Publications by André Merbach

The Periodic Table and Kinetics?

Mendeleev in his first publication ordered the chemical elements following an apparent periodicity of properties such as atomic volume and valence. The reactivity of the elements was only studied systematically many years later. To illustrate the systemati ...

2019

Lanthanide Complexes Formed with the Tri- and Tetraacetate Derivatives of Bis(aminomethyl)phosphinic Acid: Equilibrium, Kinetic and NMR Spectroscopic Studies

Laurent Quebatte, André Merbach, Eva Jakab Toth

The lanthanide(III) complexes formed with the tri- and tetraacetate derivatives of bis(aminomethyl)phosphinic acid, L1 and L2, respectively, have been studied by pH potentiometry, spectrophotometry and 1H and 17O NMR spectroscopy. L1 forms [Ln(L1)], [Ln(L1 ...

Wiley-Blackwell2012

NMR Study of Ligand Exchange and Electron Self-Exchange between Oxo-Centered Trinuclear Clusters [Fe3(μ3-O)(μ-O2CR)6(4-R´py)3]+/0

André Merbach, Lothar Helm

The syntheses, single crystal X-ray structures, and magnetic properties of the homometallic mu(3)-oxo trinuclear clusters Fe-3(mu(3)-O)(mu-O2CCH3)(6)(4-Phpy)(3) (1) and F(e)3(mu(3)-O)(mu-O(2)CAd)(6)(4-Mepy)(3) (2) are reported (Ad = adamanta ...

American Chemical Society2011

Isomerization Mechanisms of Stereolabile tris- and bis-Bidentate Octahedral Cobalt(II) Complexes: X-ray Structure and Variable Temperature and Pressure NMR Kinetic Investigation

André Merbach, Lothar Helm, Rosario Scopelliti, Fabrice Riblet

The isomerization dynamics of five labile octahedral Co(II) compounds have been investigated by variable temperature and pressure 1H and 19F NMR spectroscopy in dichloromethane solution. The X-ray crystal structure of the two tris-chelates, [Co(HFA)2bpic] ...

American Chemical Society2010

Multiple Frequency and Variable Temperature EPR study of Gd(III) polyaminocarboxylates: analysis and comparison of the magnetically dilute powder and the frozen solution spectra

André Merbach, Lothar Helm, Alain Borel

An Electron Paramagnetic Resonance (EPR) study of glasses and magnetically dilute powders of [Gd(DTPA)(H2O)]2−, [Gd(DOTA)(H2O)]-, and macromolecular Gd-P792 complexes was carried out at X-, Q-band and 240 GHz DTPA=diethylenetriaminepentaacetato; DOTA=1,4,7 ...

Wiley-VHCA AG2009

Gadonanotubes as Ultrasensitive pH-Smart Probes for Magnetic Resonance Imaging

André Merbach, Lothar Helm, Eva Jakab Toth, Sabrina Laus

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. ...

American Chemical Society (ACS)2008

A benzene-core trinuclear GdIII complex: towards the optimization of relaxivity for MRI contrast agent applications at high magnetic field

André Merbach, Lothar Helm, Eva Jakab Toth, Joao Bruno Livramento Fig.

A novel ligand, H12L, based on a trimethylbenzene core bearing three methylenediethylenetriamine-N,N,N,N- tetraacetate moieties (–CH2DTTA4–) for Gd3+ chelation has been synthesized, and its trinuclear Gd3+ complex [Gd3L(H2O) 6]3– investigated with respect ...

2008

In vivo MRI assessment of a novel GdIII-based contrast agent designed for high magnetic field applications

André Merbach, Lothar Helm, Eva Jakab Toth, Joao Bruno Livramento Fig.

Gd3L is a trinuclear Gd3R complex of intermediate size, designed for contrast agent applications in high field magnetic resonance imaging (H12L is based on a trimethylbenzene core bearing three methylene-diethylenetriamine-N,N,N00,N00-tetraacetate moieties ...

2008

Mechanism of Pyridine-Ligand Exchanges at the Different Labile Sites of 3d Heterometallic and Mixed Valence μ3-oxo Trinuclear Clusters

André Merbach, Lothar Helm, Rosario Scopelliti, Fabrice Riblet

The syntheses and single crystal X-ray structural analysis of five novel hetero- and homometallic μ3-oxo trinuclear cluster with the formula [FeIII2MII(μ3-O)(μ-O2CCH3)6(4-Rpy)3] · x(4-Rpy) · y(CH3CN) where R ) Ph for 1(Fe2Mn),2(Fe2Fe), 3(Fe2Co), 4(Fe2Ni) a ...

2008

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

André Merbach, Loïck Moriggi, Lothar Helm, Eva Jakab Toth

Springer, Springer-Verlag2007

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

André Merbach, Loïck Moriggi, Lothar Helm, Alain Borel

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. ...

2007

A PCP-Pincer RuII-Terpyridine Building Block as a Potential "Antenna Unit" for Intramolecular Sensitization

André Merbach

The redox- and photoactive mononuclear complex [Ru(PCP)(tpy-DTTANa4)]Cl {PCP = [C6H3(CH2PPh2)2-2,6]-; tpy-DTTA4- = 4'-(2,2':6',2''-terpyridine)-diethylenetriamine-N,N,N'',N''-tetraacetate} possesses an externally directed, vacant N3O4 polyaminocarboxylate- ...

2007

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

André Merbach, Lothar Helm, Eva Jakab Toth, Petra Lebduskova

2007

Understanding Paramagnetic Relaxation Phenomena for Water-Soluble Gadofullerenes

André Merbach, Lothar Helm, Eva Jakab Toth, Sabrina Laus

2007

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

André Merbach, Lothar Helm, Pascal Grundler, Marie-Line Lehaire

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 ...

2006

Positively Charged GdIII Cryptates: Slow, Associative Water Exchange

André Merbach, Lothar Helm, Eva Jakab Toth

A combined variable-temp. and multiple field 17O NMR, EPR and NMRD study was performed for the 1st time on Gd(III) complexes of cryptand ligands, L1 and L2, where L1 contains three 2,2'-bipyridine units ([bpy.bpy.bpy]) and L2 is the disubstituted Me ester ...

2006

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

André Merbach, Lothar Helm, Pascal Grundler

2006

Kinetic studies on the first dihydrogen aquacomplex, [Ru(H2)(H2O)5]2+: Formation under H2 pressure and catalytic H/D isotope exchange in water

Gabor Laurenczy, André Merbach, Lothar Helm, Pascal Grundler, Oleg Yazyev

The ruthenium(II) hexaaqua complex [Ru(H2O)6]2+ reacts with dihydrogen under pressure to give the h2-dihydrogen ruthenium(II) pentaaqua complex [Ru(H2)(H2O)5]2+.The complex was characterized by 1H, 2H and 17O NMR: d H = -7.65 ppm, J HD = 31.2 Hz, d O = -80 ...

2006

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

André Merbach, Lothar Helm, Alain Borel

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 ...

2006

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

André Merbach, Eva Jakab Toth

2006