The design, synthesis and characterization of new building blocks for the preparation of molecule-based magnetic materials /

Two new families of building blocks have been prepared and fully characterized and their coordination chemistry exploited for the preparation of molecule-based magnetic materials. The first class of compounds were prepared by exploiting the chemistry of 3,3'-diamino-2,2'-bipyridine together with 2-pyridine carbonyl chloride or 2-pyridine aldehyde. Two new ligands, 2,2'-bipyridine-3,3'-[2-pyridinecarboxamide] (Li, 2.3) and N'-6/s(2-pyridylmethyl) [2,2'bipyridine]-3,3'-diimine (L2, 2.7), were prepared and characterized. For ligand L4, two copper(II) coordination compounds were isolated with stoichiometrics [Cu2(Li)(hfac)2] (2.4) and [Cu(Li)Cl2] (2.5). The molecular structures of both complexes were determined by X-ray crystallography. In both complexes the ligand is in the dianionic form and coordinates the divalent Cu(II) ions via one amido and two pyridine nitrogen donor atoms. In (2.4), the coordination geometry around both Cu11 ions is best described as distorted trigonal bipyramidal where the remaining two coordination sites are satisfied by hfac counterions. In (2.5), both Cu(II) ions adopt a (4+1) distorted square pyramidal geometry. One copper forms a longer apical bond to an adjacent carbonyl oxygen atom, whereas the second copper is chelated to a neighboring Cu-Cl chloride ion to afford chloride bridged linear [Cu2(Li)Cl2]2 tetramers that run along the c-axis of the unit cell. The magnetic susceptibility data for (2.4) reveal the occurrence of weak antiferromagnetic interactions between the copper(II) ions. In contrast, variable temperature magnetic susceptibility measurements for (2.5) reveal more complex magnetic properties with the presence of ferromagnetic exchange between the central dimeric pair of copper atoms and weak antiferromagnetic exchange between the outer pairs of copper atoms. The Schiff-base bis-imine ligand (L2, 2.7) was found to be highly reactive; single crystals grown from dry methanol afforded compound (2.14) for which two methanol molecules had added across the imine double bond. The susceptibility of this ligand to nucleophilic attack at its imine functionality assisted via chelation to Lewis acidic metal ions adds an interesting dimension to its coordination chemistry. In this respect, a Co(II) quaterpyridine-type complex was prepared via a one-pot transformation of ligand L2 in the presence of a Lewis acidic metal salt. The rearranged complex was characterized by X-ray crystallography and a reaction mechanism for its formation has been proposed. Three additional rearranged complexes (2.13), (2.17) and (2.19) were also isolated when ligand (L2, 2.7) was reacted with transition metal ions. The molecular structures of all three complexes have been determined by X-ray crystallography. The second class of compounds that are reported in this thesis, are the two diacetyl pyridine derivatives, 4-pyridyl-2,6-diacetylpyridine (5.5) and 2,2'-6,6'-tetraacetyl-4,4'-bipyridine (5.15). Both of these compounds have been designed as intermediates for the metal templated assembly of a Schiff-base N3O2 macrocycle. From compound (5.15), a covalently tethered dimeric Mn(II) macrocyclic compound of general formula {[Mn^C^XJCl-FkO^Cl-lO.SFbO (5.16) was prepared and characterized. The X-ray analysis of (5.16) reveals that the two manganese ions assume a pentagonal-bipyramidal geometry with the macrocycle occupying the pentagonal plane and the axial positions being filled by a halide ion and a H2O molecule. Magnetic susceptibility data reveal the occurrence of antiferromagnetic interactions between covalently tethered Mn(II)-Mn(II) dimeric units. Following this methodology a Co(II) analogue (5.17) has also been prepared which is isostructural with (5.16).

Second Welland Canal - Book 1, Survey Map 9 - Lock 2 in Grantham Township

Survey map of the Second Welland Canal created by the Welland Canal Company showing a portion of the Grantham Township sometimes referred to as the Welland Vale. Identified structures associated with the Canal include Lock 2, several weirs, and the Lock Tender's House. The surveyors' measurements and notes can be seen in red and black ink and pencil. Features of the First Welland Canal are noted in red ink and include the old towing path and the Old Canal itself. Local area landmarks and businesses are also identified and include streets and roads (ex. Side Line and Old Road to Port Dalhousie), J. C. Clark's Ice House, J. L. Ranney Store House, a burnt mill, barrel shed, a building leased to Michael Kerrins, and a number of unidentified structures (possibly houses or cabins) belonging to D. Cain, R. Cain, W. Weaver and W. Huddy. A New Road to St. Catharines is featured in red ink. Properties and property owners of note are: Concession 5 Lots 20, 21 and 22, Concession 6 Lots 20 and 21, Thomas Adams, John Gould, George Rykert, Theophilus Mack, William H. Merritt, J. L. Ranney, and the Board of Works.

Second Welland Canal - Book 3, Survey Map 19 - Petersburgh and Humberstone

Survey map of the Second Welland Canal created by the Welland Canal Company showing the areas in and around Petersburg and Humberstone. Identified structures associated with the Canal include North and South Back Ditches, Bridge Tender's Building, Towing Path, Old Back Ditch, and Covered Drain. Features of the First Welland Canal are noted in red ink. Surveyor measurements and notes can be seen in red and black ink and pencil. Local area landmarks include bridge, barns, ruins of Stone Mill (burnt), Wesbern (Wabern) Hotel and spoil banks. Roads labelled running parallel to Canal is the south Road Allowance. Roads perpendicular to Canal include Road Allowance between 1st and 2nd Concession, Road to Waterloo Ferry, Road Allowance between 2nd and 3rd Concessions. Properties and property owners/renters are identified as follows: A. Augustine, Captain Duffil, O. Farres, I. Schooley, George Augustine, E. Schooley (Schooly), R. and J. Kilmer (Killmer), J. Urich, J. Thompson (Tompson), M. Reeb, G. Wilson, J. Klee, John Steel, E. Augustine, Furry, J. Jackson, Robert House, R. White, J. Crame, D. Saff, J. Kinnard, J. Schooley, Dickson, C. Erhoff, and G. Rother."Village of Petersburgh" - Scale 2 Chs. per Inch "Humberstone" - Scale 4 Chs. per Inch,

New Building Blocks for Dual-Property Molecule-Based Magnets

Two classes of compounds have been prepared and characterized as building blocks for chiral magnets and ferromagnetic conductors. In the fIrst project, the organic framework of a pentadentate, (N302) macro cycle has been synthetically modifIed to introduce phenyl substituents into its organic framework and the synthesis of four new [Fe(In(N302)(CN)2] complexes (I) - (IV) is presented. [Molecular diagram availble in pdf] This work represents the fIrst structural and magnetic studies of a family of spin crossover macrocycles that comprise of both structural and stereo-isomers. Magnetic susceptibility and Mossbauer data for the R,R-complex (I) is consistent with both a thermal and a light induced spin crossover transition. The X-ray data supports a change in geometry accompanying the thermal spin transition, from a high spin (HS) 7 -coordinate complex at room temperature to a low spin (LS) 5-coordinate complex at 100 K. The crystal structure ofthe racemic complex (III) reveals a HS, 7-coordinate complex at 200 K that undergoes no signifIcant structural changes on cooling. In contrast, the magnetic - susceptibility and Mossbauer data collected on a powder sample of the racemic complex are consistent with a LS complex. Finally, the meso complex (IV) was prepared and its structure and magnetic properties are consistent with a 5-coordinate LS complex that remains low spin, but undergoes conformational changes on cooling in solution. The chiral [Fe(H)(N302)(CN)2] macro cycle (I), together with its Mn(H) and Fe(H) derivatives have also been exploited as building blocks for the self-assembly of chiral magnets. In the second project, a synthetic route for the preparation of tetrathiafulvalene (TTF) donors covalently attached to a diisopropyl verdazyl radical via a cross conjugated pyridyl linker IS presented. Following this strategy, four new TTF-py- (diisopropyl)verdazyl radicals have been prepared and characterized (V) - (VIII) . [Molecular diagram available in pdf] The first (2:1) charge transfer complex ofa TTF-py-(diisopropyl)verdazyl radical donor and a TCNQ acceptor has been prepared and structurally characterized. The crystal packing shows that the donor and acceptor molecules are organized in a mixed stacking arrangement consistent with its insulating behaviour. EPR and magnetic susceptibility data support intramolecular ferromagnetic interactions between the TTF and the verdazyl radicals and antiferromagnetic interactions between TTF donors within a stack. In an attempt to increase the intramolecular exchange interaction between the two radicals, a TTF-x-(diisopropyl)verdazyl radical (IX) was prepared, where the two radicals are connected ia a conjugated divinylene linker. The neutral radical donors stack in a more favourable head-to-head arrangement but the bulky isopropyl groups prevent the donor radicals from stacking close enough together to facilitate good orbital overlap. [Molecular diagram available in pdf].

Second Welland Canal Lock 22

Negative of second Welland Canal at Lock 22. There is a building with a sign that reads "Artificial Stone Builder's Supply Co."