TY - JOUR
T1 - Chemical characteristics of the products of the complexation reaction between copper(II) and a tetra-aza macrocycle in the presence of chloride ions
AU - Lincoln, Kimberly M.
AU - Arroyo - Currás, Netzahualcóyotl
AU - Johnston, Hannah M.
AU - Hayden, Travis D.
AU - Pierce, Brad S.
AU - Bhuvanesh, Nattamai
AU - Green, Kayla N.
N1 - Funding Information:
The authors are grateful for generous financial support from NSF (CHE) 1213655 to B.S.P., TCU Andrews Institute of Mathematics & Science Education (to KG), TCU Research and Creativity Activity Grant (to KG), INFOR Moncrief Foundation Support (to KG), and the Robert A. Welch Foundation (to KG, P-1760). The authors are grateful for the help from collaborates regarding the electrochemical, EPR, and X-ray crystallography studies. We thank the research group of Dr Allen Bard at Center for Electrochemistry, University of Texas at Austin and Bruce Noll, Bruker AXS.
Publisher Copyright:
© 2015 Taylor & Francis.
PY - 2015/8/18
Y1 - 2015/8/18
N2 - (Figure Presented). The reaction of copper(II) perchlorate with the hydrochloride salt of 3,6,9,15-tetra-azabicyclo[9.3.1]penta-deca-1,11,13-triene (L1) in acetonitrile forms two macrocyclic complexes that can be characterized: [L1CuIICl][ClO4] (1) and [L1CuIICl]2[CuCl4] (2). The structural, electronic, and redox properties of these complexes were studied using spectroscopy (EPR and UV-visible) and electrochemistry. In addition, the solid-state structure of 1 was obtained using X-ray diffraction. The copper(II) is five-coordinate ligated by four N-atoms of the macrocycle and a chloride atom. EPR studies of 1 both in DMF and aqueous solution indicate the presence of a single copper(II) species. In contrast, EPR studies of 2 performed in frozen DMF and in the solid-state reveal the presence of two spectroscopically distinct copper(II) complexes assigned as [L1CuIICl]+ and [CuIICl4]2-. Lastly, electrochemical studies demonstrate that both [L1CuIICl]+ and [CuIICl4]2- are redox active. Specifically, the [L1CuIICl]+ undergoes a quasi-reversible Cu(II)/(I) redox reaction in the absence of excess chloride. In the presence of chloride, however, the chemical irreversibility of this couple becomes evident at concentrations of chloride that exceed 50 mM. As a result, the presence of chloride from the chemical equilibrium of this latter species impedes the reversibility of the reduction of [L1CuIICl]+ to [L1CuICl]0.
AB - (Figure Presented). The reaction of copper(II) perchlorate with the hydrochloride salt of 3,6,9,15-tetra-azabicyclo[9.3.1]penta-deca-1,11,13-triene (L1) in acetonitrile forms two macrocyclic complexes that can be characterized: [L1CuIICl][ClO4] (1) and [L1CuIICl]2[CuCl4] (2). The structural, electronic, and redox properties of these complexes were studied using spectroscopy (EPR and UV-visible) and electrochemistry. In addition, the solid-state structure of 1 was obtained using X-ray diffraction. The copper(II) is five-coordinate ligated by four N-atoms of the macrocycle and a chloride atom. EPR studies of 1 both in DMF and aqueous solution indicate the presence of a single copper(II) species. In contrast, EPR studies of 2 performed in frozen DMF and in the solid-state reveal the presence of two spectroscopically distinct copper(II) complexes assigned as [L1CuIICl]+ and [CuIICl4]2-. Lastly, electrochemical studies demonstrate that both [L1CuIICl]+ and [CuIICl4]2- are redox active. Specifically, the [L1CuIICl]+ undergoes a quasi-reversible Cu(II)/(I) redox reaction in the absence of excess chloride. In the presence of chloride, however, the chemical irreversibility of this couple becomes evident at concentrations of chloride that exceed 50 mM. As a result, the presence of chloride from the chemical equilibrium of this latter species impedes the reversibility of the reduction of [L1CuIICl]+ to [L1CuICl]0.
KW - Coordination chemistry
KW - Copper
KW - Crystallography
KW - EPR
KW - Electrochemistry
KW - Macrocycle
KW - Pyridine
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U2 - 10.1080/00958972.2015.1068935
DO - 10.1080/00958972.2015.1068935
M3 - Article
AN - SCOPUS:84939266374
VL - 68
SP - 2810
EP - 2826
JO - Journal of Coordination Chemistry
JF - Journal of Coordination Chemistry
SN - 0095-8972
IS - 16
ER -