrochloric acid) to the iminium salt [{H₂NC(Me)}₂C(CN)]Cl ( 5 ). A mixture of H₂O, Ph₂PCl and 3 in THF/toluene leads in a unusual conversion to the diphospane derivative [Ph₂P–P(O)(Me₂GaCl)] ( 6 ). 1 , 2 , 4 , 5 and 6 have been characterized by NMR, IR and MS techniques. X‐ray structure analyses were performed with 1 , 2 , 4 and 6 · 0.5 toluene. According this 1 possesses an almost linear axis AlNCC [Al1–N1–C3: 179,5(2)?; N1–C3–C4: 179,7(4)?]. 2 is an AlN₂C₃ six‐membered heterocycle with two iminium fuctions. One N–H group is responsible for a intermolecular chain‐formation through hydrogen bridges to an adjacent nitrile group along the direction [010]. The basic structural motif of the heterocycle 3 has been maintained after silylation to 4 . In 6 · 0.5 toluene an unit Me₂GaCl, originated from 3 , is coordinated to the oxygen atom of the diphosphane oxide Ph₂P–P(O)Ph₂.     

Rare‐Earth‐Metal–Hydrocarbyl Complexes Bearing Linked Cyclopentadienyl or Fluorenyl Ligands: Synthesis,Catalyzed Styrene Polymerization,and Structure–Reactivity Relationship

A series of rare‐earth‐metal–hydrocarbyl complexes bearing N‐type functionalized cyclopentadienyl (Cp) and fluorenyl (Flu) ligands were facilely synthesized. Treatment of [Y(CH₂SiMe₃)₃(thf)₂] with equimolar amount of the electron‐donating aminophenyl‐Cp ligand C₅Me₄H‐C₆H₄‐o‐NMe₂ afforded the corresponding binuclear monoalkyl complex [({C₅Me₄‐C₆H₄‐o‐NMe(μ‐CH₂)}Y{CH₂SiMe₃})₂] ( 1 a ) via alkyl abstraction and C? H activation of the NMe₂ group. The lutetium bis(allyl) complex [(C₅Me₄‐C₆H₄‐o‐NMe₂)Lu(η³‐C₃H₅)₂] ( 2 b ), which contained an electron‐donating aminophenyl‐Cp ligand, was isolated from the sequential metathesis reactions of LuCl₃ with (C₅Me₄‐C₆H₄‐o‐NMe₂)Li (1 equiv) and C₃H₅MgCl (2 equiv). Following a similar procedure, the yttrium‐ and scandium–bis(allyl) complexes, [(C₅Me₄‐C₅H₄N)Ln(η³‐C₃H₅)₂] (Ln=Y ( 3 a ), Sc ( 3 b )), which also contained electron‐withdrawing pyridyl‐Cp ligands, were also obtained selectively. Deprotonation of the bulky pyridyl‐Flu ligand (C₁₃H₉‐C₅H₄N) by [Ln(CH₂SiMe₃)₃(thf)₂] generated the rare‐earth‐metal–dialkyl complexes, [(η³‐C₁₃H₈‐C₅H₄N)Ln(CH₂SiMe₃)₂(thf)] (Ln=Y ( 4 a ), Sc ( 4 b ), Lu ( 4 c )), in which an unusual asymmetric η³‐allyl bonding mode of Flu moiety was observed. Switching to the bidentate yttrium–trisalkyl complex [Y(CH₂C₆H₄‐o‐NMe₂)₃], the same reaction conditions afforded the corresponding yttrium bis(aminobenzyl) complex [(η³‐C₁₃H₈‐C₅H₄N)Y(CH₂C₆H₄‐o‐NMe₂)₂] ( 5 ). Complexes 1 – 5 were fully characterized by ¹H and ¹³C NMR and X‐ray spectroscopy, and by elemental analysis. In the presence of both [Ph₃C][B(C₆F₅)₄] and AliBu₃, the electron‐donating aminophenyl‐Cp‐based complexes 1 and 2 did not show any activity towards styrene polymerization. In striking contrast, upon activation with [Ph₃C][B(C₆F₅)₄] only, the electron‐withdrawing pyridyl‐Cp‐based complexes 3 , in particular scandium complex 3 b , exhibited outstanding activitiy to give perfectly syndiotactic (rrrr >99 %) polystyrene, whereas their bulky pyridyl‐Flu analogues ( 4 and 5 ) in combination with [Ph₃C][B(C₆F₅)₄] and AliBu₃ displayed much‐lower activity to afford syndiotactic‐enriched polystyrene.     

Reactions of Polyfluoroarenes with MenE‐MMe3 Reagents (MenE = Me2As,Me2P,Me2N,and MeS; M = Si,Sn): Synthesis of Polyfluoroaryl MenE Compounds

Trimethylsilyldimethylarsane Me₃SiAsMe₂ was used as a reagent for the substitution of fluorine in polyfluoroarenes C₆F₅X (X = F, H, Cl) and C₅NF₅ by the Me₂As group. The reactions occur between 50 — 180 °C, either in benzene or without solvent, to give as a rule 4‐X‐1‐(dimethylarsano)tetrafluorobenzenes XC₆F₄AsMe₂, ( 1—3 ) and 4‐dimethylarsano‐tetrafluoropyridine C₅NF₄AsMe₂ ( 4 ), respectively, in yields between 43 and 94 %. In the case of C₆F₆, also double substitution is observed affording 1, 4‐bis(dimethylarsano)tetrafluorobenzene 5 in addition to the monosubstituted derivative. The time and temperature dependencies of the reactions increase in the sequence: C₆F₆< C₆F₅H < C₆F₅Cl < C₅NF₅. The arsanes 1 and 4 were transformed to the potentially valuable bidentate ligands 1‐(dimethylarsano)‐4‐(dimethylphosphano)tetrafluorobenzene 6 and 4‐(dimethylarsano)‐2‐(dimethylphosphano)trifluoropyridine 8 by reaction with trimethylsilyl‐dimethylphosphane Me₃SiPMe₂. 6 reacts with oxygen to yield the corresponding phosphane oxide 7 . Trimethylsilyl‐dimethylamine Me₃SiNMe₂ also was successfully tested as a reagent for the dimethylamination of polyfluoroarenes C₆F₅X [X = F, H, Cl, CF₃, P(S)Me₂], 1‐P(S)Me₂‐4‐H‐C₆F₄ and 4‐X‐C₅NF₄ [X = F, PMe₂, P(S)Me₂]. Sulfuration of the new Me₂P derivatives 8 and 20 leads to the corresponding thiophosphanes 9 and 21 (Schemes 2 and 3). Furthermore, the recently reported very efficient one‐pot synthesis of Me₂P substituted polyfluoroarenes (e.g. XC₆F₄PMe₂ with X = F, Me₂PC₆F₄) was extended to the preparation of Me₂As and MeS derivatives of pentafluoropyridine using a mixture of Me₃SnH, As₂Me₄ (or S₂Me₂) and C₅NF₅ as precursors for the one‐pot reaction. The expected products 4‐(dimethylarsano)tetrafluoropyridine 4 and 4‐(methylthio)tetrafluoropyridine 22 , respectively, were obtained in 84 and 82 % isolated yields. The novel compounds were characterized by spectroscopic (NMR, MS) and analytical data. Compounds 5 , 7 , 9 and 21 could be isolated in form of single crystals and their structures have been studied by X‐ray diffraction.     

A first methodical approach to salts with unsymmetrical fluorophenyl(pentafluorophenyl)difluoroiodonium(V) cations [Rf(RF)IF2] (Rf=x-FC6H4, x=2, 3, 4; RF=C6F5)

A promising approach to the unknown type of [Ar′(Ar)IF₂]X salts is offered. x-FC₆H₄IF₄ (x=2, 3, 4) reacts with C₆F₅BF₂ in CH₂Cl₂ and forms [x-FC₆H₄(C₆F₅)IF₂][BF₄] salts in good yields. For [4-FC₆H₄(C₆F₅)IF₂][BF₄] the fluoro-oxidizer property is shown in reactions with weakly reducing agents like E(C₆F₅)₃ (E=P, As, Sb, Bi) and ArI (Ar=4-FC₆H₄, C₆F₅). The fluorine/aryl substitution method is also applied to the synthesis of [(4-FC₆H₄)₂IF₂][BF₄], an example with two identical aryl groups in the difluoroiodonium(V) moiety.     

Die Reaktionen von M[BF4] (M = Li,K) und (C2H5)2O·BF3 mit (CH3)3SiCN. Bildung von M[BFx>(CN)4—x] (M = Li,K; x = 1, 2) und (CH3)3SiNCBFx(CN)3—x, (x = 0, 1)

The Reactions of M[BF₄] (M = Li, K) and (C₂H₅)₂O·BF₃ with (CH₃)₃SiCN. Formation of M[BF_x(CN)_4—x] (M = Li, K; x = 1, 2) and (CH₃)₃SiNCBF_x(CN)_3—x, (x = 0, 1) The reaction of M[BF₄] (M = Li, K) with (CH₃)₃SiCN leads selectively, depending on the reaction time and temperature, to the mixed cyanofluoroborates M[BF_x(CN)_4—x] (x = 1, 2; M = Li, K). By using (C₂H₅)₂O·BF₃ the synthesis yields the compounds (CH₃)₃SiNCBF_x(CN)_3—x x = 0, 1. The products are characterized by vibrational and NMR‐spectroscopy, as well as by X‐ray diffraction of single‐crystals: Li[BF₂(CN)₂]·2Me₃SiCN Cmc2₁, a = 24.0851(5), b = 12.8829(3), c = 18.9139(5) Å V = 5868.7(2) ų, Z = 12, R₁ = 4.7%; K[BF₂(CN)₂] P4₁2₁2, a = 13.1596(3), c = 38.4183(8) Å, V = 6653.1(3) ų, Z = 48, R₁ = 2.5%; K[BF(CN)₃] P1¯, a = 6.519(1), b = 7.319(1), c = 7.633(2) Å, α = 68.02(3), β = 74.70(3), γ = 89.09(3)°, V = 324.3(1) ų, Z = 2, R₁ = 3.6%; Me₃SiNCBF(CN)₂ Pbca, a = 9.1838(6), b = 13.3094(8), c = 16.840(1) Å, V = 2058.4(2) ų, Z = 8, R₁ = 4.4%     

Synthesen und NMR‐Untersuchungen von Salzen mit den neuen Anionen [PtXn(CF3)6‐n]2— (n = 0 ‐ 5, X = F,OH, Cl,CN) und die Kristallstrukturanalyse von K2[(CF3)2F2Pt(μ‐OH)2PtF2(CF3)2]·2H2O

Syntheses and NMR Spectroscopic Ivestigations of Salts containing the Novel Anions [PtX_n(CF₃)_6‐n]^2— (n = 0 ‐ 5, X = F, OH, Cl, CN) and Crystal Structure of K₂[(CF₃)₂F₂Pt(μ‐OH)₂PtF₂(CF₃)₂]·2H₂O The first syntheses of trifluoromethyl‐complexes of platinum through fluorination of cyanoplatinates are reported. The fluorination of tetracyanoplatinates(II), K₂[Pt(CN)₄], and hexacyanoplatinates(IV), K₂[Pt(CN)₆], with ClF in anhydrous HF leads after working up of the products to K₂[(CF₃)₂F₂Pt(μ‐OH)₂PtF₂(CF₃)₂]·2H₂O. The structure of the salt is determined by a X‐ray structure analysis, P2₁/c (Nr. 14), a = 11.391(2), b = 11.565(2), c = 13.391(3)Å, β = 90.32(3)°, Z = 4, R₁ = 0.0326 (I > 2σ(I)). The reaction of [Bu₄N]₂[Pt(CN)₄] with ClF in CH₂Cl₂ generates mainly cis‐[Bu₄N]₂[PtCl₂(CF₃)₄] and fac‐[Bu₄N]₂[PtCl₃(CF₃)₃], but in contrast that of [Bu₄N]₂[Pt(CN)₆] with ClF in CH₂Cl₂ results cis‐[Bu₄N]₂[PtX₂(CF₃)₄], [Bu₄N]₂[PtX(CF₃)₅] (X = F, Cl) and [Bu₄N]₂[Pt(CF₃)₆]. In the products [Bu₄N]₂[PtX_n(CF₃)_6‐n] (X = F, Cl, n = 0—3) it is possibel to exchange the fluoro‐ligands into chloro‐ and cyano‐ligands by treatment with (CH₃)₃SiCl und (CH₃)₃SiCN at 50 °C. With continuing warming the trifluoromethyl‐ligands are exchanged by chloro‐ and cyano‐ligands, while as intermediates CF₂Cl and CF₂CN ligands are formed. The identity of the new trifluoromethyl‐platinates is proved by ¹⁹⁵Pt‐ and ¹⁹F‐NMR‐spectroscopy.     

Univalent Gallium Complexes of Simple and ansa‐Arene Ligands: Effects on the Polymerization of Isobutylene

Using [Ga(C₆H₅F)₂]⁺[Al(OR^F)₄]^?( 1 ) (R^F=C(CF₃)₃) as starting material, we isolated bis‐ and tris‐η⁶‐coordinated gallium(I) arene complex salts of p‐xylene (1,4‐Me₂C₆H₄), hexamethylbenzene (C₆Me₆), diphenylethane (PhC₂H₄Ph), and m‐terphenyl (1,3‐Ph₂C₆H₄): [Ga(1,4‐Me₂C₆H₄)_2.5]⁺ ( 2⁺ ), [Ga(C₆Me₆)₂]⁺ ( 3⁺ ), [Ga(PhC₂H₄Ph)]⁺ ( 4⁺ ) and [(C₆H₅F)Ga(μ‐1,3‐Ph₂C₆H₄)₂Ga(C₆H₅F)]²⁺ ( 5²⁺ ). 4⁺ is the first structurally characterized ansa‐like bent sandwich chelate of univalent gallium and 5²⁺ the first binuclear gallium(I) complex without a Ga?Ga bond. Beyond confirming the structural findings by multinuclear NMR spectroscopic investigations and density functional calculations (RI‐BP86/SV(P) level), [Ga(PhC₂H₄Ph)]⁺[Al(OR^F)₄]^?( 4 ) and [(C₆H₅F)Ga(μ‐1,3‐Ph₂C₆H₄)₂Ga(C₆H₅F)]²⁺{[Al(OR^F)₄] ^?}₂ ( 5 ), featuring ansa‐arene ligands, were tested as catalysts for the synthesis of highly reactive polyisobutylene (HR‐PIB). In comparison to the recently published 1 and the [Ga(1,3,5‐Me₃C₆H₃)₂]⁺[Al(OR^F)₄]^? salt ( 6 ) (1,3,5‐Me₃C₆H₃=mesitylene), 4 and 5 gave slightly reduced reactivities. This allowed for favorably increased polymerization temperatures of up to +15 °C, while yielding HR‐PIB with high contents of terminal olefinic double bonds (α‐contents=84–93 %), low molecular weights (M_n=1000–3000 g mol^?1) and good monomer conversions (up to 83 % in two hours). While the chelate complexes delivered more favorable results than 1 and 6 , the reaction kinetics resembled and thus concurred with the recently proposed coordinative polymerization mechanism.     

Modified cyclopentadienyl molybdenum compounds with enhanced cytotoxic activity towards MOLT‐4 leukaemia cells

A series of new cyclopentadienyl molybdenum compounds bearing substituted phenanthroline ligands [(η⁵‐C₅H₄CH₂C₆H₄X‐4)Mo(CO)₂(^N,NL)][BF₄] (X = F, Cl, Br; ^N,NL = phen, 5‐NH₂‐phen, 4,7‐Ph₂‐phen) was prepared and characterized using infrared and NMR spectroscopies. Crystal structures of [(η⁵‐C₅H₄CH₂C₆H₄F‐4)Mo(CO)₂(NCMe)₂][BF₄], [(η⁵‐C₅H₄CH₂C₆H₄X‐4)Mo(CO)₂(phen)][BF₄] (X = F, Cl, Br) and [(η⁵‐C₅H₄CH₂C₆H₄Cl‐4)Mo(CO)₂(4,7‐Ph₂‐phen)][BF₄]⋅(4,7‐Ph₂‐phen)⋅HBF₄ were determined using X‐ray diffraction analysis. Biological studies revealed a strong cytotoxic effect of the chelating ligands. Although the cytostatic effect of the halogen in the side chain of the cyclopentadienyl ring is negligible, it could be used for future post‐modification of these types of cytotoxic active molybdenum‐based compounds.     

Substitution reactions of IF5

Using silyl protected organic hydroxo compounds substitution of fluorine in IF₅ is successful.Reacting IF₅ with Si(OCH₃)₄ in CH₃CN or SO₂ using different molar ratios it was shown that in the series IF_5?n(OCH₃)_n only the first member IF₄(OCH₃) (n=1) is stable enough to be isolated. The product in solution with n=2 bismutates to products with n=1 and n=3 if isolated as solids. The last one decomposes to the new oxo compound IF₂O(OCH₃) under elimination of CH₃OCH₃. With n=4,5 only redox reaction products could be isolated.IF₂O(OCH₃) can also be obtained by treating IF₄(OCH₃) with (CH₃)₆Si₂O. Similarly reaction of IF₅ with the disiloxane represents a new method to win IOF₃. Excess of the oxygen transfer reagent leads to formation of IO₂F and I₂O₅. An other oxo compound, IO(CH₃COO)₃, can be prepared by disolving IF₅, IOF₃ or IO₂F in acetic acid anhydride.Reactions of IF₅ with trimethylsilyl protected fluorinated benzoic acids R_fCOOSi(CH₃)₃ (R_f = C₆F₅, 4HC₆F₄) appeared to be independent of the educts molar ratios because the only products are IF(R_fCOO)₄.In order to stabilize iodine (V) derivates with bifunctional chelating oxo ligands we applicated bis(trimethylsilyl) pinacolate, and in smooth reactions we yielded IF₃[OC(CH₃)₂C(CH₃)₂O] and IF[OC(CH₃)₂  C(CH₃)₂O]₂, in which iodine is part of five membered heterocyclic rings. The ¹⁹F-nmr-spectra are consistent with the diolate occupying the axiale and equatorial positions.An extension of the silyl method is the new synthesis of C₆F₅IF₄ which could be obtained in the smooth reaction of IF₅ with stochiometric amounts of Si(C₆F₅)₄.     

Synthesis,Characterization, and Syndio‐Specific Styrene Polymerization of Pyrrolyl‐Substituted Cyclopentadienyl Scandium Complexes

Acid‐base reaction of Sc(CH₂C₆H₄NMe₂‐o)₃ with 1 equiv. of pyrrolyl‐substituted cyclopentadienyl ligand C₄H₂Me₂NSiMe₂C₅Me₄H in toluene gave the half‐sandwich scandium bis(aminobenzyl) complex (C₄H₂Me₂NSiMe₂C₅Me₄)Sc(CH₂C₆H₄NMe₂‐o)₂ ( 2 ). Amine elimination between Sc[N(SiHMe₂)₂]₃(THF) and one equivalent of C₄H₂Me₂NSiMe₂C₅Me₄H afforded the scandium bis(silylamide) complex (C₄Me₂H₂NSiMe₂C₅Me₄)Sc[(NSiHMe₂)₂SiMe₂](THF) ( 3 ). Both scandium complexes 2 and 3 were characterized by elemental analysis, NMR spectroscopy, and single‐crystal X‐ray diffraction. 2 and 3 could serve as highly active precursors for styrene polymerization to give syndio‐tactic polystyrene (rrrrrr > 99 %).     

Synthesis and Characterization of the 1 : 1-Adducts of In(C6F5)3 with Acetonitrile,Glyme, and DMAP (DMAP = 4-(N,N-dimethylamino)pyridine), and [PNP][In(C6F5)4] (PNP = bis(triphenylphosphinanyliden)immonium) – the Crystal Structure of [PNP][In(C6F5)4]

In(C₆F₅)₃ · CH₃CN and In(C₆F₅)₃ · glyme were synthesized from InCl₃ and Cd(C₆F₅)₂ in CH₃CN or glyme in 43% and 35% yield, respectively. Replacement of CH₃CN or (C₂H₅)₂O by DMAP yielded the corresponding 1 : 1-adduct. [PNP][In(C₆F₅)₄] was best prepared from the corresponding cesium salt which was best synthesized from the reaction of stoichiometric amounts of In(C₆F₅)₃ · CH₃CN, (CH₃)₃ SiC₆F₅ and CsF in good yield. [PNP][In(C₆F₅)₄] crystallizes in the triclinic space group P 1, a = 1104.9(4) pm, b = 1442.4(6) pm, c = 1833.8(8) pm, α = 110.87(2)°, β = 92.04(3)°, γ = 96.55(3)°, Z = 2.     

Tunable Fluorophores Based on 2‐(N‐Arylimino)pyrrolyl Chelates of Diphenylboron: Synthesis,Structure, Photophysical Characterization,and Application in OLEDs

Reactions of 2‐(N‐arylimino)pyrroles (HNC₄H₃C(H)?N‐Ar) with triphenylboron (BPh₃) in boiling toluene afford the respective highly emissive N,N′‐boron chelate complexes, [BPh₂{κ²N,N′‐NC₄H₃C(H)?N‐Ar}] (Ar=C₆H₅ ( 12 ), 2,6‐Me₂‐C₆H₃ ( 13 ), 2,6‐iPr₂‐C₆H₃ ( 14 ), 4‐OMe‐C₆H₄ ( 15 ), 3,4‐Me₂‐C₆H₃ ( 16 ), 4‐F‐C₆H₄ ( 17 ), 4‐NO₂‐C₆H₄ ( 18 ), 4‐CN‐C₆H₄ ( 19 ), 3,4,5‐F₃‐C₆H₂ ( 20 ), and C₆F₅ ( 21 )) in moderate to high yields. The photophysical properties of these new boron complexes largely depend on the substituents present on the aryl rings of their N‐arylimino moieties. The complexes bearing electron‐withdrawing aniline substituents 17 – 20 show more intense (e.g., ?_f=0.71 for Ar=4‐CN‐C₆H₄ ( 19 ) in THF), higher‐energy (blue) fluorescent emission compared to those bearing electron‐donating substituents, for which the emission is redshifted at the expense of lower quantum yields (?_f=0.13 and 0.14 for Ar=4‐OMe‐C₆H₄ ( 15 ) and 3,4‐Me₂‐C₆H₃ ( 16 ), respectively, in THF). The presence of substituents bulkier than a hydrogen atom at the 2,6‐positions of the aryl groups strongly restricts rotation of this moiety towards coplanarity with the iminopyrrolyl ligand framework, inducing a shift in the emission to the violet region (λ_max=410–465 nm) and a significant decrease in quantum yield (?_f=0.005, 0.023, and 0.20 for Ar=2,6‐Me₂‐C₆H₃ ( 13 ), 2,6‐iPr₂‐C₆H₃ ( 14 ), and C₆F₅ ( 21 ), respectively, in THF), even when electron‐withdrawing groups are also present. Density functional theory (DFT) and time‐dependent DFT (TD‐DFT) calculations have indicated that the excited singlet state has a planar aryliminopyrrolyl ligand, except when prevented by steric hindrance (ortho substituents). Calculated absorption maxima reproduce the experimental values, but the error is higher for the emission wavelengths. Organic light‐emitting diodes (OLEDs) have been fabricated with the new boron complexes, with luminances of the order of 3000 cd m^?2 being achieved for a green‐emitting device.     

Neutral and Cationic Molybdenum Imido Alkylidene N‐Heterocyclic Carbene Complexes: Reactivity in Selected Olefin Metathesis Reactions and Immobilization on Silica

The synthesis and single‐crystal X‐ray structures of the novel molybdenum imido alkylidene N‐heterocyclic carbene complexes [Mo(N‐2,6‐Me₂C₆H₃)(IMesH₂)(CHCMe₂Ph)(OTf)₂] ( 3 ), [Mo(N‐2,6‐Me₂C₆H₃)(IMes)(CHCMe₂Ph)(OTf)₂] ( 4 ), [Mo(N‐2,6‐Me₂C₆H₃)(IMesH₂)(CHCMe₂Ph)(OTf){OCH(CF₃)₂}] ( 5 ), [Mo(N‐2,6‐Me₂C₆H₃)(CH₃CN)(IMesH₂)(CHCMe₂Ph)(OTf)]⁺ BAr_F^? ( 6 ), [Mo(N‐2,6‐Cl₂C₆H₃)(IMesH₂)(CHCMe₃)(OTf)₂] ( 7 ) and [Mo(N‐2,6‐Cl₂C₆H₃)(IMes)(CHCMe₃)(OTf)₂] ( 8 ) are reported (IMesH₂=1,3‐dimesitylimidazolidin‐2‐ylidene, IMes=1,3‐dimesitylimidazolin‐2‐ylidene, BAr_F^?=tetrakis‐[3,5‐bis(trifluoromethyl)phenyl] borate, OTf=CF₃SO₃^?). Also, silica‐immobilized versions I1 and I2 were prepared. Catalysts 3 – 8 , I1 and I2 were used in homo‐, cross‐, and ring‐closing metathesis (RCM) reactions and in the cyclopolymerization of α,ω‐diynes. In the RCM of α,ω‐dienes, in the homometathesis of 1‐alkenes, and in the ethenolysis of cyclooctene, turnover numbers (TONs) up to 100 000, 210 000 and 30 000, respectively, were achieved. With I1 and I2 , virtually Mo‐free products were obtained (<3 ppm Mo). With 1,6‐hepta‐ and 1,7‐octadiynes, catalysts 3 , 4 , and 5 allowed for the regioselective cyclopolymerization of 4,4‐bis(ethoxycarbonyl)‐1,6‐heptadiyne, 4,4‐bis(hydroxymethyl)‐1,6‐heptadiyne, 4,4‐bis[(3,5‐diethoxybenzoyloxy)methyl]‐1,6‐heptadiyne, 4,4,5,5‐tetrakis(ethoxycarbonyl)‐1,7‐octadiyne, and 1,6‐heptadiyne‐4‐carboxylic acid, underlining the high functional‐group tolerance of these novel Group 6 metal alkylidenes.     

Synthesen und Eigenschaften von Bis(perfluoralkyl)zink‐Verbindungen

Syntheses and Properties of Bis(perfluoroalkyl)zinc Compounds The conditions for the syntheses of bis(perfluoroalkyl)zinc compounds Zn(R_f)₂ · 2 D (R_f = C₂F₅, n‐C₃F₇, i‐C₃F₇, n‐C₄F₉, n‐C₆F₁₃, n‐C₇F₁₅, and n‐C₈F₁₇; D = CH₃CN, tetrahydrofurane, dimethylsulfoxide) are described. Mass spectra, thermal decompositions, ¹⁹F‐ and ¹³C‐NMR spectra are discussed.