bluuebunny/crossref_metadata_2025 huggingface dataset:
Verschiedenartige Koordinationen bei η2‐Alken)‐(η5‐cyclopentadienyl)organylnickel(II)‐Komplexen
Authors: Lehmkuhl Herbert , Näser Jürgen , Mehler Gerlinde , Keil Thomas , Danowski Friedhelm , Benn Reinhard , Mynott Richard , Schroth Gerhard , Gabor Barbara , Krüger Carl , Betz Peter
Published: July 2007

Various Coordinations in (η2‐Alkene)(η5‐cyclopentadienyl)organylnickel(II) Complexes

A series of (η2‐alkene)(η5‐cyclopentadienyl)organylnickel(II) complexes with substituted cyclopentadienyl ligands is synthesized in order to compare the structures, the thermal stabilities, and chemical reactivities. In (allyl)(η5‐Cp')Ni compounds the allyl moiety is η3‐coordinated when Cp'=C5H5, C5Me5 (1), C5Ph5 (2), indenyl (3), [Hydridotri(pyrazolyl)borato] (4) (as an equivalent of the cyclopentadienyl ligand), and [C5H4((CH2)3CHCH2)] (22). It is found that the [(η2‐alkene)alkyl(η5‐Cp')nickel] compounds [Cp'=C5Me5; alkeneC2H4, alkyl=Me (10), Et (9) or alkene=(1 – 2‐η2)‐1,3‐butadiene, alkyl=Me (11); Cp'=C5Ph5; alkene=C2H4, alkyl=Me (12)] are thermally more stable and less reactive than their η5;‐ C5H5 analogues; the largest increase in thermal stability is observed when the η5‐Cp' and the η2‐alkene functions are connected by substitution of the cyclopentadienyl ligand with an alkenyl group of suitable chain length. In the case of compounds of the general type [(η5‐C5R4((CH2)nCHCH2))‐(ligand)Ni(II)] with Ph3P as the ligand these complexes are cationic [RH, n=3 (14+) or RMe, n=2 (17+)]. On the other hand, the compounds with anionic ligands are neutral complexes (RH, n=3, ligand=methyl (19), ethyl (20), isopropyl (21) or RMe, n=3 and ligand=iodide (24), bromide (25), methyl (26), ethyl (27)]. In 14+, 17+, 19 – 21 and 24 – 27 the CC bond of the alkenyl group is η2‐coordinated to the nickel atom. X‐ray structures have been determined for 4 and 25.
Synthesis, Characterization, and Some Reactions of Tricarbonyl(cyclobutabenzene)chromium(O) Derivatives
Authors: Wey Hans G. , Betz Peter , Butensch ön Holger
Published: July 2007

The tricarbonyl(cyclobutabenzene)chromium(O) complexes 12 – 20, have been prepared from the free ligand and triammintricarbonylchromium(O) or hexacarbonylchromium(O). The complexes have been characterized by spectroscopic methods (IR, 1H NMR, 13C NMR) and mass spectrometry, and 1H‐NMR signal assignments have been verified by an NOE experiment. Diastereomeric ratios have been determined by 1H NMR and the diastereomers of the 1‐methyl derivative 16 separated by HPLC. A crystal‐structure analysis is presented for exo;‐16. A photochemical ligand exchange takes place in 70% yield for the 1‐trimethylsilyl derivative 19. Metalation with n‐butyl‐lithium/tmeda at –78°C has been observed only for the aromatic and not for the benzylic protons.
Medizinisch interessante Metallchelate, I. 99mTc‐Komplexe mit sechszähnigen Tribrenzkatechin‐Liganden
Authors: Ekkehardt Hahn F. , Rupprecht Stefan
Published: July 2007

Metal Chelates of Medical Interest, I. – 99mTc Complexes with Hexadentate Tricatechol Ligands

The tricatechol ligand tris[3‐(2,3‐dihydroxyphenoxy)propyl]‐amine hydrochloride, TRIPACE (9), is prepared from tris(3‐chlorpropyl)amine (5) and the potassium salt of 2,2‐dimethyl‐1,3‐benzodioxol‐4‐ol (7). This ligand is capable of reducing the 99m[TcO4]− ion to lower valent 99mTc and subsequent complexation of the reduced 99mTc ion. The structures of 5 and of tris[3‐(2,2‐dimethyl‐1,3‐benzodioxol‐4‐yloxy)propyl]amine (8) are determined by X‐ray diffraction.
Verhalten von cis;‐2‐Boryl‐1‐stannylalkenen gegenüber (Dimethylamino)trimethylstannan, Methoxytrimethylstannan und Methanol – Aufbau neuer Zinn – Element‐Bindungen, Beispiele für Lösungsmittel‐gesteuerte Reaktionen
Authors: Wrackmeyer Bernd , Wagner Klaus
Published: July 2007

Behaviour of cis;‐2‐Boryl‐1‐stannylalkenes Against (Dimethylamino)trimethylstannane, Methoxytrimethylstannane, and Methanol – Formation of New Tin – Element Bonds, Examples of Solvent‐Controlled Reactions

When alkene derivatives1 [Me3Sn(R1)CC(R)BR2], with the trimethylstannyl‐ and the dialkylboryl group in cis position at the CC double bond, are treated with (dimethylamino)‐trimethylstannane (4), methoxytrimethylstannane (5), or methanol, the product distribution depends remarkably on the solvent [hexane or tetrahydrofuran (THF)]. In hexane, 1a, b (R1=H, REt, Pr) react with 4 to give the B‐dimethylamino compounds 6a, b in high yields as a result of addition and rearrangement. Other derivatives 1 do not react with 4 in hexane. Under the same conditions in hexane some alkenes 1 react with 5 to yield the B‐methoxy derivatives 8, which are analogous to 6. A complex mixture of various products is obtained from the reaction of 1 with methanol in hexane. If the same reactions are carried out in THF, many compounds 1 react with 4 and 5 to eliminate tetramethyltin and give dihydro‐ 1,2,5‐azonia‐ (7) or dihydro‐1,2,5‐oxoniastannaboratoles (9), respectively. The reaction with methanol in THF also leads to the oxonia‐stannaboratoles 9, this time by elimination of methane. Pure samples of compound 9g are obtained as the crystalline THF adduct 9g‐THF. A mechanism is proposed involving adduct formation at the boryl group, followed by intramolecular reactions depending on the donor quality of the respective solvent.
Preparation and Crystal Structures of 2‐Aminoethyl Phosphate Complexes of Magnesium, Calcium, and Zinc
Authors: Bissinger Peter , Kumberger Otto , Schier Annette
Published: July 2007

Crystalline magnesium, calcium, and zinc 2‐aminoethyl phosphate complexes containing the monoanions PEAH⊖ have been prepared as the tetrahydrates (Ca, Zn) and the hexahydrate (Mg), and their structures determined by single‐crystal X‐ray methods. The structures of monoclinic Ca(PEAH)2·4 H2O and Zn(PEAH)2·4 H2O (space group C2/c) both contain polymeric chains with metal ions connected by bridging phosphate groups. The zinc atoms are in a tetrahedral environment of four oxygen atoms, while the calcium atoms are found to be hexacoordinated with two additional oxygen atoms from water molecules in axial positions. The triclinic Mg(PEAH)2·6 H2O (space group \documentclass{article}\pagestyle{empty}\begin{document}$ P\bar 1 $\end{document}) contains discrete complex units with hexacoordinate magnesium atoms octahedrally surrounded by six oxygen atoms, four of which from water molecules in the equatorial plane and two from phosphate groups in axial positions.
Über die Funktion von Di(tert‐butyl)silandiolat als Anker für Metallfragmente in hohen und mittleren Oxidationsstufen. Synthese und Strukturen von (tBu2SiO2(TeCl2–μ‐Cl2 – TeCl2) und (tBu)2Si(OReO3)2
Authors: Roesky Herbert W. , Mazzah Ahmed , Hesse Detlev , Noltemeyer Mathias
Published: July 2007

Function of Di(tert‐butyl)silanediolate as an Anchor for Metal Fragments in High and Medium Oxidation States. Synthesis and Structures of (tBu)2SiO2(TeCl2 – μ‐Cl2 – TeCl2) and (tBu)2Si(OReO3))2

The compounds (tBu)2SiO2(TeCl2 – μ‐Cl2 – TeCl2) (2) and (tBu)2Si(OReO3)2 (3) have been prepared by the reactions of (tBu)2Si(OH)2 (1) with TeCl4 and Re2O7. The single‐crystal X‐ray structures of 2 and 3 are reported. The (tBu)2SiO2 group functions as an anchor for the metal fragments TeCl3 and ReO3.
Zur Struktur von 2‐Azapentadienyllithium‐Verbindungen
Authors: Wolf Gerhard , Würthwein Ernst‐Ulrich
Published: July 2007

On the Structures of 2‐Azapentadienyllithium Compounds

2‐Azapentadienyllithium compounds 3 – 10 are easily accessible by deprotonation of N‐allylimines 1,2 with lithium diisopropylamide. Their structures in THF solution at various temperatures are studied by means of 1H‐ and 13C‐NMR spectroscopy. 1‐Phenyl‐substituted 2‐aza‐pentadienyllithium derivatives adopt all‐trans W conformations, whereas 1‐alkylsubstituted 2‐azapentadienyllithium compounds show s‐cis conformations (sickle shapes). 13C shifts of the 2‐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 2‐azapentadienyllithium conformers 13,14.
Stabile Tellur‐Ylide: Darstellung und Reaktivität von Diorganyltelluronium‐4,5‐dicyanimidazol‐2‐yliden
Authors: Tappeiner Günther , Bildstein Benno , Sladky Fritz
Published: July 2007

Stable Tellurium Ylides: Synthesis and Reactivity of Diorganyltelluronium 4,5‐Dicyanoimidazol‐2‐ylides

Diorganyl tellurides R2Te (RMe, Me3SiCH2, Ph) react with 2‐diazo‐4,5‐dicyano‐2H‐imidazole (1) at – 30°C to form the title compounds 2 – 4. The ylides 3 and 4 are thermally stable up to their melting points of 159 and 243°C, resp., whereas 2 undergoes a modified Stevens rearrangement at 190°C with formation of a 2‐(methyltelluro)imidazole (10). The reactivity of 2 – 4 is determined by an extreme charge separation between the onium centre and the ylide entity. No Wittig reactivity is observed, alkylation occurs at the imidazole nitrogen and carbanions lead to tetraorganyl tellurium compounds with limited stability.
d8‐Eisennitrosylhydride
Authors: Jänicke Monika , Hund Hans‐Ulrich , Berke Heinz
Published: July 2007

d8 Iron Nitrosylhydride Complexes

The nitrogen complex [(OC)2(Et3P)2Fe]2N2 (1) reacts with carboxylic acids to form the complexes (OC)2(Et3P)2Fe(H)OC(O)R [R=4‐methoxyphenyl, 2a; R=2,4‐dimethoxyphenyl, 2b; R=2,4,6‐trimethoxyphenyl, 2c; R – Ph, 2d; R – CF3, 2e]. Treatment of 2 with N‐methyl‐N‐nitroso‐p‐tolylsulfonamide produces the nitrosylcarboxylato complexes (OC)(ON)‐(Et3P)2FeOC(O)R (3a – d) in addition to the side product Fe(NO)2(PEt3)2 (4) except for 2e which forms 4 exclusively. Reaction of 3 with LiAlH4 yields the hydridonitrosyliron complex (OC)(ON)(Et3P)2FeH (5a). A different synthetic route to the phosphorus donor‐substituted iron hydride complexes involves starting material (OC)2(L)2FeCl2 [LPEt3, 6a; L – PMe3, 6b; LP(OiPr)3, 6c]. Compounds 6 react with tBuLi and NOBF4 to form (OC)(ON)L2FeCl (7). Subsequent treatment with NaBH4 gives (OC)(ON)(L)2FeH [LPEt3, 5a; LPMe3, 5b; LP(OiPr)3, 5c]. The structures of 5b and 7a are determined by X‐ray crystallography.
Übergangsmetall‐substituierte Diphosphene, XXIII. Studien zur Synthese und Reaktivität von Dihalogenphosphido‐Komplexen des Eisens und Rutheniums
Authors: Weber Lothar , Sonnenberg Uwe
Published: July 2007

Transition‐Metal‐Substituted Diphosphenes, XXIII. ‐Studies on the Synthesis and Reactivity of Dihalophosphido Complexes of Iron and Ruthenium

(η5‐C5Me5)(CO)2FeP(SiMe3)2 (1a) reacts with two equivalents of C2Cl6 to give the dichlorophosphido complex (η5‐C5Me5)‐(CO)2FePCl2 (2a). The latter is easily converted into (η5‐C5Me5)(CO)2FeP(E)Cl2 (3; ES; 4: ESe) by treatment with the respective chalcogen. The reaction of 1a with 2a leads to a mixture of the cyclotriphosphane [(η5‐C5Me5)‐(CO)2FeP]3 (8a) and the bicyclo[1.1.0]tetraphosphane [(η5‐C5Me5)(CO)2FeP)2P2(10). The same result is obtained when 1a is treated with only one equivalent of C2Cl6. In addition the dihalophosphido complexes (η5‐C5Me5)(CO)2RuPCl2 (2c), (η5‐C5H5)(CO)(PPh3)FePCl2 (2b), (η5‐C5Me5)(CO)2FePBr2 (2d), and (η5‐C5Me5)(CO)2FePI2 (2e), and the cyclotriphosphane [(η5‐C5Me5)(CO)2RuP]3 are synthesized.
Synthese und Struktur von Ph3PNRe(NC6H3iPr2;‐2,6)3 ‐eine Aza‐Rhenium(VII)‐Verbindung
Authors: Roesky Herbert W. , Hesse Detlev , Noltemeyer Mathias , Sheldrick George M.
Published: July 2007

Synthesis and Structure of Ph3PNRe(NC6H3iPr2;‐2,6)3 ‐ An Aza‐Rhenium (VII) Compound.

Ph3PNReO3 (1) reacts with three equivalents of 2,6‐diisopropylphenyl isocyanate with evolution of CO2 to give the title compound 2. The X‐ray single crystal structure of 2 exhibits a rhenium atom tetrahedrally coordinated to four nitrogen atoms (space group P 3).
Decacarbonyl(μ3;‐η2‐‖‐1,4‐dimethoxy‐2‐butyne)triiron, an Iron Cluster with Unusual Structure
Authors: Lentz Dieter , Reuter Marion
Published: July 2007

Reaction of undecacarbonyl(acetonitrile)triiron (1) with 1,4‐dimethoxy‐2‐butyne (2) yields the alkyne complexes decacarbonyl(μ3;‐η2‐Verbar‐1,4‐dimethoxy‐2‐butyne)triiron (3) and nonacarbonyl(μ3;‐η2;‐⊥‐1,4‐dimethoxy‐3‐butyne)triiron (4). The crystal structure determination of 2 shows that the alkyne ligand is coordinated strictly parallel to one iron‐iron edge.
Über die optische Drehung von Quaterphenyl‐Derivaten
Authors: Fischer Erika , Hess Heinrich , Lorenz Thomas , Musso Hans , Ro ßnagel Ingrid
Published: July 2007

Optical Rotation of Quaterphenyl Derivatives

Quatermesityl (2) has been resolved by chromatography into pure enantiomers; (S)‐(+)‐2 shows [α]D=+ 108 as expected. (S)‐(+)‐3,3′‐Diphenylbimesityl (9) has been prepared enantiospecifically and shows [α]D=+ 106. Chromatographic resolution of 9 as well as of quinquemesityl (15) succeeded, too. The optical activity of chiral polyphenyl derivatives is discussed. The interplanar angles of the quaterphenyl derivatives 2, 9, and 14 are presented.
Small and Medium Rings, 75. Syntheses, Photoelectron Spectra, and Photoreactivity of Polycyclic 1,5‐Diketones: Transannular Interaction in the Cyclooctane‐1,5‐dione Fragment
Authors: Albert Bernhard , Els ässer Dominik , Heckel Dieter , Kopmeier Siglinde , Mayer Bernhard , Martin Hans‐Dieter , Yeh Show‐Kei , Chow Tahsin J. , Wu Tung‐Kung
Published: July 2007

Five polycyclic 1,5‐diketones 1 – 4 and 6 are synthesized and studied by means of He(Iα) PE spectroscopy. Comparison of the spectra indicates significant differences in Orbital Interaction Through Bond, which is explained by computational methods, especially by analyses of the precanonical MOs. The lone pair splitting observed in diketone 1, ΔI(n)=0.75 eV, seems to be the largest one ever found in a 1,5‐diketone, obviously due to a favourable zigzag topology of the σ frame. In addition, coupling reactions and photoreactivity are studied in compound 6, which seemed to be well suited for Orbital Interaction Through Space. The crystal structure of 6 and its photoproduct 21 is solved by X‐ray crystallography.
Chromophore Systeme, 1. Konformation und Lichtabsorption von Hexa‐1,5‐dien‐3,4‐dion (Divinylglyoxal)
Authors: Bühl Michael , Kramme Roland , Martin Hans‐Dieter , Mayer Bernhard , Nowack Gerhard
Published: July 2007

Chromophoric Systems, 1. — Conformation and Absorption of Light in Hexa‐1,5‐diene‐3,4‐dione (Divinylglyoxal)

Divinylglyoxal (1) is investigated by several spectroscopic and theoretical methods in order to set up a correlation between the CO/CO dihedral angle and the transition energies in unsaturated α‐diketones. According to the experimental (UV, IR, 13C‐NMR, PE spectroscopy and dipole moment) and theoretical (ab initio and molecular mechanics) results, 1 exists predominantly as a C2h conformer (Θco/co=180°, ΘVinyl/co=0°). The dependence of transition energies on CO/CO dihedral angles is similar in shape to that for saturated α‐diketones, but is significantly shifted to lower transition energies. 13C chemical shifts respond sensitively to CO/CO dihedral angles, and the ab initio calculated curve is supported by a few experimental results.
Monomere und überbrückte oligomere (Tetrasulfophthalocyaninato)eisen(II)‐Komplexe mit Isocyaniden und N‐Donoren als axialen Liganden
Authors: Hirsch Andreas , Hanack Michael
Published: July 2007

Monomeric and Bridged Oligomeric (Tetrasulfophthalocyaninato)iron(II) Complexes with Isocyanides and N‐Donors as Axial Ligands

(Tetrasulfophthalocyaninato)iron(II) (TsPcFe) (1) is treated with the isocyanides tert‐butyl isocyanide (tBuNC), 1,4‐diisocyanobenzene (dib), 2,3,5,6‐tetramethyl‐1,4‐diisocyanobenzene (me4dib), and 4‐isocyano‐3,5‐dimethylpyridine (me2pyNC), and also with pyrazine (pyz) leading to bisaxially coordinated monomers TsPcFe(L)2 (L=tBuNC, dib, me4dib) and the bridged oligomers [TsPcFe(L)]n (Ldib, me4dib, me2pyNC, and pyz). All these complexes are soluble in methanol or water. The spectroscopic properties of the complexes are described, and the average chain lengths of the bridged oligomers are determined by 1H‐NMR spectroscopy. The bridged stacked systems exhibit semiconducting properties with and without iodine doping.
Großflächige Makrocyclen aus p‐Quaterphenyl‐Bauteilen
Authors: Vögtle Fritz , Kadei Klaus
Published: July 2007

Flat Macrocycles Based on p‐Quaterphenyl Units

[1.1](3,3′″)‐p‐Quaterphenylophanes 1 – 3 are synthesized via 6 – 12 starting with biphenyl derivative 5. The properties of 1 – 3 (UV, NMR) and their charge‐transfer complexation are compared to p‐quaterphenyl. 1 – 3 are high‐melting, colorless solids, which are sparingly soluble in common organic solvents. They contain two “isolated” p‐quaterphenyl units. Similar to p‐quaterphenyl, 2, 2a and 3 form greenish‐blue chargetransfer complexes with tetracyanoethene (TCNE) in CH2Cl2.
Chiral Induction in Photochemical Reactions, XIII. The Paternó‐Büchi Reaction of Achiral and Chiral Acyl Cyanides with Furan
Authors: Žagar Cyrill , Scharf Hans‐Dieter
Published: July 2007

The acyl cyanides 1a—d are prepared from the corresponding acyl chlorides. The Paternó‐Büchi reaction of 1a — f with furan (2) yields the bicyclic oxetanes 3a—f with an endo/exo ratio varying from 3.5: 1 (1a) to 16: 1 (1d). However, in the reaction of the chiral acyl cyanides 1b and 1c, a low chiral induction is observed (maximum de: 13%).
übergangsmetall‐substituierte Acylphosphane und Phosphaalkene, XV. Zur Umsetzung des Phosphaallylkomplexes (η5‐C5Me5)(CO)Fe‐{η3‐P[CH(SiMe3)2](CHCO)} mit Chalcogenen und Fe2(CO)9
Authors: Weber Lothar , Nolte Uwe , Stammler Hans‐Georg , Neumann Beate
Published: July 2007

Transition‐Metal‐Substituted Acylphosphanes and Phosphaalkenes, XV. – Reaction of the Phosphaallyl Complex (η5‐C5Me5)(CO)Fe{η3‐P[CH(SiMe33)2](CHCO}} with Chalcogenes as well as with Fe2(CO)9

The (η3‐phoshaalyl)iron complex (η5‐C5Me5)(CO)Fe{η3‐P(CH(SiMe3)2](CHCO)} (1) is oxidized by sulfur and selenium to afford the methylenethioxo‐ and methyleneselenoxophosphorane complexes 4 and 5 with an anti‐configuration of the CH(SiMe3)2 substituent relative to iron. The chalcogene atoms are attached to the phosphorus atom of the ligand and do not participate in the bonding to the metal Equivalent amounts of 1 and Fe2(CO)9 lead to the phosphaalkenyl complex 6 with an Fe – C σ bond. On the other hand, a large excess of Fe2(CO)9 converts 1 as well as 6 into the cluster compound 7 featuring the bridging 1‐oxa‐4‐phosphabutadiene ligand (η5‐C2Me5)(CO)2Fe—C(O)—CHP—CH(SiMe3)2. Constitution and configuration of all compounds have been elucidated by spectroscopic methods (IR, 1H, 13C, 31P NMR, and MS). In addition complexes 5 and 7 have been characterized by single crystal X‐ray diffraction analyses.
Heterocyclen als Liganden, XI. Octamethyl‐1,1′‐diazaferrocen als bifunktionelle Stickstoff‐Base
Authors: Kuhn Norbert , Kuhn Annette , Lampe Eva‐Maria
Published: July 2007

Heterocycles as Ligands, XI. – Octamethyl‐1,1′‐diazaferrocene as a Bifunctional Nitrogen Base

(C4Me4N)2 Fe·2 HNC4Me4 (3) reacts with Brønstedt and Lewis acids to give the adducts [(C4Me4N·E)2Fe]n+ [4 – 6, 11 – 13; n=2, EH, CH3, CH3C(O); n=O, EBH3, BF3, Fe(CO)4]. The stepwise substitution of the tetramethylpyrrole molecules in 3 leads to the complexes [(C4Me4N·E)(C4Me4N·E')Fe]n+ [16, 17, 19; n – O, EC4Me4NH, E'=Fe(CO)4; n=1, EBH3, E'=H; n=2, EH, E'=CH3]. Similarly, the complexes [{(C4Me4N)C(O)CH2CH2C(O)(NC4me4}Fe]Cl2 (9) and [Ag2{μMe4N)2Fe}2Fe}2](BF4)2·2 MeOH (15) are obtained. Reaction of [(C4Me4NH)2Fe](BF4)2 (4) with nBuLi gives the protonated diazaferrocene [(C4Me4NH)(C4Me4N)Fe]BF4 (18) from which the dimeric iron diamide {(C4Me4N)2Fe}2 (20) is obtained on further deprotonation.
Metallkomplexe mit biologisch wichtigen Liganden, LVIII. C‐Allylglycin‐ und C‐Vinylglycin‐Komplexe von Palladium(II), Platin(II), Rhodium(III), Iridium(III) und deren Reaktionen mit Nucleophilen
Authors: Zahn Ingo , Polborn Kurt , Wagner Barbara , Beck Wolfgang
Published: July 2007

Metal Complexes of Biologically Important Ligands, LVIII. – C‐Allylglycine and C‐Vinylglycine Complexes of Palladium(II), Platinum(II), Rhodium(III), Iridium(III) and Reactions with Nucleophiles

The synthesis of the complexes (R13P)(Cl2Pt(C‐allylglycine ester) (1), (2) and of (η5‐C5Me5)Ir(C‐allylglycinate) (6) with tridentate O,N,η2;‐CC allylglycinate as ligand is described. Addition of enolates (Nu−) to the coordinated CC bond of 2 gives the γ‐C‐metallated α‐amino acid ester complexes (3). In most cases the platination occurs stereoselectively to yield the five‐membered metallacycle with the substitutents CH2Nu and CO2R2 in trans position. From 3d the new α‐amino acid H2NCH(CO2Me)‐(CH2)3C(Ph)(CO2Et)21 (4) is cleaved. The structures of 3c and 6 have been determined by X‐ray diffraction. C‐Vinylglycinate can be stabilized at the metal atom in the complexes (10) (MRh, Ir).
Synthesis and Structural Aspects of Phosphane – Boranes Derived from Tris(diphenylphosphino)methane, HC(PPh2)3
Authors: Schmidbaur Hubert , St ützer Albert , Herdtweck Eberhardt
Published: July 2007

The structure of tris(diphenylphosphino)methane, HC(PPh2)3 (1), has been determined by X‐ray diffraction. The molecules have approximate C3 symmetry with the lone pairs at the three phosphorus atoms in an “all‐trans” orientation. Variable‐temperature NMR experiments (+ 35 to − 90°C in CH2Cl2) show free intramolecular motion in solution. The partially or fully borylated adducts HC(PPh2)2[PPh2(BH3)] (2), HC(PPh2)[PPh2;‐(BH3)]2 (3), and HC[PPh2(BH3)]3 (4) have been prepared from 1 and THF · BH3 or Me2S · BH3. For 2 and 3 the internal rotation about the phosphorus‐methine carbon bonds is also essentially unhindered, but has been shown to be restricted in 4 (Ea=31.2 kJ/mol). The chemical shifts of the methine protons in these compounds can be calculated on the basis of a BH3 substituent constant.
Synthese stabiler Alkantellurenyl‐pseudohalogenide und ‐pseudochalkogenide: (Me3Si)3CTeX (X=–CN, – SCN, – SeCN, – NCO, – N3) und (Me3Si)3CTe–Y–TeC(SiMe3)3 (Y=– NCN–, – NSN–)
Authors: Fimml Walter , Sladky Fritz
Published: July 2007

Synthesis of Stable Alkanetellurenyl Pseudohalides and Pseudochalcogenides: (Me3Si)3CTeX (X=– CN, – SCN, – SeCN, – NCO, – N3) and (Me3Si)3CTe–Y – TeC(SiMe3)3 (Y=– NCN–, – NSN–)

The first stable and isolable alkanetellurenyl pseudohalides and pseudochalcogenides, tris(trimethylsilyl)methanetellurenyl cyanide, thiocyanate, selenocyanate, isocyanate, azide (2–6) as well as bis[tris(trimethylsilyl)methyltelluro]carbodiimide and ‐sulfur diimide (7, 8) are obtained in high yields by the reaction of tris(trimethylsilyl)methanetellurenyl iodide (1) with the silver or potassium salts of the respective pseudohalides or pseudochalcogenides. 5–8 are also the first alkyltellurium(II) compounds with Te–N bonding. All compounds have been characterized by 1H‐, 13C‐, 125Te‐NMR, mass, and IR spectroscopy.
Übergangsmetallkomplexe von Diazenen, XXVII. Eisencarbonyl‐induzierte o‐Semidin‐Umlagerung von 1‐Alkyl‐2‐aryldiazenen
Authors: Kisch Horst , Rei ßer Peter , Knoch Falk
Published: July 2007

Iron Carbonyl Induced o‐Semidine Rearrangement of 1‐Alkyl‐2‐aryldiazenes

Irradiation of pentacarbonyl iron in the presence of Me3C – NN – Ar (Arphenyl, p‐tolyl, p‐CH3OC6H4) produces in the first step ortho‐metallated complexes of the type Me3C – N – N(H)RC6H3Fe(CO)3Fe(CO)3 (2a–c, RH, Me, MeO). In a thermal consecutive step these intermediates undergo an o‐semidine rearrangement to Me3C – NFe(CO)3 – Fe(CO)3N(H)RC6H3 (1a–c). The structure of 1a has been elucidated by X‐ray structure analysis. Dynamic 13C‐NMR spectra indicate restricted rotation of the Me3C group and hindered carbonyl scrambling for the latter and former complexes, respectively.
Beiträge zur Chemie des Phosphors, 211. Pentaisopropyltetracycloundecaphosphan, P11iPr5 – Darstellung und kernresonanzspektroskopische Strukturbestimmung
Authors: Baudler Marianne , Jachow Harald , Floruss Andrea , Hasenbach Jürgen
Published: July 2007

Contributions to the Chemistry of Phosphorus, 211. – Pentaisopropyltetracycloundecaphosphane, P11iPr5 – Preparation and Structure Determination by Nuclear Magnetic Resonance

Pentaisopropyltetracycloundecaphosphane (1) has been obtained by reaction of iPrPCl2 with P4 and magnesium and subsequent thermolysis of the crude reaction product, and has been isolated in 91% purity. According to NMR‐spectroscopic investigations, 1 has a constitution analogous to that of the hydrocarbon 2,8‐ethanonoradamantane, thus being 3,4,7,9,11‐pentaisopropyltetracyclo[6.2.1.02,6.05,10]undecaphosphane Compound 1 is formed as a mixture of two configurational isomers 1a and 1b, which differ from each other in their spatial arrangements of the isopropyl groups at P3 and P4.
Lösliche Lanthanid‐alkoxide mit niedrigen Koordinationszahlen am Metall‐Atom
Authors: Wedler Michael , Gilje John W. , Pieper Ursula , Stalke Dietmar , Noltemeyer Mathias , Edelmann Frank T.
Published: July 2007

Soluble Lanthanide Alkoxides with Low Coordination Numbers at the Metal Atom

Nd[N(SiMe3)2]3(thf)2 (1) reacts with tBu3COH (2) to give the monomeric lanthanide alkoxide (tritox)3Nd(thf) (3). The chloro‐bridged dimer [(tritox)2Nd(μ‐Cl)thf]2 (6) is obtained by treatment of NdCl3(thf)2 (4) with LiOCtBu3 (5). The structure of 6 has been determined by X‐ray crystallography.
Electron‐Transfer in the Light‐Promoted 1,6‐Cyclodimerization of 1,1‐Di‐2‐thienylethylene. A Thermal and Photochemical Study
Authors: Varea Teresa , Abarca Belén , Ballesteros Rafael , Asensio Gregorio
Published: July 2007

1,1‐Di‐2‐thienylethanol (1) undergoes light‐induced (Δ > 400 nm) dehydration to afford 1,1‐di‐2‐thienylethylene (2). Compound 2 is selectively converted into 1,6‐cyclodimers under thermal or photochemical conditions. In these latter case the non‐aromatic Diels‐Alder adduct 3 can be characterized. An ET mechanism involving a methyldithienylcarbenium ion (9) as electron acceptor and a chain mechanism is proposed to account for the products.
Organophosphorverbindungen, 48. 1‐Halogen‐1H‐phosphirene aus Phosphaalkinen und Halogencarbenen
Authors: Wagner Oliver , Ehle Michael , Birkel Manfred , Hoffmann Jürgen , Regitz Manfred
Published: July 2007

Organophosphorus Compounds, 48. – 1‐Halogen‐1H‐phosphirenes from Phosphaalkynes and Chlorocarbenes

Halogen‐substituted carbenes (7a – i), generated by thermolysis of diazirines (11a–i), add onto phosphaalkynes (8a–c) to form the title compounds (10a–1). Initially formed 2H‐phosphirenes (9) could not be detected as their subsequent conversion to the 1H‐isomers 10 by a 1,3‐halogen shift is very fast. Hydrolysis of 10c,e,g–i and k yields vinylphosphonous acids (17a – e). 1‐Chloro‐1H‐phosphirenes are transformed by nucleophilic substitution into fluoro (10a,c,e → 19a–c), bromo (10c,e → 20a,b), and iodo analogs (10c,e → 21a,b) with the help of silver tetrafluoroborate, trimethylsilyl bromide, and trimethylsilyl iodide, respectively. A crystal structure analysis of 10c is reported.
Intra‐ und extraannular funktionalisierte [2.2.2]Phane mit Dreifachbindung: Synthese und Eigenschaften
Authors: Knops Peter , Vögtle Fritz
Published: July 2007

Intra‐ and Extraannularly Functionalized [2.2.2]Phanes: Syntheses and Properties

The severely strained new cyclophanes 7b–f, consisting of bridged tolane subunits and bearing intraannular substituents R, were prepared mainly to study steric interactions of R with the “π cloud” of the triple bond. These compounds exist in a rigid twisted conformation, whereas the unsubstituted reference compound 7a and the extraannularly functionalized azo compound 9 show C2 symmetry. 9 forms a 1 : 1 clathrate with toluene.
4‐Amino‐3‐pyridiniochinolin‐2(1H)‐on‐chloride und 3,4‐Diaminochinolin‐2(1H)‐one
Authors: Gewald Karl , Sch äfer Harry , Bellmann Peter , Müller Heike
Published: July 2007

4‐Amino‐3‐pyridinioquinolin‐2(1H)‐one Chlorides and 3,4‐Diaminoquinolin‐2(1H)‐ones

N;‐(Chloroacetyl)anthranilonitriles 1 react with the pyridines 2 to form the 4‐amino‐3‐pyridinioquinolin‐2(1H)‐one chlorides 4, which are converted into the pyrido[1',2′ : 1,2]imidazo[5,4‐c]‐ quinolin‐6(5H)‐ones 6 in the presence of sodium hydroxide or by cyclooxidation with bromine. Treatment of 4 with hydrazine hydrate yields the 3,4‐diaminoquinolin‐2(1H)‐ones 9. Analogously to other o‐diamines the substituted imidazo [4,5‐c]‐ quinolinones 12, the pyrazino[2,3‐c]quinolinones 13, 14, the 1,2,5‐thiadiazolo[3,4‐c]quinolin‐4‐one 15a and the 1,2,5‐selena‐diazolo[3,4‐c]quinolin‐4‐one 15b are obtainable from 9a. With chloroacetyl chloride 9a provides the oxazino[2,3‐b]quinolin‐2‐one 11.
Improved Procedure for the Reductive Intermolecular Cyclodehalogenation of 2,6‐Dibromocyclohexanones to Furan and Fulvenes
Authors: Schottelius Thilo , Hoffmann H. Martin R.
Published: July 2007

The preparation of tricyclo[4,3,1.12,5]undec‐3‐en‐10‐ones has been scaled up. By using the improved procedure a number of tricyclic compounds have been obtained for the first time.
An easy access to (S)‐ and (R)‐hydroxycyclohexenone
Authors: Brünjes Rainer , Tilstam Ulf , Winterfeldt Ekkehard
Published: July 2007

The Diels‐Alder adduct obtained by addition of quinone to the chiral cyclopentadiene 2 undergoes regioselective and stereoselective reduction after hydrogenation. The 4‐hydroxy ketone 3 thus formed yields the title compound 1 in a thermal retro Diels‐Alder process.
Beiträge zur Chemie des Bors, 208 Reaktionen eines Amino‐imino‐borans mit Phosphin‐, Phosphon‐ und Phosphorsäuren
Authors: Nöth Heinrich , Schübel Jürgen
Published: July 2007

Reactions of an Amino Imino Borane with Phosphinic, Phosphonic, and Phosphoric Acids

Controlled 1:1 reactions of R2P(O)OH with tmp – B = NtBu (1) (tmp = 2,2,6,6‐tetramethylpiperidino group) in hexane leads to R2P(O)OB(tmp)NHtBu (2). In most other cases mixtures of 2 with other products are obtained. Application of a 4:1 ratio of Me2P(O)OH and 1 results in the formation of pure [tBuNH3][B(OP(O)Me2)4] (3). Reaction of phosphonic acids with 1 in hexane at about –30°C leads preferentially to the addition of the acid to produce RP(O)[OB(tmp)NHtBu]2 (4), while H3PO4 reacts with 1 to yield OP[OB(tmp)NHtBu]3 (6). Species containing tetracoordinated boron atoms are formed as well in dichloromethane as a solvent. Spectral data for the compounds 2, 4, and 6 reveal three‐coordinate boron atoms, confirmed by an X‐ray structure analysis of 2a (R = CH3). This compound displays a fairly large B – O – P bond angle, 140.6(3)°.
Notiz/Note P4O7 und P4O6S, Vergleich der Molekül‐ und Kristallstrukturen
Authors: Frick Frank , Jansen Martin , Bruna Pablo J. , Peyerimhoff Sigrid D.
Published: July 2007

P4O7 and P4O6S, Comparison of Molecular and Crystal Structure

Single crystals of P4O6S were grown for the first time. By X‐ray diffraction the space group (P21/c), the unit cell [α = 813.5(1), b = 938.3(1), c = 993.1(1) pm; β = 90.27(1)°], and the crystal and molecular structure have been determined. As compared to P4O7, the geometry of the P4O6 cage remains virtually unchanged upon substitution of the terminal oxygen atom by a sulfur atom. Calculated charge distributions clearly confirm the experimental results. With the exception of P(1), to which the additional chalcogen atom is attached, the effective charges at all other atoms seem not to be affected by an exchange of the terminal oxygen atom by a sulfur atom.
Structures of Tris(donor)‐Tris(acceptor)‐Substituted Benzenes, 1. Steric, Polar and Hydrogen‐Bonding Effects in Triaminotrinitrobenzenes
Authors: Jens Wolff J. , Nelsen Stephen F. , Petillo Peter A. , Powell Douglas R.
Published: July 2007

The X‐ray analyses of three 1,3,5‐tris(alkylamino)‐2,4,6‐trinitrobenzenes (alkyl = iPr, neopentyl, tBu; 1d – f) show their benzene rings to be highly distorted towards boat (1d iPrNH2) and twist‐boat (1e,f) forms. The patterns found for intramolecular donor‐acceptor interaction and hydrogen bonding depend on the conformation of the benzene core: boat structures have the “stern” amino group strongly donating to the “bow” nitro group in the para position and two stronger hydrogen bonds between the substituents on the “side” of the boat, whereas twist‐boat structures have two amino groups strongly interacting with the nitro group in their common ortho position to which there are also two strong hydrogen bonds. 1d – f undergo conformational exchange on the 13C‐NMR time scale at room temperature. Cooling to 220 K allows detection of all carbon signals and shows C1 symmetry to be present. AM1 calculations reproduce the distortions of 1d – f. Computations on several 2,4,6‐tridonor‐substituted 1,3,5‐trinitrobenzenes indicate that the pronounced deviations from planarity in 1a – f originate largely from electronic effects.
Lösliche bisaxial substituierte (Phthalocyaninato)ruthenium‐Komplexe
Authors: Hanack Michael , Vermehren Petra
Published: July 2007

Soluble Bisaxially Substituted (Phthalocyaninato)ruthenium Complexes

Several attempts to prepare (tBu4Pc)Ru only led to an impure product (tBu4Pc)RuLx. This reacts quantitatively with pyridine to form (tBu4Pc)Ru(py)2, easily purified by chromatography. In addition the preparation of (tBu4Pc)RuL2 with L = pyridine, 2‐picoline (2‐pic), 3‐picoline (3‐pic), 4‐picoline (4‐pic), 2,5‐lutidine (2,5‐lut), and 2,6‐lutidine (2,6‐lut), respectively, is described. All complexes are characterized by spectroscopic methods including 1H‐NMR spectroscopy. Not even in the cases of (tBu4Pc)RuL2 with L = 2‐pic and 2,5‐lut, a careful removal of the ligands L by thermogravimetric methods (TG/DTA) leads to pure (tBu4Pc)Ru. For comparison, the bisadducts PcRuL2 with L = pyridine, picolines (2‐pic, 3‐pic, 4‐pic), lutidines (2,3‐lut, 2,5‐lut, 2,6‐lut), and chloropyridines (2‐Clpy and 3‐Clpy), respectively, are prepared by treatment of PcRu with an excess of the ligand. For the first time (phthalocyaninato)iron complexes PcFeL2 with sterically hindered axial ligands, e.g. PcFe(2‐pic)2, are prepared and characterized by 57Fe Mößbauer spectroscopy.
o‐(α‐Benzotriazolylalkyl)phenols: Versatile Intermediates for the Synthesis of Substituted Phenols
Authors: Katritzky Alan R. , Lan Xiangfu , Lam Jamshed N.
Published: July 2007

Phenols and naphthols are benzotriazolylmethylated by 1‐(hydroxymethyl)‐1H‐benzotriazole (13) (a formaldehyde derivative) in the o‐ or (if both o‐positions are occupied) in the p‐position. The reaction can be extended to other aldehydes in the case of the naphthols. The methylene group in the o‐(benzotriazolylmethyl)phenols can be lithiated (but only after trimethylsilyl protection of the hydroxy group) and then substituted by various electrophiles. The benzotriazole residues in both the primary products and in their substituted derivatives can be displaced by the alkyl anions of Grignard reagents or by hydride ions allowing the elaboration of many new types of substituted phenols.
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

To 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 Methanol

The 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‐olide

3,4‐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 TiCl4

Bis(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 Surfaces

Reaction 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 Complexes

The 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 Propynoate

The 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

The 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

The 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‐Dienes

Highly 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‐Position

5H‐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 Bonds

Reaction 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

Condensation 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

Several 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.