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Covalent immobilization of dysprosium-based metal–organic chains on silicon-based polymer brush surfaces

Cover of the New Journal of Chemistry Issue 15, 2017

New Journal of Chemistry, Issue 15, 2017

http://pubs.rsc.org/en/journals/journalissues/nj

URL

http://dx.doi.org/10.1039/C7NJ00683G

Abstract

We report on a process for immobilizing metal-organic chains constructed of dysprosium and sodium ions based on 5-aminopyridine-2-carboxylic acid{,} onto silicon-based surfaces coated with poly(acrylic acid) (PAA) polymer brushes. Atomic force microscopy (AFM) and fluorescence microscopy were used to study the film morphology before and after the deposition of the 1D metallo-organic polymer. The covalent linkage of the dysprosium complex is also confirmed using X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray spectroscopy (SEM-EDS) analysis. Using magnetic force microscopy (MFM) we particularly addressed the magnetic properties of the grafted metal-organic structure. These results suggest a simple and effective method for incorporation of such molecules onto nanometric surfaces.
 

 

Peptoid-Ligated Pentadecanuclear Yttrium and Dysprosium Hydroxy Clusters

Chemistry A Europena Journal, Issue 7, 2015

http://onlinelibrary.wiley.com/doi/10.1002/chem.201405569/abstract

URL

http://dx.doi.org/10.1002/chem.201405569

Abstract

A new family of pentadecanuclear coordination cluster compounds (from now on simply referred to as clusters) [{Ln15(OH)20(PepCO2)10(DBM)10Cl}Cl4] (PepCO2=2-[{3-(((tert-butoxycarbonyl)amino)methyl)benzyl}amino]acetate, DBM=dibenzoylmethanide) with Ln=Y and Dy was obtained by using the cell-penetrating peptoid (CPPo) monomer PepCO2H and dibenzoylmethane (DBMH) as supporting ligands. The combination of an inorganic cluster core with an organic cell-penetrating peptoid in the coordination sphere resulted in a core component {Ln15(μ3-OH)20Cl}24+ (Ln=Y, Dy), which consists of five vertex-sharing heterocubane {Ln4(μ3-OH)4}8+ units that assemble to give a pentagonal cyclic structure with one Cl atom located in the middle of the pentagon. The solid-state structures of both clusters were established by single-crystal X-ray crystallography. MS (ESI) experiments suggest that the cluster core is robust and maintained in solution. Pulsed gradient spin echo (PGSE) NMR diffusion measurements were carried out on the diamagnetic yttrium compound and confirmed the stability of the cluster in its dicationic form [{Y15(μ3-OH)20(PepCO2)10(DBM)10Cl}Cl2]2+. The investigation of both static (dc) and dynamic (ac) magnetic properties in the dysprosium cluster revealed a slow relaxation of magnetization, indicative of single-molecule magnet (SMM) behavior below 8 K. Furthermore, the χT product as a function of temperature for the dysprosium cluster gave evidence that this is a ferromagnetically coupled compound below 11 K.