The synthesis of chiral square-planar Pt II complexes using symmetrical and unsymmetrical bis(pinene)-fused 2,2Ј-bipyridine is described. The neutral diimine dichloro complexes show a strong deviation of the coordination sphere from planarity if the pinene groups are attached at the 5and 6-positions of the pyridine rings. However, this distortion
The molecular structure and crystal-packing mode of the enantiopure chiral building blocks Delta-[Ru(bpy)(2)(py)(2)][(+)-O,O'-dibenzoyl-D-tartrate].12H(2)O (I) and Lambda-[Ru(bpy)(2)(py)(2)][(-)-O,O'-dibenzoyl-L-tartrate].12H(2)O (II) have been determined by single-crystal X-ray diffraction data. This study proposes a model of how the L- and D-dibenzoyltartrate anions recognize the chirality of the hydrophobic [Ru(bpy)(2)(py)(2)](2+) complex. The monoclinic unit cell contains four complex cations, four tartrate anions, and 48 water molecules. Since there are no possibilities to form hydrogen bonds between the cations and anions, chiral recognition is due to crystal packing. Two benzoyl rings of two different tartrate anions are gripping the two bpy-planes of the Ru-complex. Further a third benzoyl ring from a tartrate anion is packed between the two pyridine rings, favoring one enantiomeric form to crystallize from aqueous solution. Crystal structure data for I at 153 K: a = 15.342(3) A, b = 19.200(4) A, c = 18.872(4) A, beta = 104.841(3) degrees, monoclinic space group C(2), R(1)= 0.0239 (I > 2sigma(I)), R(2) = 0.0606, Flack parameter = 0.0115 (with esd 0.0166). For II at 293 K: a = 15.376(4) A, b = 19.388(11) A, c = 19.085(7) A, beta = 105.11(2) degrees, monoclinic space group C121, R(1)= 0.0686 (I > 2sigma(I)), R(2) = 0.1819, Flack parameter = -0.0100 (with esd 0.0521).
Dinuclear and polynuclear metal complexes with octahedral eluent contains NaCl. Modeling the ΛΛ and the ∆Λ isomers of the dinuclear species shows crowding of the pinene centers coordinated to di-or polydentate ligands are often obtained as complicated mixtures of various stereoisomers. groups in both cases; however, the strain can be released by relatively small distortions only in the case of the ΛΛ isomer. Stereospecific synthesis of such species is therefore of high current interest. Chiral derivatives of pyridine can be used NO 3 -cleaves the dichloro bridge, yielding the mononuclear species ∆[Rh(L 2 ) 2 (NO 3 )] (2) in a completely stereoselective for this purpose. Dinuclear µ-chloro-bridged Rh III complexes with two didentate, cyclometalated thienylpyridine-type manner when NaCl is replaced by KNO 3 in the eluent mixture. The molecular structure has been determined by Xligands at each metal center are formed stereoselectively when pinene groups are fused to the pyridine rings. The two ray structure analysis for both the ∆∆ and the mononuclear complex ∆[Rh(L 2 ) 2 (NO 3 )] (2) in order to confirm the octahedral Rh III centers have homochiral configurations, ∆∆ and ΛΛ. The heterochiral diastereomer ∆Λ is not observed. configuration at the metal center.1 H-NMR, 13 C-NMR and CD spectra were measured and the latter shows that the CD With (8R,10R)-2-(2Ј-thienyl)-4,5-pinenopyridine [Hth4,5-(R,R)ppy] the ∆∆ to ΛΛ ratio is 9:1 when the separation activity is solely due to the chirality at the metal center.
Dinuclear and polynuclear metal complexes with octahedral centers coordinated to di‐ or polydentate ligands are often obtained as complicated mixtures of various stereoisomers. Stereospecific synthesis of such species is therefore of high current interest. Chiral derivatives of pyridine can be used for this purpose. Dinuclear μ‐chloro‐bridged RhIII complexes with two didentate, cyclometalated thienylpyridine‐type ligands at each metal center are formed stereoselectively when pinene groups are fused to the pyridine rings. The two octahedral RhIII centers have homochiral configurations, ΔΔ and ΛΛ. The heterochiral diastereomer ΔΛ is not observed. With (8R,10R)‐2‐(2′‐thienyl)‐4,5‐pinenopyridine [Hth4,5‐(R,R)ppy] the ΔΔ to ΛΛ ratio is 9:1 when the separation eluent contains NaCl. Modeling the ΛΛ and the ΔΛ isomers of the dinuclear species shows crowding of the pinene groups in both cases; however, the strain can be released by relatively small distortions only in the case of the ΛΛ isomer. NO3− cleaves the dichloro bridge, yielding the mononuclear species Δ[Rh(L2)2(NO3)] (2) in a completely stereoselective manner when NaCl is replaced by KNO3 in the eluent mixture. The molecular structure has been determined by X‐ray structure analysis for both the ΔΔ and the mononuclear complex Δ[Rh(L2)2(NO3)] (2) in order to confirm the configuration at the metal center. 1H‐NMR, 13C‐NMR and CD spectra were measured and the latter shows that the CD activity is solely due to the chirality at the metal center.
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