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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Magnetic resonance studies of copper (II) sorbitol complex, in solution, reveal a supramolecular structure compatible to the crystal structure

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Author(s):
Crizostomo Kock, Flavio Vinicius [1] ; Higuera-Padilla, Angel Ruben [2] ; Santos Vigatto, Maiara da Silva [3] ; Martin Neto, Ladislau [2] ; Colnago, Luiz Alberto [2]
Total Authors: 5
Affiliation:
[1] Univ Sao Paulo, Inst Quim Sao Carlos, Sao Carlos, SP - Brazil
[2] Embrapa Instrumentacao, Rua 15 Novembro 1452, BR-13560970 Sao Carlos, SP - Brazil
[3] Inst Fed Educ Ciencia & Tecnol Fluminense, Bom Jesus Do Itabapoana - Brazil
Total Affiliations: 3
Document type: Journal article
Source: Magnetic Resonance in Chemistry; v. 57, n. 7, p. 404-411, JUL 2019.
Web of Science Citations: 0
Abstract

Although the Cu2+-sorbitol complex {[}Cu2+-Sorb] structure in crystalline state has been determined by X rays, it is not known in solution, where most studies of this complex are performed. Therefore, the goal of this work was to obtain information about the structure of this complex in aqueous solution using nuclear magnetic resonance and electron paramagnetic resonance spectroscopies. The magnetic resonance results indicate that the complex is formed at approximately pH 12. In this pH the sorbitol H-1 relaxation times were so short (broad line) that was not possible to use standard nuclear magnetic resonance parameters (nuclear Overhauser effect and spin-spin coupling constants values) to solve the three-dimensional structure. However, valuable structural information about the complex in solution was obtained. The relaxation results indicate that the Cu2+ ions are buried in the structure and not accessible to solvent; the H-1 and C-13 spectra shows strong paramagnetic shift effect indicating short distance between these nuclei and Cu2+ in the structure. No electron paramagnetic resonance signal was observed in pH 12 indicating strong Cu2+- Cu2+ dipolar interaction, compatible to Cu2+-Cu2+ distances measured in crystal, from 1.148 to 1.393 Angstroms. The complex self-diffusion coefficient (D) of 1.58 x 10(-10) m(2)/s value, determined by Diffusion-Ordered Spectroscopy, is compatible to a molecular weight of 3-6 KDa. Therefore, these results corroborate that the {[}Cu2+-Sorb] complex is assembled in solution, at pH 12, with several structural parameters compatible to the toroidal hexadecacuprate supramolecular structure determined in solid state. (AU)

FAPESP's process: 12/23169-8 - In situ study of action of quitosan biopolymer in the decontamination of metals and herbicides in aqueous system by electrochemistry coupled to high and low field NMR
Grantee:Flavio Vinicius Crizostomo Kock
Support Opportunities: Scholarships in Brazil - Doctorate
FAPESP's process: 14/22126-9 - Development of time domain NMR spectrometers and methods for chemical analyses in field
Grantee:Luiz Alberto Colnago
Support Opportunities: Regular Research Grants
FAPESP's process: 17/02197-7 - Reaction monitoring of deuterated compounds synthesis, with use of metal catalysts, by NMR
Grantee:Angel Rubén Higuera Padilla
Support Opportunities: Scholarships in Brazil - Post-Doctoral
FAPESP's process: 18/16040-5 - Biorational control of Pest-Insect
Grantee:Flavio Vinicius Crizostomo Kock
Support Opportunities: Scholarships in Brazil - Post-Doctoral