Nanomagnetic molecular materials based on the hexacyanometallate building block: the preparation and characterization of high-spin cluster and chain compounds

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dc.contributor.advisor Dunbar , Kim en_US
dc.contributor.committeeMember Naugle , Donald en_US
dc.creator Berlinguette , Curtis Paul en_US 2005 -08 -29T14 :35 :21Z 2014 -02 -19T19 :20 :09Z 2005 -08 -29T14 :35 :21Z 2014 -02 -19T19 :20 :09Z 2003 -05 en_US 2005 -08 -29T14 :35 :21Z
dc.identifier.uri http : / /hdl .handle .net /1969 .1 /2196
dc.description.abstract The work presented herein describes efforts to synthesize and characterize cyanide -bridged molecular compounds with high -spin ground states . This investigation focused primarily on the assembly of hexacyanometallate units with convergent cationic metal complexes that are coordinated to capping ligands . In this manner , a family of related compounds was developed that serve as models for understanding the role of magnetic exchange interactions and anisotropy in nanomagnetic materials . The work presented in Chapter II describes the successful incorporation of the [Fe (CN )6]3 - building block into planar geometries with nuclearities ranging from three to ten metal centers . In Chapter III , this methodology was optimized to yield two pentanuclear FeIII /NiII clusters , namely , the trigonal bipyramidal unit , {[Ni (tmphen )2]3[Fe (CN )6]2} , and the extended square , {[Ni (bpy )2 (H2O )][Ni (bpy )2]2 -[Fe (CN )6]2} . Magnetic measurements on pure phases of these samples revealed that each system exhibits ferromagnetic coupling between the L .S . FeIII and NiII centers , but neither exhibits slow paramagnetic relaxation effects down to T=2K . In Chapter IV , this chemistry was extended to the [Mn (CN )6]3 -building block in order to increase magnetic exchange coupling and anisotropy in this cluster type , efforts that resulted in the isolation of the molecule , {[Mn (tmphen )2]3[Mn (CN )6]2} . This cluster exhibits intramolecular antiferromagnetic exchange interactions between the Mn centers which lead to an S=11 /2 ground state and a negative ZFS value (D= -0 .348 cm -1 ) , parameters that support the experimental observation of Single -Molecule Magnet (SMM ) behavior at low temperatures . A detailed investigation of the physical and structural properties of {[Co (tmphen )2]3[Fe (CN )6]2} in Chapters V and VI led to the realization that the cluster exhibits sensitivity to temperature and humidity . The molecule exists in three different electronic isomeric forms in the solid state and undergoes a charge -transfer induced spin -transition (CTIST ) under the influence of temperature . The results presented in Chapter VI describe the behavior of this same cluster in solution , the highlight of which is the discovery that water reacts with the cluster to form a fourth electronic isomer . Finally , it is described in Chapter VII that this Co /Fe trigonal bipyramidal unit can be used as a building block for systematically incorporating three metal types into a family of 1 -D chain and cluster compounds . en_US
dc.format.extent 4457680 bytes
dc.format.medium electronic en_US
dc.format.mimetype application /pdf
dc.language.iso en _US en_US
dc.publisher Texas A &M University en_US
dc.subject high -spin molecules en_US
dc.title Nanomagnetic molecular materials based on the hexacyanometallate building block : the preparation and characterization of high -spin cluster and chain compounds en_US
dc.type Book en
dc.type.genre Electronic Dissertation en_US
dc.type.material text en_US
dc.format.digitalOrigin born digital en_US


Nanomagnetic molecular materials based on the hexacyanometallate building block: the preparation and characterization of high-spin cluster and chain compounds. Available electronically from http : / /hdl .handle .net /1969 .1 /2196 .

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