Coordination chemistry of a mono-dibenzofuran derivative of 1,4,7,10-tetraazacyclododecane

Jose Alejandro Barreto Solano, Tanmaya Joshi, Taracad Venkatachalam, David Charles Reutens, Bimbil Graham, Leone Spiccia

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Copper(II) and cadmium(II) complex of a mono-dibenzofuran derivative of 1,4,7,10-tetraazacyclododecane (cyclen), L1, have been prepared by reaction of the mono-dibenzofuran-substituted cyclen with either copper(II) or cadmium(II) perchlorate in acetonitrile. This yielded the corresponding divalent metal complexes, [Cu(L1)](ClO4)2·H2O (C1) and [Cd(L1)](ClO4)2·H2O (C2), which were isolated as single crystals suitable for X-ray crystallography by diffusing diethyl ether into an acetonitrile solution of each complex. For the copper(II) complex, C1, the X-ray crystal structure revealed a distorted square pyramidal Cu(II) coordination sphere occupied by four amine nitrogens from the cyclen ring and one oxygen from the amide linkage present in L1. On the other hand, the metal center in the cadmium complex is seven coordinate, with two weakly bound acetonitrile molecules occupying two additional coordination sites about the Cd(II) center; these bind cis to the amide oxygen. The coordination geometry is best described as monocapped trigonal prismatic. In both complexes, the secondary amine nitrogens on the cyclen macrocycle form hydrogen bonds with perchlorate counterions present in the crystal lattice. Titration of L1 with various metal ions (Mn2+, Co2+, Ni2+, Cu2+, Zn2+, and Cd2+) in acetonitrile revealed a gradual quenching of the benzofuran emission with increasing [M2+] consistent with formation of metal complexes with a 1: 1 M2+: L1 stoichiometry. From the emission data, the conditional stability constant was determined to be 10-20 times higher for the Cu(II) complex than the other divalent metal complexes investigated
Original languageEnglish
Pages (from-to)335-349
Number of pages15
JournalJournal of Coordination Chemistry
Volume68
Issue number2
DOIs
Publication statusPublished - 2015

Keywords

  • Coordination chemistry
  • Macrocyclic ligands
  • Crystal structures
  • Fluorescence
  • Metal ion-binding affinity

Cite this

Barreto Solano, J. A., Joshi, T., Venkatachalam, T., Reutens, D. C., Graham, B., & Spiccia, L. (2015). Coordination chemistry of a mono-dibenzofuran derivative of 1,4,7,10-tetraazacyclododecane. Journal of Coordination Chemistry, 68(2), 335-349. https://doi.org/10.1080/00958972.2014.986115
Barreto Solano, Jose Alejandro ; Joshi, Tanmaya ; Venkatachalam, Taracad ; Reutens, David Charles ; Graham, Bimbil ; Spiccia, Leone. / Coordination chemistry of a mono-dibenzofuran derivative of 1,4,7,10-tetraazacyclododecane. In: Journal of Coordination Chemistry. 2015 ; Vol. 68, No. 2. pp. 335-349.
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title = "Coordination chemistry of a mono-dibenzofuran derivative of 1,4,7,10-tetraazacyclododecane",
abstract = "Copper(II) and cadmium(II) complex of a mono-dibenzofuran derivative of 1,4,7,10-tetraazacyclododecane (cyclen), L1, have been prepared by reaction of the mono-dibenzofuran-substituted cyclen with either copper(II) or cadmium(II) perchlorate in acetonitrile. This yielded the corresponding divalent metal complexes, [Cu(L1)](ClO4)2·H2O (C1) and [Cd(L1)](ClO4)2·H2O (C2), which were isolated as single crystals suitable for X-ray crystallography by diffusing diethyl ether into an acetonitrile solution of each complex. For the copper(II) complex, C1, the X-ray crystal structure revealed a distorted square pyramidal Cu(II) coordination sphere occupied by four amine nitrogens from the cyclen ring and one oxygen from the amide linkage present in L1. On the other hand, the metal center in the cadmium complex is seven coordinate, with two weakly bound acetonitrile molecules occupying two additional coordination sites about the Cd(II) center; these bind cis to the amide oxygen. The coordination geometry is best described as monocapped trigonal prismatic. In both complexes, the secondary amine nitrogens on the cyclen macrocycle form hydrogen bonds with perchlorate counterions present in the crystal lattice. Titration of L1 with various metal ions (Mn2+, Co2+, Ni2+, Cu2+, Zn2+, and Cd2+) in acetonitrile revealed a gradual quenching of the benzofuran emission with increasing [M2+] consistent with formation of metal complexes with a 1: 1 M2+: L1 stoichiometry. From the emission data, the conditional stability constant was determined to be 10-20 times higher for the Cu(II) complex than the other divalent metal complexes investigated",
keywords = "Coordination chemistry, Macrocyclic ligands, Crystal structures, Fluorescence, Metal ion-binding affinity",
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Barreto Solano, JA, Joshi, T, Venkatachalam, T, Reutens, DC, Graham, B & Spiccia, L 2015, 'Coordination chemistry of a mono-dibenzofuran derivative of 1,4,7,10-tetraazacyclododecane' Journal of Coordination Chemistry, vol. 68, no. 2, pp. 335-349. https://doi.org/10.1080/00958972.2014.986115

Coordination chemistry of a mono-dibenzofuran derivative of 1,4,7,10-tetraazacyclododecane. / Barreto Solano, Jose Alejandro; Joshi, Tanmaya; Venkatachalam, Taracad; Reutens, David Charles; Graham, Bimbil; Spiccia, Leone.

In: Journal of Coordination Chemistry, Vol. 68, No. 2, 2015, p. 335-349.

Research output: Contribution to journalArticleResearchpeer-review

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T1 - Coordination chemistry of a mono-dibenzofuran derivative of 1,4,7,10-tetraazacyclododecane

AU - Barreto Solano, Jose Alejandro

AU - Joshi, Tanmaya

AU - Venkatachalam, Taracad

AU - Reutens, David Charles

AU - Graham, Bimbil

AU - Spiccia, Leone

PY - 2015

Y1 - 2015

N2 - Copper(II) and cadmium(II) complex of a mono-dibenzofuran derivative of 1,4,7,10-tetraazacyclododecane (cyclen), L1, have been prepared by reaction of the mono-dibenzofuran-substituted cyclen with either copper(II) or cadmium(II) perchlorate in acetonitrile. This yielded the corresponding divalent metal complexes, [Cu(L1)](ClO4)2·H2O (C1) and [Cd(L1)](ClO4)2·H2O (C2), which were isolated as single crystals suitable for X-ray crystallography by diffusing diethyl ether into an acetonitrile solution of each complex. For the copper(II) complex, C1, the X-ray crystal structure revealed a distorted square pyramidal Cu(II) coordination sphere occupied by four amine nitrogens from the cyclen ring and one oxygen from the amide linkage present in L1. On the other hand, the metal center in the cadmium complex is seven coordinate, with two weakly bound acetonitrile molecules occupying two additional coordination sites about the Cd(II) center; these bind cis to the amide oxygen. The coordination geometry is best described as monocapped trigonal prismatic. In both complexes, the secondary amine nitrogens on the cyclen macrocycle form hydrogen bonds with perchlorate counterions present in the crystal lattice. Titration of L1 with various metal ions (Mn2+, Co2+, Ni2+, Cu2+, Zn2+, and Cd2+) in acetonitrile revealed a gradual quenching of the benzofuran emission with increasing [M2+] consistent with formation of metal complexes with a 1: 1 M2+: L1 stoichiometry. From the emission data, the conditional stability constant was determined to be 10-20 times higher for the Cu(II) complex than the other divalent metal complexes investigated

AB - Copper(II) and cadmium(II) complex of a mono-dibenzofuran derivative of 1,4,7,10-tetraazacyclododecane (cyclen), L1, have been prepared by reaction of the mono-dibenzofuran-substituted cyclen with either copper(II) or cadmium(II) perchlorate in acetonitrile. This yielded the corresponding divalent metal complexes, [Cu(L1)](ClO4)2·H2O (C1) and [Cd(L1)](ClO4)2·H2O (C2), which were isolated as single crystals suitable for X-ray crystallography by diffusing diethyl ether into an acetonitrile solution of each complex. For the copper(II) complex, C1, the X-ray crystal structure revealed a distorted square pyramidal Cu(II) coordination sphere occupied by four amine nitrogens from the cyclen ring and one oxygen from the amide linkage present in L1. On the other hand, the metal center in the cadmium complex is seven coordinate, with two weakly bound acetonitrile molecules occupying two additional coordination sites about the Cd(II) center; these bind cis to the amide oxygen. The coordination geometry is best described as monocapped trigonal prismatic. In both complexes, the secondary amine nitrogens on the cyclen macrocycle form hydrogen bonds with perchlorate counterions present in the crystal lattice. Titration of L1 with various metal ions (Mn2+, Co2+, Ni2+, Cu2+, Zn2+, and Cd2+) in acetonitrile revealed a gradual quenching of the benzofuran emission with increasing [M2+] consistent with formation of metal complexes with a 1: 1 M2+: L1 stoichiometry. From the emission data, the conditional stability constant was determined to be 10-20 times higher for the Cu(II) complex than the other divalent metal complexes investigated

KW - Coordination chemistry

KW - Macrocyclic ligands

KW - Crystal structures

KW - Fluorescence

KW - Metal ion-binding affinity

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