bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chirale Tripod‐Liganden mit Phosphit‐Donorgruppe: Synthese und Komplexchemie
Authors: Scherer Johannes , Huttner Gottfried , Büchner Michael 
Published: July 2007

Chiral Tripodal Ligands Bearing a Phosphite Donor Group: Synthesis and Coordination ChemistryThe mechanism of the reaction of epichlorohydrine (H–CH2Cl) (1) with lithium phosphides is analysed. A neighbouring‐group mechanism has been found to be the essential driving force in this reaction. Monophosphanyl alcohols such as HOCH(CH2P(Ph)2)(CH2Cl) (2) and epoxides (Ph)2PCH2– (3) are characterized as intermediates. The mechanism leads to a rapid one‐pot method for the synthesis of chiral racemic as well as enantiomerically pure bis(phosphanyl) alcohols HOCH(CH2PR2)(CH2PR) (4). The resulting bis(phosphanyl) alcohols 4 react easily with X2PCl (X = Cl; Ph; or X2 = 1,2‐ethanedioxy‐2,2′‐biphenyldiyldioxy‐) to yield the mixed donor group tripodal ligands X2POCH(CH2PR2)(CH2PR′2) (5, 6) containing both phosphite, phosphinite or phosphorodichloridite and phosphane donor groups. The identity of these compounds were proved by 1H‐, 31P‐ and 13C‐NMR spectroscopy, mass spectra, microanalysis as well as X‐ray analysis. The coordination capabilities of these novel ligands are demonstrated by the synthesis and characterization of a (cyclooctadiene)rhodium complex {[(5c)Rh(I)COD]PF6} (7) of the ligand 5c, exhibiting the typical hetero‐bicyclooctane tripod metal cage of this type of tripod complexes.
Electrochemical Preparation of Nanostructured Titanium Clusters: Characterization and Use in McMurry‐Type Coupling Reactions
Authors: Reetz Manfred T. , Quaiser Stefan A. , Merk Claudia 
Published: July 2007

AbstractThe electrochemical preparation of nanostructured titanium clusters is possible by using a titanium sacrificial anode as the metal source and tetrabutylammonium bromide in THF as the electrolyte and stabilizer. Transmission electron microscopy shows the presence of spherical 3.0‐nm‐sized particles. THF solutions of these Ti clusters induce olefin‐forming McMurry‐type coupling of aldehydes and ketones.
Syntheses and Photochemistry of Fluorinated and Chlorinated Titanium Porphyrinates: Crystal Structure of Oxotitanium meso‐Tetrakis(2,3,4,5,6‐pentafluorophenyl)porphyrinate
Authors: Esser Peter E. , Englert Ulli , Keim Wilhelm 
Published: July 2007

AbstractThe syntheses of oxotitanium(IV) meso‐tetrakis(2,3,4,5,6‐pentafluorophenyl)porphyrinate O=Ti(TPPF20) (1), oxotitanium(IV) meso‐tetrakis(2,6‐difluorophenyl)porphyrinate O=Ti‐(TPPF8) (3), and oxotitanium(IV) meso‐tetrakis(2,6‐dichlorophenyl)porphyrinate O=Ti(TPPCl8) (5) from titanium tetrachloride and the corresponding porphine are described. The structure of 1 was determined by single‐crystal X‐ray diffraction. The reaction of oxotitanium porphyrinates with aqueous hydrogen peroxide leads to the corresponding light‐sensitive peroxotitanium(IV) complexes: Ti(O2)(TPPF20) (2), Ti(O2)‐(TPPF8) (4), Ti(O2)(TPPCl8) (6). All complexes are efficient and stable photosensitizers for the generation of singlet oxygen.
Zinc Complexes of Amino Acids and Peptides, 7. Solution Behavior and Zinc Complexation of Dipeptides Made up Solely from Histidine and Cysteine
Authors: Gockel Peter , Vogler Raphael , Vahrenkamp Heinrich 
Published: July 2007

AbstractThe eight possible types of dipeptides made up from histidine and cysteine, namely the unprotected ones H‐His‐Cys‐ OH (1) and H‐Cys‐His‐OH (2), the N‐protected ones Ac‐His‐Cys‐OH (3) and Ac‐Cys‐His‐OH (4), the C‐protected ones H‐His‐Cys‐OEt (5) and H‐Cys‐His‐NH2 (6), and the fully protected ones Ac‐His‐Cys‐OEt (7) and Ac‐Cys‐His‐OEt (8) were prepared analytically pure. Their acid‐base behavior and zinc complexation in solution were studied potentiometrically. In all cases 1:1 (zinc:peptide) complexes are the dominant species near neutral pH. 1:2 complexes could only be detected for 4, 6, 7, and 8, and precipitations occurred in basic media. From equimolar mixtures of the peptides and zinc salts (chloride, iodide, perchlorate) solid complexes were obtained upon addition of a base. They always contain coordinating anions (chloride, iodide, or trifluoroacetate which was introduced with the peptide). They have the composition LZnX for L = 5‐8 and L4Zn5X2 for L = 1–4. It is proposed that all complex species observed contain tetrahedral zinc, that they are monomers in dilute solution and thiolate‐bridged oligomers in the solid state, and that the peptides as a rule occupy at least three coordination sites.
Twofold Insertion of Isocyanides into the GaGa Bond of Tetrakis[bis(trimethylsilyl)methyl]digallane(4)
Authors: Uhl Werner , Hahn Ingo , Schütz Uwe , Pohl Siegfried , Saak Wolfgang , Martens Jürgen , Manikowski Jens 
Published: July 2007

AbstractTetrakis[bis(trimethylsilyl)methyl]digallane(4) (1) reacts with tert‐butyl or aryl=isocyanides [aryl = phenyl, o‐methylphenyl, o‐methoxyphenyl, p‐methoxyphenyl) by a twofold insertion of the central carbon atoms into the Ga–Ga bond and formation of C–C single bonds. 1,4‐Diazabutadiene derivatives bound to two R2Ga groups are formed (2–6), which in contrast to an aluminium analog exhibit only weak interactions between the imine nitrogen atoms and the coordinatively unsaturated gallium atoms as indicated by NMR spectroscopy and the long Ga–N distances in the molecular structures of three products: 2 (R = C6H5), 4 (R = o‐MeOC6H4), and 6 (R = CMe3).
ansa‐Titanocene and ‐Zirconocene η2‐Alkyne Complexes ‐Synthesis, Spectral Characteristics, and X‐ray Crystal Structure
Authors: Peulecke Normen , Lefeber Claudia , Ohff Andreas , Baumann Wolfgang , Tillack Annegret , Kempe Rhett , Burlakov Vladimir V. , Rosenthal Uwe 
Published: July 2007

AbstractThe reduction of the complex [(η5‐C5H4)‐ansa‐(η5‐C5H4)]TiCl2 with magnesium in the presence of Me3SiC2‐SiMe3 in THF at room temperature gives the ansa‐titanocone alkyne complex [(η5‐C5H4)‐ansa‐(η5‐C5H4)]Ti(η2‐Me3SiC2‐SiMe3) (ansa = Me2Si‐O‐SiMe2, 1). The similar pyridine‐stabilized zirconium complexes could be obtained by analogous reactions and addition of pyridine: [(η5‐C5H4)‐ansa‐(η5‐C5H4)]Zr(L)(η2‐Me3SiC2SiMe3) (ansa = Me2Si‐O‐SiMe2, L = pyridine: 2; ansa = SiMe2, L = pyridine: 3). All complexes were characterized by spectroscopic methods. An X‐ray structure determination of complex 3 was conducted, and the data were compared to those of the complexes rac‐(EB‐HI)Zr(L)(η2‐Me3SiC2SiMe3) [L = (S)‐(‐)‐nicotine: 6, EBHI = ethylenebis(tetrahydroindenyl)] and Cp2Zr(py)(Me3SiC2‐SiMe3).
Control of Regioselectivity in the Transition‐Metal‐Catalysed Conjugate Additions of Alkylaluminium Compounds and Methyltitanium Ate Complexes to Androsta‐1,4‐diene‐3,17‐dione
Authors: Westermann Jürgen , Neh Harribert , Nickisch Klaus 
Published: July 2007

AbstractBy a variation of the nature of the reagent system conjugate addition to the cross‐conjugated steroidal dienone 1 occurs selectively either at C‐1 or at the sterically hindered C‐5. With Me3Al or Me4AlLi in the presence of catalytic amounts of Cu1 salts, a high regioselectivity (up to 97:3) in favour of position 1 is achieved. Application of ate complexes of aluminium and titanium in the presence of Ni(acac)2 as catalyst, however, leads to a reversal of the regioselectivity in favour of position 5 (up to 11:89). Aluminium and titanium ate complexes are efficient reagents in the Ni(acac)2‐catalysed conjugate addition to sterically hindered enones.
Synthesis and Characterisation of Ionic Ozonides with Bisquaternary Ammonium Counterions
Authors: Seyeda Hady , Armbruster Klaus , Jansen Martin 
Published: July 2007

AbstractThe bisquaternary ammonium ozonides Me3N+(CH2)n +NMe3(O3‐)2 with n = 3, 4, 6 (1, 2, 3), Me3N+(CH2)3+NMe3(O3‐)2 · 3 NH3 (1a), Me3N+(p‐Ph)+NMe3(O3‐)2 (4) and Me3N+(p‐Ph)+NMe3(O3‐)2 · NH3 (4a) were obtained in quantitative yields by cation exchange starting from CsO3. The compounds 1a and 3 have been studied by single crystal X‐ray analysis. The influence of C–H…O and N–H…O hydrogen bonds on the bond length and the bond angle of the ozonide anion is discussed; earlier results are included. The difference between the two bond lengths within the O3‐ ion [137.4(3) pm and 129.5(3) pm] in 1a is unexpectedly large. Thermal stabilities determined by DTA/TG methods range from 24–83°C.
Synthesis and Dynamic Behavior of the Dimeric, Monocyclic Barium Bis[bis(isopropyldimethylsilyl)phosphanide] – Molecular Structures of P(SiMe2Ph)3, of Monomeric (thf)4Ba[P(SiMe2iPr)2]2 and of the Dimer {(thf)2Ba[P(SiMe2iPr]2]2}2
Authors: Westerhausen Matthias , Lang Gerhard , Schwarz Wolfgang 
Published: July 2007

AbstractBarium bis[bis(trimethylsily)amide] metalates bis(isopropyldimethylsilyl)phosphane (1) to yield nearly quantitatively the corresponding barium bis[bis(isopropyldimethylsilyl)phosphanide] (3). This compound shows a temperature‐dependent monomer‐dimer equilibrium in toluene solution. Both the isomers were characterized by X‐ray crystal structure analyses. The monomeric derivatives precipitate as a tetrakis(tetrahydrofuran) complex with a P–Ba–P bond angle of 139.9°. The barium atoms of the monocyclic, centrosymmetric dimer are pentacoordinated by two tetrahydrofuran molecules, one terminal and two bridging phosphanide ligands. The endo‐ and exocyclic Ba–P distances with values of 332 and 316 pm, respectively, lie within the characteristic range.
Activation of Molecular Oxygen by Biomimetic Schiff Base Complexes of Manganese, Iron, and Cobalt
Authors: Jäger Ernst‐Gottfried , Knaudt Jutta , Rudolph Manfred , Rost Michael 
Published: July 2007

AbstractThe metal complexes (E,E)‐[{diethyl 2,2′‐[1,2‐phenylenebis(iminomethylidyne)]bis[3‐oxobutanoato]}(2–)‐N,N′,O3,O3′]manganese (Mn1a), [3,3′]‐[1,2‐phenylenebis(iminomethylidyne)bis(2,4‐pentanedionato)(2–)‐N,N′,O2,O2′]manganese (Mn1b), and (Z,Z)‐[diethyl 3,3′‐(1,2‐phenylenediimino)bis(2‐cyano‐2‐propenoato)](2–)‐N3,N3′,O1,O1′]manganese (Mn1c) were sythesised and the oxygenation of these complexes was investigated by gas volumetry. All complexes except Mn1c are able to take up oxygen but with different magnitudes. The catalytic activity of the Mn, Co, and Fe complexes of the ligands 1a and 1c and (E,E)‐[{diethyl 2,2′‐[1,2‐ethylenebis(iminomethylidyne)]bis[3‐oxobutanoato]} (2–)N,N′,O3,O3′] iron (Fe1d) and [diethyl (all‐E)‐5,14‐dihydro‐6,17‐dimethyldibenzo[b,i][1,4,8,11]tetraazacyclotetradecine‐7,16‐dicarboxylato)(2–)‐N5,N9,N14,N18]iron (Fe2a) has been compared with respect to the oxidation of hydroquinone by molecular oxygen. The results are interpreted with the aid of electrochemical properties, Lewis acidities, and other relevant factors. However, no simple relationship between the catalytic activity and the other factors could be found.
Preparation and Structure of Dithioxo‐ and Diselenoxophosphoranes Stabilized by Intramolecular Coordination with a Dialkylamino Group
Authors: Yoshifuji Masaaki , Sangu Shinya , Kamijo Kazunori , Toyota Kozo 
Published: July 2007

AbstractSome dithioxophosphoranes 3 stabilized by intramolecular coordination with a dialkylamino group were prepared, and their structures were analyzed by X‐ray crystallography involving [2,4‐di‐tert‐butyl‐6‐(isopropylmethylamino)phenyl]‐ (3c), {2,4‐di‐tert‐butyl‐6‐[(dimethylamino)methyl]phenyl}‐ (3f), and {2,4‐di‐tert‐butyl‐6‐[2‐(dimethylamino)‐1,1‐dimethylethyl]phenyl}dithioxophosphorane (3h). The bond between the phosphorus atom and the aromatic ring is flexible and the angle narrows with decreasing ring size of the intramolecular coordination. The 31P‐NMR signals are shifted to higher field with increasing ring size of the intramolecular coordination or strength of coordination. Similarly, the corresponding diselenoxophosphoranes 4 were prepared. Both their 31P‐ and 77Se‐NMR signals are shifted to higher field with increasing contribution of intramolecular coordination.
Diphosphonio‐1,2‐diphospholes: Structural PIII/Pv Hybrids
Authors: Jochem Georg , Nöth Heinrich , Schmidpeter Alfred 
Published: July 2007

AbstractP‐Methylation of the 3,5‐bis(triphenylphosphonio)‐1,2‐diphospholide 1 leads to the dicationic diphosphole 3a. A crystal of its bis(triflate) was used for a structure analysis. It indicates that in contrast to the known phospholes the cyclic π6 system is preserved in 3a. The coordination geometry of the methylated phosphorous atom shows a flat pyramid with a sum of angles of 339°. Therefore, 3a represents a state that is intermediate between a phosphane and a bis(methylene)phosphorane, i.e. between PIII and Pv.
Chiral Homoenolate Equivalents, V. Hydroxylakylation of Lithiated 3‐[(S)‐2‐(Methoxymethyl)pyrrolidino]‐1,3‐diphenylpropene – An Asymmetric Homoaldol Reaction
Authors: Ahlbrecht Hubertus , Kramer Andreas 
Published: July 2007

AbstractThe hydroxyalkylation of lithiated 3‐[(S)‐2‐(methoxymethyl)‐pyrrolidino]‐1,3‐diphenylpropene (2) with aldehydes is completely regioselective giving homoaldol adducts in good yields. The simple diastereoselectivity is low with typical ratios ranging between 1:1 and 1:3 with the syn isomer predominating. The induced diastereoselectivity is much higher and is strongly solvent‐dependent. The reaction predominantly proceeds according to a metalloretentive mechanism from the si side of the allylic system in THF as well as in TBME. The induced diastereoselectivity obtained by the use of the less solvating TBME is considerably higher than in the strongly solvating THF, selectivities of up to 97% ee being reached.
Thietane and Selenetane Complexes by Thermal Cycloaddition of Vinyl Ethers to Transition‐Metal‐Coordinated Thio‐ and Selenoaldehydes – Crystal Structure of Pentacarbonyl(7‐phenyl‐2‐oxa‐8‐thiabicyclo[4.2.0]octane‐S)tungsten(0)
Authors: Fischer Helmut , Kalbas Claudia , Sumpf Rüdiger 
Published: July 2007

AbstractPentacarbonyl(thiobenzaldehyde)tungsten und pentacarbonyl(selenobenzaldehyde)tungsten (1a and 1b) undergo a thermal [2 + 2] cycloaddition with several vinyl ethers to give highly substituted transition metal‐coordinated thietanes and selenetanes. The addition is highly regio‐ and stereospecific. The products undergo acid‐catalyzed rearrangements, which lead to thermodynamically more stable diastereomers of the thietanes and selenetanes. The stereochemistry of both addition and rearrangement was established by reaction of deuterium‐labeled vinyl ethers and by reaction of the cis and trans isomers of ethyl propenyl ether. The crystal structure of the bicyclic addition product of 1a and 3,4‐dihydro‐2H‐pyran is reported.
Synthesis and X‐ray Crystal Structure of the First Mononuclear Nickel(II) Alkane Thiolate Complex with a Mixed (S,N,N,O) Ligand Field
Authors: Berkessel Albrecht , Bolte Michael , Neumann Thomas , Seidel Lutz 
Published: July 2007

AbstractThe six‐step synthesis of a chiral, pentadentate dihydrosalen ligand, carrying a mercaptomethyl group as additional binding site, is described. When this ligand was treated with nickel(II) salts, a planar tetracoordinated nickel chelate was obtained, and not the expected pentacoordinated species. This complex was fully characterized, including X‐ray crystallography. The crystal structure revealed that the nickel ion is coordinated by the thiolate anion, both the amine and the imine nitrogen atoms of the ligand, and by one phenolate anion. The second phenolic oxygen atom of the ligand does not participate in the coordination of the nickel ion. This chelate is the first mononuclear nickel(II) thiolate complex having a mixed (S,N,N,O) ligand field. Cyclic voltammetry did not indicate a reduction up to –2.1 V (vs. Fc/Fc+). In the anodic range, no reversible but two irreversible oxidation processes were observed.
The Unexpected Formation of a Tetradentate Tripyrrolic Complex of Nickel(II)
Authors: Br ückner Christian , Mar Eduardo K. , Rettig Steven J. , Dolphin David 
Published: July 2007

Abstract(2‐Pyrrolylmethane)(2‐pyrrolylmethyl)imine (2) and an equimolar amount of 2‐formylpyrrole give, in the presence of nickel(II) in hot methanol, the novel tripyrrolic nickel(II) complex [SP‐4]‐[(2‐dipyrrinato‐k2N,N′‐methyl)(2‐pyrrolylmethenato‐ kN′′)imine‐kN′′′]nickel(II) (4). This planar complex has been characterized by X‐ray crystallography, a mechanism for its formation is proposed and its mass spectral behavior is discussed.
Fluxionality and Phosphane Arm‐off Reactions of Octahedral Rhodium(III) Complexes with the Tripodal Polyphosphane MeC(CH2PPh2)3
Authors: Brandt Katja , Sheldrick William S. 
Published: July 2007

AbstractTreatment of [RhCl3(triphos)] or [Rh(MeCN)3(triphos)](CF3SO3)3 [triphos= MeC(CH2PPh2)3] with Na(S2C‐NEt2) affords the complexes [RhCl(S2CNEt2)(triphos)]Cl (1) and [Rh(S2CNEt2)(MeCN)(triphos)](CF3SO3)2 (2). Whereas 1 is stereochemically rigid in solution at 25°C, 2 and the analogous complex [Rh(S2CNBz2)(MeCN)(triphos)](CF3SO3)2 (3) exhibit a rapid exchange of their phosphorus environments. In contrast, the 31P‐NMR spectra of both 2 and 3 at –30°C consist of well‐resolved A2MX spin systems. k2P‐coordinated complexes of the type [Rh(S2CNR2)2(triphos‐k2P)]+ (R = Et 4, R = Me 5) with ABX spin systems may be obtained by treatment of the starting compounds with two equivalents of the respective dialkyl dithiocarbamate. The dangling phosphane arm can be readily oxidised to a phosphane oxide as in [Rh(S2CNEt2)2(triphosO‐k2P)]Cl (6) [triphosO = O=P(Ph)2CH2C(Me)(CH2PPh2)2]. The analogous compound [Rh(mpy)2(triphosO‐k2P)]Cl (7) (Hmpy = 2‐mercaptopyridine) was isolated as the OC‐6‐13 isomer with trans‐positioned sulphur atoms, a siting which is in accordance with a reaction mechanism involving a phosphane arm‐off k3P' k3P dissociation equilibrium.
Coordination Chemistry with CF Units as σ Donors: Ag+Complexes of Partially Fluorinated Crown Ethers with Direct Metal–Fluorine Interactions
Authors: Plenio Herbert , Diodone Ralph 
Published: July 2007

AbstractThe partially fluorinated cryptandsFN2O4andBenzoFN2O4, which are relatives of the [2.2.1]cryptand, were synthesized in good yields from 1,3‐bis(bromomethyl)‐2‐fluorobenzene and diaza‐18‐crown‐6 or benzodiaza‐18‐crown‐6, respectively. These macrobicyclic ligands form very stable complexes with Ag(I) salts, and it was shown that close fluorinesilver interactions occur in solution as well as in the solid state. Numerous experimental evidence for this is available: NMR competition experiments show that Ag+complexes ofFN2O4are significantly more stable than those ofHN2O4(the two ligands are identical except that one fluorine atom is replaced by one hydrogen atom inHN2O4); the1JCFcoupling constants of Ag+·FN2O4and Ag+·BenzoFN2O4are reduced by 10 Hz compared to those of the respective free ligandsFN2O4(1JCF=253 Hz) andBenzoFN2O4. (1JCF=252 Hz). The X‐ray crystal structure of Ag+·FN2O4revelas short Ag+–F distances [271.4(3) pm]; coupling of the107,109Ag+and19F nuclei is observed in the19F‐NMR spectra (J=24 Hz for Ag+·FN2O4,J=25 Hz for Ag+·BenzoFN2O4). The1H‐NMR spectrum of Ag+·FN2O4is very complex and exhibits sixteen unique proton resonances, whose evaluation yielded coupling constants and NOEs, which show that the structure in solution is compatible with the results obtained by the X‐ray crystal structure determination.
Contributions to the Chemistry of Boron, 233. Reactions of a 1,2,3,4‐Diphosphadiboretane with Some Carbonylmetal Compounds
Authors: Grundei Stefan , Nöth Heinrich , Paine Robert T. 
Published: July 2007

Abstract1,2‐Di‐tert‐butyl‐3‐(diisopropylamino)‐4‐(dimethylamino)‐ 1,2,3,4‐diphosphadiboretane (1) reacts with Fe2(CO)9 to give two isomeric tetracarbonyliron complexes 2, 3 with P–Fe bonds and a bis(tetracarbonyliron) complex 4. In contrast, 1 displaces the olefinic ligand from tetracarbonyl(η4‐norbornadiene)metal (metal = Cr, Mo) to form the tetracarbonylmetal complexes 5 and 6 with a rearranged ligand molecule, i.e. a 1,3,2,4‐diphosphadiboretane. This process is accompanied by a change of the tert‐butyl groups from an anti orientation in 1 to a syn orientation in 5 as shown by X‐ray crystallography.
Zinc Complexes of Amino Acids and Peptides, 8[]. Difunctional Dipeptides Containing Cysteine or Histidine: Solution Behavior and Zinc Complextion
Authors: Gockel Peter , Vahrenkamp Heinrich 
Published: July 2007

AbstractThe dipeptides Ac–Cys–Val–OH (1a) and Ac–His–Val–OH (1b), H–Gly–Cys–OEt (2a) and H–Val–His–OEt (2b) as well as Z–Asp–Cys–OH (3a) and Z–Asp–His–OH (3b) (Z = benzyloxycarbonyl) were prepared, and their zinc complexation was investigated by potentiometric methods. They have in common that in addition to the cysteine thiolate or the histidine imidazole the second amino acid offers one donor function. The complex stabilities are very close to those of the corresponding difunctional derivatives of the single amino acids cysteine or histidine. This indicates the presence of seven‐ to ten‐membered chelate rings.
Zinc Complexes of Amino Acids and Peptides, 9[]. Coordination of Cysteine and Histidine Derivatives to the Pyrazolylborate‐Zinc Unit
Authors: Ruf Michael , Burth Rainer , Weis Karl , Vahrenkamp Heinrich 
Published: July 2007

AbstractHighly substituted pyrazolylborate ligands TpR,Me were used to limit the coordination number of zinc towards cysteine‐ and histidine‐derived coligands. Monodentate thiolate attachment (→ 1a–f) was achieved with N‐ and C‐protected cysteine, monodentate carboxylate attachment (→ 3) with N‐protected histidine. C‐protected cysteine was found to form a five‐membered N,S‐chelate ring (2). While imidazole coordination with N‐ and C‐protected histidine could not be achieved, cationic pyrazolylborate‐zinc‐coligand complexes [TpZn–L]+ (4a, b) were obtained for L = 2‐methylimidazole. The new complexes were characterized by their spectra and three structure determinations.
Reactive E=C [p‐p]π Systems, 45[]. 1‐Aza‐3,4‐diphospholenes by [3 + 2] Cycloaddition of 2‐(Diisopropylamino)phosphaethyne to Diazo Derivatives R1R2C=N2
Authors: Grobe Joseph , Van Duc Le , Immel Franz , Krebs Bernt , Läge Mechtild 
Published: July 2007

AbstractThe reaction of the (diisopropylamino)phosphaethyne (1) with diazo compounds of the type R1R2C=N2 (2a–2c) unexpectedly leads in high yields (60–90%) to the 1‐aza‐3,4‐diphospholene derivatives 3a–3c, a new class of heterocycles. NMR investigations of the analogous reaction of 1 with diazocyclopentadiene 2d show that the multi‐step formation of 3a–3c proceeds via the 1‐aza‐3,4‐diphospholes 6a–6d as intermediates.
Controlled Hydrolysis of Tripodal Titanium Amido Halides: The Influence of the Ligand Periphery upon the Basicity of the Amido‐N Functions
Authors: Friedrich Stefan , Gade Lutz H. , Li Wan‐Sheung , McPartlin Mary 
Published: July 2007

AbstractHydrolysis of the tripodal amidotitanium halides H3CC(CH2NSiMe3)3TiX (X = Cl: 1a; Br: 1b) in the presence of Et3N affords the linear μ‐oxo‐bridged complex [H3CC(CH2NSiMe3)3Ti]2 (μ‐O) (3) which was characterized by X‐ray crystallography. Treatment of H3CC(CH2NiPr)3TiX (X = Cl: 2a; Br: 2b), obtained in low yields, under the same conditions only leads to decomplexation of the amido ligand. Under conditions of very slow exposure to H2O the primary addition product of water across two Ti–N bonds in 2a could be isolated and was characterized as [H3CC(CH2‐i(μ‐Cl)]2(μ‐O) (4), the crystal structure analysis establishing a triply bridging central Ti(μ‐O)(μ‐Cl)2 Ti unit. Deprotonation with two molar equivalents of nBuLi and subsequent LiCl elimination afforded the μ‐oxo complex [H3CC(CH2NiPr)3Ti]2(μ‐O) (5).