bluuebunny/crossref_metadata_2025_split huggingface dataset:
Durch Verklammerung gespannte Perylene — Das Coronen‐Isomer Dicyclopenta[1,2,3‐cd:1′,2′,3′‐Im]perylen und Dimethanoperylen
Authors: Jaworek Wilfried , Vögtle Fritz 
Published: July 2007

Strained Perylenes By Clamping — The Coronene Isomer Dicyclopenta[1,2,3,‐cd: 1′,2′,3′‐Im]perylene and DimethanoperylenePerylene (3) is clamped by C2 and C1 bridges with formation of the heptacyclic title compound dicyclopenta[1,2,3‐cd: 1′,2′,3′‐Im]perylene (10) (characterized) and 1H,6H‐dicyclobuta[1,2,3‐cd: 1′,2′,3′‐Im]perylene (4) (detected by mass spectrometry and 1H‐NMR absorptions). The influence of strain on UV and fluorescence spectra and on cyclic voltammetry is discussed
Photoelectron Spectra of geminal Vinyl‐ and Ethynyl‐Disubstituted Cyclopropane Derivatives
Authors: Eckert‐Maksić M. , Gleiter R. , Zefirov N. S. , Kozushkov S. I. , Kuznetsova T. S. 
Published: July 2007

AbstractThe He(I) photoelectron (PE) spectra of 1,1‐divinylcyclopropane (1), (Z,E)‐ and (Z,Z)‐1,1‐di‐1‐propenylcyclopropane (2 and 3), 1,1‐diethynylcyclopropane (4), 1‐ethynyl‐1‐propynylcyclopropane (5), 1‐ethynyl‐1‐vinylcyclopropane (6), and (Z)‐1‐(1‐propenyl)‐1‐(propynyl)cyclopropane (7) have been recorded. The interpretation of the first bands of the PE spectra is based on the comparison with related compounds and on the results of MO calculations. For the calculations on 1 – 7 the MNDO method, and in case of 1, 4, and 6 an ab‐initio procedure with a 3–21 G basis has been applied. The investigations show that 1, 2, 6, and 7 prefer the bisected conformation while in 3 the propenyl groups are strongly twisted. Our studies reveal also that the three‐membered ring shows relais properties and interacts strongly with both π systems.
Dispiro‐1,2,4‐trioxolane durch Ozonolyse von Cycloalkylidencycloalkanen auf Polyethylen
Authors: Griesbaum Karl , Krieger‐Beck Petra , Beck Johannes 
Published: July 2007

Dispiro‐1,2,4‐trioxolanes by Ozonolysis of Cycloalkylidenecycloalkanes on PolyethyleneOzonolyses of symmetrical (1b – d) and of unsymmetrical cycloalkylidenecycloalkanes (8a, b) afforded the dispiro‐1,2,4‐trioxolanes 4b – d and 9a, b, respectively. Their thermal decompositions gave mixtures of the cyclic ketones (3) and lactones (6). Photolyses afforded in addition to 3 and 6 the cyclic anhydrides 13, which are isomeric with the corresponding dispiro‐1,2,4‐trioxolanes.
Concave Reagents, 71) Concave Benzoic Acids
Authors: Lüning Ulrich , Wangnick Carsten , Peters Karl , Schnering Hans Georg Von 
Published: July 2007

AbstractBased on m‐terphenyl units, concave benzoic acids 11a and 12a were prepared via the 2,6‐diarylbenzoic acid 7a. Bromination of 7a with NBS gave 9, and cyclization of 9 with dithiols 10 led to the bimacrocyclic concave acids 11a and 12a. Their relative acidities were determined by photometric titrations in ethanol, and the three‐dimensional structure of 11a was determined by X‐ray analysis.
Schwefel(IV)‐Verbindungen als Liganden, XIII. Schwefeldioxid als Brückenligand in unsymmetrischen Zweikernkomplexen
Authors: Schenk Wolfdieter A. , Hilpert Georg H. J. 
Published: July 2007

Sulfur(IV) Compounds as Ligands, XIII. – Sulfur Dioxide as a Bridging Ligand in Unsymmetrical Dinuclear ComplexesA series of known or newly synthesized dinuclear complexes with the following combinations of elements: Mo/Ir, Mo/Pd, W/Pd, Mn/Pd, Fe/Rh, Rh/Pt, Ir/Pd, and Ir/Pt has been treated with sulfur dioxide. Only electron‐rich systems are capable of taking up SO2 into a bridging position. [Mo(CO)3(η2‐dppe) (η1‐dppm)] (2) reacts with [PdCl2(C8H12)] to form [MoPdCl2(CO)3(dppe)(μ‐dppm)] (3), which is unstable and does not take up SO2. However, the complexes [FeRhCl(CO)4(μ‐SO2)(μ‐dppee)] (5), [MoIr(μ‐Cl)(CO)3(μ‐SO2)(μ‐dppm)2] (8), and [MnPdBr(CO)2(μ‐SO2)(μ‐dppm)2] (14) have been obtained. Reactions of fac;‐[M(CO)3(η2‐dppm)(η1‐dppm)] (MMo: 6a, W: 6b) or the corresponding mer‐isomers 10a, b with [PdCl2;‐(C8H12)] give the dinuclear complexes [MPdCl(μ‐Cl)(CO)2(μ‐CO)(μ‐dppm)2] (11a, b). From [Ir(CO)(dppm)2]Cl and [Pd(dba)2] in the presence of CO [IrPdCl(CO)2(μ‐dppm)2] (16) is obtained, whereas in dichloromethane under an inert gas the oxidation product [IrPdC]3(CO)(μ‐dppm)2] (17) is formed. 11a, b, 16, and 17 apparently are too electron‐poor to form stable adducts with SO2. However, from 17 and (Me3Si)2S the sulfur‐bridged complex [IrPdCl(μ‐S)(CO)(μ‐dppm)2] (18) is obtained. The alkynyl complexes [MPtCl(CCPh)2(μ‐dppm)2] (M  Rh: 19, Ir: 21) readily add SO2, reversibly in the case of 19. From [IrPtCl‐(C  CPh)2(μ‐SO2)](μ‐dppm)2] (22) the salt [IrPt(C  CPh)2(SO2) (μ‐dppm)2]PF6 (23) is formed by Cl abstraction. 23 is one of the rare examples of terminal coordination of SO2 in a dinuclear complex.
Medizinisch interessante Metallchelate, III. 99mTc‐Komplexe mit vierzähnigen Dibrenzkatechin‐Liganden
Authors: Ekkehardt Hahn F. , Rupprecht Stefan 
Published: July 2007

Metal Chelates of Medical Interest, III. – 99mTc Complexes with Tetradentate Dicatechol LigandsThe dicatechol ligand bis[3‐(2,3‐dihydroxyphenoxy)propyl]‐amine hydrochloride, DIPACE (6), reduces the 99m[TcO4]− ion to lower valent 99mTc and subsequently forms a complex with the reduced 99mTc. The structure of benzylbis[3‐(2,2‐dimethyl‐1,3‐benzodioxol‐4‐yloxy)propyl]amine (4) is determined by X‐ray crystallography.
The Azo/Nitrene Route to cis,cis‐Trialkyltriaziridines, 1 Synthesis of syn‐Azo Azides of Defined Proximity
Authors: Marterer Wolfgang , Klingler Otmar , Thiergardt Regina , Knothe Lothar , Prinzbach Horst 
Published: July 2007

AbstractBi‐ and polycyclic syn‐azo azide substrates H, 5, 14 and I, 15–18, 36, 41d, respectively, of varying rigidity and proximity (with the potential nitrene nitrogen atom in the π plane of the azo function) are prepared in order to synthesize kinetically stabilized cis,cis‐trialkyltriaziridines.
Photochemical Transformations, 75. The Azo/Nitrene Route to cis,cis‐Trialkyltriaziridines, 21b) Photolysis of syn‐Azo Azides of Defined Proximity – Attempts for N3 → N3X Ring Enlargement
Authors: Marterer Wolfgang , Klingler Otmar , Thiergardt Regina , Beckmann Eberhard , Fritz Hans , Prinzbach Horst 
Published: July 2007

AbstractThe as yet unknown route to triaziridines by the addition of nitrenes to the π side of the NN bond is achieved intramolecularly by the photolysis (thermolysis) of syn‐azo azide substrates with high proximity; the yields reflect the sterical (and possibly inductive) influences of the skeleton. The product composition is rather independent of the exciting light; intramolecular azo → azide energy transfer is assumed. The kinetic skeleton stabilization of the triaziridines permits the synthesis of 17 (18) by the thermolysis of 7 (8) at 200°C with the product composition deviating only marginally from that of the photolysis. Attempts towards enlargement of the triaziridines to N3X rings (XCHR, O, NR) lead exclusively to products of intramolecular fragmentation.
Tellurium Cations by Lewis Acid‐Base Reactions: Syntheses and Crystal Structures of (Te24⊕)Zr2Br210⊖ and (TeBr3p⊕)(Zr2Br9⊖)
Authors: Beck Johannes 
Published: July 2007

AbstractZrBr4 reacts with Te2Br in a sealed evacuated ampoule at 210°C in quantitative yield to afford (Te24⊕)(Zr2Br210⊖) as blueblack, moisture‐sensitive crystals. The crystal‐structure determination shows, that (Te4)(Zr2Br10) consists of planar, nearly square Te24⊕ and Zr2Br210⊖ ions, that form edge‐sharing double octahedra. Both ions possess crystallographic 2/m (C2h) symmetry. At temperatures above 250°C (Te4)(Zr2Br10) decomposes with cleavage of Te –Te bonds into (TeBr3⊕)(Zr2Br9⊖), which forms yellow, hygroscopic crystals. (TeBr3)(Zr2Br9) can also be obtained by the reaction of two equivalents of ZrBr4 with TeBr4 at 260°C. The crystal structure is built of Zr2Br9⊖ ions, that form face‐sharing double octahedra, and of pyramidal TeBr3⊕ ions. Each TeBr3⊕ ion exhibits three Te – Br contacts to two different Zr2Br9⊖ ions, resulting in a strongly deformed octahedral coordination for the Te atom. The Zr2Br9 double octahedra and the TeCl6 octahedra are connected by common edges and corners to infinite chains.
Synthese von Imidodiphosphaten des Aluminiums, Galliums, Indiums, Zinns und Titans
Authors: Mazzah Ahmed , Gosink Hans‐Jürgen , Liebermann Johannes , Roesky Herbert W. 
Published: July 2007

Synthesis of Imidodiphosphates of Aluminum, Gallium, Indium, Tin, and Titanium.Me3SiN[P(O)Cl2]2, (1) and Me3SnN[P(O)Cl2]2 (2) are synthesized from NaN[P(O)Cl2]2 and Me3SiCl or Me3SnCl, respectively. Treatment of 1 with AlCl3, GaCl3 InCl3, Me2SnCl2, and TiCl4 yields (3), (4), (5), (6), and (7), respectively. Reaction of LiN[P(O)Ph2]2 with TiCl4 leads to (8). NMR spectra demonstrate that the tetrachloroimidodiphosphate ligand coordinates through the oxygen atoms towards the metal atom.
[K{V4O4(μ‐O)4(μ‐O2CCH2tBu)4}] [O2CCH2tBu] · 2 tBuCH2CO2H, ein Kaliumkomplex eines „anorganischen Kronenethers”︁
Authors: Priebsch Wolfgang , Rehder Dieter , Oeynhausen Maren Von 
Published: July 2007

[K{V4O4(μ‐O)4(μ‐O2CCH2tBu)4}][O2CCH2tBu] · 2 tBuCH2CO2H, a Potassium Complex of an “Inorganic Crown Ether”The reaction of VOCl3 with Ag/KO2CCH2tBu yields the title compound (characterized by crystal and molecular structure analyses), which is the first oligonuclear vanadium complex with monofunctional carboxylate containing Vv centres exclusively. The potassium ion is coordinated by two planes of O2;−: the four μ‐oxo bridges of the puckered V4(μ‐O)4 ring and the plane spanned by the eight oxygen functions of the bridging carboxylate ligands, from wich it protrudes only slightly.
Small and Medium Rings, 74. Syntheses and Photoelectron Spectra of 7‐Azanorbornadiene and Related Compounds An Analysis with Fragment Orbitals
Authors: Altenbach Hans‐Josef , Martin Hans‐Dieter , Mayer Bernhard , Müller Monika , Constant Dieter , Vogel Emanuel 
Published: July 2007

AbstractThe He(I) photoelectron spectra (PE) of 7‐azanorbornane (5), 7‐azanorbornene (6), and 7‐azanorbornadiene (7) as well as of related urethanes have been recorded. The syntheses of these bicyclic compounds are described in detail. A most convenient analysis of the PE spectroscopic results is based on the procedure of Heilbronner‐Schmelzer on an ab initio STO‐3G level. This method allows to construct fragment orbitals elucidating the orientation of the nitrogen lone pair, the through‐space interaction with π bonds, and the participation of σ bond orbitals. The result is remarkable: whereas the direct interaction of localized lone‐pair and π orbitals is significant in both syn;‐ and anti‐orientation, the interaction of a localized lone pair with a precanonical fragment π orbital is completely different in the two geometries. In 6;‐syn a considerable interaction matrix element FantiΨnπ=−0.71 eV comes to the fore, whereas the corresponding parameter in 6;‐anti turns out to be almost zero, FantiΨnπ=+ 0.09 eV. Since 6;‐syn is calculated to be more stable than 6;‐anti, it is this invertomer, 6;‐syn, which is likely to be responsible for the main bands in the PE spectrum of 6. The comparatively large experimental split between the first two PE bands of 6 (0.98 eV) is in accord with the 6;‐syn geometry and compares well with the calculated band separation of 1.26 eV for 6;‐syn.
Bisaxial koordinierte (Tetraphenylporphinato)eisen(II)‐Komplexe
Authors: Mezger Martin , Hanack Michael , Hirsch Andreas , Kleinw ächter Jörg , Mangold Klaus‐Michael , Ramaswami Subramanian L. 
Published: July 2007

Bisaxially Coordinated (Tetraphenylporphinato)iron(II) ComplexesThe coordination behavior of (tetraphenylporphinato)iron(II) (TPPFe) has been studied with the preparation of the monomeric complexes TPPFe(L)2 with Lpy (pyridine), pyz (pyrazine), 2,6‐dimepyz (2,6‐dimethylpyrazine), bpy (4,4′‐bipyridine), bpyac [1,2‐bis(4‐pyridyl)acetylene], dabco (1,4‐diazabicyclo [2.2.2]octane), and BzINC (benzyl isocyanide). Pure TPPFe has been obtained by thermal decomposition of TPPFe(py)2. The monomeric complexes TPPFe(L)2 with Lpyz, bpy, bpyac, and dabco can be transformed into the bridged systems [TPPFe(L)]n by heating them in toluene or chlorobenzene. The bridged structure of the complexes [TPPFe(L)]n has been confirmed by IR and TG/DTA investigations and especially by Mößbauer spectroscopy. In comparison with the corresponding (phthalocyaninato)iron compounds the bridged TPPFe complexes exhibit lower semi conducting properties even after doping with iodine.
OrganosubstituierteBicyclen undMonocyclen aus 2,5‐Dihydro‐1,2,5‐oxasilaboratolaten
Authors: Köster Roland , Seidel Günter , Müller Gerhard 
Published: July 2007

OrganosubstitutedBicyclic and Monocyclic Compounds from 2,5‐Dihydro‐1,2,5‐oxasilaboratolates1a)The potassium salts of the cyclic anions of (A: R, R′ = CH3; B: R = C2H5, R′ = CH3; C: R = C6H5, R′ = CH3 react with [(CH3)2NCH2]Br in THF to yield the bicyclic compounds 1a (X‐ray crystal structure analysis), 1b/1b' (endo/exo‐C2H5), and 1c/1c' (endo/exo‐C6H5). D (RCH3, R'=C6H5) reacts with [(CH)32NCH2]Br to form a 1:4 mixture of 1d together with the heterocycle (3d) with elimination of (CH3)2N‐C3H7. – From A – D and CIP(C6H5)2 the six‐membered heterocycles (2a−d) are obtained in yields of ca. 90%.
Addition anorganischer und organischer Nucleophile an den Vinyliden‐Liganden des Clusters FeCo2(CO)9(μ3‐CCH2)
Authors: Albiez Thomas , Heineke Daniel , Vahrenkamp Heinrich 
Published: July 2007

Addition of Inorganic and Organic Nucleophiles to the Vinylidene Ligand of the Cluster FeCo2(CO)9(μ3‐CCH2)The CCH2 ligand of the cluster FeCo2(CO)9(μ3‐CCH2) (1) is electrophilic at the terminal C atom. Soft inorganic nucleophiles [Nu – PR3, (CH3)2SO, CN−, SCN−] are added to form the zwitterionic complexes FeCo2(CO)9(μ3‐C–CH2–Nu) (4, 7, 8), as proved by the structure determination of FeCo2(CO)9(μ3‐CCH2 – PMe3) (4a). The products are of low thermal stability. Upon heating, the PR3 derivatives rearrange to the CO substitution products FeCo2(CO)8(PR3)(μ3‐CCH2) (5, 6). C–C coupling is achieved by addition of malonic ester anion derivatives [X – CH – CO2Me] (XMeO2C, CN, Br). The anionic addition product for XMeO2C (10a) can be protonated to form HFeCo2(CO)9[μ3 CCH2 – CH(COOMe)2] (11) which liberates H2 upon warming resulting in FeCo2(CO)9[μ3‐CCH – CH(COOMe)2] (12). Thus, a substitution of a vinylidene H atom has been performed by an HX addition/H2 elimination sequence. Phosphorus ylides R3PCHX [XH, SiMe3, Cl, CHO, C(O)Ph, COOR] are also added with CC coupling to yield the complexes FeCo2(CO)9(μ3‐CCH2 – CHX – PR3) (15, 16). The structure determination of the compound with XEtO2C and RPh (16c) proves that these complexes differ from the complexes 4 just by insertion of one methylene unit.
Diazadienkomplexe elektronenarmer übergangsmetalle: Synthese, Eigenschaften und Struktur von CpTi(diazadien)Cl
Authors: Scholz Joachim , Thiele Karl‐Heinz , Dietrich Andreas , Schumann Herbert 
Published: July 2007

Diazadiene Complexes of Electron‐Deficient Transition Metals: Synthesis, Properties, and Structure of CpTi(diazadiene)ClThe electron‐deficient 1,4‐diazadiene (DAD) complex CpTi‐(DAD)Cl (3), [DAD=1],4‐bis(4‐methoxyphenyl)‐2,3‐dimethyl‐1,4‐diazabutadiene] is prepared either by reduction of CpTiCl3 (1) with magnesium in the presence of free DAD (2) or by the reaction of 1 with Na2DAD. NMR spectroscopic and X‐ray diffraction analysis of 3 indicate that the bonding of the DAD ligand has σ2,π‐metallacyclopentene rather than η4;‐π character. As a result of steric repulsion between the Cp ring and methyl groups of the DAD ligand 3 exhibits a supine (exo) geometry for DAD coordination is solid state. Substitution reaction of 3 affords the novel complex CpTi(DAD)R (RCH2Ph).
Darstellung und Struktur von Thallium(I)‐2,4,6‐tris(trifluormethyl)thiophenolat, einer Verbindung mit faltblattartig‐polymerem Aufbau
Authors: Labahn Dieter , Phol Ehmke , Herbst‐Irmer Regine , Stalke Dietmar , Roesky Herbert W. , Sheldrick George M. 
Published: July 2007

Preparation and Structure of Thallium(I) 2,4,6‐Tris(trifluoromethyl thiophenolate, a Compound with a Folded Polymeric StructureThe title compound, thallium(I) 2,4,6‐tris(trifluoromethyl)thiophenolate (1) has been prepared by using either TlOEt and (CF3)3C6H2SH or Tl2CO3 and (CF3)3C6H2SNa. A single X‐ray structural analysis shows a folded polymeric structure for 1; the crystal lattice incorporates half of a 1,4‐dioxane molecule per Tl atom. This compound has a surprisingly high kinetic stability compared to known thallium(I) thiolates.
Additionsreaktionen an intramolekular basenstabilisierte GeN‐ und GeS‐Doppelbindungen
Authors: Veith Michael , Detemple Astrid , Huch Volker 
Published: July 2007

Addition Reactions of Intramolecularly Base‐Stabilized GeN and GeS Double Bonds.The GeN bond of 1 adds hydrogen chloride, ethanol, tert‐butyl alcohol, methyllithium, and methyl iodide to form 3–6 and 8. The GeS bond in 2 analogously adds methyl iodide to yield 10. In the resulting products the electropositive part of the polar reactand is bound to nitrogen or sulfur, while the electronegative one is on the germanium atom. In the lithium derivative 6 and in the iodine derivative 8 Li and I can be replaced by hydrogen to form two isomers of the same composition 7 and 9, which differ only in the positions of the hydrogen and methyl groups with respect to Ge or N. The X‐ray structure analyses on 4, 9, and 10 reveal that the germanium atom is fourfold coordinated by two nitrogen atoms and two other ligands. The intramolecular nitrogen base of the silazyl moiety in 1 and 2 is, thus, expelled from the coordination sphere of germanium by insertion of the double bonds into polar σ bonds, and the tricyclic molecule is changed to a bicyclic one. Thus these “base stabilized π bonds” in 1 and 2 behave as normal unsaturated systems.
Beiträge zur Chemie des Phosphors, 215. Einfache Darstellung des Pentaphosphacyclopentadienid‐Ions, cyclo‐P⊖5, durch Abbau von rotem Phosphor mit Kaliumdihydrogenphosphid
Authors: Baudler Marianne , Etzbach Thomas 
Published: July 2007

Contributions to the Chemistry of Phosphorus, 215. – Simple Preparation of the Pentaphosphacyclopentadienide Ion, cyclo‐P⊖5, by Degradation of Red Phosphorus with Potassium DihydrogenphosphideThe pentaphosphacyclopentadienide ion 1 is easily obtained in the form of a KP5 solution by the reaction of red phosphorus with potassium dihydrogenphosphide (1.9:1) in boiling dimethylformamide. The IR absorption at ṽ = 815 cm−1 previously observed for NaP5/[18]crown‐6/THF solutions is not to be assigned to 1. The formation of 1 in the degradation process of red phosphorus is discussed.
Reaktion von KSi mit M(CO)6 (MCr, Mo, W) und Cr(CO)5NMe3 – Struktur von [K(DME)2]2[Cr2(CO)10] (DME=1,2‐Dimethoxyethan)
Authors: Hey‐Hawkins Evamarie , Schnering Hans Georg Von 
Published: July 2007

Reaction of KSi with M(CO)6 (MCr, Mo, W) and Cr(CO)5NMe3 – Crystal Structure of [K(DME)2]2[Cr2(CO)10] (DME=1.2‐Dimethoxyethane)M(CO)6 (MCr, Mo, W) and Cr(CO)5NMe3 are reduced by KSi in DME during several days with formation of the anions [M2(CO)10]2⊖. These can be obtained from a DME/toluene solution as pale yellow or orange crystals of [K(DME)2]2[M2(CO)10] [MCr (1), Mo (2), W (3)]. A crystal structure determination of the chromium compound shows that strong interactions between the [Cr2(CO)10]2⊖ and the K⊕ ions exist in the solid state, leading to the formation of one‐dimensional polymeric chains. 2 and 3 are isomorphous to 1 (powder diffraction, Rietveld method).
Chiral Organometallic Reagents, III. On the Configurational Stability of α‐Bromoalkyllithium Compounds
Authors: Hoffmann Reinhard W. , Bewersdorf Martin 
Published: July 2007

AbstractThe carbenoids 2 undergo at ‐110°C a bromine/lithium exchange reaction with 1,1‐dibromo alkanes. This leads to partial equilibration of the carbenoids 2 during their generation from the 1,1‐dibromo compound 1. In the absence of the precursor 1, the carbenoids 2 have been found to be configurationally stable at ‐110°C.
4,9,14,19‐Tetrafunctionalized Pagodanes de novo Synthesis – Functional Group Manipulations
Authors: Melder Johann‐Peter , Prinzbach Horst 
Published: July 2007

AbstractVarious 4,9,14,19‐tetrafunctionalized pagodanes are prepared by a de novo route commencing from appropriately substituted isodrin analogues (3, 4). With the 14,19‐dimethoxypagodane‐4,9‐dicarboxylic esters 30/31, isolated after 16 one‐pot operations (ca. 40 functional changes) in ca. 6.5% overall yield (ca. 84% per operation, ca. 93% per functional change), the scope for further functional group manipulations on the pagodane sphere is explored (e.g. diketone dicarboxylic ester 35, dimethoxy diketone 37, tetraketone 41). In two face‐to‐face dibenzo substrates (17, 49), clean photoequilibration with the corresponding syn‐o,o'‐dibenzo isomers (19, 50) (75: 25 and 80: 20, resp.) is observed upon direct excitation (λ=254 nm).
Photolysis of Diazo(pentamethyldisilanyl)methyl Ketones in the Presence of Carbonyl Compounds: Trapping of the Acylsilene Intermediates
Authors: Maas Gerhard , Alt Mechthild , Schneider Klaus , Fronda Antonio 
Published: July 2007

AbstractUV photolysis of diazo(pentamethyldisilanyl)methyl ketones 1b – d generates acylsilenes (3‐oxo‐1‐sila‐1‐propenes) 3 as reactive intermediates, which can be trapped by enolizable carbonyl compounds in an ene‐type reaction. With non‐enolizable carbonyl compounds or ethyl acetate, they undergo a [4 + 2] cycloaddition. In contrast to the photolysis in the absence of these carbonyl compounds, a Wolff rearrangement of 1b – d (or the derived carbenes) to silyl ketenes 5b – d is observed as a competitive reaction.
Bis[2,3‐naphthalindiolato(2–)](pyrrolidiniomethyl)silicat‐Acetonitril‐Solvat: Synthese sowie Kristall‐ und Molekülstruktur eines zwitterionischen λ5‐Spirosilicats
Authors: Tacke Reinhold , Sperlich Jöurg , Strohmann Carsten , Mattern Güunter 
Published: July 2007

Bis[2,3‐naphthalenediolato(2—)](pyrrolidiniomethyl)silicate Acetonitrile Solvate: Synthesis and Crystal and Molecular Structure of a Zwitterionic λ5‐SpirosilicateThe zwitterionic spirocyclic bis[2,3‐naphthalenediolato[2–)](pyrrolidiniomethyl)silicate (3) was synthesized and the crystal and molecular structure of its acetonitrile solvate 3 · CH3CN investigated. 3 was prepared by reaction of trimethoxy(pyrrolidinomethyl)silane (8) or dimethoxy(methyl)(pyrrolidinomethyl)silane (8) or dimethoxy(methyl)(pyrrolidinomethyl)silane (9) with 2,3‐dihydroxynaphthalene in acetonitrile. Reaction 9 → 3 involves a remarkable Si—C cleavage with formation of CH4. The pentacoordinate silicon atom of 3 · CH3CN is surrounded by 4 oxygen atoms and 1 carbon atom, the latter being in an equatorial position. The coordination polyhedron can be described as a distorted trigonal bipyramid (the structure is displaced by 20.5% from the trigonal bipyramid towards the square pyramid). The crystal lattice of 3·CH3CN contains centrosymmetric dimers of 3, built up by intermolecular N—H … O hydrogen bonds.
Darstellung, Struktur und Komplexierung von 2,2′,5,5′‐Tetrahydro‐1,1′‐bi(1H‐1,2,5‐phosphadiborol)‐Derivaten
Authors: Drieß Matthias , Frankhauser Pascal , Pritzkow Hans , Siebert Walter 
Published: July 2007

Synthesis, Structure, and Complexation of 2,2′,5,5′‐Tetrahydro‐1,1′‐Bi(1H‐1,2,5‐phosphadiborole) DerivativesReactions of (Z)‐1,2‐diborylethenes [HC — B(Cl)R]2 with LiPH2 and LiP(SiMe3)2 lead to the 2,5‐dihydro‐1H‐1,2,5‐phosphadiboroles 1a — d in good yields. 1a, b react with (Me3C)2Hg to give yellow 2a (56%) and 2b (90%), which are also obtained from 1c, d and TlCl or C2Cl6, respectively. The constitution of 2b is established by an X‐ray structure analysis. 2a reacts with Cr(CO)3(CH3CN)3 to yield the bis(pentacarbonyl)chromium complex 4a, whereas 2b and Fe(CO)3(C8H14)2 form the bis(tricarbonyliron) compex 5b. Spectroscopic studies and X‐ray structure analyses of 4a and 5b show that in 4a the chromium atom is η1‐bound to phosphorus, whereas in 5b the iron interacts with all atoms of the folded C2B2P ring.