bluuebunny/crossref_metadata_2025_split huggingface dataset:
Metallorganische Verbindungen der Lanthanoide, 73. Synthese und Struktur neuer Monocyclooctatetraenyl‐Komplexe von Yttrium, Terbium und Lutetium
Authors: Schumann Herbert , Winterfeld Jörn , Köhn Randolf D. , Esser Lothar , Dietrich Andreas , Sun Junquan 
Published: July 2007

Organometallic Compounds of the Lanthanoids, 73[1]. – Synthesis and Structure of New Monocyclooctatetraenyl Complexes of Yttrium, Terbium, and Lutetium[(C8H8)Ln(μ1‐Cl)(THF)]2 (LnY, Lu) react with NaOR (RPh, C6H3Me2‐2,6) to give the dinuclear cyclooctatetraenyl rare earth alkoxides [(C8H8)Ln(μ1‐OR)(THF)]2 [RPh, LnY (1a), Lu (1b); RC6H3Me2‐2,6, LnY (2a), Lu (2b)]. The reactions of [(C8H8)Ln(μ1‐Cl)(THF)]2 with LiOC(tBu)3, NaOSiPh3, and NaC5H3tBu2 result in the formation of (C8H8)LnOC(tBu)3(THF) [LnY (3a), Lu (3b)], (C8H8)LnOSiPh3(THF) [LnY (4a), Lu (4b)], and (C8H8)Tb(C5H3tBu2) (5), respectively. Treatment of (C8H8)Y(C5Me5) with acetylacetone yields (C5Me5)Y(acac)2 (6). The 1H‐and 13C‐NMR and mass spectra of the new compounds as well as the X‐ray crystal structures of 1a and 5 are discussed.
The Intriguing Structural Characteristics of the Heterosiloxane Molecule Na4[Sb2O(OSiMe3)8]
Authors: Baier Michael , Bissinger Peter , Blümel Janet , Schmidbaur Hubert 
Published: July 2007

AbstractTreatment of Sb(OSiMe3)3 with NaOSiMe3 in the molar ratio 1:2 in hexane at ambient temperature leads to the formation of Me3SiOSiMe3 and a crystalline complex of the formula Na4[Sb2O(OSiMe3)8] in ca. 35% yield. The composition of the product has been confirmed by elemental analysis and negative‐ion CI mass spectrometry. The single crystal X‐ray structure analysis (rhombohedral, space group R\documentclass{article}\pagestyle{empty}\begin{document}$\bar{3}$\end{document}c, Z6) resulted in a disorder model for the complex with pseudo‐cubic symmetry owing to virtually random distribution of sodium and antimony atoms over the vertices of an oxygen‐centered octahedron with the eight silyloxy groups capping the faces. Low solubility in non‐coordinating solvents prevented solution NMR studies, but solid‐state NMR investigations using cross polarization and magic‐angle spinning techniques (13C, 29Si) allowed the assignment of a point group C2v structure with the SbIII atoms in cis position relative to the oxo center of the complex.
Einkernige Nickel‐Thiolato‐Komplexe mit Nickel‐Zentren in unterschiedlichen Oxidationszuständen: Molekularer Aufbau von [Ni(SC6H4O)2]2– und [Ni(SC6H4O)2]
Authors: Köckerling Martin , Henkel Gerald 
Published: July 2007

Mononuclear Nickel Thiolate Complexes Containing Nickel Sites in Different Oxidation States: Molecular Definition of [Ni(SC6H4O)2]2− and [Ni(SC6H4O)2]Herrn Professor Dietrich Mootz zum 60. Geburtstag gewidmet.
A solution of NiCl2·6 H2O in EtOH/H2O reacts with nBu3N and o1‐mercaptophenol to form [nBu3NH]2[Ni(SC6H4O)2]·EtOH (2) containing the nickel(II) complex [Ni(SC6H4O)2]2− (1). The molecular structures of 1 and its oxidation product, [Ni(SC6H4O)2]− (3), have been determined by X‐ray diffraction. With respect to the chemical as well as electrochemical properties of the nickel sites of various hydrogenases, 3 is the first relevant model complex of coordination number four whose structural properties have been determined in different oxidation states.
Tetraindeno‐Fused Cyclooctatetraene and Oligomeric Biindenyls by Oxidative Coupling of 2,2′1‐Biindenyl
Authors: Simmross Ulrich , Müllen Klaus 
Published: July 2007

AbstractLithiated biindenyls 2 and 4, prepared by deprotonation of 2,2′1‐biindenyl (1) and 10,11‐dihydrodiindeno[1,2‐b:2′,1′‐d]thiophene (3) with n1‐butyllithium, are oxidatively coupled to give oligomeric biindenyls (17) as well as tetraindeno‐fused eight‐membered rings (16, 19, 24).
Ein neuer Weg zu isoanellierten Heteroaromaten, 1. Synthese und Reaktionen von Furofuranen, Thienofuranen, Furobenzofuranen und Benzothienofuranen
Authors: Eberbach Wolfgang , Laber Norbert , Bussenius Jörg , Fritz Hans , Rihs Grety 
Published: July 2007

A Novel Route to Isoannulated Heteroaromatic Compounds, 1. – Synthesis and Reactions of Furofurans, Thienofurans, Furobenzofurans, and BenzothienofuransA general method for the synthesis of furo‐and thienofurans 4–7 has been developed. The reaction principle is based on the thermal transformation of suitably structured epoxyhexenynes (15–19) following the general reaction sequence 1→2→3 (annulation type A). Derivatives of the so far unknown diheteropentalenes furo[3,4‐b]furan (4b, c, d, g, h), furo‐[3,4‐b]benzofuran (6b, d, e, 45) as well as benzo[4,5]thieno‐[2,3‐c]furan (7b, d) are obtained by short‐time thermolysis. Likewise two representatives of the previously reported thieno[2,3‐c]furan system are prepared (5b, c). By flash vacuum thermolysis the benzo‐annulated epoxyhexenyne 19b rearranges in poor yield to the isobenzofuran 52 (identified as dimethyl acetylenedicarboxylate adduct 47) and 2‐cyano‐α1‐naphthol (46). The structure of the furo[3,4‐b]furan 4b has been established by X‐ray structural analysis. A mechanistic explanation of the transformation of the epoxyhexenynes to diheteropentalenes is proposed. Indications for the occurrence of carbenes as product‐determining species are obtained with the phenylcyano‐substituted oxiranes 15c, h and 17e which – in additon to the furofurans 4c, h and 6e – lead to the furylindenes 31c, h/32c, h and 41, resp. The Diels‐Alder reactivity of the furo‐and thienofurans 4g, 5b, c, and 6b has been examined.
Reaktionen an Silicium‐Silicium‐Bindungen, 3. Ein neuer Weg zur Knüpfung von Si – Ge‐und Si – Sn‐Bindungen: Hexachlordisilan‐Spaltung von Organometallphosphanen und (Trichlorsilyl)phosphan‐Recycling
Authors: Martens Reiner , Mont Wolf‐Walther Du 
Published: July 2007

Reactions at Silicon‐Silicon Bonds, 3[1]. – A New Path to Si – Ge and Si – Sn Bonds: Hexachlorodisilane Cleavage of Organometalphosphanes and (Trichlorosilyl)phosphane RecyclingTrimethyl(trichlorsilyl)germane and ‐stannane (4, 5) have been prepared through hexachlorodisilane cleavage by germyl‐and stannylphosphanes R2PMMe3 (1, 2, Ri1‐C3H7, t1‐C4H9; MGe, Sn). The (trichlorosilyl)phosphane byproduct R2PSiCl3 (3) may be recycled by transmetalation and methylation steps to provide starting germylphosphane (MeGeCl3, 2 MeLi) and stannylphosphane (Me3SnCl, 3 MeLi).
Beiträge zur Chemie des Bors, 217. [2 + 2]1‐Cycloadditionsreaktionen von 9‐Fluorenyliden‐(tetramethylpiperidino)boran mit Carbonyl‐und Thiocarbonyl‐Verbindungen
Authors: Channareddy Sreelatha , Glaser Bernd , Mayer Erwin P. , Nöth Heinrich , Helm Scott W. 
Published: July 2007

Contributions to the Chemistry of Boron, 217[1]. – [2 + 2] Cycloaddition Reactions of 9‐Fluorenylidene(tetramethylpiperidino)borane with Carbonyl and Thiocarbonyl CompoundsAmino‐9‐fluorenylidene‐borane 1 reacts with acetone or benzophenone in a [2 + 2] cycloaddition manner to give stable 1,2‐oxaboretane derivatives 2. Aldehydes behave similarly but the oxaboretanes formed decompose readily. The esters MeCO2Et and MeCC – CO2Me as well as Cp(CO)2Fe – COCH3 also provide access to novel oxaboretane derivatives (2e, f, h). In contrast, no oxaboretane is obtained from 1 and MeC(O)NMe2 and only (tmpBO)n (n2, 3) was isolated as a decomposition product. The amides MeC(O)NHMe and MeC(O)NH2 also provide no access to cycloaddition since their NH bonds insert into the BC double bond of 1. Thioketones react with 1 to yield 1,2‐thiaboretanes 5. Tetramethyl‐cyclobutan‐1‐one‐3‐thione 8 adds 1 at its carbonyl function regiospecifically to form 9. No reaction between 1 and CO2 was observed, but COS produces an 1,2‐oxaboretane‐4‐thione 7, and CS2 in the form of [CpFe(CO)2]2CS2 the corresponding 1,2‐thiaboretane‐4‐thione 10. Analogously, the ketimine Ph2CNMe adds to 1 producing the 1,2‐azaboretidine 11. X‐ray structure determination of the 1,2‐oxaboretane 2h reveals a butterfly structure (folding anlge: 159.9°) of the four‐membered ring in contrast to the 1,2‐thiaboretane 5a whose four‐membered ring is almost planar, the folding angle being 176.9°.
Zur Kenntnis der Reaktionen von Mes2GeX2 (XF, Cl) mit [LiPH2(dme)]: Synthese von 1,1,4,4‐Tetramesityl‐2,3,5,1,4‐triphosphadigermolan
Authors: Drieß Matthias , Pritzkow Hans 
Published: July 2007

Concerning the Reactions of Mes2GeX2 (XF, Cl) with [LiPH2(dme)]: Synthesis of the 1,1,4,4‐Tetramesityl‐2,3,5,1,4‐triphosphadigermolaneMes2GeX2 (Mes2,4,6‐trimethylphenyl; XF, Cl) reacts with [LiPH2(dme)] (dmedimethoxyethane) in a 1:2 molar ratio to yield the first 2,3,5,1,4‐triphosphadigermolane derivative 3 as major product. Along 3, the monosubstituted compound Mes2Ge(PH2)Cl (4) and the 1,1,3,3‐tetramesityl‐substituted 2,4,1,3‐diphosphadigermetane (2) are formed by the reaction of Mes2GeCl2 with LiPH2 and were characterized by 31P‐NMR spectroscopy. Surprisingly, Mes2GeF2 instead of Mes2GeCl2 does not give 2. A possible mechanistic approach is presented.
Imidyl Radicals – Free‐Radical Addition of N1‐Bromoimides to Alkenes
Authors: Lüring Ulrich , Kirsch André 
Published: July 2007

AbstractN1‐Bromoimides 1 add to alkenes 3 in a free‐radical chain reaction on a multigram scale with imidyl radicals 2 as chain carriers. High regioselectivities are found when the substituents at the non‐attacked sp2 carbon atom to the alkene 3 are alkoxy or sterically bulky residues. The stereochemistry of the addition is determined by the bromine transfer from the N1‐bromoimide 1 to the adduct radical 4. Formation of the trans1‐addition products 5 is favored. In competition reactions vinyl ethers react faster with the imidyl radicals 2 than alkyl‐substituted alkenes.
Sterically Hindered Free Radicals, 21. 1,2‐ and 1,4‐Additions of Diphenylmethyl Radicals to Substituted Acrylonitriles
Authors: Zarkadis Antonios K. , Neumann Wilhelm P. , Dünnebacke Dieter , Peñeñory Alicia , Stapel Ralf , Stewen Ulrich 
Published: July 2007

AbstractAdditions of the substituted diphenylmethyl radicals Ar11‐Ar2CR 2 (RCMe3, SiMe3, GeMe3, SnMe3, OSiMe3, CF3, CO2Me, CN) to various acrylonitriles CH2C(X)CN 3 (XSMe, SiPr, StBu, OAc, OSiMe3, OSiEt3, OMe, OEt) lead to 1,2‐5 or 1,4‐adducts 6 (ketenimines), depending mainly on the steric hindrance by the substituents R and X. Bulky substituents like tBu in 2 and tBuS in the acrylonitrile favour the formation of the extended and nearly strainless ketenimine system 6 (1,4‐adduct); smaller substituents like OSiMe3 (radical 2) and SMe, OAc, OSiMe3, OSiEt3, OMe, OEt (acrylonitrile) allow isolation of the sterically crowded 1,2‐adducts. Substituents of intermediate bulkiness like CF3 (radical 2) and SiPr (acrylonitrile) give a mixture of 1,2‐adducts (6cb, hb) and dimers 7 of the adduct radicals 4 (7cb, hb). The voluminous tBu group directly bound to the olefin (3j,k) prevents addition. The latter is generally reversible, and the various adducts 5, 6, or 7 dissociate to the adduct radicals 4 and/or fragment to the initial radicals 2 at temperatures which reflect the steric strains of the corresponding substituents R, X. The complete inertness, even toward the electron‐rich olefin 3i, of the electrophilic α1‐carbonyl‐substituted radicals 2q – s (RCHO, COMe, COPh) in the above additions is discussed. Additions of the radicals 2a – c, f, i, n, o to the conjugated olefin 3n are described and are in accordance with the conclusion that steric effects predominate in adduct formation, whereas electronic effects are of distinct but minor importance.
Synthesis of Alkyl‐Substituted Helianthrones and Mesonaphthobianthrone by Highly Regioselective Photocyclization of Bianthronylidenes
Authors: Müller Uwe , Enkelmann Volker , Adam Martin , Müllen Klaus 
Published: July 2007

AbstractThe synthesis of the novel alkyl‐substituted helianthrones8a, cand mesonaphthobianthrone9by photocyclization of the corresponding bianthronylidenes7a, bis described. Regioselectivity and scope of the photocyclizations of7aand7bdepend on the substitution pattern. The structures of7aand8ahave been established by X‐ray crystallography and indicate an isomerization about the central double bond of7ain the photoreaction. The structures of the protonated species of8aand9are elucidated, and their optical absorption and emission behavior is examined.
FMO Approach in [4 + 2] Cycloadditions. Kinetic Studies with 1,2‐Dimethylenecyclopentane
Authors: Sustmann Reiner , Siangouri‐Feulner Ioana 
Published: July 2007

AbstractKinetic measurements on [4 + 2] cycloadditions of 1,2‐dimethylenecyclopentane (1) as a model diene for normal Diels‐Alder reactions are described. This diene was selected in order to check whether a synperiplanar diene is a good test case for the FMO model. Using HOMO and LUMO energies from semi‐empirical quantumchemical calculations, we indeed obtained a good linear correlation between the lg k2 values and 1/(EHomo – ELUMO). The cycloadditions of E/Z isomeric dienophiles to 1 are stereospecific. These reactions are best described in terms of concerted processes.
Metallated Bicyclo[3.2.2]nona‐2,6,8‐trienes, Their Rearrangement to Barbaralanes, and a Short Synthesis of the Bicyclo[3.2.2]nona‐2,6,8‐trien‐4‐yl Anion
Authors: Blümel Janet , Köhler Frank H. 
Published: July 2007

AbstractFive different anions are formed when bicyclo[3.2.2]nona‐2,6,8‐triene (1a) is deprotonated: the 6‐ and 7‐yl anions when using tBuLi/TMEDA, the 4,6‐ and 4,7‐diyl dianions when using nBuLi/tBuOK, and the 4‐yl anion (1–) after quenching the dianions with THF. Reaction of the anions with Me3SnCl gives the 6‐, 7‐, and 4‐monostannylated bicyclo[3.2.2]nona‐2,6,8‐trienes 1b, 1c, and 1d as well as the exo‐4,7‐, endo‐4,6‐, and endo‐4,7‐distannylated bicyclo[3.2.2]nona‐2,6,8‐trienes 1e, 1f, and 1g, respectively. Reaction of 1– with Me3SiCl and Me3PbCl leads to the corresponding 4‐silyl derivative 1h and its plumbyl analogue 1i. Inversely, cleavage of 1d with MeLi allows to generate 1– under particularly mild conditions. The metallation of tricyclo[3.2.2.02,4]nona‐6,8‐diene (3a), which was tested for an alternative route to 1–, gives two stannyl derivatives 3b and 3c which are substituted in the vinylic positions. – On heating 1d and 1i rearrange to yield 9‐trimethylstannylbarbaralane (2d) and its plumbyl analogue 2i quantitatively. The reactivity decreases on passing from 1i to 1d whereas 1h does not react. Mercury and zinc derivatives of 1– are so labile that only dibarbaralylmercury (2j) and ‐zinc (2k) are observed by NMR spectroscopy. The title rearrangement proceeds by a 1,5‐homodienyl metallatropic shift which involves an endo1‐type transition structure. – The new compounds 1b – i, 2d, 2i, 3b and 3c are characterized with emphasis on the NMR data including 1H, 13C, 119Sn, 207Pb signal shifts and various heteronuclear couplings.
Darstellung und Reaktionen von 1,1,2,2‐Tetraborylethan‐Derivaten
Authors: Frankhauser Pascal , Kuhlmann Frank , Krämer Albrecht , Pritzkow Hans , Siebert Walter 
Published: July 2007

Synthesis and Reactions of 1,1,2,2‐Tetraborylethane DerivativesHerrn Professor Heinrich Nöth zum 65. Geburtstag gewidmet.
Reaction of (Z)1‐1,2‐bis(dichloroboryl)ethene with B2Cl4 leads to 1,1,2,2‐tetrakis(dichloroboryl)ethane (1a) in 90% yield. Substitution of the chlorine atoms in 1a results in the formation of the iodo and amino derivatives 1b and 1c, d. Compound 1b reacts with alkynes to give the 2,2′‐linked 2,3‐dihydro‐1,3‐diborole derivatives 2b, c which are aminated to yield 2d, e. Dehalogenation of 1d leads to the organoboron C2B4 cage 3d. The heterobicyclic compound 4d with two fused phosphadiborolane rings is obtained from 1d and LiPH2. Reaction of 4d with (CO)3Fe(C8H14)2 gives the unusual diiron complex 5d. The constitutions of the new compounds are derived from spectroscopic data and are proven for 2e, 4d and 5d by X‐ray structure analyses.
Zur Komplexchemie von Cyclopentadienyl‐Liganden mit Oligoethylenglycolether‐Tentakeln
Authors: Siemeling Ulrich , Neumann Beate , Stammler Hans‐Georg 
Published: July 2007

On the Complex Chemistry of Cyclopentadienyl Ligands with Oligoethylene Glycol Ether TentaclesHerrn Professor Eckehard V. Dehmlow zum 60. Geburtstag gewidmet.
The potassium cyclopentadienides KCp′[SiMe2(OCH2CH2)m1‐OCH3]n (2) react with trimethyltin chloride to give the respective stannanes Me3SnCp′[SiMe2(OCH2CH2)mOCH3]n (3a–e). Reaction of 2a–e with iron(II) chloride affords the ferrocenes Fe{Cp′[SiMe2(OCH2CH2)mOCH3]n}2 (4a–e), which are soluble in solvents of all polarities. 4a–d were investigated with respect to their ability to act as podands for alkaline metal cations. 4c, d prove to be much better podants than 4a, b; 4a, c show a certain selectivity for K+, 4b, d show a preference for Cs+. Without rigorous exclusion of moisture, 4e yeilds the tetrasiladioxa[3](1,1‐)[3](3,3‐)ferrocenophane 5 upon prolonged standing at room temperature. The structure of 5 was determined by a single‐crystal X‐ray diffraction study. The molecule is essentially unstrained with the cyclopentadienyl rings being exactly parallel to each other; the distance between the iron atom and the ring centroid is 165 pm.
Fluktuierendes Verhalten von kationischen cis1‐Bis(ether‐phosphan)1‐palladium(II)1‐Komplexen. – 31P‐DNMR‐spektroskopische Untersuchungen, Linienformanalyse und Bestimmung der thermodynamischen Austauschparameter
Authors: Lindner Ekkehard , Dettinger Johannes , Mayer Hermann August , Kühbauch Hartwig , Fawzi Riad , Steimann Manfred 
Published: July 2007

Fluxional Behavior of Cationic cis Bis(ether‐phosphane)palladium(II) Complexes. – 31P‐DNMR Spectroscopic Investigations, Line‐Shape Analysis, and Determination of Rearrangement BarriersHerrn Professor Heinrich Nöth zum 65. Geburtstag gewidmet.
Reaction of X2Pd(P∼O)2 (XCl: 1a – g, k – n, p; XBr: 1′; XI: k″, l″, o″) with stoichiometric amounts of AgClO4 results in the formation of the monochelate complexes cis‐[ClPd(P∼O)(P∩O)][ClO4] (2a – g, k – n, p, l′, l″) (P∼O: η11‐P‐coordinated; P∩O: η21‐O,P‐chelated). In the case of compounds 1o, 1k″, and 1o″, which are provided with less basic etherphosphanes, the halide‐bridged dimers [(μ1‐X)Pd(P∼O)2]2[ClO4]2 (3o, k″, o″) are obtained. Temperature‐dependent 31P{1H}1‐NMR spectra of the fluxional complexes 2a – g, k – n, p, l′, l″ lead to δG≢ values. By using a modified version of DNMR5, computer‐generated spectra of 2a, b, f, k, l, p, l′, l″ were obtained and fitted to the experimental spectra. Graphic application of the Eyring equation to the kinetic data afforded the thermodynamic parameters δH≢, δS≢, and δG≢. The δS≢ values are in agreement with an associative exchange mechanism for 2a, b, f, l, p, l′, l″ and with a dissociative exchange mechanism for 2k, 2k and 3o crystallize in the monoclinic and triclinic space group P21/c and P&1marc; with Z4 and Z2, respectively.
OsO3F2 and OsO2F4, Preparation and Crystal Structures
Authors: Bougon Roland , Buu Ban , Seppelt Konard 
Published: July 2007

AbstractThe new method for preparing OsO3F2 is presented. Its crystal structure reveals a polymeric chain structure with distorted octahedral geometry for the OsO3F3 units and symmetrical, non‐linear fluorine bridges. The OsO3F3 unit has a facial geometry. This structure is not in accord with predictions on the molecular structure of OsO3F2. OsO2F4, obtained from KrF2 and OsO4, crystallizes in the space group P61 forming a sixfold helical chain arrangement of nearly octahedral OsO2F4 molecules. Oxygen or fluorine atoms are partially disordered. The cis orientation of the two oxygen atoms is established by means of NMR, vibrational spectroscopy, and X‐ray data.
Synthesis of Macrocyclic Mercury(II) Derivatives of S,S′1‐Trimethylene‐and S,S′1‐Tetramethylenebis(cis1‐stilbene‐α,β1‐dithiol) with Unusual Structures
Authors: Schrauzer Gerhard N. , Zhang Cheng , Reddy Hussain K. , Schlemper Elmer O. 
Published: July 2007

AbstractThe reaction of the ligand cis ‐ –SC(Ph)C(Ph)–S–[CH2]n – S – C(Ph)=C(Ph)–S– with n3 (dianion of 1) with HgCl2 in ethanol produces a yellow linearly trinuclear, μ1‐S and μ1‐Cl‐bridged complex of composition C62H52Cl2Hg3S8 (4), in which the central Hg(II) ion is in a near octahedral arrangement of four HgS and two HgCl bonds, whereas the two terminal Hg(II) ions are tetracoordinated with three HgS bonds and one HgCl bond in distorted tetrahedral arrangements. The two ligands are bidentate with respect to the terminal and central Hg(II) ions. The corresponding ligand with n4 (dianion of 2) reacts with HgCl2 to yield a yellow Hg(II) complex of composition C32H28HgS4 (5), in which the ligand is tetradentate and in the trans‐syn configuration. The Hg(II) ion in the unit cell of 5 is pentacoordinated, due to symmetric dimerization of two molecules of 2 by two weak coordinate HgS bonds of 3.442(2) Å length.
Synthesis, X‐Ray Structure and Complexation Behavior of the New Tripodal Phosphane Ligand cis, cis‐1,3,5‐Tris[(diphenylphosphanyl)methyl]1‐1,3,5‐trimethylcyclohexane (tdppmtmcy). Crystal Structure of Ir(tdppmtmcy)(CO)Cl
Authors: Mayer Hermann A. , Fawzi Riad , Steimann Manfred 
Published: July 2007

AbstractThe introduction of three methyl groups into the ipso positions of the cyclohexane ring in cis,cis‐1,3,5‐tris[diphenylphosphanyl)methyl]cyclohexane (tdppmcy) (1) leads to the new tripodal phosphane ligand cis,cis‐1,3,5‐tris(diphenylphosphanyl)methyl]1‐1,3,5‐trimethylcyclohexane (tdppmtmcy) (5). The dynamic behavior is studied by variable‐temperature NMR spectroscopy and compared with the structure (X‐ray analysis) in the solid state. Treatment of 5 with Ir(PPh3)2(CO)Cl gives 6 where the two PPh3 groups are replaced by two (diphenylphosphanyl)methyl groups of the ligand 5. In addition, an intramolecular CH metalation takes place resulting in the oxidative addition of a ring methylene CH bond to the metal. The X‐ray structure of 6 is determined.
Eigenschaften von Chalkogen–Chalkogen‐Bindungen, XVII. Di‐und Trisulfane mit sterisch anspruchsvollen Alkyl‐Substituenten: Das erste trans1‐Dialkyldisulfan
Authors: Ostrowski Martin , Jeske Jörg , Jones Peter G. , Mont Wolf‐Walther Du 
Published: July 2007

Properties of Chalcogen–Chalcogen Bonds, XVII[1]. – Di‐and Trisulfanes with Sterically Congested Alkyl Substituents: The First trans1‐DialkyldisulfaneBis[tris(trimethylsilyl)methyl]trisulfane (1) is obtained from tris(trimethylsilyl)methyllithium and sulfur with subsequent oxidation by oxygen or from tris(trimethylsily)methanethiol with sulfur dichloride. The solid trisulfane contains a transoid (helical) CS–SS–C backbone without severe distortion from steric strain. Desulfuration of the byproduct bis[tris(trimethylsilyl)methyl]tetrasulfane (2) with mercury provides 1, but further desulfuration of 1 to bis[tris(trimethylsilyl)1‐methyl]disulfane (3) has not been achieved. 3 was isolated after oxidation of lithium tris(trimethylsilyl)methanethiolate with bromine. 3 contains a trans1‐CS–SC moiety with an unusually long SS bond (210–211 pm). The less crowded bis(triphenylmethyl)disulfane (4) contains a “normal” CS–SC moiety with anticlinal conformation (torsion angle – 110°).