bluuebunny/crossref_metadata_2025 huggingface dataset:
Electronic Structure of Mono‐ and Bis(carbonyliron) as well as Bis(cyclopentadienyliron) Complexes of 1,4‐Dihydro‐1,4‐diboranaphthalene
Authors: Gleiter Rolf , Hyla‐Kryspin Isabella , Siebert Walter
Published: July 2007

The structure and bonding of four iron complexes involving the 1,4‐dihydro‐1,4‐diboranaphthalene ligand C8B2H8 (1), namely of the complexes (CO)3Fe(η6‐C8B2H8) (2), (μ, η4,η6‐C8B2H8)[Fe(CO)3]2 (3), (CO)3Fe(μ,η4,η6‐C8B2H8)Fe(CO)2 (4), and of the triple‐decker (μ,η6‐C8B2H8)[Fe(η5‐C5H5)]2 (5), have been investigated by means of the perturbational molecular orbital theory on the basis of the Extended Hückel calculations. Compounds 2 and 3 are 18‐VE complexes, whereas 5 is a 30‐VE species. The structure of 4 can be best described in terms of a 16‐VE complex “Fe(CO)3 heterocycle” and a 18‐VE “Fe(CO)2 carbocycle” unit with its iron centers being not directly bond.
Synthesis and Structure of the New α‐Aminosilanolate [LiOSiMe2(NMe2)]6
Authors: Herberich Gerhard E. , Spaniol Thomas P. , Fischer Andreas
Published: July 2007

Lithium (dimethylamino)dimethylsilanolate (1) is obtained from trimeric dimethylsiloxane and lithium dimethylamide in quantitative yield. In the crystal 1 is a hexamer [LiOSiMe2(NMe2)]6 with crystallograpic C3i (S6, 3) symmetry. The molecule of 1 consists of a hexagonal prismatic (LiO)6 core and an N,O‐chelating anion.
Zur Reaktion von Isocyaniden mit Nitriliminen[1]
Authors: Moderhack Dietrich , Lorke Michael , Ernst Ludger , Schomburg Dietmar
Published: July 2007

On the Reaction of Isocyanides with Nitrile Imines

Four competing reactions have been found to occur when nitrile imines 2 are generated from 1 in the presence of isocyanides 3. The products obtained include i) 1,2,3‐triazolium salts 6, ii) 1,2,4‐triazolium salts 8, iii) dihydrotriazolyl‐substituted pyrazolamines 11, and iv) unstable 1,2‐diazetimine derivatives 12 which in turn give carbodiimides 13, nitriles 14, quinoxalinamines 15, and possibly 1,2,4‐triazoles 16 (after addition of 2). The proportions, in particular those of 6, 8, and 11, depend on the reaction conditions; thus, triethylamine used in excess can oppress the formation of 6 in favour of 8 and 11. ‐ The structure of 11 has been elucidated by means of X‐ray diffraction analyses of 11a and c.
Oxidative Cyclisierung von Anilinopyrazolen zu Pyrazolo[1,5‐a]benzimidazolen
Authors: Kluge Ralph , Schulz Manfred , Pobišova Miroslava , Nüchter Matthias
Published: July 2007

Free Radical Reactions of N‐Heterocyclic Compounds, XIV[1]. ‐ Oxidative Cyclization of Anilinopyrazoles to Pyrazolo[1,5‐a]benzimidazoles

Herrn Professor Christoph Rüchardt zum 65. Geburtstag gewidmet.

Substituted Anilinopyrazoles 1 were oxidized by dibenzoyl peroxide or lead(IV) oxide. Different oxidation products were isolated depending on the substituents in the anilino group of anilinopyrazoles 1. Intermediate pyrazolyl radicals 5, which could be trapped by triphenylmethyl or phenoxyl radicals, undergo cyclization reaction with formation of pyrazolo[1,5‐a]benzimidazoles 4. The structures of compounds 4 were proven by 1H‐ and 13C‐NMR spectroscopy, 15N labeling and transformation of 4e to the betain 7e.
Carbon‐Carbon Bond Formation Promoted by “Bare” Lanthanide Cations: The Reactions of Ce+ and La+ with Propene in the Gas Phase
Authors: Heinemann Christoph , Schröder Detlef , Schwarz Helmut
Published: July 2007

The cationic butadiene and benzene complexes CeC4H6+ and CeC6H6+ are the main products in the reaction of thermalized Ce+ ions with propene in the gas phase, as shown by FT MS. Following the formation of the primary products, i.e. CeCH2+ and CeC3H4+, selective C‐C coupling processes at the lanthanide cation occur as secondary reactions with high efficiency. Ligand‐exchange reactions and comparative collision‐induced dissociation experiments are applied to probe the structures of the final reaction products of this first example of Ce+ gas‐phase chemistry. The reaction of Ce+ with cyclopropane yields a product distribution very similar to the propene reaction; however, it reacts significantly slower. Furthermore, La+ reacts in nearly the same manner with propene as Ce+ which indicates that the single f electron in the latter ion is chemically inert.
Four‐Membered 1,8‐Naphthalenediyl Transition Metallacycles
Authors: Tinga Marcus A. G. M. , Schat Gerrit , Akkerman Otto S. , Bickelhaupt Friedrich , Smeets Wilberth J. J. , Spek Anthony L.
Published: July 2007

Five 1,8‐naphthalenediyl transition metal compounds 2 were prepared by treating either 1,8‐naphthalenediylmagnesium (1) or 1,8‐dilithionaphthalene with the appropriate transition metal dichloride LnMCl2: LnM = Cp2Ti (2a), (PEt3)2Pt (2b), Cp* PPh3Rh (2c), Cp* PPh3Ir (2d), or Cp*2Zr (2e). The resulting metallacycles were characterized by NMR and mass spectrometry. X‐ray crystal structure analyses were performed for (1,8‐naphthalenediyl)titanocene (2a) and (1,8‐naphthalenediyl)bis(triethylphosphane)platinum (2b). Despite the strain induced by the four‐membered metal‐containing rings, the naphthalene units show remarkably small distortions.
[2,3]‐Thia‐Wittig Rearrangements of α‐Lithiated Sulfides Via De‐aromatized Cyclohexadiene Intermediates Proceed with Inversion of Configuration at the Carbanionic Center
Authors: Brickmann Kay , Hambloch Frank , Spolaore Emanuela , Brückner Reinhard
Published: July 2007

The nBuLi‐induced tin/lithium exchange reactions of the di‐astereomeric γ‐[(methoxyethoxy)methoxy]‐]α‐(tributylstannyl) sulfides anti‐ and syn‐8 delivered the α‐(lithioalkyl) benzyl sulfides anti‐ and syn‐11, respectively. Within 1 h at ‐78°C, these species underwent [2,3]‐thia‐Wittig rearrangements in THF via the de‐aromatized cyclohexadiene intermediates syn‐ and anti‐12. Tautomerization and protonation yielded 81:19 (85%) and 19:81 mixtures (96%) of the ortho‐functionalized toluenes syn‐ and anti‐13. Probably, both Wittig rearrangements proceeded with 100% inversion of configuration at the carbanionic stereocenter, and the overall loss of stereoselectivity is due to an epimerization anti‐11 ⇌ syn‐11 of the lithio sulfide intermediates at a rate which is 3.3 times slower than the rearrangement.
Enantioselektive Protonierung von Lacton‐Enolaten
Authors: Gerlach Uwe , Haubenreich Thomas , Hünig Siegfried
Published: July 2007

Stereoselective Protonation of Carbanions, 4[1]. — Enantioselective Protonation of Lactone Enolates[2]

The prochiral lithium enolates derived from the five‐membered lactones rac‐1 and rac‐2 were protonated by 37 OH‐and 21 NH‐chiral proton sources in THF at — 78°C. The enantioselectivities, determined directly from the reaction mixture by chiral HPLC, are always higher for system 1, probably due to restricted rotation of the phenyl group in 1Li at low temperature (NMR) and range from 0–54% ee. The strongest stereodifferentiation is observed if the OH or NH acids carry an adjacent O‐ or N‐containing group (structures G–J) which allows complexation with the lithium ion. A plausible transition state involving the dimeric lithium enolate is proposed.
Oligooxa[3n.3]paracyclophane Quinhydrones — Cation‐Induced Charge‐Transfer Absorptions and Structures of the Metal Complexes
Authors: Bauer Helmut , Matz Volker , Lang Martina , Krieger Claus , Staab Heinz A.
Published: July 2007

The intramolecular oligooxa[3n.3]paracyclophane quinhy‐drones 2–5 (with n = 3 to 6) were synthesized and their interactions with alkali and alkaline earth metal and mercury(II) ions were studied by electron absorption and NMR spectroscopy. Remarkable enhancements of the CT absorptions were observed by complexation with metal ions of the pentaoxa[15.3]paracyclophane quinhydrone 4 and the hexaoxa[18.3]paracyclophane quinhydrone 5 to the corresponding complexes 6a–e and 7, respectively. The various donor‐acceptor orientations and the crown ether‐like complexation in the calcium complex 6d, the mercury complex 6e and the barium complex 7 were determined by X‐ray analysis. Moreover, the X‐ray structures of the tetramethoxy‐2,5,8‐trioxa[9.3]paracyclophane 8a, a precursor of the quinhydrone 2, and of the pentaoxa[15.3](2,5)‐p‐benzoquinonophane 20, the product of oxidative demethylation of the quinhydrone 4, are given. For comparison with the cyclic quinhydrones acyclic analogs are also described.
The enthalpies of formation ΔHf and the ring strain energies Eg were calculated for the nine isomeric dithiacyclooctynes 1‐‐9 by applying the MNDO method. Reaction Scheme 2 shows the synthesis of 1,4‐dithia‐2‐cyclooctyne (1), which was the highest Eg value in this series. It dimerizes to 13 in the absence of reaction partners. Scheme 4 summarizes the preparation of 1,5‐dithia‐2‐cyclooctyne (2) and its homologue 1,5‐dithia‐2‐cyclononyne (23) and Scheme 6 the preparation of 1,4‐dithia‐6‐cyclooctyne (6) and its homologue 1,5‐dithia‐7‐cyclononyne (29). Depending on the position of the sulfur atoms, all three reaction sequences contain different steps for the introduction of the triple bonds.
Authors: Meier Herbert , Dai Yujia , Schuhmacher Hans , Kolshorn Heinz
Published: July 2007

Dithiacyclooctine
Synthesis, Separation and Characterization of Unsymmetrically Substituted Phthalocyanines
Authors: Linßen Torsten Golo , Hanack Michael
Published: July 2007

Unsymmetrically substituted (phthalocyaninato)nickel(II) complexes –7 were synthesized by statistical condensation of 4,5‐dipentoxy‐ (2a), 4,5‐diheptyl‐ (2b), 3,6‐dihexoxy‐ (2c), and 3,6‐diheptylphthalonitrile (2d) with 3,4,5,6‐tetraphenylphthalonitrile (1) and separated by column chromatography. The obtained phthalocyanines 3–7 were characterized by UV‐, IR‐, and 1H‐NMR spectroscopy.
Die fördernde Rolle von Phosphinoester‐Liganden bei der Synthese neutraler Carben‐, Vinyliden‐ und Allenyliden‐Ruthenium(II)‐Komplexe
Authors: Werner Helmut , Stark Arthur , Grönwald Paul Steinert, Claus , Wolf Justin
Published: July 2007

Vinylidene Transition‐Metal Complexes, XXXV[1]. — The Supporting Role of Phosphino Ester Ligands for the Synthesis of Neutral Carbene, Vinylidene and Allenylidene Ruthenium(II) ComplexesThe reaction of [RuCl2(PPh3)3] (1) with the phosphino esters iPr2P(CH2)nCO2R (2–4) leads to complete (n = 1; R  CH3, C2H5) or partial (n = 2; R CH3) displacement of the PPh3 ligands and formation of the octahedral ruthenium(II) complexes [RuCl2{k2(P,O)‐iPr2PCH2CO2R}2] (5, 6) and [RuCl2(PPh3){k(P)‐iPr2PCH2CH2CO2Me}{k2(P,O)‐iPr2PCH2CH2CO2Me}] (7). Treatment of 5 with LiBr and LiI affords the dibromo‐ and diiodoruthenium derivatives 8 and 9. While compound 5 reacts with CO and SO2 by cleavage of one Ru—O bond to yield the 1:1 adducts [RuCl2(L){k(P)‐iPr2PCH2CO2Me}{k2(P,O)‐iPr2PCH2CO2Me}] (10, 11), the reaction of the dibromo derivative 8 with CO in solution gives the dicarbonyl complex [RuBr2(CO)2{k(P)‐iPr2PCH2CO2Me}2](13). If CO is passed over 8 in the solid state, the corresponding monocarbonyl compound 14 is formed. The hydridoruthenium(II) complex 16, which is obtained from equimolar amounts of [RuHCl(CO)(PiPr3)2] (15) and 2, reacts with HCCMe by insertion to give the vinyl derivative [RuCl{E—CHCHMe}(CO)(PiPr3){k2(P,O)‐iPr2CH2CO2Me}] (17). Treatment of 5 with HC̊' (R'  H, Me, tBu, Ph) and of 6, 8, 9 with HCCPh affords upon photochemical activation the octahedral vinylidene complexes [RuX2‐(CCHR){k(P)‐iPr2PCH2CO2R}{k2(P,O)‐iPr2PCH2CO2R}] (18–21 and 23–25) in good to excellent yield. At room temperature, these compounds (with the exception of 25) are highly fluxional in solution. From 31P‐NMR measurements, the free energies of activation ΔG‡ for the intramolecular rearrangement have been determined. Whereas the reaction of 5 with HCČH2CH2OH leads to the carbene complex 30 containing the cyclic oxycarbene :C(CH2)3O as ligand, the functionalized vinylidene derivatives 31 and 32 are formed on treatment of 5 with aryl‐substituted alkynols HC≡RR'OH (R  Ph, R'  Ph, o‐Tol). These react in toluene solution at 80°C by elimination of water to give the allenylidene complexes [RuCl2(CCCRR'){k(P)‐iPr2PCH2CO2Me}{k2(P,O)‐iPr2PCH2CO2Me}] (33, 34). The X‐ray structure analysis of 33 reveals a trans disposition of the chloro ligands, the phosphorus atoms as well as of one CO oxygen and the α‐C atom of the allenylidene unit. Compound 33 reacts with CO, CNtBu and pyridine to give the 1:1 adducts [RuCl2(L)(CCCPh2){k(P)‐iPr2PCH2CO2Me}2] (35–37) and with HCl by attack on the central CC bond to yield the vinylcarbene complex [RuCl2(C(Cl)CHCRR'){k((P)‐iPr2‐PCH2CO2Me}{k2(P,O)‐iPr2PCH2CO2Me}] (38). The preparation of the phosphino ketone iPr2PCH2C(O)CH3 (40) and its ruthenium complexes 41 and 42 is briefly described.
Synthesis of Transient Silenes by a Modified Peterson Reaction
Authors: Krempner Clemens , Reinke Helmut , Oehme Hartmut
Published: July 2007

Tris(trimethylsilyl)silylmagnesium bromide, obtained in situ from tris(trimethylsilyl)silyllithium and magnesium bromide, reacts with acetone, pivalaldehyde, or 2,4,6‐trimethylbenzaldehyde to give the (1‐hydroxyalkyl)tris(trimethylsilyl)silanes (Me3Si)3SiC(OH)Me2 (1a), (Me3Si)3CH(OH)tBu (1b), and (Me3Si)3SiC(OH)Mes (1c), resp. After deprotonation with methyllithium in ether at ‐78°C 1a‐c eliminate trimethylsilanolate according to a modified Peterson mechanism to form transient silenes (Me3Si)2Si=CR1R2 (6a: R1 = R2 = Me; 6b: R1 = H, R2 = tBu; 6c: R1 = H, R2 = Mes). In the absence of trapping agents these silenes dimerize, 6a leading to the linear dimer 1‐isopropenyl‐2‐isopropyl‐1,1,2,2‐tetrakis(trimethylsilyl)disilane (7) and 6b giving the head‐to‐head cyclodimerization product (E)‐3,4‐di‐tert‐butyl‐1,1,2,2‐tetrakis(trimethylsilyl)‐1,2‐disilacyclobutane (8), whereas 6c in a very unusual cyclodimerization step affords (E)‐1,2,3,8a‐tetrahydro‐1‐mesityl‐5,7,8a‐trimethyl‐2,2,3,3‐tetrakis(trimethylsilyl)‐2,3‐disilanaphthalene (9). Compound 9 is the result of an unexpected [2 + 4] reaction, in which the silene formally acts as the monoene and – involving the aromatic substituent – simultaneously also as the diene. The reaction of 1a‐c with methyllithium in THF at low temperature initiates 1,3‐Si,O‐trimethylsilyl migrations leading to (trimethylsiloxy)‐[bis(trimethylsilyl)silyl]alkanes (Me3Si)2SiH–CR1R2OSiMe3 3a‐c. Reaction of 1a‐c with an excess of methyllithium, tert‐butyllithium, or phenyllithium, leads to trisilanes (Me3Si)2‐SiR3–CHR1R2 11a‐e, formed by the addition of the organolithium reagent to the Si=C bond of the transient silences 6a‐c. Deprotonation of 1b and 1c in the presence of 2,3‐dimethyl‐1,3‐butadiene gives the [2 + 4] cycloadducts 6‐tert‐butyl‐3,4‐dimethyl‐1,1‐bis(trimethylsilyl)‐1‐sila‐3‐cyclohexene (12a) and 6‐mesityl‐3,4‐dimethyl‐1,1‐bis(trimethylsilyl)‐l‐sila‐3‐cyclohexene (12b). For 8 and 9 the results of the X‐ray analyses are given.
Platin(II)‐Komplexe mit Porphyrinliganden: Synthese und Synergismen bei der photodynamischen Tumortherapie
Authors: Brunner Henri , Obermeier Herbert , Szeimies Rolf‐Markus
Published: July 2007

Platinum(II) Complexes with Porphyrin Ligands: Synthesis and Synergisms in the Photodynamic Tumor Therapy

Twelve porphyrin ligands (2–5, 8, 13–16, 19, 27, 28) and their platinum(II) complexes (29–40) were synthesized and characterized. Nine of the porphyrins are derived from hemin, and three are based on tetraphenylporphyrin. The ligands were transformed into diammine‐dicarboxylatoplatinum(II) complexes and diamine‐dichloroplatinum(II) complexes. The antitumor activity in the photodynamic therapy of the ligands and their complexes was tested in vitro towards the MDA‐MB‐231 mammary carcinoma cell line. The results obtained showed an additive effect of the photodynamic activity of the porphyrin skeleton when irradiated with visible red light and the cytotoxic activity of the platinum moiety in the complexes.
Derivate des Imidazols, XIII. Carben‐Komplexe des Siliciums und Zinns
Authors: Kuhn Norbert , Kratz Thomas , Bläser Dieter , Boese Roland
Published: July 2007

Imidazole Derivatives, XIII. – Carbene Complexes of Silicon and Tin

Herrn Professor Peter Paetzold zum 60. Geburtstag gewidmet.

Stable adducts of the composition L · SiCl4 (2), L · SiR2Cl2 (3,4), and L · SnR2Cl2 (6) are formed by the reaction of the imidazol‐2‐ylidenes L (1) with the corresponding silicon and tin halides. For L = SiCl4 (2b; L = 1,3‐diethyl‐4,5‐dimethylimidazol‐2‐ylidene) and L · SnPh2Cl2 (6c; L = 1,3‐diisopropyl‐4,5‐dimethylimidazol‐2‐ylidene) the monomeric nature of the compounds containing pentacoordinated silicon and tin is established by X‐ray structure analyses. The reaction of 1,3‐diisopropyl‐4,5‐dimethylimidazol‐2‐ylidene (1c) with SnCl2 leads to the formation of the monomeric stannylene complex L · SnCl2 (7c; L = 1,3‐diisopropyl‐4,5‐dimethylimidazol‐2‐ylidene) whose molecular geometry indicates a week carbon‐to‐tin donor bond [SnC(1) 2.290(5) Å].
Metallorganische CO2‐Speichersysteme aus Nickel(0)‐1‐azadieneinheiten und ihre Reaktivität bei der Carboxylierung von Acetophenon
Authors: Walther Dirk , Geßer Susann , Ritter Uwe , Schmidt A. , Hamza Khairi , Imhof Wolfgang , Görls Helmar , Sieler Joachim
Published: July 2007

Organometallic CO2 Reservoires from Nickel(0)‐1‐Azadiene‐Type Ligands and Their Reactivity in the Carboxylation of Acetophenone

1‐Azadiene‐type ligands yield with nickel(0) binuclear organometallic compounds of the type [Ni(1‐azadiene)n,]2 (n = 1, 2). The structures of the complexes 1 (n = 2, ligand A) and 3 (n = 1, ligand C) have been characterized by X‐ray crystallography. 1 is unreactive towards CO2, 3 and similar compounds are able to react with CO2 to give metallacyclic carbamato complexes of Ni(II). In these compounds CO2 is activated and can carboxylate acetophenone to yield benzoylic acid upon protolysis. These reactions mimic biologic conversion reactions of CO2 into organic material by organometallics. – The addition of two moles of the (bpy)Ni(0)‐fragment [from (bpy)Ni(COD)] to 3 gives the tetranuclear complex 6. The X‐ray analysis of the monomeric model compound (bi‐py)Ni(A) (11) shows that only the olefin part is coordinated. 6 and 11 can also react with CO2. Cu(I) complexes with 1‐azadiene‐type ligands are not reactive towards CO2.
Charge‐Transfer‐Komplexe von Metalldithiolenen, XVIII. Ionenpaare von Dithiolencobaltaten mit Bipyridinium‐Akzeptoren
Authors: Schmauch Georg , Knoch Falk , Kisch Horst
Published: July 2007

Charge‐Transfer Complexes of Metal Dithiolenes, XVIII. – Ion Pairs of Dithiolene Cobaltates with Bipyridinium Acceptors

Ion pair charge‐transfer (IPCT) complexes of the type {A2+[Co(mnt)2]2−}, mnt2− = cis‐1,2‐dicyano‐1,2‐ethenedithiolate, A2+ = a bipyridinium derivative, posses IPCT bands in the range from 590 to 950 nm. An X‐ray structure analysis of {BQ2+[Co(mnt)2]2−}, BQ2+ = 6,7,8,9‐tetrahydrodipyrido[1,2‐a:2,1‐c][1,4]diazocinium, reveals that the strongly twisted acceptor and planar donor do not form mixed stacks, as usually observed in less twisted systems. Electrical conductivities of pressed powder pellets are in the range of 10−15 to 10−7 Ω−1 cm−1 and do not exhibit a simple correlation with the driving force of electron transfer between the ion pair components. The cis‐trans isomerization of an ethene‐bridged methyl viologen acceptor leaves the conductivity almost unchanged.
Pyridine as an C‐Orthometalated and σ‐N‐Complexed Heteroarene Ligand on the Surface of a Co3 Cluster
Authors: Schneider JöRg J.
Published: July 2007

Reaction of [(η5‐Cp*)(acac‐O,O′)Co] (1) with potassium metal in pyridine results in reductive ligand transfer of the acac ligand to potassium and formation of a mixture of two organocobalt complexes which can be separated from each other by chromatography. Besides a mononuclear complex containing no pyridine unit the trinuclear cobalt cluster [{(η5‐Cp*)‐Co}3‐μ‐pyridine] (3) is formed in a cyclometalation reaction in 57% yield. The pyridine ligand in 3 is located on one edge of the Co3 core according to the spectroscopic data and a preliminary X‐ray crystal structure analysis.
Synthesis, Structures and Properties of CF3S‐Substituted Tellurium Compounds
Authors: Boese Roland , Dworak Jürgen , Haas Alois , Pryka Michael
Published: July 2007

New preparations for the following compounds are described: Te(SCF3)2, Te(NSO)2, and Cl2Te(NSO)2. The catalytic or thermal SO2 elimination from Cl2Te(NSO)2 affords a coordinated or non‐coordinated thiachalcogenadiazole. Conversions of these compounds are reported. Evidence for the proposed mechanism for the reaction between Te(NSO)2 and SbCl5 is provided. Cl4Te2N2(SCF3)2, prepared from TeCl4 and CF3SN(SiMe3)2, reacts with LiN(SiMe3)2 to form [(Me3Si)2N]4Te2N2(SCF3)2. An X‐ray structural analysis of Cl4Te2N2(SCF3)2 is presented.
On the Regioselectivity and Stereoselectivity of the Carbene Transfer from Fischer Carbene Complexes to Trisubstituted Electron‐Deficient 1,3‐Dienes
Authors: Buchert Matthias , Hoffmann Matthias , Reißig Hans‐Ulrich
Published: July 2007

Thermal reactions of Fischer carbene complex 1 with trisubstituted electron‐deficient 1,3‐dienes 7, 8, 23, 25, 32, and 35 provided highly substituted vinylcyclopropanes in good yields. The carbene transfer proceeds highly regioselectively favouring cyclopropanation of the double bond not bearing the ester function. In addition, the diastereoselectivity is generally fairly high in preference of cyclopropanes with the methoxy group cis‐positioned with respect to the olefin moiety. The reaction of methylcarbene complex 2 with diene ester 8 displays inversed regioselectivity. These observations are discussed together with solvent effects, and a mechanistic rationale is presented.
Formation and Structure of a New Dinuclear Rhodium Complex [(iPr3P)RhCl]2[P3C3tBu3]
Authors: Binger Paul , Haas Josef , Betz Peter , Krüger Carl
Published: July 2007

The new dinuclear rhodium complex 4 was synthesized by reaction of [(iPr3P)2RhCl]2 (1) or [(iPr3P)2(CH2=CH2)RhCl] (2) with 2‐tert‐butyl‐1‐phosphaacetylene (3) in 58% yield. An X‐ray analysis reveals that in 4 a 1,3,6‐triphosphahexadiene‐1,6‐diyl chain is bound to each of the two rhodium atoms in an η1,η3 manner.
DBU ‐ nicht einfach nur eine starke Base: Eine Eintopfreaktion für ein polycyclisches Ringgerüst mit Diphosphet ‐ Grundstruktur unter Einbeziehung von doppelt deprotoniertem DBU
Authors: Karsch Hans H. , Rupprich Thomas , Heckel Maximilian
Published: July 2007

DBU ‐ Not Simply a Strong Base: A One‐Pot Synthesis of a Polycyclic Framework Consisting of a Diphosphete Central Unit and Two Units of Doubly Deprotonated DBU

Two condensed five‐, six‐ and seven‐membered rings are fused in a spirocyclic fashion with a central four‐membered diphosphete ring in 4, which unexpectedly is formed in a simple two‐component‐one‐pot reaction from Cl2P‐CH(SiMe3)2 and DBU. The latter is doubly deprotonated and acts as a bridge via C‐6 and N‐8 to a P‐P unit. The polyheterocycle 4 crystallizes in two modifications, whose molecular structures are almost identical.
Organophosphorus Compounds, 103. Thermal Transformation of Kinetically Stabilized Phosphaalkynes with Phosphinidene Precursors. Synthesis of Phosphorus‐Carbon Cage Compounds by Cocyclooligomerization Processes
Authors: Julino Markus , Slany Michael , Bergsträßer Uwe , Merçier Françlois , Mathey Françlois , Regitz Manfred
Published: July 2007

Phosphaalkynes 2 undergo cocyclooligomerization reactions with the phosphinidene 14 or the phosphinidene‐W(CO)5 complex 18 to furnish the phosphorus‐carbon cage compounds 16 or 23. The phosphinidene 14 is generated by the thermal reaction of 2a‐c with the phosphole 11, a process in which the initially formed 7‐phosphanorbornadienes 12a‐c decompose to the λ3‐phosphinines 13a‐c and the desired reactive intermediate. When three further equivalents of the phosphaalkynes 2a‐c are employed, the tetraphosphahomoquadricyclanes 16a‐c can be isolated in 53‐65% yields. The second approach is based on the thermal fragmentation of 17 to generate the phosphinidene‐W(CO)5 complex 18 which, in turn, reacts with four equivalents of the phosphaalkynes 2a or b to produce the pentaphosphadeltacyclanes 23a or b. The constitutions of these novel phosphorus‐carbon cage compounds were confirmed by X‐ray crystal structure analyses of 16a and 23a.
Ylidyl 1,2,4‐Thiadiphosphetane and 1,2,4‐Selenadiphosphetane Sulfides and Selenides
Authors: Jochem Georg , Schmidpeter Alfred , Kulzer Florian , Dick Stefan
Published: July 2007

Phosphoniumylidyl thioxophosphanes and selenoxophosphanes, the only known monomeric chalcogenoxophosphanes, react in a 2:1 ratio with triphenylphosphonium ylides. With loss of PPh3 the 1,2,4‐thia(or selena)diphosphetane monosulfides (or selenides) are formed. Their prominent structural feature are the very different PS bond lengths in the ring. They can be oxidized to the corresponding disulfides or sulfide selenides. The latter rearrange to the isomer in which the selenium atom has become a ring member.
Metal Complexes of Functional Isocyanides, XXV. Amino(hydrazino)carbene Complexes
Authors: Fehlhammer Wolf Peter , Metzner Robert , Luger Peter , Dauter Zbigniew
Published: July 2007

The N‐isocyanodialkylamine metal complexes [M(CO)5CN‐NR2] (M = Cr, W), trans‐[MI2(CNNR2)2] (M = Pd, Pt), trans‐[Pt(Cl)(CNNR2)(PPh3)2]BF4, and cis‐[PtCl2(CNNR2)(PPh3)] [R = Et, iPr; 2 R = ‐{CHMe(CH2)3CHMe}‐] react with primary amines to give the amino(hydrazino)carbene metal complexes [M(CO)5(C(NHR′)NHNR2}] (R′ = Me, nPr, Cy) (1–9), trans‐[PtI2{C(NHMe)NHNR2}2] (10–12) and transmagnified image, and the amine adducts cis‐[PtCl2{C(NHMe)NHNC(H)(Me) (CH2)3CHMe}(PPh3)] magnified image H2NMe (14), and trans‐[PdI2{C (NHMe)NHNC(H)(Me)(CH2)3CHMe}2] magnified image 2 H2NMe (15). With secondary amines the amino(hydrazino)carbene metal complexes transmagnified image (18) and trans‐[PtCl{C(NEt2)NHNEt2} (PPh3)2]BF4 (19) Were isolated. The complexes trans‐[PtI2{C(NHCy)NHNiPr2}CNNiPr 2] (20) and trans‐[PdI2 (NH2Cy){C(NHCy)NHNiPr2}] (21) were obtained by reaction of trans‐[MI2(CNNiPr2)2] (M = Pd, Pt) with cyclohexylamine. The structures were assigned on the basis of IR, NMR‐ (1H, 13C, 31P), and mass spectroscopy as well as an X‐ray structural analysis of 21.
Metallkomplexe mit biologisch wichtigen Lisganden, LXXX. (η3:η3‐C10H16)Ru(IV)‐Komplexe mit α‐Aminocarboxylaten, α‐Aminosäureestern und Peptidestern als Liganden
Authors: Severin Kay , Mihan Shahram , Beck Wolfgang
Published: July 2007

Metal Complexes Containing Biologically Important Ligands, LXXX

LXXIX. Mitteilung: Lit.

.
— (η3:η3‐C10H16)Ru(IV) Complexes with α‐Amino Carboxylates, α‐Amino Acid Esters, and Peptide Esters as Ligands

Reactions of the chloro‐bridged bis(allyl) complex [(η3:η3‐C10H16)Ru(Cl)(μ‐Cl)]2 with α‐amino carboxylates and α‐amino acid esters afford the complexes (η3:η3‐C10H16)(Cl)Rmagnified imageuNH2CHRCO2 (2) and (η3:η3‐C10H16)(Cl)2‐RuNH2CHRCO2R′ (3). Abstraction of chloride from 3 by Ag+ gives the N,O‐chelates [(η3:η3‐C10H16)(Cl)Rmagnified imageuNH2CHRCO2R′]+BF4 (4). Cysteine methyl ester forms the N,S‐chelate complex (η3:η3‐C10H16)(Cl)Rmagnified imageuNH2CH(CO2CH3)CH2S (5), and with histidine methyl ester a dinuclear complex 6 with N,N‐histidine bridge is obtained. Compound 3d with L‐PheOEt as ligand was characterized by X‐ray diffraction.
Metallkomplexe mit biologisch wichtigen Lisganden, LXXXI. Synthese und Kristallstruktur von Rh(I)‐Komplexen mit α‐Aminocarboxylat‐Liganden
Authors: Severin Kay , Mihan Shahram , Beck Wolfgang
Published: July 2007

Metal Complexes Containing Biologically Important Ligands, LXXX

Part LXXX: Ref.

.
— Synthesis and Crystal Structure of Rhodium(I) Chelates with α‐Amino Carboxylates

Part LXXX: Ref.

The α‐amino carboxylate complexes magnified image were prepared from Rh(Cl)(CO)(PPh3)2 and H2NC(H)(R)CO2 in the presence of AgBF4 and characterized by X‐ray diffraction. In the crystal the complexes form chains by hydrogen bridges between amino and carboxylate groups of adjacent molecules.
Thioselonocarboxylic Ester, Selenetane, and Dihydrodiselenine Complexes Prepared from Pentacarbonyl(selenobenzaldehyde)tungsten with π‐Donor‐Substituted Alkynes
Authors: Fischer Helmut , Treier Kornelia , Troll Carsten
Published: July 2007

Pentacarbonyltungsten‐coordinated selenobenzaldehyde, [(CO)5W{Se=C(Ph)H}] (1), reacts with tBu‐CC‐SMe (2) by insertion of the CC into the Se=C bond to form in a highly regio‐ and stereoselective manner the α,β‐unsaturated thioselonocarboxylic ester complex (Z)(C=C)‐[(CO)5W{1‐Se=C(SMe)C(tBu)=C(Ph)H}] (3). The thioselonocarboxylic ester ligand is cleaved intact from the metal by treatment of 3 with [NEt4]Br. Three complexes are formed in the reaction of 1 with Me‐CC‐SMe (5): the thioselonocarboxylic ester complex [(CO)5W{1‐Se=C(SMe)C(Me)=C(Ph)H}] (6) as a mixture of the (E) and (Z)(C=C) isomers, a selenetane complex (7) and a dihydrodiselenine complex (8). The product distribution depends on the ratio 1:5 and on the solvent. The reaction of 1 with the bis(organylthio)alkynes RS‐CC‐SR (9) [R = Me (a), iPr (b), 2,6‐C6H3Me2 (c)] yields mixtures of the (E) and (Z)(C=C) isomers of the α,β‐unsaturated α‐organylthio thioselonocarboxylic ester complexes [(CO)5W{1‐Se=C(SR)C(SR)=C(Ph)H)] (10a‐c). In contrast, the reaction of 1 with tert‐butoxyethyne, H‐CC‐OtBu (11), affords a bis(pentacarbonyltungsten) 5,6‐dihydro‐1,2‐diselenine complex (12). Compound 12 is probably formed by consecutive reaction of 1 with 11 to give the selonocarboxylic ester complex [(CO)5W{1‐Se=C(OtBu)C(H)=C(Ph)H}] which then further reacts as a heterodiene by highly regioselective [4 + 2] cycloaddition with the Se=C bond of a second molecule of 1 to give 12. In the reaction of 1 with 5 and 9a the isomer with a trans arrangement of C(=Se)SMe and Ph is the kinetically controlled reaction product [(E)‐6 and (Z)‐10a, respectively]. The formation of (E)‐6 and (Z)‐10a is followed by isomerization until an (E)/(Z) equilibrium is reached. Complexes 3 and 7 were characterized by X‐ray structural analyses.
Tin for Organic Synthesis, 13. A New and Regioselective Method for the Synthesis of Aromatic, Heteroaromatic, and Olefinic Sulfonamides by Electrophilic Destannylation
Authors: Lube Andreas , Neumann† Wilhelm P. , Niestroj Michael
Published: July 2007

A mild and effective method for the preparation of aromatic and olefinic sulfonamides is described. The reaction of trialkylaryl‐ (4a–f), heteroaryl‐ (4g), and vinylic stannanes (4h) with sulfuryl chloride and secondary amines provides the corresponding sulfonamides in an ipso‐specific manner.
Synthesis and Characterization of Copper(II) Complexes of a 14‐Membered cis‐N2S2 Dibenzo Macrocycle and of Its Bis‐acetato and Bis(methylpyridyl) Derivatives
Authors: Bentfeld Roland , Ehlers Norbert , Mattes Rainer
Published: July 2007

The synthesis and characterization of seven copper coordination compounds with the 14‐membered macrocyclic cis‐N2S2 dibenzo ligand 6,7,13,14,15,16,17,18‐octahydrodibenzo[e,m]‐[1,4,8,11]dithiadiazacyclotetradecine (L1) and its N,N'‐bisacetato and ‐bis(methylpyridyl) functionalized derivatives H2L2 and L3 are described. The structures of five compounds were determined by single‐crystal X‐ray diffraction. The tetrahedrally distorted square‐planar coordination geometry of [CuL1](ClO4)2 (1) changes upon reduction of copper to a severely distorted tetrahedral geometry in [CuL1]Br · MeCN (2). The Cu–N bond lengths increase from 1.988(3) to 2.029(5) Å; the Cu–S bond lengths decrease from 2.293(1) to 2.255(2) Å. Copper(II) is hexacoordinated in [CuHL2]HSO4 · 2.5 H2O (5) and [CuHL2]ClO4 · H2O (6). Both compounds exhibit very similar overall structures in the cationic part. The macrocyclic ring of the ligand is folded along an N ⃜S axis, the octahedral geometry is strongly Jahn‐Teller distorted, with O and S donor atoms in the apical positions. Compound 5 contains one very short [2.271(3) Å] and one long [2.701(3) Å] Cu–S (thioether) bond. In [CuL3](ClO4)2 · 2 H2O (7) one thioether group of the ligand L3 remains uncoordinated. The coordination polyhedron is rather irregular: Cu–S 2.506(3) and Cu–N 1.960(7)–2.107(8) Å. The compounds were further characterized by electronic and EPR spectroscopy and by cyclic voltammetry. Some relationships to the structural and spectroscopic properties of “blue” copper proteins were found.
(η8‐Cyclooctatetraene)(η4‐1,2‐ and ‐1,3‐diphosphacyclobutadiene)titanium: Preparation, Structure, and Reactivity
Authors: Binger Paul , Glaser Gerald , Albus Stefan , Krüger Carl
Published: July 2007

The synthesis of the (η8‐cyclooctatetraene)(η4‐1,3‐ and ‐1,2‐diphosphacyclobutadiene)titanium complexes 3a‐c and 4a, b by cyclodimerization of the phosphaalkynes 2a‐c [a: R = tBu, b: R = adamantyl (ad), and c: R = (iPr)(Me3Si)N] in the coordination sphere of the (η8‐cyclooctatetraene)titanium complex 1 is described. The molecular structures of 3a‐c and 4a, b were determined by spectroscopic methods (31P, 1H, and 13C NMR). In the case of 3a and 4a, X‐ray analyses were carried out. The increased reactivity of 4a compared to 3a was utilized to separate 3a from 4a. Displacement of the 1,2‐diphosphete (isolated as its cyclodimer 5) from 3b was achieved by reaction with hexachlorethane.
Stable Carbonyl‐ and Thiocarbonylrhodium(I) Complexes Containing s̀‐Bonded Phenyl and Vinyl Groups as Ligands
Authors: Wiedemann Ralf , Wolf Justin , Werner Helmut
Published: July 2007

The phenyl‐ and vinylrhodium(I) complexes trans‐[Rh(R)(CO)(PiPr3)2] (2, 3) were prepared from the chloro derivative 1 and Grignard reagents. The corresponding thiocar‐bonyl compound trans‐[Rh(CH=CH2)(CS)(PiPr3)2] (7) was obtained similarly from trans, ‐[RhCl(CS)(PiPr3)2] (6) and CH2=CHMgBr. The preparation of 6 occurred via trans‐ [RhCl(η2‐S=C=S)(PiPr3)2] (5) as intermediate. The carbonyl complexes 2 and 3 are quite inert in the presence of CO and do not react by migratory insertion to give acylrhodium derivatives.
Tin for Organic Synthesis, 14. Synthesis of Aromatic and α,β‐Unsaturated Aldehydes by a Friedel‐Crafts‐like Electrophilic Destannylation Using 1,1‐Dichloromethyl Methyl Ether
Authors: Niestroj Michael , Neumann† Wilhelm P.
Published: July 2007

A mild and effective method for the preparation of a variety of aromatic (7a–m), heteroaromatic (7n–r), and α,β‐unsaturated aldehydes (8a–f) is described. The reaction of trialkylaryl‐ (2a–o), heteroaryl‐ (2p–t), and 1‐alkenylstannanes (4a–f and 5a–f) with dichloromethyl methyl ether (1, DCME) in the presence of aluminium trichloride followed by hydrolysis provides the corresponding aldehydes. In the case of arylstannanes the ipso‐isomers are generally formed; the p‐alde‐hydes occur as side products. The electrophilic substitution of 1‐alkenylstannanes with 1 leads to α,β‐unsaturated aldehydes in an ipso‐ and stereospecific manner. A comparison of the leaving abilities of the stannyl and silyl groups shows a lower or even zero reactivity of the silyl‐substituted compounds 6a–c towards the electrophile 1. In the silylstannylal‐kene 6c only the stannyl group reacts whereas the stannyl function remains unaffected in the product, aldehyde 11.
Phosphaniminato‐Komplexe des Arsens. Kristallstrukturen von [AsCl(NPMe3)]2Cl2, [AsCl(NPMe3)2SbCl4]SbCl6 und [AsCl(NPMe3)2SnCl4] · CH3CN
Authors: Garbe Ralf , Wocadlo Sigrid , Kang Hak‐Chul , Massa Werner , Harms Klaus , Dehnicke Kurt
Published: July 2007

Phosphane Iminato Complexes of Arsenic. Crystal Structures of [AsCl(NPMe3)]2Cl2, [AsCl(NPMe3)2SbCl4]SbCl6, and [AsCl(NPMe3)2SnCl4] · CH3CN

[AsCl(NPMe3)]2Cl2 (1) was prepared by the reaction of arsenic trichloride with the silylated phosphane imine Me3‐SiNPMe3 in acetonitrile solution. According to the crystal structure determination, 1 has an ionic structure with [AsCl(NPMe3)]22+ ions, in which the As atoms are linked by the μ2‐N atoms of the NPMe3– groups. Compound 1 reacts with antimony pentachloride to give [AsCl(NP‐Me3)2SbCl4]+SbCl6– (2), with tin tetrachloride to form [AsCl(NPMe3)2SnCl4] (3), which is isoelectronic to the cation of 2. In 2 and 3 AsCl(NPMe3)2 acts as a chelating agent forming and , respectively, four‐membered ring structures.
Synthesis and Structure of Metal‐Functionalized Phosphaarsiranes
Authors: Weber Lothar , Sommer Oliver , Stammler Hans‐Georg , Neumann Beate , Becker Gerd , Kraft Hans
Published: July 2007

Reaction of (η5‐C5Me5)(CO)2FeAs(SiMe3)2 (1) with equimolar amounts of (bis(trimethylsilyl)methylene]chlorophosphane afforded the 1‐metallo‐1‐arsa‐2‐phosphapropene (η5‐C5‐Me5)(CO)2FeAs(SiMe3)P=C(SiMe3)2 (2) in addition to a few crystals of dimetallophosphaarsirane (η5‐C5Me5)(CO)2Fe‐ AsC(SiMe3)2PFe(CO)2(η5‐C5Me5) (3). Treatment of 2 with an excess of [(Z)‐cyclooctene]Cr(CO)5 and subsequent chromatography furnished the phosphaarsirane‐[Cr(CO)5] adduct (η5‐C5Me5)(CO)2Fe‐ηAsC(SiMe3)2PH[Cr(CO)5] (5). The molecular structures of 3 and 5 were established by single‐crystal X‐ray structure analyses.
Nickel Hemiporphyrazines as Bisdienes and Bisdienophiles: Synthesis and Characterization
Authors: Rack Michael , Hauschel Bernd , Hanack Michael
Published: July 2007

The bisdienophilic (hemiporphyrazinato)nickel complexes 1a‐d bearing various alkoxy groups were synthesized from diiminoisoindoles 9a‐d, diaminopyridines 10a, d, and nickel acetate. Reaction of 1a‐d with an excess of pentaene 3 delivered the macrocyclic bisdienes 2a‐d. The hemiporphyrezines were characterized by 1H‐ and 13C‐NMR spectroscopy. The NMR spectra of the 1,6,16,21‐tetrabutoxy‐substituted compounds 1b and 2b are discussed with respect to the presence of syn/anti isomers.
Formation of Metallophosphenium Cluster Complexes: Synthesis and Structure of Cp(Ph)[N(SiMe3)2]
Authors: Reisacher Hans‐Ulrich , Duesler Eileen N. , Paine Robert T.
Published: July 2007

The reaction of [(Me3Si)2N](Ph)PW(CO)2Cp with Fe2(CO)9 produces in good yield the bimetallic compound Cp(Ph)[N(SiMe3)2] that was characterized by mass spectrometry, IR, 1H‐, and 31P‐NMR spectroscopy, and single crystal X‐ray diffraction analysis. The molecular structure consists of Fe(CO)3 and CpW(CO)2 fragments joined by a bridging CO ligand and a phosphenium ion fragment which comprise a four‐membered bicyclic structure.
The Catalytic Ring‐opening Cyclooligomerization (ROC) of Thietane by the Complexes M(CO)5L (M  Cr and W; L = CO, thietane and 1,5,9‐Trithiacyclododecane)
Authors: Adams Richard D. , Falloon Stephen B. , Perrin Joseph L. , Queisser Joachim A. , Yamamoto John H.
Published: July 2007

The following four compounds have been synthesized: M(CO)5L (3 and 4, where M = Cr and W, and L = H2), W(CO)5(12S3) (5, where 12S3 = 1,5,9‐trithia‐cyclododecane), and [W(CO)5]2(12S3) (6). The molecular structures of 4 and 5 were established by single‐crystal X‐ray diffraction analyses. Both compounds contain a W(CO)5 group coordinated to one of the sulfur atoms of the hetero‐cycle. The ability of the compounds M(CO)6, 1 and 2 (M = Cr and W), and 3 – 5 to catalytically produce ring opening cyclooligomerization (ROC) of thietane into 12S3 and 24S6, (24S6 = 1,5,9,13,17,21‐hexathiacyclotetracosane) has been investigated. Compounds 1 – 3 have relatively low activity. Compounds 4 and 5 have the highest activity and selectivity for 12S3 formation. Crystal Data for 4: space group = P212121, a = 12.906(2) Å, b = 13.730(4) Å, c = 6.427(1) Å, Z = 4, 1306 reflections, R = 0.033; for 5: space group = P1¯, a = 12.703(1) Å, b = 13.510(2) Å, c = 5.833(1) Å, α = 101.75(1)°, β = 97.54(1)°, γ = 101.70(1)°, Z = 2, 2225 reflections, R = 0.023.
[Bis(phosphonio)isophosphindolide]silver Complexes
Authors: Gudat Dietrich , Schrott Martin , Bajorat Volker , Nieger Martin , Kotila Sirpa , Fleischer Roland , Stalke Dietmar
Published: July 2007

The outcome of reactions of bis(phosphonio)isophosphindolide salts 1[X] and 6[X] (X‐  Cl‐, Br‐, CF3SO3‐) with silver salts AgY (Y‐ = CF3SO3‐, CF3CO2‐, CH3CO2‐, 1/2 SO4‐) depends strongly on the available anions X, Y. If X‐, Y‐  CF3SO3‐, both mononuclear and dinuclear silver complexes are formed which exhibit either μ1,μ1(P) or μ2,η1(P) coordination of the cations 1, 6 to one or to both metals. In solution, dynamic equilibria between both types of products and free 1, 6 were detected by 31P‐NMR spectroscopy. Mononuclear (4a, 7) and dinuclear (5a, 8) complexes were isolated as solvates with CHCl3 or THF. If X‐, Y‐ = CF3CO2, only equilibrium mixtures between the free ligands and silver complexes and no isolable products were obtained. 31P‐NMR investigations revealed a preference for the formation of dinuclear complexes. Anion metathesis and precipitation of AgX were observed for X‐ = Cl‐, Br‐. No coordination of 1, 6 to Ag+ took place in the case of Y‐  CH3CO2‐, SO42‐. The formed complexes were characterised in solution by 31P‐ and in part by 109Ag‐NMR spectroscopy. Complexes 7, 8 were further studied by single crystal X‐ray diffraction which revealed the presence of a THF molecule coordinated to silver in both cases. The μ2‐coordinated cation 1 is the only bridging ligand in 8, whereas the presence of additional μ2‐CF3CO2 ligands was deduced from the results of 31P,31P EXSY measurements in the case of the trifluoroacetato complexes.
Diastereoselective Substitution of PR3 for CO in Carbohydrato‐ and Menthyloxycarbene Complexes of Manganese – Synthesis of Chiral‐at‐metal Carbene and Carbyne Complexes
Authors: Fischer Helmut , Schleu Joachim
Published: July 2007

The substitution of PR3 (R = C6H4CH3‐p, C6H4Cl‐p, C6H11,OCH3) for a CO ligand in chiral carbohydratocarbene complexes [(η5‐C5H5)(CO)2MnC(OR*)Ph] [OR* = α‐ (1α) and β‐mannofuranosyl (1β), (–)‐menthyloxy (9)] proceeds diastereoselectively. The diastereoselectivity depends on PR3 and on the OR* substituent and ranges from 12% de (R = OCH3) to 80% (R = C6H4CH3‐p). In contrast, the reaction of 1β with P(OPh)3 is non‐selective. The diastereoselectivity generally increases with increasing nucleophilicity of PR3 and decreases in the series 1β > 1α > 9. The highest diastereoselectivity was observed in the reaction of 1β with P(C6H4CH3‐p)3. Predominantly, the isomer with the (S) configuration at the metal [(S Mn)‐2β] was formed which could be separated from the diastereomeric mixture by chromatography and be obtained in a pure form. Subsequent reaction of (SMn)‐2β with BF3 afforded the carbyne‐manganese complex (SMn)‐[(η5‐C5H5){P(C6H4CH3‐p)3}(CO)MnCPh]BF4.
Derivate des Imidazols, XVII. Synthese und Eigenschaften von Dichlor(1,3‐dimethyl‐2‐imidazol‐2‐ylidenimino)‐phosphan – ein Methylenamino‐Substituent mit ungewöhnlichen Donoreigenschaften
Authors: Kuhn Norbert , Fawzi Riad , Steimann Manfred , Wiethoff Jörg
Published: July 2007

Imidazole Derivatives, XVII. – Synthesis and Properties of Dichloro(1,3‐dimethyl‐2‐imidazol‐2‐ylidenimino)phosphane – a Methylenamino Substituent with Uncommon Donor Properties

Dichloro(1,3‐dimethyl‐2‐imidazol‐2‐ylidenimino)phosphane (5) is obtained from 1,3‐dimethyl‐2,3‐dihydro‐2‐trimethylsilyliminoimidazole (4) and PCl3 in almost quantitative yield. Strong PN‐π interaction (5B) is revealed by its X‐ray structure analysis [P(1)–N(1) 1.579(2) Å]. AlCI3 causes chloride abstraction to give the cationic cyclophosphazane 8 identified by NMR spectroscopy.
Paramagnetic Planar Complexes of NiII: Influence of R and R′ on the Formation, Coordination Geometry and Magnetic Properties of Phosphinic Amidato Bischelates [R2P(O)NR′]2Ni
Authors: Brück Arno , Englert Ulli , Kuchen Wilhelm , Peters Wilfried
Published: July 2007

After a brief review of previous work the results of the metathesis reaction between Ni(dme)Br2 and R2P(O)NR′Li [R = tBu, iPr, Ph; R′ = Et, Pr, iPr, (±)‐sBu, tBu, tPen, Cy, Ph, (–)‐α‐methylbenzyl = Mb, 1‐adamantyl = Ad] are reported. Complex formation occurred only with lithiated amides of tert‐butylphosphinic acid, and bischelates [tBu2P(O)NR′]2Ni were obtained when R′ = sBu, Mb, tPen, Ad (1d – g). With R′ = Et, Pr bischelation was incomplete. Vis spectroscopy showed the paramagnetic compounds 1d – f to be planar in the solid state but tetrahedral in solution. 1g is tetrahedral in both phases. The planar structure of 1f was confirmed by X‐ray single‐crystal analysis (monoclinic, space group P21/n). The magnetic moments μeff of 1d, e, g are ca. 3.2–3.5 μB in both phases and the Curie‐Weiss law is obeyed in the range 293–183 K. The same is valid for dissolved 1f. The μeff values of solid 1f are however, strongly temperature‐dependent, varying from 1.38 to 0.55 μB (300–90 K). NMR data (31P, 1H, 13C) are reported. Obviously, a favorable combination of electronic and steric factors of substituents R and R′ produces with ligands [R2P(O)NR′]– the donor quality necessary for bischelation as well as the singular field strength required for the formation of planar paramagnetic species. As the combination of paramagnetism and planarity is bound to the solid state, lattice energy effects may be finally decisive for this unique constellation of tetracoordinated NiII complexes.
Synthesis, Structure, and Magnetic Properties of a 2,2‐Dipyridyl‐2,5‐dihydro‐imidazole‐1‐oxyl‐(L‐)Bridged Disilver Complex [Ag2L2](SbF6)2: A Four‐Membered Ring from two Ag(I) Ions and two Imine Nitrogen Atoms
Authors: Hintermaier Frank , Mihan Shahram , Gerdan Michael , Schünemann Volker , Trautwein Alfred , Beck Wolfgang
Published: July 2007

The reaction of 2,5‐dihydro‐4,5,5‐trimethyl‐2,2‐di‐2‐pyridyl‐imidazole‐1‐oxyl (L) with AgSbF6 gives the complex [Ag2L2]2+[SbF6–]2 which was characterized by X‐ray diffraction. – The complex (a biradical) forms a four‐membered ring with two Ag(I) ions and two imine nitrogen atoms of the imidazolines with a relatively short Ag – Ag distance [2.839(2) Å]. Magnetic measurements indicate that two nitroxide radicals are slightly coupled.
Chiral Organometallic Reagents, XX. An Enantiomerically Enriched (α‐Phenylselenoalkyl)magnesium Compound
Authors: Klute Wolfgang , Krüger Michael , Hoffmann Reinhard W.
Published: July 2007

α‐Selenoalkyl Grignard reagents 2 are chiral. On reaction with the magnesium chelate 3a of α‐benzyloxypropionaldehyde they show significant degrees of kinetic resolution, especially when the reactions are run in CH2Cl2. Under these conditions, racemic 2 was resolved by reaction with 0.59 equivalents of 3a at temperatures below –20°C. The remaining 2 had an enantiomer enrichment of 80–86% e.e. (as found by trapping). Hence, 2 has a considerably higher configurational stability than its lithium counterpart 1.
Preparation, Properties, and Reactions of Metal‐Containing Heterocycles, XCIII. Diosma[5.n.5.n]ortho‐, ‐meta‐, and ‐paracyclophanes (n = 0–2)
Authors: Lindner Ekkehard , Pitsch Markus W. , Fawzi Riad , Steimann Manfred
Published: July 2007

The reaction of the ortho‐, meta‐, and para‐bis(triflates) [(F3CSO2OCH2CH2C6H4)2(CH2)n] with n = 0 (ortho: 1a), n = 0, 1 (meta: 1b, d), and n = 0–2 (para: 1c, e, g) with [Os(CO)4]2– results in the formation of the diosma[5.n.5.n]‐ortho‐, ‐meta‐, and ‐paracyclophanes with n = 0 (ortho: 2a), n = 0, 1 (meta: 2b, d), and n = 0–2 (para: 2c, e, g). On reaction of the bis(triflates) 1a, b with the dianionic [Fe(CO)4]2– the corresponding ferracyclophanes are formed only in situ. Carbon monoxide insertion into the Fe–C s̀ bonds of the ferracycles affords the ketones 6a, b. The structures of 2a and 2e were investigated by X‐ray structural analysis. Compounds 2a and 2e crystallize in the space group P21/c with Z = 8 and P1 with Z = 2, respectively.
Dithio and Thiono Esters, 62. Reactions of Alkanedithioic Acid Dianions with Iodine, Sulfur, and Tin Compounds
Authors: Hartke Klaus , Wagner Uwe
Published: July 2007

The monoanion of the alkanedithioic acid 1a is oxidized with hypervalent iodine compounds to form the 1,2‐dithiine 6, the monoanion of 1b yields the 1,2,4‐trithiolane 7 and the dianions 2b, c furnish the 1,2,4,5‐tetrathianes 3b, c. With diphenyltin or dimethyltin dichlorides 8 the monoanions of 1b, c afford the monothioacyl or bisthioacyl organotin sulfides 10a–c or 11a, b respectively. When treated with lithium hexamethyldisilazane, 10b undergoes an intramolecular cyclization to the 1,3,2‐dithiastannetane 9b; 10a is deprotonated by triethylamine to the 1,3,5‐trithia‐2‐stanninane 13. The dianion 2c reacts with diphenyltin dichloride 8 to yield the 1,3,2‐dithiastannetane 9d, with dimethyltin dichloride the 1,2,4‐trithiolane 16 is formed. 9d is cleaved by thionyl chloride, sulfur dichloride, and disulfur dichloride to give a complex mixture of the 1,2,4,5‐tetrathiane 3c and the cyclic polysulfides 1,2,3,4,5,6‐hexathiepane 18, 1,2,3,5,6,7‐hexathiocane 19 and the 1,2,3,5,6‐pentathiepane 20 in varying amounts. Reaction of the dianion 2b with thionyl chloride leads to the formation of the 1,2,4,5‐tetrathiane 3b as main product; byproducts are cyclic polysulfides, the 1,2,3,5,6‐pentathiepane 21 and the 1,2,3,4,5,6‐hexathiepane 22.