Showing papers by "Jerzy Lisowski published in 2013"

Incorporation of trinuclear lanthanide(III) hydroxo bridged clusters in macrocyclic frameworks.

Abstract: A cluster of lanthanide(III) or yttrium(III) ions, Ln3(μ3-OH)2, (Ln(III) = Nd(III), Sm(III), Eu(III), Gd(III), Tb(III), Dy(III), Yb(III), or Y(III)) can be bound in the center of a chiral macrocyclic amines H3L1R, H3L1S, and H3L2S obtained in a reduction of a 3 + 3 condensation product of (1R,2R)- or (1S,2S)-1,2-diaminocyclohexane and 2,6-diformyl-4-methylphenol or 2,6-diformyl-4-tertbutylphenol. X-ray crystal structures of the Nd(III), Sm(III), Gd(III), Dy(III), and Y(III) complexes reveal trinuclear complexes with Ln(III) ions bridged by the phenolate oxygen atoms of the macrocycle as well as by μ3-hydroxo bridges. In the case of the Nd(III) ion, another complex form can be obtained, whose X-ray crystal structure reveals two trinuclear macrocyclic units additionally bridged by hydroxide anions, corresponding to a [Ln3(μ3-OH)]2(μ2-OH)2 cluster encapsulated by two macrocycles. The formation of trinuclear complexes is confirmed additionally by 1H NMR, electrospray ionization mass spectrometry (ESI MS), and...

Anion and Solvent Induced Chirality Inversion in Macrocyclic Lanthanide Complexes

Abstract: A series of the lanthanide(III) or yttrium(III) complexes of the type [LnL(NO3)(H2O)2](NO3)2, [LnL(NO3)(H2O)](NO3)2, [LnL(H2O)2](NO3)3, and [LnLCl(H2O)2]Cl2 where L is an all-R or all-S enantiomer (L(R) or L(S)) of the chiral hexaaza macrocycle, 2(R),7(R),18(R),23(R)- or 2(S),7(S),18(S),23(S)-1,8,15,17,24,31-hexaazatricyclo[25.3.1.1.0.0]-dotriaconta-10,12,14,26,28,30-hexaene, and Ln(III) = Sm(III), Tb(III), Ho(III), Er(III), Tm(III), Yb(III), Lu(III), or Y(III), have been synthesized and structurally characterized. The crystal structure of the free macrocycle shows a highly twisted molecule, preorganized for the formation of helical complexes. The crystal structures of the lanthanide(III) complexes show two different diastereomeric forms of the macrocycle with different configurations at the stereogenic amine nitrogen atoms: (RRRR) or (RSRS) (denoted as L(RI) and L(RII), respectively). The L(RI) diastereomeric form of the nitrate derivatives [LnL(NO3)(H2O)](NO3)2 (Ln = Ho, Er) and [LnL(H2O)2](NO3)3 (Ln = Tm, Yb, Lu) convert slowly to the L(RII) form in methanol or acetonitrile solutions, while this process is not observed for the L(RI) diastereomers of analogous chloride derivatives [LnL(H2O)2]Cl3 (Ln = Tm, Yb, Lu). On the other hand, the L(RI) → L(RII) conversion for these Tm(III), Yb(III), and Lu(III) chloride derivatives can be triggered by the addition of external nitrate anions. The circular dichroism (CD) and (1)H NMR data indicate initial fast exchange of axial chloride for axial nitrate ligand, followed by slow chirality inversion of the equatorial macrocyclic ligand.

Structural characterization and DFT calculation of the Fe–C coordinating bond in bis(tert-butyl isocyanide) iron(II) phthalocyanine

Abstract: Bis(tert-butyl isocyanide) iron(II) phthalocyanine complex in the crystalline form was obtained by a direct reaction of β-FePc with tert-butyl isocyanide. This complex crystallizes in the centrosymmetric space group P 21/c of the monoclinic system. The Fe(II) cation is equatorially ligated by the four N-isoindole atoms of Pc2- macrocycle and axially by the C atom of tert-butyl isocyanide on both sides of a planar FePc molecule. Gas-phase conformation of the bis(tert-butyl isocyanide) iron(II) phthalocyanine molecule obtained by molecular orbital calculations shows a similar conformation as in the crystal. In both phases (solid and gas) a similar correlation between the equatorial Fe–N and axial Fe–C bonds are observed. Steric hindrance of the tert-butyl isocyanide molecules ligated to Fe in axial positions of planar FePc leads to the lowering of the π–π interaction between the π-clouds of Pc macrorings and makes the crystals of the bis(tert-butyl isocyanide) iron(II) phthalocyanine complex better soluble ...