Coordination Polymers: Discrete Systems

Constable, Edwin C.

doi:10.1016/b0-08-043748-6/06203-4

Cited by 9 publications

(3 citation statements)

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“…Metallostars are by definition first-generation metallodendrimers. [21] Usually, only compounds having a core connectivity of three or greater are considered, which excludes topologically linear dinuclear and trinuclear systems. The ligand H 8 bpy(DTTA) 2 was designed by considering the following features.…”

Section: Introductionmentioning

confidence: 99%

A Starburst‐Shaped Heterometallic Compound Incorporating Six Densely Packed Gd³⁺ Ions

Livramento

Sour

Borel

et al. 2006

Chemistry A European J

115

144

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The heterotritopic ligand [bpy(DTTA)2]8- has two diethylenediamine-tetraacetate units for selective lanthanide(III) coordination and one bipyridine function for selective Fe(II) coordination. In aqueous solution and in the presence of these metals, the ligand is capable of self-assembly to form a rigid supramolecular metallostar structure, [Fe[Gd2bpy(DTTA)2(H2O)4]3]4-. We report here the physicochemical characterization of the dinuclear complex [Gd2bpy(DTTA)2(H2O)4]2- and the metallostar [Fe[Gd2bpy(DTTA)2(H2O)4]3]4- with regard to potential MRI contrast agent applications. A combination of pH potentiometry and 1H NMR spectroscopy has been used to determine protonation constants for the ligand [bpy(DTTA)2]8- and for the complexes [Fe[bpy(DTTA)2]3]22- and [Y2bpy(DTTA)2]2-. In addition, stability constants have been measured for the dinuclear chelates [M2bpy(DTTA)2]n- formed with M = Gd3+ and Zn2+ (log K(GdL) = 18.2; log K(ZnL) = 18.0; log K(ZnHL) = 3.4). A multiple field, variable-temperature 17O NMR and proton relaxivity study on [Gd2bpy(DTTA)2(H2O)4]2- and [Fe[Gd2bpy(DTTA)2(H2O)4]3](4-) yielded the parameters for water exchange and the rotational dynamics. The 17O chemical shifts are indicative of bishydration of the lanthanide ion. The exchange rates of the two inner-sphere water molecules are very similar in the dinuclear [Gd2bpy(DTTA)2(H2O)(4)]2- and in the metallostar (k(ex)298 = 8.1 +/- 0.3 x 10(6) and 7.4 +/- 0.2 x 10(6) s(-1), respectively), and are comparable to k(ex)298 for similar Gd(III) poly(amino carboxylates). The rotational dynamics of the metallostar has been described by means of the Lipari-Szabo approach, which involves separating global and local motions. The difference between the local and global rotational correlation times, tau(lO)298 = 190 +/- 15 ps and tau(gO)298 = 930 +/- 50 ps, respectively, shows that the metallostar is not completely rigid. However, the relatively high value of S2 = 0.60 +/- 0.04, describing the restriction of the local motions with regard to the global one, points to a limited flexibility compared with previously reported macromolecules such as dendrimers. As a result of the two inner-sphere water molecules, with their near-optimal exchange rate, and the limited flexibility, the metallostar has a remarkable molar proton relaxivity, particularly at high magnetic fields (r1 = 33.2 and 16.4 mM(-1) s(-1) at 60 and 200 MHz, respectively, at 25 degrees C). It packs six efficiently relaxing Gd(III) ions into a small molecular space, which leads, to the best of our knowledge, to the highest relaxivity per molecular mass ever reported for a Gd(III) complex. The [bpy(DTTA)2]8- ligand is also a prime candidate as a terminal ligand for constructing larger sized, Fe(II) (or Ru(II))-based metallostars or metallodendrimers loaded with Gd(III) on the surface.

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Section: Introductionmentioning

confidence: 99%

A Starburst‐Shaped Heterometallic Compound Incorporating Six Densely Packed Gd³⁺ Ions

Livramento

Sour

Borel

et al. 2006

Chemistry A European J

115

144

View full text Add to dashboard Cite

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“…FeCl 3 is essential when triggering catechols' chelating ability toward Fe 3+ that subsequently leads to strong complexes and, thus, high adhesion strengths while creating an acidic environment at the same time, similarly to the HCl case. [26] Additionally, FeCl 3 favors SF aggregation via the coordination of polar amino acids such as tyrosine and serine residues. [27] Figure 2b summarizes the tensile strength testing results as a function of the different curing agents used.…”

Section: Resultsmentioning

confidence: 99%

Bioinspired Biomaterial Composite for All‐Water‐Based High‐Performance Adhesives

et al. 2021

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The exceptional underwater adhesive properties displayed by aquatic organisms, such as mussels (Mytilus spp.) and barnacles (Cirripedia spp.) have long inspired new approaches to adhesives with a superior performance both in wet and dry environments. Herein, a bioinspired adhesive composite that combines both adhesion mechanisms of mussels and barnacles through a blend of silk, polydopamine, and Fe3+ ions in an entirely organic, nontoxic water‐based formulation is presented. This approach seeks to recapitulate the two distinct mechanisms that underpin the adhesion properties of the Mytilus and Cirripedia, with the former secreting sticky proteinaceous filaments called byssus while the latter produces a strong proteic cement to ensure anchoring. The composite shows remarkable adhesive properties both in dry and wet conditions, favorably comparing to synthetic commercial glues and other adhesives based on natural polymers, with performance comparable to the best underwater adhesives with the additional advantage of having an entirely biological composition that requires no synthetic procedures or processing.

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“…This ligand has a 2,2 0 -bipyridine moiety for specific Fe 2+ -, and two poly(amino carboxylates) for Gd 3+ -binding. In the presence of Fe 2+ and Gd 3+ , the system self-assembles to a metallostar {Fe[Gd 2 bpy(DTTA) 2 (H 2 O) 4 ] 3 } 4À structure (Scheme 3) (metallostars are by definition first-generation metallodendrimers [29]). More recently, a similar structure was constructed by self-assembly around the Ru 2+ ion, possessing very similar relaxation properties as the Fe 2+based analogue [30].…”

Section: Gd-based Mri Contrast Agents For Application At High Magneti...mentioning

confidence: 99%

Towards highly efficient, intelligent and bimodal imaging probes: Novel approaches provided by lanthanide coordination chemistry

Bonnet

Tóth

2010

Comptes Rendus. Chimie

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Coordination Polymers: Discrete Systems

Cited by 9 publications

References 254 publications

A Starburst‐Shaped Heterometallic Compound Incorporating Six Densely Packed Gd³⁺ Ions

A Starburst‐Shaped Heterometallic Compound Incorporating Six Densely Packed Gd³⁺ Ions

Bioinspired Biomaterial Composite for All‐Water‐Based High‐Performance Adhesives

Towards highly efficient, intelligent and bimodal imaging probes: Novel approaches provided by lanthanide coordination chemistry

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Coordination Polymers: Discrete Systems

Cited by 9 publications

References 254 publications

A Starburst‐Shaped Heterometallic Compound Incorporating Six Densely Packed Gd3+ Ions

A Starburst‐Shaped Heterometallic Compound Incorporating Six Densely Packed Gd3+ Ions

Bioinspired Biomaterial Composite for All‐Water‐Based High‐Performance Adhesives

Towards highly efficient, intelligent and bimodal imaging probes: Novel approaches provided by lanthanide coordination chemistry

Contact Info

Product

Resources

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A Starburst‐Shaped Heterometallic Compound Incorporating Six Densely Packed Gd³⁺ Ions

A Starburst‐Shaped Heterometallic Compound Incorporating Six Densely Packed Gd³⁺ Ions