Date of Award
1-1-2009
Document Type
Campus Access Dissertation
Department
Chemistry and Biochemistry
Sub-Department
Chemistry
First Advisor
Daniel L. Reger
Abstract
A new phenylene-linked multitopic family of bis(pyrazolyl)methane ligands, (C6H6-n[CH2OCH2CH(pz)2]2)n, where pz is a pyrazolyl ring, has been synthesized by the general reaction of (pz)2CHCH2OH with NaH, followed by the addition of C6H6-n[CH2Br]n. The silver(I) complexes of ligand o-C6H4[CH2OCH2CH(pz)2]2 form coordination polymer. The two other ditopic ligands, which have meta- and para-oriented "arms" (-CH2OCH2CH(pz)2), were treated with Ag(I) salts and recrystallized from acetone or acetonitrile to give nine silver(I) complexes, in which the four pyrazolyl rings of the ligand chelate a single silver(I) cation in a distorted tetrahedral environment forming unusually sized mononuclear metallacycles. The silver(I) complexes of the tetratopic and hexatopic ligands form double, mononuclear metallacycles, a new structural form. In the silver complexes of the tetratopic ligand, the double, mononuclear metallacycles are formed by two pairs of para-oriented arms chelating two silver ions on opposite sides of the central arene ring. The silver complexes of the hexatopic ligand also form double, mononuclear metallacycles; however, one metallacycle is formed by para-oriented arms and the other metallacycle is formed by meta-oriented arms. The remaining two arms link these metallacyles into coordination polymers.
The more rigid, ditopic, bis(pyrazolyl)methane ligand m-[CH(pz)2]2C6H4, Lm, yields the monofluoride bridged, binuclear [M2(μ-F)(μ-Lm)2](BF4)3 complexes when treated with M(BF4)2*xH2O, where M is Fe, Co, Cu, and Zn. In contrast, a similar reaction of Lm with Ni(BF4)2*6H2O yields dibridged [Ni2(μ-F)2(μ-Lm)2](BF4)2. The solid state structures
of seven [M2(μ-F)(μ-Lm)2](BF4)3 complexes show that the divalent metal ion is in a five-coordinate, trigonal bipyramidal, coordination environment with either a linear or nearly linear M-F-M bridging arrangement. In the solid state, the [Fe2(μ-F)(μ-Lm)2](BF4)3 and [Co2(μ-F)(μ-Lm)2](BF4)3complexes show weak intramolecular antiferromagnetic exchange coupling between the two metal(II) ions with J values of -10.4 and -0.67 cm-1, respectively; there is no observed long-range magnetic order. Three different solvates of [Cu2(μ-F)(μ-Lm)2](BF4)3 are diamagnetic between 5 and 400 K, thus showing strong antiferromagnetic exchange interactions of -600 cm-1 or more negative.
Because of unusually large J value in [Cu2(μ-F)(μ-Lm)2](BF4)3, the complexes [Cu2(μ-Cl)(μ-Lm)2](BF4)3, [Cu2(μ-Cl)(μ-Lm)2](ClO4)3, [Cu2(μ-OH)(μ-Lm)2](ClO4)3, and [Cu2(μ-Br)(μ-Lm)2](BF4)3 were synthesized. The solid state structures of the [Cu2(μ-Cl)(μ-Lm)2]3+ complexes show that the divalent copper ion is in a five-coordinate, trigonal bipyramidal, coordination environment with most of the monochloro bridges in a linear arrangement. The [Cu2(μ-OH)(μ-Lm)2]3+ complexes have a bent hydroxo bridge and a distorted square pyramidal coordination environment. In the solid state, all of these complexes are diamagnetic up to 350 K, which is indicative of very strong antiferromagnetic exchange interactions. nylene-linked multitopic family of bis(pyrazolyl)methane ligands, m-[CH(pz)2]2C6H4, Lm, yields the monofluoride bridged, binuclear [M2(μ-F)(μ-Lm)2](BF4)3 complexes when treated with M(BF4)2*xH2O, where M is Fe, Co, Cu, and Zn. In contrast, a similar reaction of Lm with Ni(BF4)2*6H2O yields dibridged [Ni2(μ-F)2(μ-Lm)2](BF4)2. The solid state structures
of seven [M2(μ-F)(μ-Lm)2](BF4)3 complexes show that the divalent metal ion is in a five-coordinate, trigonal bipyramidal, coordination environment with either a linear or nearly linear M-F-M bridging arrangement. In the solid state, the [Fe2(μ-F)(μ-Lm)2](BF4)3 and [Co2(μ-F)(μ-Lm)2](BF4)3complexes show weak intramolecular antiferromagnetic exchange coupling between the two metal(II) ions with J values of -10.4 and -0.67 cm-1, respectively; there is no observed long-range magnetic order. Three different solvates of [Cu2(μ-F)(μ-Lm)2](BF4)3 are diamagnetic between 5 and 400 K, thus showing strong antiferromagnetic exchange interactions of -600 cm-1 or more negative.
Because of unusually large J value in [Cu2(μ-F)(μ-Lm)2](BF4)3, the complexes [Cu2(μ-Cl)(μ-Lm)2](BF4)3, [Cu2(μ-Cl)(μ-Lm)2](ClO4)3, [Cu2(μ-OH)(μ-Lm)2](ClO4)3, and [Cu2(μ-Br)(μ-Lm)2](BF4)3 were synthesized. The solid state structures of the [Cu2(μ-Cl)(μ-Lm)2]3+ complexes show that the divalent copper ion is in a five-coordinate, trigonal bipyramidal, coordination environment with most of the monochloro bridges in a linear arrangement. The [Cu2(μ-OH)(μ-Lm)2]3+ complexes have a bent hydroxo bridge and a distorted square pyramidal coordination environment. In the solid state, all of these complexes are diamagnetic up to 350 K, which is indicative of very strong antiferromagnetic exchange interactions.
Recommended Citation
Foley, E. A.(2009). Synthesis and Characterization of Transition Metal Complexes of Multitopic, Third-Generation, Phenylene-Linked Bis(1-Pyrazolyl)Methane Ligands. (Doctoral dissertation). Retrieved from https://scholarcommons.sc.edu/etd/28