Soluble Ligand-Stabilized Cyano-Bridged Coordination Polymer Nanoparticles

Abstract

Size controlled organic phase soluble cyano-bridged bimetallic coordination polymer nanoparticles made of M n+ and [M′(CN)6]3− (with M n+ = Mn2+, Ni2+, Fe2+, Eu3+, Tb3+, Sm3+ and M′ = Fe3+, Cr3+) were synthesized by using oleic acid and trialkylamines or a triarylamine as stabilizing agents. The obtained nanoparticles were studied by transmission electronic microscopy (TEM), infrared and electronic spectroscopy, X-ray diffraction, and magnetic measurements. These analyses revealed the formation of spherical metallic cyano-bridged nanoparticles with sizes in the range of 2–5 nm depending on the nature of the metal ion used. The magnetic studies of these colloidal solutions revealed the presence of a pure superparamagnetic regime for the nanoparticles based on [Cr(CN)6]3− and a collective regime caused by weak dipolar interparticle interactions for the nanoparticles based on [Fe(CN)6]3−.

Towards the Ultimate Size Limit of the Memory Effect in Spin‐Crossover Solids

“…Herein, we report the synthesis and study of ultra‐small monodisperse nanoparticles of the 3D spin crossover coordination polymer [Fe(pyrazine){Ni(CN) 4 }],10 obtained using the biopolymer chitosan as matrix. It should be noted that investigations on the synthesis of cyano‐bridged coordination polymers at the nanoscale level have attracted a great deal of attention in recent years, and numerous methods have been reported, including the use of reverse micelles,11 ionic liquids,12 various ligands13 and polymers14 as stabilizing agents, biopolymers,15 amorphous16 and mesostructured silica,17 as well as porous alumina electrode18 as matrixes. Some of us recently published the synthesis and study of magnetic cyano‐bridged metallic coordination polymer nanoparticles M n + /[Fe(CN) 6 ] 3− with controlled size of 2–3 nm using chitosan beads as matrix 19.…”

Magnetization Reversal in CsNiIICrIII(CN)6 Coordination Nanoparticles: Unravelling Surface Anisotropy and Dipolar Interaction Effects

“…[ 1 ] In the past 10 years, the synthesis and the magnetic behaviour of coordination nanoparticles based on cyanidebridged networks has been the subject of intense research effort because of their versatile physical properties and particularly because of their magnetic, optical and thermal bistability. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] Among those networks are the bimetallic cyanide-bridged Prussian blue analogues (PBA) with face centred cubic structure ( Fm3m ) and general formula A x M y [M′(CN) 6 ] z , where M and M′ are divalent and trivalent metallic ions respectively and A is an alkaline ion. [19][20][21][22][23][24] The fi rst reports on PBA coordination nanoparticles using a bottom-up approach started in 1997 using different chemical processes that required the presence of an agent (organic or inorganic) to stabilize the particles, and thus precluded bulk of the particles and thus induce relatively large local anisotropy on the surface.…”

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5402www.MaterialsViews.com wileyonlinelibrary.com their post-modifi cation. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] We have reported an alternative surfactant-free synthesis that led, by adjusting the physico-chemical para meters, to the formation of stable colloidal aqueous solutions of nanocrystals with a narrow size distribution. [ 25,26 ] This stability originates from the negatively charged surface and has been exploited to set a versatile simple synthetic route for core-multishell heterostructured nanoparticles.

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Towards the Ultimate Size Limit of the Memory Effect in Spin‐Crossover Solids

“…This range is, however, accessible by chemical methods, which have the further advantage of allowing the synthesis of a large number of particles, and thus their physical characterization becomes feasible by standard averaging techniques, such as magnetometry.Herein, we report the synthesis and study of ultra-small monodisperse nanoparticles of the 3D spin crossover coordination polymer [Fe(pyrazine){Ni(CN) 4 }], [10] obtained using the biopolymer chitosan as matrix. It should be noted that investigations on the synthesis of cyano-bridged coordination polymers at the nanoscale level have attracted a great deal of attention in recent years, and numerous methods have been reported, including the use of reverse micelles, [11] ionic liquids, [12] various ligands [13] and polymers [14] as stabilizing agents, biopolymers, [15] amorphous [16] and mesostructured silica, [17] as well as porous alumina electrode [18] as matrixes. Some of us recently published the synthesis and study of magnetic cyano-bridged metallic coordination polymer nanoparticles M n+ /[Fe(CN) 6 ] 3À with controlled size of 2-3 nm using chitosan beads as matrix.…”