Substitutionally inert complexes as chiral synthons for stereospecific supramolecular syntheses

MacDonnell, Frederick M.; Kim, Mahn Jong; Bodige, Swamy

doi:10.1016/s0010-8545(99)00030-2

Cited by 62 publications

(42 citation statements)

References 29 publications

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“…[51][52][53][54] It is noteworthy that MacDonnell's group have found that although a linear fit exists between the CD intensity of the MLCT band (500 nm) and the "enantiomeric excess" of Ru(II) stereocenters for a series of polynuclear complexes, 52 the same is not true for the ligandcentered bands. 55 (ii) Complexes of the HAT Ligand.…”

Section: Resultsmentioning

confidence: 99%

CD Spectra of Polynuclear Complexes of Diimine Ligands: Theoretical and Experimental Evidence for the Importance of Internuclear Exciton Coupling

2004

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We have recently reported on dinuclear complexes Lambda,Lambda-[Co(2)L(2)Cl(2)]CoCl(4) of two novel chiral ligands (1a and 1b) which contain pyridyl-imine chelate groups (Telfer, S. G.; Sato, T.; Kuroda, R. Chem. Commun. 2003, 1064-1065). The absolute configuration of the cobalt(II) centers was unambiguously assigned by X-ray crystallography. However, the sign of the exciton couplets in their CD spectra was opposite to that expected on the basis of the stereochemistry of the metal centers. We present a rationalization of these anomalous spectra in terms of an "internuclear" exciton coupling model which takes into account the coupling of chromophores located on different metal centers. We have performed a series of semiempirical (ZINDO) calculations which provide quantitative support to this model. These findings show that the absolute configuration of the metal centers in a polynuclear complex may be incorrectly assigned on the basis of CD data if internuclear coupling effects are not taken into consideration. We summarize the CD spectral data of number of other chiral polynuclear complexes from the literature, including dinuclear complexes bridged by the 2,2'-bipyrimidine ligand, complexes of the HAT ligand, and dinuclear triple-stranded helicates. The amplitude of the CD spectra of many of these complexes is not additive with the number of chromophores. These anomalous spectra can be accounted for by taking internuclear coupling effects into consideration.

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Section: Resultsmentioning

confidence: 99%

CD Spectra of Polynuclear Complexes of Diimine Ligands: Theoretical and Experimental Evidence for the Importance of Internuclear Exciton Coupling

2004

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“…Analyses were conducted in a CH 3 OH/ H 2 O 1:1 mixture, chosen because our DNA cleavages were performed in aqueous solution. High concentrations of CuCl 2 complexes (10 Ϫ4 and 10 Ϫ5 ) and different orifice voltages (50,5, but also 0 V) were tested with the goal of promoting the observation of L 2 Cu 2 complexes (see ref.…”

Section: Mass Analysismentioning

confidence: 99%

DNA Cleavage by Copper Complexes of 2‐ and 3‐Clip‐Phen Derivatives

et al. 2003

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The DNA cleavage activity of copper complexes of phenanthroline has been increased by the use of “2‐Clip‐Phen” and “3‐Clip‐Phen” ligands containing two phenanthroline entities linked by a serinol bridge. In order to optimize DNA cleavage activity, two series of new Clip‐Phen ligands (L) with two phenanthroline residues linked through their C‐2 or C‐3 carbon atoms by different bridges have been synthesized. The physicochemical properties and the DNA cleavage activities of the corresponding (Clip‐Phen)copper complexes were investigated in the presence of a reductant and air. X‐ray analyses of single crystals showed that the cupric complexes of Clip‐Phen were able adopt dimeric double‐helical geometries with L2Cu2 stoichiometries in the solid state. These complexes adopt different geometries and stoichiometries in solution, with monomeric LCu species predominant. The compounds with a bridge connected at C‐2 are less active as DNA cleavage agents than complexes with the bridge at the C‐3 positions. Copper complexes with a bridge containing three methylene units appear to give the best results in DNA cleavage experiments. This activity is increased in the case of 3‐Clip‐Phen·CuCl2 by the presence of the primary amine function of the serinol bridge. This amine function is probably coordinated to the copper atom in the case of 2‐Clip‐Phen·CuCl2, decreasing the reactivity toward DNA. (© Wiley‐VCH Verlag GmbH & Co KGaA, 69451 Weinheim, Germany, 2003)

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“…The metal chelating properties of 1,10-phenenthroline have been widely utilized in all aspects of coordination chemistr such as ligand substitution, redox reactions, photochemical reactions and photophysical properties, as well as in its recent applications to develop biomimetic models of metalloenzymes and to prepare supramolecules, self-assembling systems, or metal complexes with interesting anticancer properties. 1,2 In this work, we synthesized the title compound and determined its crystal structure.Preparation. The title compound, Fig.…”

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confidence: 99%

Synthesis and Crystal Structure of (Carbonato)bis(1,10-phenanthroline)-cobalt(III) Nitrate Trihydrate, [Co(phen)2CO3]NO3 3H2O

et al. 2007

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1,10-Phenenthroline (phen) complexes have been studied extensively. Phen is a well-known N-heterocyclic chelating agent with a rigid planar structure. The metal chelating properties of 1,10-phenenthroline have been widely utilized in all aspects of coordination chemistr such as ligand substitution, redox reactions, photochemical reactions and photophysical properties, as well as in its recent applications to develop biomimetic models of metalloenzymes and to prepare supramolecules, self-assembling systems, or metal complexes with interesting anticancer properties. 1,2 In this work, we synthesized the title compound and determined its crystal structure.Preparation. The title compound, Fig. 1, was prepared by adding 1,10-phenenthroline (396 mg, 2 mmol) to a solution of Co(NO3)2·6H2O (291 mg, 1 mmol) in 50 ml water under N2. To the orange solution was then added (NH4)2CO3 (96 mg, 1 mmol) and stirred at 60˚C for 30 min. The dark-brown solution was then aerated for 3 h. The resulting red precipitate was filtered and recrystallized from water to yield the title complex as red crystals.The X-ray data were collected on a diffractometer (Mo Kα radiation, graphite monochromator) at 293(2)K. The crystal data and the experimental parameters are given in Table 1. The non-hydrogen atoms were refined anisotropically, and all hydrogen atoms were located from sequent difference Fourier maps and refined with the riding model to final R indices of R1(0.0581) and wR2(0.1412).A view of this compound, including the atomic numbering scheme, is illustrated in Fig. 2. Selected bond distances and bond angles are given in Table 2

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Substitutionally inert complexes as chiral synthons for stereospecific supramolecular syntheses

Cited by 62 publications

References 29 publications

CD Spectra of Polynuclear Complexes of Diimine Ligands: Theoretical and Experimental Evidence for the Importance of Internuclear Exciton Coupling

CD Spectra of Polynuclear Complexes of Diimine Ligands: Theoretical and Experimental Evidence for the Importance of Internuclear Exciton Coupling

DNA Cleavage by Copper Complexes of 2‐ and 3‐Clip‐Phen Derivatives

Synthesis and Crystal Structure of (Carbonato)bis(1,10-phenanthroline)-cobalt(III) Nitrate Trihydrate, [Co(phen)2CO3]NO3 3H2O

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