The Crystal and Molecular Structures of Two Acid‐Catalysed Rearrangement Products of Taxochinon

Abstract

Zusamm~raJuusw#. Die SlrukturcnVUII zwci slnrckatal!.sicr.ic:n ~J~nlng~:~-ungs~~rotlrililc~i von Taxochinon (1) wurclcn kristallographisch Ixxtiiiiinl: J)io c:inu Vorbinrlung stclltc sich 51s (:in 20 (10 + 9) alreo-Abictan (2) heraus, die andcre als cin :icliimlcs Phcnnlcnon (3). IXo Abictanvcrbindung, CaoH&s, kristallisiert in der Kauriigruppc l"212121 m i t 4 Molckcln in dcr Zellc untl wurcle init 879 aignifikanten Iieflcxioncn bis R i 0,032 vcrfcinorl. W e l'~iendcnonvc:rl~inclung, CzoHsaC)s. kristallisiert in rler Kaumgnippe lJ21/c iiiit 12 Molokcln in dt:r Zcllc untl wurdc I i i i t 3823 signifikantcn Reflektioncn bis K = 0,058 verfcincrt. 1) In addition to the positional parameters of all atoms, anisotropic &j for C and 0 atoms. isotropic R-values for H-atoms, a scaIc factor and an isotropic cxtinction parameter G [4] were introduced. The final value of C = 10.0(3) for an assumed T = 0.02 cm.

Structure of the 2,5,8-trithia[9](2,6)pyridinophane–silver nitrate complex (1:1)

“…The C--S bond parameters are normal and are comparable with other cyclic thioethers (Campbell, Larson & Dalley, 1981a,b;Weber, Jones & Sheldrick, 1983). C(sp2)--N bonds of the pyridine ring differ slightly and are comparable with those observed by Weber (1982) and Chacko, Ruban, Aoki & Weber (1988). The pyridine ring is planar to within 0.011(4) ,~.…”

The solution and solid-state structures of a macrocyclic silver(I) complex with 6,9,12-trioxa-3,15-dithia-21-azabicyclo[15.3.1]henicosa-1(21),17,19-triene

“…It is evident that simultaneous coordination of the pyridine N atom, the two S atoms and any O atom in the polyether chain leads to a rather strained conformation for the complex, as evidenced by the rather obtuse S8B-Ag2-S20B bond angle of 141.82 (9) ° [cf. 169.8 and 165.1 ° in the five-coordinate rhodiumcarbonyl (Ferguson, Matthes & Parker, 1987a) and copper(II) chloride (Weber, 1982) complexes of L I, the long Ag2-N1B bond length [2.528 (8)A1, and some of the torsional angles in the silver complex showing large disparities from the idealized strain-free values of 180 ° (trans) for C-X-C-C and _+60 ° (gauche) for X-C-C-X. Abstract.…”

“…The ligand contains two thioether donors and, in recent work, the tendency of S atoms in macrocycles to adopt exodentate conformations, with the lone pairs directed away from the macrocyclic cavity, has been highlighted (Wolf, Hartman, Storey, Foxman & Cooper, 1987;DeSimone & Glick, 1975, 1976. In the copper (Weber, 1982) and rhodium-carbonyl (Ferguson, Matthes & Parker, 1987a) complexes of L, the S atoms are exocyclic with the polyether chain being folded away from the metal centre, and back toward the electron-poor pyridine ring. In contrast, in the barium complex of L (Weber, 1982), the six donor lone pairs are focused towards the centre of the cavity and both S atoms are accordingly endocyclic.…”

“…In the copper (Weber, 1982) and rhodium-carbonyl (Ferguson, Matthes & Parker, 1987a) complexes of L, the S atoms are exocyclic with the polyether chain being folded away from the metal centre, and back toward the electron-poor pyridine ring. In contrast, in the barium complex of L (Weber, 1982), the six donor lone pairs are focused towards the centre of the cavity and both S atoms are accordingly endocyclic.…”