bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cyclopropannelation of the Bicyclo[3.3.0]octane Framework. On the Chemical Significance of exo‐Positioned Substituents
Authors: Müllen Klaus , Klabunde Michaela , Enkelmann Volker 
Published: July 2007

AbstractTo facilitate the synthesis of tetracycles containing the framework 2, the reaction of the tetrabromide 8 with cyanide and bis(phenylsulfonyl)methane under various conditions was investigated. Instead of the expected twofold bridging, novel cyclopropa derivatives were obtained. Product formation is a consequence of the stereochemistry of the starting material 8, with the exo configuration of the bromomethyl substituents being the crucial factor.
Reaktionen vinyloger Oxycarbene mit Methanol
Authors: Hömberger Günter , Kirmse Wolfgang , Lelgemann Rudolf 
Published: July 2007

Reactions of Vinylogous Oxycarbenes with MethanolThe carbenes 16 and 30 were generated in methanol/sodium methoxide by photolyses of 2‐methylchromone tosylhydrazone (14) and 3,5‐dimethoxy‐4,4‐dimethyl‐2,5‐cyclohexadienone tosylhydrazone (28), respectively. Neither 16 nor 30 accept methanol at the carbenic site to give products of a formal O – H insertion. Carbene 16 affords 2‐methoxy‐2‐methyl‐2H‐1‐benzopyran (19) by way of the benzopyrylium ion 17. The same ether was obtained from the independently prepared perchlorate of 17. Protonation of 30 was followed by demethylation of the delocalized carboxonium ion 31 to give 5‐methoxy‐6,6‐dimethyl‐2,4‐cyclohexadienone (33) as the only product.
Synthese mittlerer und großer Ringe, XXIX. Oxidation von 3,4‐Hexamethylenfuran zu 2,9‐Dioxodecan‐10‐olid
Authors: Molkentin Joachim , Goepfert Andreas , Tochtermann Werner 
Published: July 2007

Synthesis of Medium and Large Rings, XXIX. ‐ Oxidation of 3,4‐Hexamethylenefuran to 2,9‐Dioxodecan‐10‐olide3,4‐Hexamethylenefuran (1 a) is oxidized by various methods to give the butenolide 2. Ozonolysis of 2 affords 2,9‐dioxodecan‐10‐olide (3) in 80% yield.
Synthese, Strukturen und Eigenschaften der Cyclothiaselenazenium‐Kationen [Se2N2S]22+, [XSe2N2S]+, [Se2N2S]2+, [S3SeN5]+ sowie Cl2Se2N2S und SeSN2 ṁ TiCl4
Authors: Haas Alois , Kasprowski Jörg , Angermund Klaus , Betz Peter , Krüger Carl , Tsay Yi‐Hung , Werner Stefan 
Published: July 2007

Synthesis, Structures, and Properties of Cyclothiaselenazenium Cations [[Se2N2S]22+, [XSe2N2S]+, [Se2N2S]2+, [S3SeN5]+as well as Cl2Se2N2S and SeSN2 and SeSN2 ṁ TiCl4Bis(sulfinylamino)selane (1), prepared from Se2Cl2 and (CH3)3SiNSO, reacts with Lewis acids such as MF5 (M = As, Sb, Nb) and BF3 to form bis(1,3,4,2,5‐thiadiselenadiazolium) cations (3) with counter anions AsF‐6 (3a), SbF‐6 (3b), NbF‐6 (3c), BF‐4 (3d). Treatment of Se2Cl2 with LiN[Si(CH3)3]2 leads to [(CH3)3Si]2NSexN[Si(CH3)3]2 (x = 1, 2a: 2, 2b). From 2a and 2a and SeCl4 explosive Se4N4 is obtained. Chlorination of 3a and 3c gives [ClSe2N2S]+[MF6]‐ (M = As, 4a, and Nb, 4c). Analogous bromination of 3a provides [BrSe2N2S]+ [AsF6]‐ (4b). This type of chlorinated five‐membered rings is also obtained directly from 1 and SbCl5 and PCl5 or SeCl4. The products isolated are [ClSe2N2S]+ [SbCl6]‐ (4d) and [ClSe2N2S]+Cl‐ (4e). – A covalent species 5, isomeric to 4e, is obtained from 1 and POCl3, and a four‐membered ring SeSN2 ṁ TiCl4 (6) from 1 and TiCl4. When 3a or 1 is treated with a two‐ or threefold excess of AsF5 the stable dication [Se2N2S]2+ (7) is formed. It arises also from 4e and AgAsF6. Attempts to replace TiCl4 in 6 by AsF5 lead to [SeS3N5]+ [AsF6]‐ (8) with a bicyclic structure for the cation. X‐ray structure analyses for 1, 4c, 4d, 4e, 5, and 8 are performed.
Modellreaktionen von Metalloxiden an Silicium‐Sauerstoff‐Oberflächen
Authors: Roesky Herbert W. , Hesse Detlev , Bohra Rakesh , Noltemeyer Mathias 
Published: July 2007

Model Reactions of Metal Oxides at Silicon‐Oxygen SurfacesReaction of (tBu)2Si(OReO3)2 (1) with ArNCO (Ar = 2,6‐iPr2‐C6H3) leads to the novel compound [(tBu)2SiO2]2(μ2‐O)4 (μ3‐O)4‐[ReO(NAr)]2[Re(NAr)]2 (2). The X‐ray structure of 2 containing two molecules of deuterated benzene (2 2 C6D6) is reported.
Notizen/Notes Synthese und Struktur von 2‐Phosphonioallen‐Komplexen
Authors: Metternich Hans‐Jürgen , Niecke Edgar , Nixon John F. , Bartsch Rainer , Hitchcock Peter B. , Meidine Mohamed F. 
Published: July 2007

Synthesis and Structure of 2‐Phosphonioallene ComplexesThe reaction of the chlorobis(methylene)phosphorane 1 with reactive olefin complexes of nickel and platinium affords the 2‐phosphonioallene complexes 4b and 6a,b. The structure of this new class of three‐electron donor ligands, involving a lowcoordinated phosphorus (V) cation, has been elucidated by NMR spectroscopy and a single‐crystal X‐ray study of 6a. The reaction proceeds via a metallobis(methylene)phosphorane intermediate, which could be isolated in the case of the (Et3P)2Pt complex 3a.
Darstellung und Eigenschaften von und Reaktionen mit metallhaltigen Heterocyclen, LXXVI Regioselektive Cyclocotrimerisierung einer Thiophosphinit‐Einheit mit Methylpropinoat
Authors: Lindner Ekkehard , Haase Cornelius , Mayer Hermann August 
Published: July 2007

Metal‐Containing Heterocycles: Preparation, Properties, Reactions, LXXVI. – Regioselective Cyclocotrimerization of a Thiophosphinito Unit with Methyl PropynoateThe P = S function of (η2‐PCy2=S)Mn(CO)4 (1) undergoes a regiospecific cyclocotrimerization with methyl propynoate to give the bicyclic compound 3. Oxidation of 3 with (NH4)2[Ce(NO3)6] results in the formation of the thiophene 4. Compound 3 was characterized on the basis of MS, IR, 31P{1H}‐, 1H‐, 13C{1H}‐NMR spectra and with a 2D‐H,C‐COSY experiment.
Molecular Structures of a Lithiated Schiff Base and a Related Dialkyl Ketone Imine
Authors: Knorr Rudolf , Dietrich Hans , Mahdi Waruno 
Published: July 2007

AbstractThe ether‐solvated lithium derivative of pinacolone anil (2a) is shown to be a centrosymmetric dimer (1) by X‐ray diffraction analysis. Each lithium atom is bound to two nitrogen atoms, to the oxygen atom of diethyl ether, and weakly to two carbon atoms of a phenyl ring, but not to the vinyl moiety of the enamide anion. Despite conformational deconjugation, 1 is methylated at the carbon atom by methyl iodide. 1H‐NMR shifts of 1 in solution are solvent‐dependent. The results are discussed with respect to the “syn effect” in 1‐azaallyl anions. The molecular structure of the dianil 3 of 2,2,7,7‐tetramethyl‐3,6‐octanedione shows that a CH proton may approach the π face of an aromatic carbon atom down to a nonbonding distance of 274 A without causing much strain.
Photoelectron Spectra of λ‐Di‐ and ‐Triphosphabenzenes
Authors: Gleiter Rolf , Veszprémi TamÁS , Fluck Ekkehard 
Published: July 2007

AbstractThe He(I) photoelectron spectra of 1,1,3,3‐tetrakis(dimethyl‐amino)‐1λ5,3λ5‐diphosphabenzene (1a), 1,1,3,3,5,5‐hexakis(dimethylamino)‐1λ5,3λ5,5λ5‐ triphosphabenzene (2a), 4‐tert‐butyl‐1,1,3,3‐tetrakis(dimethylamino)‐1λ5,3λ5,5λ3‐triphosphabenzene (3a), and the substitution products 4a and 5a of 1a have been recorded. The assignment of the PE spectra is based on a comparison of the PE spectra of related species with the MO calculations carried out by using the MNDO procedure. The investigations reveal that the first bands correspond to π‐MOs which are mainly localized on the C atoms of the six‐membered ring. The MO calculations predict a strong negative net charge for the ring carbon atoms adjacent to the P atoms and strong positive net charges for the P atoms.
Sterisch gehinderte Doppelbindungssysteme, 2. Über die Darstellung hochsubstituierter 1,3‐Diene
Authors: Hopf Henning , Lipka Helmut 
Published: July 2007

Sterically Hindered Double Bond Systems, 2. — On the Preparation of Highly Substituted 1,3‐DienesHighly alkylated 1,3‐dienes may be prepared by treatment of 2‐butyne‐1,4‐diol derivatives with organocuprates in good yield. Thus, the 2,3‐dialkylated butadienes 6a—d are obtained by treating the diacetate 4 with two equivalents of the cuprates prepared from the Grignard reagents 5a—d with CuBr/LiBr. Analogously, meso‐14 is converted into a mixture of the di‐tert‐butyl‐2,4‐hexadienes (Z,E)‐ and (Z,Z)‐15. The procedure may be extended to the synthesis of unsymmetrically substituted 1,3‐dienes by either treating the appropriate diacetates with two equivalents of the same cuprate as examplified by the conversion of 18 into 19a and 19b or by employing a stepwise approach in which only one reactive acetate leaving group is available for the cuprate reagent at any given time, thus allowing the change of the organometallic reagent in the course of the synthesis (preparation of the dienes 26 from the monoacetates 22). The mechanisms of these reactions as well as those of several reactions leading to sideproducts are discussed.
Heterocyclen mit einem Azaallyl‐System, 4. 5H‐Dibenz[c,e]azepine mit Donor‐Gruppen in 7‐Stellung
Authors: Röhrkasten Ralf , Kreher Richard P. 
Published: July 2007

Heterocycles with an Azaallyl System, 4. — 5H‐Dibenz[c,e]azepines with Donor Groups at the 7‐Position5H‐Dibenz[c,e]azepines substituted with a methoxy (1) or methylthio group (10) at the 7‐position have been synthesized from 6,7‐dihydro‐5H‐dibenz[c,e]azepin‐5‐one (5) by regioselective O‐ or S‐alkylation with methyl trifluoromethansulfonate and subsequent NH‐deprotonation. According to the spectroscopic properties the semicyclic 7‐membered alkyl imidates exist exclusively in the benzenoid 5H structure.
Übergangsmetall‐Stannyl‐Komplexe, 4 Palladium‐ und Platin‐Komplexe mit Phosphinoalkylstannyl‐Chelatliganden durch oxidative Addition von Sn—C‐Bindungen
Authors: Müller Christine , Schubert Ulrich 
Published: July 2007

Transition Metal Stannyl Complexes, 4. — Palladium and Platinum Complexes with Chelatting Phosphinoalkylstannyl Ligands by Oxidative Addition of Sn—C BondsReaction of (Ph3P)4Pd with two equivalents of Ph2PCH2CH2‐SnR3 (R = Ph, Me) gives the Pd(II) stannyl complexes trans‐Pd(PPh2CH2CH2SnR2)2 (2) by oxidative addition of two Sn—R groups and elimination of R—R. Products corresponding to earlier steps of the reaction are obtained by the reaction of (Ph3P)2Pt(C2H4) with Ph2P(CH2)nSnR3 (n = 2, 3). The phenylderivatives Ph2P[CH2]nSnPh3 afford the Pt(II) complexes (Ph3P)(Ph)PtPPh2[CH2]nSnPh2 (3), in which the two phosphorus atoms are cis‐configurated, while Ph2PCH2CH2SnMe3 gives the Pt(IV) complex cis,cis,cis‐(Me)2Pt(PPh2CH2CH2SnMe2)2 (3) as stable product.
Mono‐, Bis‐ and Tris(cyclopentadienyl) Compounds ‐ Syntheses of New Polydentate Ligands and their Molybdenum and Tungsten Complexes
Authors: Plenio Herbert 
Published: July 2007

AbstractCondensation reactions of cyclopentadienyl‐substituted chlorosilanes CpSiMe2Cl (Cp = C5H5, C5HMe4) with a number of phenols [C6H5OH, 1,3‐C6H4(OH)2, 1,4‐C6H4(OH)2, 1,3,5‐C6H3(OH)3] in the presence of excess base led to six novel molecules containing up to three cyclopentadienyl groups {e.g. 1,3,5‐C6H3[OSiMe2(C5Me4H)]3). The dynamic behavior of 1,4‐C6H4[OSiMe2(C5H5)]2 (2) was investigated by temperature‐variable 1H NMR and the reaction rate of the degenerate 1,2‐silicon shift determined. C6H5OSiMe2(C5H5) (1) and (2) were treated with NaH, (MeCN)3M(CO)3 (M = Mo, W), and Mel to give the η5‐complexes C6H6OSiMe2—(C5H4)M(CO)3Me (8: M = Mo, 9: M = W) and 1,4‐C6H4[OSiMe2‐(C5H4)M(CO)3Me]2 (10: M = Mo, 11: M = W) in good yields. The X‐ray crystal structure of 11 was determined.
BN‐Achtringe (RBNR')4 aus BN‐Vierringen (RBNtBu)2 durch NtBu/NR'‐Austausch
Authors: Thiele BjÖRn , Schreyer Peter , Englert Ulli , Paetzold Peter , Boese Roland , Wrackmeyer Bernd 
Published: July 2007

Eight‐Membered BN Rings (RBNR')4 from Four‐Membered BN Rings (RBNtBu)2 by an Exchange NtBu/NR'Reactions of the four‐membered BN ring compounds (RBNtBu)2 (1a – e: R = Me, Et, iPr, iBu, Pr) with azides R'N3 (R' = PhCH2, Pr, iBu, Ph) and with the nitrone PhHC=N(Me)=O are studied. The five‐membered ring [=(Me)B=N(tBu)‐N=N‐(PhCH2)N=] (2a) is formed from the four‐membered ring 1a and PhCH2N3 in the ratio 1:2. An exchange of NtBu for NR' with elimination of tBuN3 is observed, however, in the reaction of the ring compounds 1b –d with R'N3. Instead of four‐membered BN rings, the six‐membered BN ring (RBNR')3 (3a: R/R' = Et/PhCH2) and the eight‐membered BN rings (RBNR')4 (4a –h: R/R' = iPr/PhCH2, iBu/PhCH2, iPr/Pr, iBu/Pr, iPr/iBu, iBu/iBu, Et/Ph, iBu/Ph) are formed, respectively. The NMR spectra reveal diastereotopic methylene protons (Et, Pr, iBu, PhCH2) and methyl groups (iPr, iBu) and thus elucidate the tub‐like structure of the eight‐membered rings. 3a and 4a crystallize in the space group P2,/c. The reaction of the four‐membered rings 1c – e with the nitrone gives five‐membered rings [=(R)B=N(tBu)=B(R)=N(Me) – O=] (5c – e). Both of the reactions of the four‐membered rings with azides and with the nitrone can be rationalized in terms of a similar sequence of reaction steps.
Functionalized Oxovanadium Alkoxides — Potential Haptens
Authors: Hillerns Frank , Rehder Dieter 
Published: July 2007

AbstractSeveral new oxovanadium alkoxides and alkoxides/chlorides of the composition VOCl3‐n(OR)n (n = 1, R = CPh3; n = 2 and 3, R = CPh3, iBu, cyclopentyl, tert‐pentyl, octyl; n = 3, R = dodecyl, 3‐methylbutyl) and the mixed ester VO(OiBu)‐ (OCPh3)2 have been prepared. The compounds VO(OiBu)2OR' have been synthesized, where R' is a functionalized long‐chain alkyl group [ — (CH2)8OH, — (CH2)6NH(FMOC), — (CH2)6NH2, — C(O)(CH2)5C(O)OMe, p‐C6H4CN, p‐C6H4NH2]. The chloride/carboxylate VOCl2{O2C(CH2)5CO2H} has also been obtained. The compounds are characterized, inter alia, by 51V‐NMR spectroscopy. Typical 51V shift ranges are observed for specific ligand functionalities (chloride, alkoxide, carboxylate). δ(51V) values also depend on the steric requirement of the groups R and the coordination number. The importance of the functionalized esters as potential triggers for the production of abzymes with phosphatase activity is discussed.
η2‐ und η4‐[(Dimethylamino)vinylboran]eisencarbonyl‐Komplexe
Authors: Schmid Günter , Alraun Felix , Boese Roland 
Published: July 2007

η2‐ and η4‐[(Dimethylamino)vinylborane]iron Carbonyl Complexes1)Amino‐vinylboranes can act as η2 (via the C = C bond) and as η4 ligands (via the C = C and B = N group) in iron carbonyl complexes. From bromo(dimethylamino)vinylborane and (dime‐thylamino)methylvinylborane and Fe2(CO)9 [η2‐bromo(dimethylamino)vinylborane] tetracarbonyliron (1) and tetracarbonyl[η2‐(dimethylamino)methylvinylborane]iron (2), respectively, are formed in the absence of light. The η2 coordination via the C = C group in 1 is proved by an X‐ray structure analysis. The C2BN frame is trans‐arranged. By the action of light, 1 and 2 are transferred into the very unstable tetrahapto complexes [η4‐bromo(dimethylamino)vinylborane]tricarbonyliron (3) and tricarbonyl[η4‐(dimethylamino)methylvinylborane]‐ iron (4), which can only be investigated in solution. By using tert‐butyl(dimethylamino)vinylborane the reaction leads, even in the absence of light, directly to [η4‐tert‐butyl(dimethylamino)vinylborane)tricarbonyliron (5), a compound likewise easily unstable. The transition of the η2 into the η4 complexes can be followed IR‐ and 11B‐NMR‐spectroscopically.
Synthese und flüssigkristalline Eigenschaften von Multiethern des myo‐ und scyllo‐Inosits
Authors: Marquardt Peer , Praefcke Klaus , Kohne Bernd , Stephan Werner 
Published: July 2007

Synthesis and Liquid‐Crystalline Properties of myo‐ and scyllo‐Inositol Multi EthersSelectively alkylated myo‐ and scyllo‐inositol ethers were obtained by multi‐step syntheses starting from commercially available myo‐inositol. Necessary conversions of axial hydroxy groups into equatorial ones were achieved using either potassium superoxide (KO2) or potassium nitrite (KNO2) as oxygen nucleophiles for the transformation of myo‐ into scyllo‐ inositol derivatives. Polarizing microscopic and thermoanalytical studies of numerous members of three families (6, 13, and 20) of inositol ethers reveal for most of them thermotropic liquid‐crystalline behavior. Furthermore, in case of the two long‐chain scyllitol tetraethers 13d and e an unusual thermopolymorphism has been found. The number, position, and stereochemical arrangement of alkyl chains attached to the inositol cores strongly influence the mesogenic properties of these biomolecule derivatives, chemically vicinal diols and tetrols. The self‐assembly of the studied inositol multi ethers to columnar mesophases of “supramolecular structures” is discussed considering geometrical features of these molecules and their capabilities to aggregate by hydrogen bonding.
Mit Donorzentren versehener korbförmiger Molekülhohlraum — Darstellung, Struktur, Eigenschaften
Authors: Breitenbach Jörg , Rissanen Kari , Wolf Ute U. , Vögtle Fritz 
Published: July 2007

Basket‐shaped Molecular Cavity‐Containing Donor Centres — Synthesis, Structure, PropertiesThe macrocyclic basket‐shaped molecule 2, composed of three 4‐donor‐substituted pyridine units, is synthesized by cyclisation of the chloromethyl compound 7 with sulfonamide 8. The X‐ray structure analysis of 2 gives an impression of the shape of the molecular basket. Furthermore it demonstrates that the toluenesulfonamide residues interlink, creating dimeric units of 2 in the crystal.
Organische Synthesen mit Übergangsmetallkomplexen, 53 4‐Methylencyclopentene und 5‐Methylencyclohexenone aus „Fischer‐Carben”︁‐ Chromkomplexen, Allenen und Alkine
Authors: Aumann Rudolf , Trentmann Beate 
Published: July 2007

Organic Syntheses via Transition Metal Complexes, 53. — 4‐Methylenecyclopentenes and 5‐Methylenecyclohexenones from “Fischer Carbene” Chromium Complexes, Allenes, and AlkynesA method is described for the two‐step construction of 4‐methylenecyclopentenes 6 and 5‐methylenecyclohexenones 7 from Fischer carbene chromium complexes, allenes, and alkynes. In the first step a tri(methylene)methane complex 3 is generated by the addition of the carbene chromium complex (CO)5Cr = C(0Et)Ph (1) to the allene 2. The second step involves an addition of 3 to alkynes HC≡CR [5: R = Ph (a), SiMe3 (b)] at 75°C to give 6 and/or 7 in high chemical yields. The product ratios strongly depend on the substituents R.
Highly Efficient Hydroxylation of Carbonyl Compounds with Dimethyldioxirane
Authors: Adam Waldemar , Prechtl Frank 
Published: July 2007

AbstractThe enolates and/or enols of ketones, esters, β‐diketones, β‐oxo esters, and β‐oxo lactones were transformed by dimethyl‐dioxirane (isolated in acetone solution or generated in situ) into their α‐hydroxy compounds in good to excellent yields. The direct hydroxylation of the enols was significantly enhanced by the use of fluoride ion. For the enolate of camphor the exo/endo diastereoselectivity depended significantly on the metal ligand; the highest exo/endo ratio (93:7) was observed for the enol trimethylsilyl ether of camphor.
Notiz/Note Zur Stereochemie der Reaktion von Vinylhalogeniden mit Perchlorcyclopentadien: Cycloaddition über Vinylkationen
Authors: Buddrus Joachim , Preut Hans 
Published: July 2007

The Stereochemistry of the Reaction between Vinyl Halides and Perchlorocyclopentadiene: Cycloaddition via Vinyl CationsIn the presence of aluminium chloride vinyl halides react with perchlorocyclopentadiene to yield stereoselectively bicyclic compounds (e.g. 2a), the structure of which is determined in two cases (2a, b) by X‐ray analysis. Vinyl cations are proposed as intermediates.
Isocyanatosulfonium‐Salze
Authors: Erhart Markus , Mews Rüdiger , Pauer Frank , Stalke Dietmar , Sheldrick George M. 
Published: July 2007

Isocyanatosulfonium SaltsRR'SF2 reacts with Me3SiNCO to give the corresponding N‐(fluoroformyl)sulfur imides FC(O)NSRR' [R = NMe2, R' = F (7); R' = CF3 (9)]. From these AsF5 abstracts F‐ with formation of isocyanatosulfonium salts ONC—SRR' + AsF‐6 [R = F, R' = CF3 (6); R = NMe2, R' = F (8); R = NMe2, R' = CF3 (10)]. The spectroscopic properties of the fluoroformyl derivatives and of the isocyanato salts are discussed. The structures of 8 and 10 are determined by X‐ray analyses.
η4‐Complexes of 4,7‐Dihydroacepentalene: Facile Degenerate Haptotropic Rearrangement of (η5‐Cyclopentadienyl)(η4‐4,7‐dihydroacepentalene)cobalt(I) in Contrast to its Tricarbonyliron Counterpart
Authors: Schröder Günter , Butenschön Holger , Boese Roland , Lendvai Tomas , Meijere Armin De 
Published: July 2007

AbstractThe (cyclopentadienyl)cobalt(I) complex 4 of the 4,7‐dihydroacepentaleneThe numbering of the ring system corresponds to the tricyclo‐decatetraene nomenclature used in the Exp. Part. Thus, 4,7‐substitution would be 2a,4a‐substitution in acepentalene numbering.
derivative 2b has been prepared by the reaction of the ligand with (cyclopentadienyl)bis(ethene)cobalt(I). NOE experiments indicate a complexation at the convex face of the polyolefinic ligand. 1H‐NMR spectra establish a degenerate haptotropic rearrangement with CpCo migration from one diene unit to the adjacent one. The activation energy of this process is estimated to be 15 kcal/mol. An X‐ray crystal structure determination of (η4‐4,7‐dihydroacepentalene)tricarbonyliron derivative 3a shows a distorted coordination of Fe(CO)3 at the convex face of the ligand, too.
Metallkomplexe mit biologisch wichtigen Liganden, LXIII Aspartam als dreizähniger Ligand in metallorganischen Komplexen: Darstellung und Struktur von Cp*Rh[O2CCH2CH(NH2)C(O)NCH(CH2Ph)CO2Me]
Authors: Krämer Roland , Polborn Kurt , Beck Wolfgang 
Published: July 2007

Metal Complexes of Biologically Important Ligands, LXIII1). — Aspartame as Tridendate Ligand in Organometallic Complexes: Preparation and Structure of Cp*Rh[O2CCH2CH(NH2)C(O)NCH(CH2Ph)CO2Me]Aspartame reacts with [Cp*RhCl2]2 in the presence of base to give the title complex 1 with the deprotonated tridendate dipeptide ester as ligand.
Kohlenwasserstoffverbrückte Metallkomplexe, XXII1) Addition von anionischen Fischer‐Carben‐Komplexen an koordinierte ungesättigte Kohlenwasserstoffe unter C – C‐Kupplung
Authors: Breimair Josef , Weidmann Torsten , Wagner Barbara , Beck Wolfgang 
Published: July 2007

Hydrocarbon‐Bridged Metal Complexes, XXII1). – Addition of Anionic Fischer Carbene Complexes to Coordinated Unsaturated Hydrocarbons with C – C CouplingThe addition of [(OC)5MC(OMe)CH2]– (M = Cr,W) to the cationic complexes [(OC)5Re(C2H4)]+ and [(OC)3M' (λ7‐C7H7)]+ (M' = Cr, Mo) affords the bimetallic hydrocarbon‐bridged complexes (OC)5M = C(OMe)CH2CH2CH2Re(CO)5 (1) and (OC)5M = C(OMe)CH2C7H7 – λ6 – M'(CO)3 (2), respectively. The structures of 1a and 2d have been determined by X‐ray diffraction.
Reaktionen der Azadiboriridine: Clusterbildung und Ringerweiterung
Authors: Paetzold Peter , Redenz‐Stormanns Burkhard , Boese Roland 
Published: July 2007

Reactions of the Azadiboriridines: Formation of Clusters and Ring Expansions*Nine bis(haloboryl)amines 1 were synthesized by haloboration of iminoboranes RB = NR” with dihaloboranes R'BHal2 [R/R'/R” = Et/iPr/tBu (1b), Et/sBu/tBu (c), iPr/iPr/iPr (d), iPr/tBu/iPr (e), tBu/Me/tBu (g), tBu/Et/tBu (h), tBu/Et/SiMe3 (k), tBu/tBu/SiMe3 (1), tBu/Cl/tBu n)]. The borane 1n can be transformed into 1o (R' = NMe2) by the reaction with Me3SiNMe2; an equilibrium between 1o and the four‐membered ring 1o' is observed, 1o' being formed from 1o by intramolecular B – N coordination. On reduction with lithium, the nido‐diazahexaboranes 3b–e, g, h are formed from the corresponding bis‐(haloboryl)amines 1. In the case of 3e, g, h, the ligands R and R' are unsymmetrically distributed to axial and equatorial positions of the fragment structure derived from the pentagonal bipyramid. In particular cases, azadiboriridines of type 2 are either isolated or proven as intermediates on the way from 1 to 3. The three‐membered ring of the known azadiboriridines 2i, m (R/R'/R” = tBu/iPr/tBu, tBu/tBu/tBu) is expanded to the five‐membered ring of the corresponding azadiborolines 4i, m by the reaction with 3‐hexyne. The products 4i, m are reduced to the dilithium azadiborolinates 5i, m by the action of lithium; the molecular structure of a closo‐azadicarbadili‐thiaheptaborane is recognized in crystals of 5i. The threemembered ring of 2m is also expanded by the reaction with the iminoborane EtB ≡ NtBu giving the diazatriborolidin 6m, which crystallizes in the space group Pca21