bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ein sterisch gehindertes Brückenkopfsystem: 13‐Substituierte 1,4,5,8,9,12‐Hexamethyltriptycene
Authors: Pakusch Joachim , Rüchardt Christoph 
Published: July 2007

A Sterically Hindered Bridgehead System: 13‐Substituted 1,4,5,8,9,12‐HexamethyltriptycenesThe synthetic access to five 13‐X‐substituted 1,4,5,8,9,12‐hexamethyltriptycenes (X  NO2, NC, CN, NH2, NHCHO) is described. Due to steric hindrance of the bridgehead position by the methyl groups in position 1, 8 and 9 it was impossible neither to formylate nor acetylate the 13‐amino compound 23, nor to dehydrate the 13‐formamido compound 22 to the isocyanide 19 by standard methods.
Wittig‐Synthese und Röntgen‐Struktur eines 26‐gliedrigen, zwei Bipyridin‐Einheiten enthaltenden Makrocyclus
Authors: Vogtle Fritz , Hochberg Robert , Kochendörfer Frank , Windscheif Paul‐Michael , Volkmann Martin , Jansenb Martin 
Published: July 2007

Wittig Synthesis and X‐Ray Structure of a 26‐Membered Macrocycle Containing two Bipyridine UnitsWittig‐type macrocyclization of bipyridinedicarbaldehyde 5 with bis(phosphonium bromide) 6 leads to the new bipyridinophanes 7 8. The X‐ray structural analysis of 8 reveals a step‐type conformation, which according to 1H‐NMR results is also present in solution.
Metal complexes with tetrapyrrole ligands, LVII. Synthesis, spectra, and structure of nitridorhenium(V) porphyrins
Authors: Buchler Johann W. , Cian André De , Fischer Jean , Kruppa Steffen B. , Weiss Raymond 
Published: July 2007

AbstractOxorhenium(V) porphyrins ReO(P)X (X = Cl, Br) or [ReO(P)]2O, or trichlororhenium(V) porphyrins ReCl3(P) (P = OEP, TPP, TTP, TAP, TCIP, TMP)2,3, respectively, are transformed into nitridorhenium(V) porphyrins ReN(P) with hydrazine hydrate in the presence of ethanol, in good yields. The diamagnetic complexes are stable towards hydrolysis and contain pentacoordinate ReV in a square pyramid of nitrogen donor atoms. Their structure is deduced spectrometrically and is proven in the case of ReN(OEP) by X‐ray crystallography. The UV/Vis‐ and 1H‐NMR spectra of the new nitrido complexes are compared with those of the corresponding zinc(II) porphyrins.
Orotate complexes. Synthesis and crystal structure of lithium orotate(—I) monohydrate and magnesium bis[ orotate(—I)] octahydrate
Authors: Bach Ina , Kumberger Otto , Schmidbaur Hubert 
Published: July 2007

AbstractNeutralization of orotic acid (OrH2) by lithium or magnesium hydroxide in aqueous medium yields the crystalline metal orotate hydrates Li(OrH). H2O (1) and Mg(OrH)2. (H2O)6 (2). By single‐crystal X‐ray diffraction studies it has been shown that 1 (space group P1) forms a layer structure, with lithium in a tetrahedral environment of oxygen atoms from three different orotate( ‐ I) anions (one carboxylate and two uracil oxygen atoms) and the water molecule. 2 (space group P21/c) has been shown to feature a hexaquo complex of magnesium, the Mg(H2O)26 cations being associated with two hydrated OrH⊖ ions only through hydrogen bonds. The anions are also engaged in “base‐pairing” hydrogen bonds between the planar uracil ring systems of different units. The results are relevant for applications of magnesium orotates in magnesium therapy.
Reaktive EC(p‐p)π‐Systeme, XXVI. Einfache Synthese für Methylenphosphane (Phosphaalkene) des Typs HPC(F)NR2 und das Phosphaalkin PC‐N(iPr)2
Authors: Grobe Joseph , Van Duc Le , Lüth Bettina , Hegemann Marianne 
Published: July 2007

Reactive EC(p‐p)π‐Systems, XXVI. — Facile Synthesis of Phosphaalkenes of the Type HPC(F)NR2 and the Phosphaalkyne PC‐N(iPr)2The reaction of trifluoromethylphosphane CF3PH2 with secondary amines in a 1:3 molar ratio leads to the novel methylenephosphanes (phosphaalkenes) HP  C(F)NR2 [R  Me (1), Et (2), Pr (3), piperidine (4)] in yields between 40 and 60%. The analogous deuterium compound DP  C(F)NEt2 (5) is formed by the reaction of CF3PD2 with Et2ND. However, with di(isopropyl)amine the new phosphaalkyne P  CN(iPr)2 (6) is produced instead of the expected phosphaalkene.
Cyclization of a chiral α‐(δ′‐benzyloxyalkyl)acrylate to a novel tetrahydrofuran derivative
Authors: Drewes Siegfried E. , Njamela Owen L. , Roos Gregory H. P. 
Published: July 2007

AbstractMethyl 3‐hydroxy‐2‐(iodomethyl)‐5‐methyltetrahydrofuran‐2‐carboxylate (4) is synthesized from (3S)‐3‐(benzyloxy)butanal (2) via methyl 5‐(benzyloxy)‐3‐hydroxy‐2‐methylenehexanoate (3a) as intermediate.
Synthese und Struktur der Polycyclohexaphosphane P6(C5Me5)4 und P6(C5Me5)2
Authors: Jutzi Peter , Kroos Rainer , Müller Achim , Bögge Hartmut , Penk Michael 
Published: July 2007

Synthesis and Structure of the Polycyclohexaphosphines P6(C5Me5)4 and P6(C5Me5)2The cyclotriphosphine (PC5Me5)3 (1) decomposes in boiling benzene to give the bicyclo[3.1.0]hexaphosphine P6(C5Me5)4 (2) which yields the tricyclo[3.1.0.02.6] hexaphosphine P6(C5Me5)2 (3) in boiling xylene. The structures of 2 and 3 have been determined by 31P‐, 13C‐, and 1H‐NMR spectroscopy and by X‐ray crystallography. 3 represents the first member of a new class of polyphosphines. The specific thermolysis of 1 and 2 under comparatively mild conditions is based on the easy homolytic cleavage of P — C5Me5 bonds in these compounds.
Kurzmitteilung / Short Communication P  C Bond Activation and η4‐Coordination of Arene: X‐ray Crystal Structure of a Dinuclear μ‐Phosphido μ‐η2:η2‐Phenoxo Zwitterionic Complex of Palladium Trapping an Aggregate of Three Hydrogen‐Bonded Phenol Molecules
Authors: Sommovigo Milena , Pasquali Marco , Leoni Piero , Braga Dario , Sabatino Piera 
Published: July 2007

AbstractPd[P(tBu)3]2 reacts photochemically with an excess of phenol in n‐hexane to give the dinuclear complex [{P(tBu)2H}2Pd2{μ‐P(tBu)2}(μ‐η2:η2‐C6H5O)]  3 C6H5OH (1); X‐ray crystallography shows a linear chain of three phenol molecules hydrogenbonded to the phenoxide ligand which is η4‐coordinated to the Pd2 framework. The π coordination of the phenoxide ring is retained in solution, as evidenced by 1H‐NMR spectroscopy.
A New Route to Alkoxy Radicals — Photochemical Reactions with (Alkylperoxy)cobaloximes
Authors: Hartung Jens , Giese Bernd 
Published: July 2007

AbstractAlkoxy radicals have been generated by photochemical reactions of (alkylperoxy)cobaloximes 1. The occurrence of alkoxy radicals has been proved by characteristic cyclization and β‐scission reactions of the reactive intermediates.
Electrochemical Investigations on Methylenephosphines and Related Systems
Authors: Schoeller Wolfgang W. , Niemann Jürgen , Thiele Rüdiger , Haug Wilfried 
Published: July 2007

AbstractElectrochemical investigations on a selection of methylenephosphines 1 and related systems are reported. They are shown to possess an irreversible oxidation and reduction wave. An exception is diaminodiphosphene, which reversibly forms a radical anion. A relative ordering of frontier orbitals is possible, based on the redox properties of these systems.
Neue σ2λ3‐PC – O‐Systeme: Stabile nichtkonjugierte Phosphaalkenether – Synthese und Reaktionen
Authors: Heinicke Joachim , Kovacs Ilona , Nyulaszi Laszlo 
Published: July 2007

New σ2λ3‐PC – O Systems: Stable Non‐Conjugated Phosphaalkene Ethers – Synthesis and ReactivityNon‐conjugated cyclic phosphaalkene ethers (2, 4, 6) are obtained by cyclocondensation of (2‐ or 3‐hydroxyalkyl)phosphanes 1, 3 with N‐arylpivalimidoyl chlorides. Hydrolysis of 2, 4 with H2O (→7, 8), addition of hydrogen compounds (HCl, HSPh, MePhPH) (→ 9–12), and oxidation with air (→ 14) are studied. The reactivity of the title compounds and of benzoxaphospholes are compared.
Darstellung von [Dimethylamino(thiocarbonyl)thioamido]titan(IV)‐dihalogeniden – Verbindungen mit kurzen Ti – N‐Bindungen
Authors: Meller‐Rehbein Birgit , Roesky Herbert W. , Noltemeyer Mathias 
Published: July 2007

Preparation of [Dimethylamino(thiocarbonyl)thioamido]titanium(IV) Dihalides – Compounds with Short Ti – N BondsReaction of Me2NC(S)SN(SiMe3)2 (1) with TiCl4 and TiBr4 yields (2) and (3). Treatment of 2 and 3 with pyridine (py) leads to the solvates · 3 py [2a (XCl), 3a (XBr)]. These adducts have been characterized by X‐ray structure determination.
Synthese von nichtsymmetrisch substituierten Perylen‐Fluoreszenzfarbstoffen
Authors: Kaiser Harald , Lindner Jörg , Langhals Heinz 
Published: July 2007

Synthesis of Nonsymmetrically Substituted Perylene Fluorescent DyesA general method for the preparation of perylene‐3,4:9,10‐tetracarboxdiimides 1 with two different substituents at the nitrogen atoms is described: The easily prepared symmetrical tetracarboxdiimides 1 (R1=R2) are transformed into carboxdiimide anhydrides 2 and condensed with primary amines to the corresponding tetracarboxdiimides 1 (R1 ≢ R2). Applications as fluorescent tracers in biochemistry and polymer chemistry are discussed.
Geminale Vinyldiazide, X. 3,3‐Diazido‐2‐cyanacrylsäure‐methylester: Synthese von Vinylaziden, 4,5‐Dihydro‐1H‐tetrazol‐5‐ylidenen, Oxazolen und N‐Cyaniminen
Authors: Saalfrank Rolf W. , Lurz Claus‐Jürgen , Hassa Jürgen , Danion Daniel , Toupet Loic 
Published: July 2007

Geminal Vinyl Diazides, X. – Methyl 3,3‐Diazido‐2‐cyanoacrylate: Synthesis of Vinyl Azides, 4,5‐Dihydro‐1H‐tetrazol‐5‐ylidenes, Oxazoles, and N‐CyaniminesReaction of methyl 3,3‐diazido‐2‐cyanoacrylate (1) with amines 2 at –30°C yields aminovinyl azides 4. In the presence of equivalent amounts of triethylamine the vinyl azides 4 undergo 1,5′‐ring closure to afford the triethylammonium salts 5. Treatment of 5 with hydrochloric acid gives the corresponding 4,5‐dihydro‐1H‐tetrazol‐5‐ylidene derivatives 6. In contrast thermolysis of 4 leads via azirines 7 to oxazoles 8. Reaction of vinyl diazide 1 with lysine and cystine, respectively, yields bis(vinyl azides) 9. Triethylamine‐induced 1,5′‐ring closure of 9 produces the bis(triethylammonium) salts 10, which can be transformed under acidic conditions into the corresponding bis(4,5‐dihydro‐1H‐tetrazol‐5‐ylidene) derivatives 11. With methyl acrylate (17) oxazole 15 reacts via carbonyl ylide 16 in a 1,3‐dipolar cycloaddition to give pyrroline 18 (X‐ray structure analysis). Thermolysis of the geminal vinyl diazide 1 in the presence of alcohols 19 or primary amines 21 forms the cyanimines 20 and 22, respectively, via methyl 3‐aza‐2,3‐dicyanoacrylate 25. 25 exists as syn/anti isomers which fully agrees with AM1 calculations carried out on cyanimine model systems.
Regio‐ und Stereoselektivität bei anionischen Ringöffnungsreaktionen in 2‐Azabicyclo[3.2.0]heptan‐Derivaten
Authors: Franzisket Ludwig , Heesing Albert 
Published: July 2007

Regio‐ and Stereoselectivity in Anionic Ring Opening Reactions of 2‐Azabicyclo[3.2.0]heptane DerivativesIn the regioselective ring opening of 1 via the dianion 1c the intermediacy of 2a is proven by labeling experiments. The regioselective cleavage of the four‐membered ring in 3 by LiAlH4 proceeds stereoselectively both in the ring and the side chain positions of 4 as shown with deuterated compounds. The regioselectivity is kinetically controlled, the transition state 13 being stabilized by the tendency of lithium ions for complexation.
Pseudooxokohlenstoff‐Anionen der Semidreiecksäure
Authors: Landau Andreas , Seitz Gunther 
Published: July 2007

Pseudooxocarbon Anions of Semideltic AcidNovel pseudooxocarbon anions of semideltic acid (2) can easily be obtained by stepwise substitution of the dimethylamino groups of the cyclopropenium perchlorate 8. Treatment of 8 with cyanamide or malononitrile in the presence of triethylamine leads to the triafulvenes 9 and 13. Two cyanoimino groups are successfully introduced into the cyclopropenylium system by treating 9 with excess cyanamide/potassium ethoxide. Under the same conditions malononitrile reacts with 13 to yield the potassium salts 14 and 17. The thioamide 26 of semideltic acid is obtained by treating the triphenylphosphonium salt 24 with H2S/pyridine and subsequent hydrolysis of the intermediate 25. With the anions of cyanamide or malononitrile ring‐opening reaction of the cyclopropenylium system of 24 occurs to yield the push‐pull phosphonium salts 28 and 29.
Cyclische Metall(IV)‐amide
Authors: Herrmann Wolfgang A. , Denk Michael , Albach Rolf W. , Behm Joachim , Herdtweck Eberhardt 
Published: July 2007

Cyclic Metal(IV)AmidesSynthesis and structure of cyclic amide complexes of quadrivalent titanium, vanadium, and chromium are described, and their electrochemical behavior is investigated by cyclic voltammetry. The novel amides of formula ML2 {MTi, (3b); MV, (3c); MCr, (3d); L=[(CH3)3SiNCH2CH2NSi(CH3)3]} are formed by reaction of the halide adducts MCl3(THF)3 with the dilithium salt Li2L with concomitant disproportionation. Formation of 3d proceeds via the complex [3 d]⊖ and requires additional oxidation with oxygen or iodine. An X‐ray crystalstructure determination of 3b reveals the titanium atom in strongly distorted tetrahedral environment with approximate symmetry D2d. The amide complexes 3b –d are monomeric, thermally stable, and sublime readily without decomposition; they are very sensitive to water and soluble in all common organic solvents.
Metallkomplexe mit biologisch wichtigen Liganden, LVII. 1‐Selenoglucose als Ligand in Metallkomplexen
Authors: Pill Thomas , Beck Wolfgang , Breu Walter , Wagner Hildebert 
Published: July 2007

Metal Complexes of Biologically Important Ligands, LVII. – 1‐Selenoglucose as Ligand in Metal ComplexesReactions of the in situ‐prepared anion of acetylated 1‐selenoglucose with chloro complexes give the compounds R'3 PAuSeR (R'=Me, El, Ph), cis;‐(Ph3P)2Pt(SeR)2 and (η5C5H5)2Ti(SeR)2 (SeR=2,3,4,6‐tetra‐O‐acetyl‐1‐seleno‐β‐D‐glucopyranosato‐Se). The complexes (η5‐C5H5)(OC)2FeSeR and (OC)3M(μ‐SeR)2M(CO)3 (MFe, Ru) are prepared by the reaction of the diselenide RSeSeR with the dinuclear compound [η5‐C5H5Fe(CO)2]2 and M3(CO)12 (MFe, Ru), respectively.
Synthesis, Structure, and Reactivity of Chiral Rhenium Cycloalkene Complexes of the Formula ; Facile Vinylic Deprotonation of a Coordinated Alkene
Authors: Kowalczyk James J. , Arif Atta M. , Gladysz J. A. 
Published: July 2007

AbstractReactions of [(η5‐C5H5)Re(NO)(PPh3)(ClC6H5)]+BF−4 and (n = 5, a; 6, b; 7, c; 8, d) give cycloalkene complexes (6a – d, 94 to 79%). A crystal structure of the methylcyclopentadienyl analog of 6a shows the Re – plane and Re – PPh3 bond to be coplanar, with the vinyl protons syn to the cyclopentadienyl ligand. Reaction of 6a and tBuO−K+ leads to the vinyl complex (9a, 90%) instead of expected allyl complex (10a) Analogous reactions of 6b – d give varying mixtures of 9b – d/10b – d. HBF4 · OEt2 and 9a react to form the cyclopentylidene complex (10+ BF−4, 96%), the stability of which precludes any intermediacy in the deprotonation of 6a. A crystal structure of 11+ PF−6 shows the ReCC planes to be perpendicular to the Re – P bond. Spectroscopic features of compounds 6 are analyzed in detail, and NMR data show a high barrier to cyclopentylidene ligand rotation in 11+ BF−4 (ΔG≢ (110°C) ≥ 19 kcal/mol).
Azaphosphaboriridine und Azadiphosphiridine durch Phosphandiyl‐Transfer
Authors: Streubel Rainer , Niecke Edgar , Paetzold Peter 
Published: July 2007

Azaphosphaboriridines and Azadiphosphiridines by Phosphinediyl Transfer ReactionsThe azaphosphaboriridines (4a – d) are obtained by the reaction of the corresponding chloro(trimethyl‐silyl)posphines RP(Cl)SiMe3 (1a – d) with the iminoborane 2. Equally, reaction of 1a – c with the iminophosphine 5 leads to the azadiphosphiridines (8a – c) via an imino‐λ3,λ5‐diphosphene intermediate tBuNP(CEt3)=PCH‐(SiMe3)2 (7a).
Undecacarbonyl(μ2‐trifluoromethyl isocyanide)triruthenium, a Derivative of [Ru3(CO)12] with [Fe3(CO)12] Structure
Authors: Lentz Dieter , Marschall Robert , Hahn Ekkehardt 
Published: July 2007

Abstract[Ru3(CO)10(μ2‐CO)(μ2‐CNCF3)] (1), [Ru3(CO)10(CNCF3)2] (2), and [Ru2(CO)6(μ2‐CNCF3)3] (3) are obtained by the reaction of [Ru3(CO)11(CH3CN)] with CNCF3. An X‐ray crystal structure determination revealed, that 1 has an unusual [Fe3(CO)12] structure, different from most other derivatives of [Ru3(CO)12].
Zur Struktur von 1‐Azapentadienyllithium‐Verbindungen
Authors: Wolf Gerhard , Würthwein Ernst‐Ulrich 
Published: July 2007

On the Structures of 1‐Azapentadienyllithium Compounds1‐Azapentadienyllithium compounds 2–6 have been prepared by deprotonation of the α,β‐unsaturated imines 1 with lithium diisopropylamide. Their structures in THF solution at various temperatures have been studied by 1H‐ and 13C‐NMR spectroscopy. All N‐alkyl‐substituted derivatives 2 – 5 adopt W conformations of the 1‐azapentadienyl unit. The N‐tert‐butylsubstituted compound 2 shows an (E)‐configurated NC‐ bond, whereas compounds 3 –5 prefer (Z)‐NC configurations. According to NOE experiments, the triphenyl system 6 has a U‐shape structure, probably because of steric interactions of the phenyl substituents. 13C‐shifts of the 1‐azapentadienyl carbon atoms are discussed in terms of HOMO coefficients. The experimental structural results are compared with theoretical data obtained by MNDO and ab initio calculations for the corresponding anions. MNDO results are also given for monomeric 1‐azapentadienyllithium conformers 11.
Ozonolysen von α‐Oxo‐alkenen: Zur Existenz von α‐Oxo‐ozoniden
Authors: Griesbaum Karl , Greunig Hans‐Joachim , Volpp Willi , Jung In‐Chan 
Published: July 2007

Ozonolyses of α‐Oxo‐alkenes: On the Existence of α‐Oxo‐ozonidesOzonolyses of nine acyclic (1a–i) and of two cyclic (14, 29) α‐Oxo‐alkenes on polyethylene or in pentane afforded in eight cases (1d–i, 14, 29) isolable α‐Oxo‐ozonides. α‐Diozonides (9) are obtained from five of the acyclic α‐Oxo‐alkenes (1a, b, d, g, h). All isolated ozonides are labile; the 2,4‐dinitrophenylhydrazones of the α‐Oxo‐ozonides, however, are very stable. Decomposition of the α‐Oxo‐ozonides affords not only the hitherto known fragments, but non‐peroxidic isomers (8) of the ozonides, too.
Zur Bildung von Vinylcyclopropan‐ und Cyclopentenderivaten aus alkenylsubstituierten Chromcarben‐Komplexen: Konkurrenz von formalen [2 + 1]‐ und [3 + 2]‐Cycloadditionen
Authors: Wienand Anette , Rei ßig Hans‐Ulrich 
Published: July 2007

Formation of Vinylcyclopropane and Cyclopentene Derivatives from Alkenyl‐Substituted Chromium Carbene Complexes: Competition between Formal [2 + 1] and [3 + 2] Cycloadditions.The alkenyl‐substituted chromium carbene complexes 1 – 4 were synthesized following the method of Aumann which starts from the corresponding aldehydes. At 80°C the styryl‐substituted complex 1 and electron‐deficient olefins smoothly provide vinylcyclopropane derivatives 6,8, 10, and 12 in good yields. On the other hand, methyl acrylate and the anisyl‐ and furyl‐substituted vinylcarbene complexes 2 and 3 give mixtures of the expected vinylcyclopropanes and of cyclopentene derivatives. The pyrrolyl‐substituted complex 4 and methyl acrylate exclusively afford the cyclopentenes 24a/b which are the result of a hitherto unprecedented formal [3 + 2] cycloaddition of the vinylcarbene complex to the olefin. However, there are strong arguments suggesting the corresponding vinylcyclopropanes as intermediates. The very smooth vinylcyclopropane→cyclopentene rearrangement probably occurs via zwitterionic intermediates that are wellstabilized by donor and acceptor substituents. Hydrolysis of 24a/b to the cyclopentanone derivatives 25a/b demonstrates that this new route to five‐membered carbocycles should have synthetic potential.
Redoxreaktivität Phosphido‐verbrückter Heterodimetallkomplexe
Authors: Lindner Ekkehard , Funk Torsten 
Published: July 2007

Redox Reactivity of Phosphido‐Bridged Heterodimetallic ComplexesThe metal‐metal bond in (3a,b,e) [LCO: RPh (a), Cy (e); LPMe3: RPh (b)] is cleaved reductively, oxidatively, and by nucleophiles by using Na[HBEt3], bromine or iodine, and PMe3, respectively. The action of PMe3 on 3a affords Me3P(OC)4Mn – PPh2 – Fe(CO)4 (5), which is photolyzed to give 3b. While the reduction of 3a can be regarded as a nucleophilic bond opening functionalizing only manganese, oxidation of 3a,b with halides results in the formation of the complexes XMn(CO)4 – PPh2 – Fe(X)(CO)3L (4a – d) [LCO: XI (a), Br (c); LPMe3: XI (b), XBr (d)], which provide two functionalized metals. To elucidate the redox behavior of 3a cyclovoltammetric investigations were carried out. They indicate a complex reaction scheme including reactions of higher order.
Arsen(III)‐, Antimon(III)‐ und Bismuth(III)‐halogenid‐Komplexe des [2.2.2]Paracyclophans: Vom lockeren van‐der‐Waals‐Addukt zu stark gerichteten π‐Komplexen mit zwei‐ und dreifacher externer η6‐Koordination
Authors: Probst Thomas , Steigelmann Oliver , Riede Jürgen , Schmidbaur Hubert 
Published: July 2007

Arsenic(III), Antimony(III), and Bismuth(III) Trihalide Complexes of [2.2.2]Paracyclophane: From Weak van der Waals Coordination to Strongly Directional π Complexation with Single or Double External η6 Coordination[2.2.2]Paracyclophane forms the adducts C24H24·AsCl3 (1), C24H24·(SbCl3)2·1/2 C6H6 (2), and C24H24·(BiCl3)3·C6H6 (3). For solutions in polar solvents NMR spectra indicate extensive dissociation and/or fluxionality. In the crystals adduct 1 features a weak addition of the AsCl3 molecule to one open side of a paracyclophane molecule with long intermolecular contacts approaching C3v symmetry. – Crystalline 2 shows SbCl3 coordination to two of the benzene rings of the hydrocarbon in a quasi‐centered η6 mode, while one of the benzene rings remains uncoordinated. Chlorine‐bridging between antimony atoms leads to tetrameric units (SbCI3)4 in the lattice. – In the bismuth compound 3 each benzene ring of the hydrocarbon is engaged in centroid (η6)π complexation, with the BiCl3 units crosslinked by chlorine bridges. The average of the Bi–ring distances (3.08,2.98, and 2.99 Å) is shorter than for the Sb–ring distances in 2 (3.047 and 3.050 Å), indicating stronger bonding. The crystal benzene is not coordinating.
Metallcarbonyl‐Synthesen, XX. Einfache Methode zur Darstellung von Tc(CO)3‐Komplexen: Synthese und Struktur der neuartigen Technetium(I)‐Clusterverbindung Na[Tc3(CO)9(OCH3)4] mit Cuban‐Struktur
Authors: Herrman Wolfgang A. , Alberto Roger , Bryan Jeff C. , Sattelberger Alfred P. 
Published: July 2007

Metal Carbonyl Syntheses, XX. – Simple Method for the Preparation of Tc(CO)3Complexes: Synthesis, Structures, and Reactivity of the Novel Cubane‐Type Cluster Na[Tc3(CO)9(OCH3)4]Carbonyltechnetium complexes of type LTc(CO)3are accessible along a simple route from Na[Tc3(CO)9(OCH3)4] (2) which represents a novel alkoxy complex of cubane‐type geometry (single‐crystal X‐ray diffraction study).2is an isolable product of the incomplete carbonylation of sodium pertechnetate (1) conducted in methanol. Under carbon monoxide pressure,2yields the binary metal carbonyl Tc2(CO)10(3), pentamethyl‐cyclopentadiene gives the halfsandwich complex (η5‐C5Me5)Tc(CO)3(4), and with benzene/hydrochloric acid the ionic complex [(η6‐C6H6)Tc(CO)3]Cl (5) is formed.
Anticancer Agents, 15. Squaric Acid Diethyl Ester: A New Coupling Reagent for the Formation of Drug Biopolymer Conjugates. Synthesis of Squaric Acid Ester Amides and Diamides
Authors: Tietze Lutz F. , Arlt Michael , Beller Matthias , Gl üsenkamp Karl‐Heinz , Jähde Eckhard , Rajewsky Manfred F. 
Published: July 2007

AbstractReaction of squaric acid diethyl ester (1) with a slight excess of a primary or secondary amine 2 in ethanol, dichloromethane or aqueous buffer (pH 7) at 20°C for 0.3–12 h gives the squaric acid amide esters 3 in mostly excellent yields. Treatment of 3 with amines 2 or 4 in organic solvents in the presence of triethylamine or in aqueous buffer (pH 9) leads to the corresponding symmetrical and unsymmetrical squaric acid diamides 5, respectively. The reaction can be followed by UV spectroscopy.