Publications by André Merbach

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n a previous paper, we reported the first longitudinally detected electron paramagnetic resonance (LODEPR) measurements of fast T1e values in aqueous solutions of two Gd3+ chelates, and we included predicted values for these relaxation times, based on zero field splitting (ZFS) parameters derived from multifrequency EPR data on the two systems [Atsarkin, V. A.; Demidov, V. V.; Vasneva, G. A.; Odintsov, B. M.; Belford, R. L.; Radüchel, B.; Clarkson, R. B. J. Phys. Chem. 2001, 105, 9323-9327]. The model used

High‐pressure 1H‐NMR. has been used to determine volumes of activation (ΔV #) for solvent exchange with [M(S)6]3+ ion (M = Al(III), Ga(III); S = dimethylsulfoxide (DMSO) and N,N‐dimethylformamide (DMF)) in [2H]3‐nitromethane solution. For Al(III),Δ V # = + 15.6 ± 1.4 (S = DMSO, 358.5 K) and ΔV # = + 13.7 ± 1.2 cm3mol−1 (S = DMF, 354.5 K), whilst for Ga(III), ΔV # = + 13.1 ± 1.0 (S = DMSO, 334.6 K) and ΔV # = +7.9 ± 1.6 cm3mol−1 (S= DMF, 313.8 K). Variable temperature studies over a temperature range of 107.

An account of our most recent studies on the application of high pressure kinetic techniques in mechanistic studies of inorganic reactions is presented. The investigated reactions include substitution, addition, insertion, elimination, electron-transfer, photo-induced substitution, and irradiation-induced processes. In addition some data for typical bioinorganic systems are reported and future perspectives are described. The account clearly demonstrates that high pressure kinetics adds a further dimension t

The equilibrium between [Ce(H2O)9]3+ and [Ce(H2O)8]3+ has been followed in aqueous solution at 298 K by variable‐pressure UV spectroscopy at 295 nm. The dervied volume of reaction for the dissociation of this enneaaqua ion is ΔV 0 = +10.9 cm3. mol−1. This value, together with the previously determined activation volume, ΔV ≠ = −6 cm3. mol−1, for H2O exchange on [Ln(H2O)8]3+ (Ln = Tb to Tm), allows the assignment of an associative interchange I a mechanism on these octaaqua ions.

With their nanoscalar, superparamagnetic Gd3+-ion clusters (1 ´ 5 nm) confined within ultrashort (20-80 nm) single- walled carbon nanotube capsules, gadonanotubes are high- performance T1-weighted contrast agents for magnetic resonance imaging (MRI). At 1. ...

Platinum resistance thermometry has been used for temperature measurement in situ in a high-pressure vessel up to 360 MPa. Commercially available 100 Omega platinum resistors have been calibrated against pressure for temperatures between -60 and +100 degrees C. A convenient small four-wire electrical connector has been developed for use up to 500 MPa.

A multiple-frequency (9.4-325 GHz) and variable-temperature (276-320 K) electron paramagnetic resonance (EPR) study on low molecular weight gadolinium(III) complexes for potential use as magnetic resonance imaging (MRI) contrast agents has been performed. ...

Good things come in small packages: For its moderate molecular weight, the metallostar complex [Fe{Gd2L(H2O)4}3]4− (see picture; L is a bipyridine–poly(aminocarboxylate) derivative) displays exceptionally high proton relaxivity, which is explained in terms ...

Gd(III) (S = 7/2) polyaminocarboxylates, used as contrast agents for Magnetic Resonance Imaging (MRI), were studied in frozen solutions by High-Frequency-High-Field Electron Paramagnetic Resonance (HF-EPR). EPR spectra recorded at 240 GHz and temperatures ...

The labile cobalt (II) complex [Co(TUF)2(Pic)2] with 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione (TUF) bidentate and 4-methylpyridine (Pic) monodentate ligands was studied by variable temp. (VT) 19F NMR from 184 to 312 K. In contrast to the solid state, ...

The pH-dependent water-exchange rates of [(CO)2(NO)Re(H2Ocis)2(H2Otrans)]2+ (1) in aq. media were investigated by means of 17O NMR spectroscopy at 298 K. Because of the low pKa value found for 1 (pKa = 1.4 ± 0.3), the water-exchange rate const. kobsH2Otran ...

André Merbach

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T1e in Four Gd3+ Chelates: LODEPR Measurements and Models for Electron Spin Relaxation

Supramolecular Assembly of an Amphiphilic GdIII Chelate: Tuning the Reorientational Correlation Time and the Water Exchange Rate

High-pressure NMR kinetics. Part 10. Volumes of activation for dimethyl sulfoxide and N,N-dimethylformamide exchange with hexasolvates of aluminum(III) and gallium(III) ions in deuterionitromethane solution

High pressure kinetics. A decisive dimension in mechanistic studies of inorganic reactions

The reaction volume for the equilibrium between the lanthanide(III) ennea- and octaaqua ions as a diagnostic aid for their water-exchange mechanisms

Gadonanotubes as Ultrasensitive pH-Smart Probes for Magnetic Resonance Imaging

Temperature measurement under high pressure using commercial platinum resistors

Unexpected Aggregation of Neutral, Xylene-Cored Dinuclear GdIII Chelates in Aqueous Solution

Design of Gd(III)-Based Magnetic Resonance Imaging Contrast Agents: Static and Transient Zero-Field Splitting Contributions to the Electronic Relaxation and Their Impact on Relaxivity

High Relaxivity Confined to a Small Molecular Space: A Metallostar-Based, Potential MRI Contrast Agent

Relevance of the Ligand Exchange Rate and Mechanism of fac-[(CO)3M(H2O)3]+ (M = Mn, Tc, Re) Complexes for New Radiopharmaceuticals

Separation and Characterization of the Two Diastereomers for [Gd(DTPA-bz-NH2)(H2O)]2-, a Common Synthon in Macromolecular MRI Contrast Agents: Their Water Exchange and Isomerization Kinetics

A High-Frequency EPR Study of Frozen Solutions of Gd(III) Complexes: Straightforward Determination of the Zero-Field Splitting Parameters and Simulation of the NMRD Profiles

Gadolinium(III) complexes of mono-and diethyl esters of monophosphinic acid analogue of DOTA as potential MRI contrast agents: solution structures and relaxometric studies

Fine-tuning water exchange on GdIII poly(amino carboxylates) by modulation of steric crowding

Physicochemical and MRI characterization of Gd3+-loaded polyamidoamine and hyperbranched dendrimers

Rigid M(II)L2Gd(III)2 (M=Fe, Ru) Complexes of a Terpyridine-Based Heteroditopic Chelate: A Class of Candidates for MRI Contrast Agents

Isomerization mechanisms of a labile Co(II) octahedral complex

Water-Exchange Study Revealed Unexpected Substitution Behavior of [(CO)2(NO)Re(H2O)3]2+ in Aqueous Media

Inorganic and Bioinorganic Solvent Exchange Mechanisms