Two new types of bismuth(III) tropolonato complexes, nitratobis(tropolonato)bismuth(III) (1d) and phenylbis(tropolonato)bismuthin (1f), are synthesized and characterized by elemental analysis, 1H‐NMR, 13C‐NMR, IR spectroscopy, and conductivity measurements. The structures of 1d and aquabis(4,5‐benzotropolonato)bismuth(III) nitrate (6b) are confirmed by X‐ray structural analyses. Derivatives of tropolone (2a) and their bismuth(III) complexes are synthesized and characterized in the same manner. Eight of these compounds are tested against Helicobacter pylori (H.p.) bacteria, which cause chronic gastritis and peptic ulcus. Most of the bismuth compounds show high in vitro activity against H.p.
The reactions of bismuth(III) nitrate pentahydrate and bismuth(III) chloride with heterocyclic
thiosemicarbazones and derivatives of dithiocarbazonic acid methylester were used to synthesize
the respective bismuth(III) complexes, which could be divided into five groups D-H because
of their stoichiometrical properties and their molecular structures. The molecular
structure and the near coordination sphere of the bismuth(III) central atom of four representative
compounds were determined by single-crystal X-ray studies. Bis[1-azepanyl-4-(2-pyridyl)-2,3-diazapenta-1,3-diene-1-thiolato-N′,N3,S]bismuth(III) nitrate (5) belongs to group D. The
two tridentate ligands and the nitrate ion surround the bismuth atom. The best description of
the coordination sphere appears to be that of a distorted trigonal dodecahedron with one position
occupied by the lone pair of the bismuth atom. Bis[1-azepanyl-4-(2-thienyl)-2,3-diazapenta-1,3-diene-1-thiolato-N3,S]bismuth(III) nitrate (9) is assigned to complex type E.
Here, two deprotonated ligand molecules are coordinated to the bismuth(III) central atom as
bidentate ligands. The structure of this complex can best be described as a distorted trigonal
antiprism with a five-coordinated central atom. The two triangular faces are formed by the atoms
S(4), N(6), O(11) and S(3), N(4) and the lone pair of the central atom. The two chelate
rings are almost perpendicular to each other. Complex molecules of group F form dimeric
units with bichloro-bridged bismuth atoms. The structure of di-μ-chlorobis[1-azepanyl-4-(2-pyridyl)-2,3-diazapenta-1,3-diene-1-thiolato-N′,N3,S-chloro]dibismuth(III) (15) can be described
as two six-coordinated bismuth atoms, which are bound together via two bridging
chlorine atoms. The two bismuth atoms Bi(1) and Bi(1a) and the two bridging chlorine atoms
Cl(2) and Cl(2a) form the Bi2Cl2 plane. The two tridentate ligand molecules coordinate via the
same atoms as shown in complex 5. In addition, they form two parallel planes, which are perpendicular
to the Bi2Cl2 plane. With regard to the center of the Bi(1)-Bi(2) axis they are central
point symmetrical, i.e. one pyridine ring lies above and the other beneath the Bi2Cl2 plane. Bismuth(III) chloride and pyridine-2-carboxaldehydethiosemicarbazone 1 b or 2-acetylpyridine-thiosemicarbazone
1 c form complexes of group G. Three chlorine atoms and a bidentate ligand
are coordinated to the bismuth(III) central atom. The bidentate ligand bound to the
central atom through the N(3) atom and the sulfur atom of the thioketo group. The structure
of 18 is completely different from the structures of the bismuth(III) complexes discussed so
far and was therefore assigned to group H. The bismuth central atom is coordinated with two
ligands, which are bound in different ways. One of them is deprotonated. This ligand is bound
to the central atom via the sulfur atom S(3) of the thiolate group and the N(5) atom. An interaction
between the sulfur atom of the thiophene ring and the bismuth atom is not possible.The other ligand molecule is not de...
COMMUNICATIONSh=15.387(4). L' = 41.57(2) A, / l = 99.44(3)-, V = 12814.5 A'. monoclinic. spacegroup ('2/r,Z= 8,p,,,,, ~1 . 2 5 1 gcm-3,p = j1.2cm-',F(000) = 4912. Ci-ystal mounted in perflouroether oil; measurements at 213 K. Data collection:1.7738 measured reflections. 7354 of which were independent and 4339 with F 4o(F). Structure solution and refinement: heavy atom method. T1 and Si atoms anisotropically refined. C atoms isotropically. The htructure solution converged without inclusion of H atoms and posaible solvent molecules at R , = 0.135. wR2 = 0.417. GOF =1.097. The crystal decomposed considerably during the measurement; the measurement m'as stopped uhen the intensity of two standard reflections became smaller than 50'4,. which is why the C atoms were not refined anisotropically. Further details of the crystal structure investigation may be obtained from the Fachint'ormationszentrum Karlsruhe, D-76344 Eggenstein-Leopoldshafen (German)) on quoting the depository number CSD-404429.
ZUSCHRIFTENwurden mit dem DISCOVER-Kraftfeldprog~amm durchgefuhrt. In allen Berechnungen wurden entfernungsabhlngige Dielektriritltskonstanten verwendet. Die von DGEOM erzeugten Strukturen wurden 100 Schritte mit dem ,,Steepest-descent"-Algorithmus, gefolgt vom VA09A-Algorithmus, minimiert, bis alle Ableitungen unter 0.001 k c a l m o l -' k ' lagen. Eingegangen am 24. Juli 1995 [Z 82421 Stichworte: Lanthionine . Peptidmimetica [I] Fur neuere Beispiele siehe a) M. Goodman. S. Telefax: Int. + 6221/564955 schen Forschungsgemeinschaft gefordert.["*I Diese Arbeit wnrde vom Fonds der Chemischen Industrie und von der Deut-90 (C VCH ~~rl~~gsgesell.schafi mhH, 0-69451 WeinheOn. 1996
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