[Structure: see text]. The crystal structures of a new series of alpha,beta-unsaturated ketoximes, 8-14, carrying the terminal 4-pyridinyl, 3-pyridinyl, or 4-quinolinyl subunit have been investigated by X-ray structural analysis. The dominating intermolecular interaction in all structures, except 11, is the head-tail OH...N hydrogen bond between the oxime moiety and the nitrogen atom of the heterocyclic unit. This intermolecular interaction generates infinite chains, which are cross-linked by CH...O/N/Cl or CH...pi interactions. Compound 10 has been shown to adopt a double-helical structure in the crystalline state. Compound 11 represents the only case where the unexpected head-head NOH...N(OH) hydrogen bonds determine the crystal packing. Both hydrogen-bonding and aromatic interactions stabilize the crystal structures of 8-14.

1,3-Diisopropyl- (4), 1-tert-butyl-3-isopropyl- (5), 1,3,5-triisopropyl- (6) and 1-tert-butyl-3,5-diisopropyladamantane (7) were prepared from the same synthetic precursor - methyl 3-isopropyladamantane-1-carboxylate (10) - applying a standard set of repetitive procedures in 65, 77, 24, and 34 % overall yield, respectively. 1,3,5,7-Tetraethenyladamantane (17) was obtained in two steps - Swern oxidation and Wittig olefination - from 1,3,5,7-tetrakis(hydroxymethyl)adamantane (15) in 45 % overall yield and converted into 1,3,5,7-tetracy-clopropyladamantane (8) by fourfold cyclopropanation with diazomethane catalyzed by palladium(II) acetate (91 % yield). Hydrogenolysis of 8 over a platinum catalyst furnished 1,3,5,7-tetraisopropyladamantane (9) in quantitative yield. 1-Isopropyladamantane (3) as well as the hydrocarbons 4-7 did not give any crystals suitable for X-ray crystal structure analysis, even when using the Optical Heating and Crystallization Device (OHCD). This method was rather successful when applied to the tetravinyl derivative 17, X-ray crystal structure analysis of which revealed an approximately C-2- symmetric conformation in the solid state at 150 K However, no well-defined orientation was detected for the cyclopropyl groups in 8, and the molecules were severely disordered even at 30(1) K. In contrast to this, X-ray crystal structure analysis of the tetraisopropyl derivative 9 revealed an S-4-symmetric conformation for this hydrocarbon at 203 K. ((c) Wiley-VCH Verlag GmbH 1 Co. KGaA, 69451 Weinheim, Germany, 2005).

Novel molecular clips with anthracene sidewalls (1 a-c) were synthesized; they form stable host-guest complexes with a variety of electron-deficient aromatic and quinoid molecules. According to single-crystal structure analyses of clip 1 c and 1,2,4,5-tetracyanobenzene (TCNB) complex 14@1 b, the clips' anthracene sidewalls have to be compressed substantially during the complex formation to provide attractive pi-pi interactions between the aromatic guest molecule and the two anthracene sidewalls in the complex. The compression and expansion of aromatic sidewalls are calculated by molecular mechanics to be low-energy processes, so the energy required for compression of the anthracene sidewalls during complex formation is apparently overcompensated by the gain in energy resulting from the attractive pi-pi interactions. The finding that complexes of the clips 1 a-c are more stable than those of the corresponding clips 2 a-c can be explained in terms of the larger van der Waals contact surfaces of the anthracene sidewalls in 1 a-c (relative to the naphthalene sidewalls in 2 a-c). Color changes resulting from charge-transfer (CT) bands are observed in complex formation by 1 a-c: from colorless to red or purple with TCNB (14), and from yellow to green with 2,4,7-trinitro-9-fluorenone TNF (17). Independently, the host 1 b and guest 14 fluoresce from their respective excited singlet states, whilst in the complex 14@1 b the charge-transfer state quenches the higher-energy singlet states of the two components, and as a result luminescence is only observed from this new CT state. To the best of our knowledge, complex 14@1 b is the first example of CT luminescence from a host-guest complex. The binding constant determined for the formation of the TCNB complex 14@1 b from a UV/Vis titration experiment (Ka = 12 400 m(-1)) agrees well with the value (K(a) = 12 800 m(-1)) obtained by 1H NMR titration.

The macrolactams cyclo(3 alpha-aminodeoxycholic amide)(2) (1) and cyclo(3 alpha-aminodeoxycholic amide)(3) (2) were prepared in high yields (1: 32%; 2: 41%) from the pentafluorophenyl esters of the linear precursors. The solid-state structures of both macrocycles were determined by X-ray diffraction. Compound 1 forms a Cleft Of C-2 symmetry which holds two methanol and two water molecules fixed by hydrogen bonds. The crystals of compound 2 contain two slightly different macrolactam rings of 7-8 A diameter. The polar a-surface of the deoxycholanic parts and the amide NH groups are oriented into the center of the rings. The cavity formed by the ring system and the void volume between the macrocycles is filled by disordered solvent molecules.

In Bayern läuft seit dem 01.04.2003 ein qualitätsgesichertes, flächendeckendes Mammographiescreening mit dezentralem Charakter (BMS). Zugrunde liegen die Empfehlungen der European Guidelines sowie der S-3-Leitlinie.

Molecular tweezers and clips of type 1-3 substituted with OAc, OH, OCONHPh, OMe, OCH2COOR and OCH2-CONHR groups in the central spacer units have been synthesized by modification, by standard methods, either of the known diacetoxy-substituted derivatives 1b, 2b and 3b, or of the correspondingly substituted bis-dienophiles 4b and 5b. The synthesis of the dimethoxy-diacetoxy-substituted tweezer 1d could be accomplished through pressure-induced repetitive Diels-Alder reactions between the bis-dienophile 4b and the newly prepared diene 6b and subsequent DDQ oxidation. The thermodynamic parameters (K-a and DeltaG) of complex formation between the new receptors and aromatic substrates such as DCNB 21, TCNB 22, TCNQ 24 and Kosower salt 25 and the maximum complexation-induced H-1 NMR shifts (Deltadelta(max.)) were determined by H-1 NMR titration experiments. It was found that the presence of substituents OH, OAc and OCONHPh in the central spacer units of the tweezers and clips 1-3 favours complex formation, whereas that of the substituents OMe, OCH2COOR and OCH2- CONHR disfavours it. This finding can be explained in terms of the size and different conformations of these groups in the tweezer and clip molecules as calculated by force-field (MMFF) techniques rather than of their influence on the electrostatic potential surfaces (EPSs) of the adjacent aromatic rings as calculated by quantum mechanical methods. The complementary natures of the negative EPSs inside the tweezer and clip cavities and the positive EPSs of the substrates forming complexes explained the high selectivity of these receptors toward electron-deficient substrates. The finding that the self-assembly of the OCH2COOCH2CH3 side chain is only observed for the benzene-spaced tweezers 1i and 1o confirms earlier results obtained for the intermolecular complexation of these receptors. Accordingly, the benzene-spaced tweezers of type I selectively bind aliphatic substrates, whereas the naphthalene-spaced tweezers of type 2 and clips of type 3 preferentially complex aromatic substrates. (C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.

Using C-H...N interactions, acetylene can be introduced at increased pressure to form molecular complexes with azacyclic N-acceptors which can be crystallized and investigated by X-ray methods. With pyridine, we expected dumbbell-like 2: 1 complexes with acetylene in the middle, instead a 1: 1 zigzag chain is formed where each of the N-atoms accepts two hydrogen atoms from two acetylene molecules. The same happens with 2,5-dimethylpyridine which, together with water, results in a complex having the water chains networked by acetylene molecules. With 2,5-dimethylpyrazine, linear chains are found which are additionally stabilized by sp(3) and sp(2) C-H...N interactions. 2,6-Di-tert-butylpyridine forms a clathrate with acetylene.

A new supramolecular crystal engineering approach toward quadratic nonlinear optics is inferred from an acentric cocrystalline template made of two different bi-dimensional octupolar molecules: trinitrobenzene (TNB) and triphenylene (TP). The resulting 2-D octupolar cocrystalline lattice is proposed as a generic template toward multipolar crystalline engineering studies. X-ray diffraction data evidence parallel stacks with alternating vertically overlapping TNB and TP units, leading to a significant, pi-pi intermolecular charge transfer which cannot be accounted for by an oriented gas model.

The synthesis, isolation, spectroscopic characterization (IR, multi-nuclear NMR) and single-crystal X-ray diffraction analysis of FSi(PH2)(3) (1a), the first isolable fluorophosphanylsilane, is reported along with the gas phase, decomposition of la, MeSi(PH2)(3) (1b) and EtSi(PH2)(3) (1c) under flash vacuum or pulsed pyrolysis conditions and matrix isolation of the products. The title compound is formed quantitatively by PH2/F-ligand exchange reaction of tetraphosphanylsilane Si(PH2)(4) with the difluorodiarylstannane Is(2)SnF(2) (Is = 2,4,6-triisopropylphenyl) in the molar ratio of 1: 1 in benzene as solvent. Since la cannot be separated from the solvent by fractional condensation its isolation was achieved by means of preparative GC. A single crystal of 1a (triclinic, P 1) suitable for X-ray diffraction analysis was grown by in situ crystallization on a diffractometer at 175 K through miniaturized zone melting with focused infra-red radiation. Interestingly, the Si atom is remarkably distorted tetrahedral coordinated with F-Si-P angles of 120.4(7), 110.4(7), 106.3(1)degrees and normal Si-F (1.60(2) Angstrom) and Si-P distances (av. 2.241(2) Angstrom). According to ab initio (MP2/6-31G(d,p); MP2/6-311G(2d,p)) and DFT calculations (BLYP, B3LYP, B3PW91 functionals), the distortion is not an intrinsic property of the molecule but due to crystal packing forces. The best agreement between the experimental versus calculated geometrical and vibrational data is achieved at the B3PW91/6-311G(2d,p) level of theory. Since la-c appeared as potential precursors for the respective silylidyne-phosphanes ('silaphospha -acetylene') RSiP through stepwise extrusion of PH3, Some thermodynamical data for the decomposition and the relative energies of linear RSiP versus bent :SiPR isomers (R = H, Me, Et, Pr, Ph, CF3, OMe, halogen and SiH3) were also calculated. The latter revealed that electronegative substituents R favor the Si-P triple bond in RSiP (except for R = CF3 which stabilizes the: SiPR form) while strong sigma-donating substituents R (H, SiH3) favor the :SiPR isomer with Si P double bond. Although elimination of PH3 and other fragmentation products could be detected by controlled thermal decomposition and matrix isolation, neither flash vacuum experiments of la, 1b and 1c (400-600 degreesC) nor pulsed pyrolyses of la at (1100 degreesC) did provide any direct evidence for the formation of the desired species with Si-P multiple bonds. (C) 2003 Elsevier B.V. All rights reserved.

The centrosymmetric crystal structure of the title complex, C(12)H(12)N(2)S(2).C(6)H(7)NS, is built up of dimers of the constituent molecules and stabilized by a herring-bone geometry between the phenyl rings. The structure reveals an N-H...N-H...N-H...S co-operative hydrogen-bonded chain, and C-H...S and N-H...pi hydrogen bonds. The S-H group forms an uncommon S-H...pi interaction.

Reaction of a pyridine carbaldimine 2-(BuN)-Bu-t=CHC5H4N 1a with a molar equivalent of boron tribromide afforded a bicyclic 1,3,2-diazaborolium bromide 2a as an orange solid, whereas 1a and the corresponding 2-(2,6-Me2C6H3)N=CHC5H4N 1b with two equivalents of boron trifluoride gave non-ionic yellow adducts 3a and 3b. The reduction of compounds 2a, 3a and 3b with an excess of sodium amalgam in a hexane slurry led to the formation of 1-X-2-R-1,2-dihydro[1,3,2]diazaborolo[1,5-a]pyridines 4 (X=Br; R=Bu-t), 5a (F; Bu-t) and 5b (F; 2,6-Me2C6H3) as yellow oils (4a, 5a) or a yellow wax (5b), respectively. Treatment of 4 with an excess of chlorotrimethylsilane caused a Br/Cl exchange to afford chloro derivative 6. The addition of a methyl group to the boron atom was effected by reaction of heterocycle 4 with methyllithium. The BCN derivative 8 resulted from treatment of 4 with silver cyanide. Reduction of 4 with lithium aluminium hydride gave the 1-hydro-derivative 9, whereas the (BSBu)-Bu-t compound was obtained from the reaction of 4 with (KSBu)-Bu-t. Compound 8 was subjected to an X-ray diffraction analysis.

α,β-Unsaturated ketones 1–4 carrying a terminal pyridine subunit form aggregates in the crystalline state with the molecules linked together through CH⋯N/CH⋯O hydrogen bonds. The hydrogen-bonding motifs are discussed.

The dicationic 2,2-biimidazolyl derivative 5 has been obtained from the imidazolium salt 3 and the carbene 4 in good yield. The presence of the carbene 4 and its unstable dimer 7 were detected by NMR in the reduction product of 5 with potassium. The crystal structure of 5 . H2O is reported.

The spirocyclopropanated bicyclobutylidenes 3-7 have been prepared by McMurry coupling of the corresponding spirocyclopropanated cyclobutanone (3 and 5), Staudinger-Pfenniger reaction (4), oxidative coupling of a Wittig ylide (4) or Wittig olefination of perspirocyclopropanated cyclobutanone (6 and 7). The structure of the parent 2a and the perspirocyclopropanated bicyclobutylidene 5 was determined by X-ray crystallography which disclosed considerable steric congestion around the double bond. As a result 5 did undergo addition of dichlorocarbene, epoxidation with meta-chloroperbenzoic acid, and cyclopropanation with CH2I2/ZnEt2, but did not add the more bulky dibromocarbene. The reaction of 5 with tetracyanoethene proceeded smoothly, but led to a formal [3+2] cycloadduct across the proximal single bond of one of the inner cyclopropane rings. The consecutive spirocyclopropanation of bicyclobutylidene led to a bathochromic shift in the UV spectra of 12 and 17nm, respectively, for each pair of beta- and alpha-spirocyclopropane groups. In the He(I)-photoelectron spectra of these bicyclobutylidenes, the effect of spirocyclopropanation upon their pi-ionization energies (pi-IE,) was found to be almost additive, leading to a lowering of 0.05 eV per any additional beta-spirocyclopropane, and 0.28-0.22 eV per additional alpha-spirocyclopropane group; this indicates an increasing nucleophilicity of the double bonds in the order 1 < 4 < 3 < 5. Following the radical cations of the three symmetrical bicyclobutylidenes without (2a, b) and with six (5) spiroannelated cyclopropane rings, the radical cations of two symmetrical bicyclobutylidenes with two (4) and four (3) such rings were studied by ESR spectroscopy. Whereas 2b.+, 3.+, and 5.+ could be generated by electrolytic oxidation of the corresponding hydrocarbons in solution, the spectra of 2a.+ and 4.+, with unsubstituted 2,2',4,4'-positions, were observed upon radiolysis of their neutral precursors in a Freon matrix. On going from 2a.+ to 4.+, the coupling constant [aH] of the eight beta protons in the 2,2',4,4'-positions of bicyclobutylidene increases from 2.62 to 3.08 mT, and that of the four gamma protons in the 3,3'-positions changes from 0.27 to 0.049 to 0.401 mT on passing from 2a.+ via 2b.+ to 3.+. Computations by means of the density functional theory (DFT) at the B3LYP/6-311+G*//B3LYP/6-31G* level reproduce well the experimental hyperfine data.

The unusual N-H.O hydrogen bond pattern in a family of primary cubanecarboxamides is described. 4-Chloro-1-cubanecarboxamide, 1, and the corresponding bromo and iodo derivatives, 2 and 3, form the "shallow-glide" hydrogen-bonded motif instead of the usual 5.1 A translated ribbon pattern, more characteristic of primary amides. This behavior is also seen, somewhat unexpectedly, for cubanecarboxamide, 4, but more or less unsurprisingly for 1,4-cubanedicarboxamide, 5. This repetitive occurrence of the same hydrogen bond pattern is of significance in crystal engineering wherein synthon robustness is measured in terms of such repetitivity. The cubyl group is directly responsible for the appearance of the shallow-glide motif in this family in preference to the 5.1 A translation pattern for two reasons: (1) steric--it is too large to fit in a 5.1 A translated structure and (2) electronic--its carbon acidity is sufficient to result in the appearance of C-H.O hydrogen bonds to the C=O group, disrupting any putative 5.1 A translated structure. Such a molecule --> supermolecule relationship is of value in crystal engineering strategies.

Cyclobutylidenecyclopropane (7) was prepared in multigram quantities by a new three-step sequence starting from ethyl cyclobutanecarboxylate (4) (39% overall yield), 1,3-Dipolar cycloadditions of phenyl- (9), pyridyl- (10), and the newly prepared (four steps, 43% overall yield) spirocyclic nitrone 11 onto 7 resulted in the regioselective formation of the corresponding adducts 15-17, with the spirobutane moieties adjacent to the oxygen atom in the oxazolidine rings, in 52, 84, and 48% yields, respectively. Under flash vacuum pyrolysis conditions, the cycloadducts 15-17 underwent thermal rearrangement with opening of the four-membered ring, to afford the spirocyclopropanated azepinones 21-23 in 32, 30, and 19% yields, respectively. In the case of 17, the indolizidinone 25 was also isolated (13% yield). Mechanistically this rearrangement is interpreted in terms of a cyclobutylmethyl-to-penten-5-yl radical rearrangement.

(Me3Si)(3)Si(Me2Si)(2)(Me3Si)(2)SiLi (1) and LiSi(Me3Si)(2-) Si(Me3Si)(2)Li (2) were synthesized by the reaction of (Me3Si)(3-) Si(Me,Si),Si(Me,Si), in THF with one or two mol-equivalents, respectively, of MeLi. Both 1 and 2 were characterized spectroscopically and by trapping reactions, and 1 also by X-ray crystallography.

The reaction of equimolar amounts of [(eta(5)C(5)Me(5))(CO)(2)RuSb(SiMe3)(2)] (Ib) and the carboxylic chlorides RC(O)Cl (R = tBu, Ph, 1-adamantyl) afforded the acyl(trimethylsilyl)stibanido complexes [(eta(5)-C5Me5)(CO)(2)RUSb. {C(O)R}(SiMe3)] 2b (R = tBu), 4b (R = Ph), and 6b (R = 1-Ad). The treatment of Ib with two molar equivalents of pivaloyl chloride and benzoyl chloride led to the diacylstibanido complexes [(eta(5)-C5Me5)(CO)(2)Rusb{C(O)R}(2)] (3b, 5b). Analogously, the iron complex [(eta(5)-C5Me5)(CO)(2)FeSb (SiMe3)(2)] (1a) is converted into the corresponding diacylstibanido complexes 3a (R = tBu), 5a (R = Ph) and 7a (R = 1-Ad) by an excess of acid chloride. The treatment of la with equimolar amounts of RC(O)Cl gave inseparable mixtures of starting material and the monoacyl- and diacyl stibanido complexes. Oxalyl chloride reacted quantitatively with two equivalents of la to give complex [{(eta(5)-C5Me5) (CO)(2)Fesb(SiMe3)C(O)}(2)] (8). The molecular structures of 1a, 2b and 5b were elucidated by single crystal X-ray analyses.

Reaction of equimolar amounts of diphenylketene with a series of 1,3-di-tert-butyl-2,3-dihydro-1H-1,3,2-diazaboroles [X = Br (1a), F (1b), NH2 (1c), NMe2 (1d), Me (1e), SnMe3 (1f), CHC(SnMe3)C6H4-4-Cl (1g)] regioselectively afforded good yields of the 1,3,2-oxazaborolidines (2a−g). The X-ray structure analysis of 2d revealed an essentially planar five-membered heterocycle with a long B−O bond and a strong exocyclic BN−π bond.