Structure of metal adducts of anthracyclines probed by absorption, circular dichroism and paramagnetic NMR

Bari, Lorenzo Di; Pintacuda, Guido; Ripoli, Silvia; Salvadori, Piero

doi:10.1002/mrc.1026

Cited by 19 publications

(18 citation statements)

References 40 publications

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“…The solution structure was optimized on the basis of the experimental proton pseudocontact shifts (PCS) through the computer program PERSEUS. 16,18 PERSEUS modifies the dihedrals describing the rotation around N -C and C -C bonds of the side arms, starting from a tentative structure of Yb-3 and varying the position of the metal with respect to the ligand. For each conformation, the paramagnetic shifts of the ligand protons are calculated using Eq.…”

Section: Analysis Of the Pseudocontact Shiftsmentioning

confidence: 99%

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Monitoring proton dissociation and solution conformation of chiral ytterbium complexes with near‐IR CD

et al. 2005

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The ytterbium complex [Yb((S)-THP)](3+) ((S)-THP = (1S,4S,7S,10S-tetrakis(2-hydroxypropyl)-1,4,7,10-tetraazacyclododecane) is investigated in solution through NMR, near-IR absorption, and CD spectroscopy. Quantitative analysis of the paramagnetic pseudocontact NMR shift shows Lambda helicity of the ligand cage around the metal. The NIR CD spectrum recorded at acidic pH is found to be very similar to that of [Yb((R)-DOTMA)](-) ((R)-DOTMA = (1R,4R,7R,10R)-alpha,alpha',alpha'',alpha'''-tetramethyl-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid), which in solution assumes a twisted square antiprism (TSA) conformation. The similarity of the NIR CD spectra is discussed, and it is the first proof of the Lambda(lambda,lambda,lambda,lambda) conformation of [Yb((S)-THP)](3+). NIR CD spectra recorded in the pH range of 2-9 allow one to easily follow proton dissociation and to calculate the pK of this equilibrium in water (pK(A) = 6.4 +/- 0.1). This value agrees well with that determined for [Lu((S)-THP)](3+) using potentiometric methods. This demonstrates once again that NIR CD spectroscopy is a powerful technique for investigating the solution structure and dynamics of these complexes.

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Section: Analysis Of the Pseudocontact Shiftsmentioning

confidence: 99%

“…Thus PCSs can be used as structural restraints for calculation of the solution structure. 16,18 The Yb(III) ion is also active in optical spectroscopy owing to the intra-configurational f -f electronic transitions of the metal ion. The relative absorptions fall in the near-IR region, far from the typical bands of most ligands.…”

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Monitoring proton dissociation and solution conformation of chiral ytterbium complexes with near‐IR CD

et al. 2005

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“…However, lanthanides such as Yb III and Nd III are being explored for their use as probes because they emit in the near IR (NIR), which is beneficial for biological studies since NIR wavelengths are efficiently absorbed by cells. [28][29][30][31][32][33] Time-resolved luminescence lifetimes, luminescence intensity, [32] ratiometrics of emission bands, [11,13] excitation spectra, and polarization [34,35] of Ln III photoluminescence are characteristics that have been used to discriminate between anions of biological interest upon interaction with Ln III complexes. Dinuclear Ln III ion complexes are of interest as luminescent sensors partly because their anion binding properties are different than those of their mononuclear analogs.…”

Section: The Preferred Lnmentioning

confidence: 99%

Luminescence Resonance Energy Transfer in Heterodinuclear Ln^III Complexes for Sensing Biologically Relevant Anions

Andolina

Morrow

2010

Eur J Inorg Chem

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“…An interpretation of the spectra of Yb1 and Yb2 was achieved with the aid of the program PERSEUS. 21,22 The MM structures for Yb1 and Yb2 were assumed for the input ligand geometry. These provided reasonably good fits of the δ pc , leaving only the five independent components of the tensor χ as variables, as shown in Table 1 and Table 2.…”

Section: Analysis Of the Paramagnetic Nmr Shiftsmentioning

confidence: 99%

Structural and Chiroptical Properties of the Two Coordination Isomers of YbDOTA-Type Complexes

et al. 2005

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Studies of the structural, physical, and chemical properties of the lanthanide(III) complexes of DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) and related ligands are often complicated by the presence of two coordination isomers in solution. Since these coordination isomers are in exchange and cannot be separated, many techniques offer information only on the weighted average of the two isomers. Lanthanide ion complexes formed with the ligands S(RRRR)NO 2 BnDOTMA and S(SSSS)NO 2 BnDOTMA preferentially adopt only one of the two common coordination isomers in solution, so the ytterbium complexes of these ligands offer a unique opportunity to study the nearinfrared circular dichroism (NIR-CD) characteristics of each coordination geometry in isolation. The spectra acquired support many of the conclusions and assumptions of previous studies and demonstrate that this spectroscopy is particularly sensitive to the distortion of the coordination polyhedron. This will have particularly relevant consequences when studying achiral YbDOTA-like systems forming labile adducts with (chiral) hosts and receptors.

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Structure of metal adducts of anthracyclines probed by absorption, circular dichroism and paramagnetic NMR

Abstract: A structural study of metal ion adducts of a new anthracycline disaccharide (MEN 10755) was undertaken.

Cited by 19 publications

References 40 publications

Monitoring proton dissociation and solution conformation of chiral ytterbium complexes with near‐IR CD

Monitoring proton dissociation and solution conformation of chiral ytterbium complexes with near‐IR CD

Luminescence Resonance Energy Transfer in Heterodinuclear Ln^III Complexes for Sensing Biologically Relevant Anions

Structural and Chiroptical Properties of the Two Coordination Isomers of YbDOTA-Type Complexes

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Structure of metal adducts of anthracyclines probed by absorption, circular dichroism and paramagnetic NMR

Abstract: A structural study of metal ion adducts of a new anthracycline disaccharide (MEN 10755) was undertaken.

Cited by 19 publications

References 40 publications

Monitoring proton dissociation and solution conformation of chiral ytterbium complexes with near‐IR CD

Monitoring proton dissociation and solution conformation of chiral ytterbium complexes with near‐IR CD

Luminescence Resonance Energy Transfer in Heterodinuclear LnIII Complexes for Sensing Biologically Relevant Anions

Structural and Chiroptical Properties of the Two Coordination Isomers of YbDOTA-Type Complexes

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Luminescence Resonance Energy Transfer in Heterodinuclear Ln^III Complexes for Sensing Biologically Relevant Anions