Date of Award
Master of Science (MS)
Scorpionate ligands are one of the most crucial nitrogen donor ligands in coordination chemistry. The scorpionate ligands have served as excellent ligand scaffolds for investigating iron(II) spin crossover chemistry. In this study, the complex, [Fe(HL*)2](OTf)2, 1, where HL* = bis(3,5-dimethylpyrazol-1-yl)(3-1H-pyrazole)methane was prepared which exhibited multiple solid-state structures and solvates. Six crystalline forms of 1 were prepared by controlling the crystallization conditions. Thus, when reagents are combined in CH3CN, an equilibrium mixture of cis- and trans- is established that favors the latter below 310K. Among the six crystal forms, trans-1, trans-1.CH3CN, cis-1 and co-1 undergo SCO below 250K while trans-1.xCH3CN (x=2,4) solvates do not undergo SCO before desolvation. Another application of the scorpionates is in nitrene transfer reactions. In this contribution, two new N-confused C-scorpionates, TsLipr2 and HLipr2, each with two ‘normal’ 3,5-diisopropylpyrazolyl groups, and either an N-tosyl or N-H group on the ‘confused’ pz were synthesized. These new ligands complement those previously described dimethylpyrazolyl derivatives, HL* and TSL*, which have less bulky ‘normal’ pyrazol-1-yls. For these two bulky N-confused scorpionate ligands, the 2:1 and 1:1 ligand:silver complexes were prepared and characterized both structurally and spectroscopically. Their potential as catalysts for nitrene transfer reactions was also investigated.