2.2](2,7)-Fluorenophanediene, [2.2.2](2,7)-fluorenophanetriene, and their fluorenide ions

The McMurry coupling of 2,7-diformylfluorene affords a dimer, anti-[2.2](2,7)-fluorenophanediene, and a trimer, [2.2.2](2,7)-fluorenophanetriene, as cyclic oligomers. X-Ray crystallography of the dimer establishes its strained, layered structure with anti-conformation. While the fluorenyl groups of the dimer do not show any sign of rotation in the variable temperature 1H NMR spectra up to 120 degrees C, those of the trimer are fast rotating even at -50 degrees C. Treatment of the dimer and trimer with KH in DMSO furnished the respective dianion and trianion that are stable at room temperature in the solutions. While the trianion shows substantial conjugation through the etheno bridges, the dianion shows little conjugation through the etheno bridges and almost no proton-deuterium exchange of the fluorenyl C9-H with the solvent DMSO-d6 probably due to stereospecific protonation-deprotonation associated with the tightly layered structure.     

Synthese,Kristallstruktur und Konformation vontrans-[2.2](1,2)Ferrocenophan und seinen 1-Hydroxyderivaten

Starting from1-(dimethylaminomethyl)-2-iodo-ferrocene (3) [2.2](1,2)ferrocenophane (2) was prepared in an 8-step synthesis with 17% overall yield. Both from the oxoderivative12 and the ferrocenophane2 puretrans-isomers (12b and2b, resp.) were obtained; the former (12b) was reduced to a separable mixture ofexo andendo 1-hydroxy-ferrocenophanes13a andb, resp. (～ 3:7), the configurations of which were assigned by the LIS-method. X-ray crystal structure analysis of2b revealed a centrosymmetrical chair conformation. From¹H- and¹³C-NMR spectra both for2b and for the hydroxyderivatives13 a rigidexo-exo chair conformation was deduced.     

Synthese und struktur von dicyclopentadienyl(trimethylsilyl)titanchlorid

Dicyclopentadienyl(trimethylsilyl)titanium chloride, a stable trimethylsilyltitanium compound, is synthesized by reaction of dicyclopentadienyltitanium dichloride and tris(trimethylsilyl)aluminium, coordinated with diethyl ether, or lithium tetarakis(trimethylsilyl)aluminate. The IR and NMR spectra are reported. The crystal structure of the title compound has been determined. It shows a distorted tetrahedral surrounding of the titanium atom; the Ti–Si distance is 267 pm.     

Versuche zur Synthese von [2.2]- und [2.3]Cyclopentadienophanen

Synthetic Attempts towards [2.2]- and [2.3]Cyclopentadienophanes . The first [2.2]Cyclopentadienophane (=2,2,3,3,8,8,9,9-octamethyltricyclo[8.2.1.1^4,7]tetradecatetraene; 1b ) has been synthesized (Scheme 5) by reductive coupling of 6,6-dimethylfulvene 3 → 5 (50%) followed by base-induced twofold condensation of 1,2-di(cyclopentadienyl)-1,2-dimethylbutane 5 with acetone to give difulvene 15 (95%). Reductive coupling of 15 gives a complex mixture of tautomers of 16 , 17 , and 1b , which contains ca. 50% of the target molecule 1b . Other synthetic attempts towards [2.2]cyclopentadienophanes 1a and 1b and [2.3]cyclopentadienophane 18 are discussed.     

[4](2,7)troponophane

The title compound $\text{5}$ and its dehydro analog $\text{6}$ were synthesized from $\text{10}$ and $\text{9,}$ respectively, and their physical properties were examined. Tropone ring in these compounds are deeply bent to tub shapes and conjugation of the carbonyl group is greatly reduced.     

Übergangsmetall-fulven-komplexe : XIX. Synthese und struktur von tricarbonyl(2,5,7-trimethylcyclopenta[cdazulen)chrom

Tricarbonyl(2,5,7-trimethylcyclopent[cdazulene)chromium has been synthesized and characterized by X-ray diffraction.     

Transannular interactions insyn- andanti- [2.2](1,4) napthalenophanes andsyn- andanti- [2.2](1,4) anthracenophanes

The UV spectra of the title compounds were interpreted as a result ofPPP-CI-1 calculations of excitation energies and oscillator strengths for the singlet—singlet transitions. A good agreement of the theoretical transitions with the experimental spectrum was found. A strong transannular effect was characteristic for thesyn isomers, the effect decreased in the order:syn-ring anthracenophane,syn-ring naphtalenophane,anti-ring naphthalenophane,anti-ring anthracenophane. Also the influence of a pseudo-substituent effect was found and discussed.     

Synthese und struktur von 2,2-bis(trifluormethyl)4-dimethyl-amino-1,3-diazolon

Cyanogen, O-(trimethylsilyl)hexafluoracetone cyanhydrin and dimethylformamide react to yield a five-membered heterocycle of composition (CH₃)₂NC₃N₂H(O) (CF₃)₂. The composition and the molecular structure were determined on the basis of mass spectra and a single-crystal X-ray analysis. The compound crystallizes in the space group P2₁/n with a = 9.469(1), b = 11.540(2), c = 10.205(4) Å, β = 106.O2(2)^o. The final R_w(F) is 0.047 for 1168 observed reflections.     

[2.2](2,6)Biphenylenophane and [2](2,6)Biphenyleno[2](2,6)naphthalenophane

Two cyclophanes, [2.2](2,6)biphenylenophane and [2](2,6)biphenyleno[2](2,6)naphthalenophane, were prepared.