Structural and EPR studies of pyrophosphate-bridged dinuclear Cu II complexes
Two new pyrophosphate-bridged copperII complexes, [Cu(dpa)(H2O7P2)]2 1 and [Cu 2(terpy)2(HO7P2)·(H 2O4P)·(H3O4P)·(H 2O)] 2 (dpa = 2,2′-dipyridylamine and terpy = 2,2′:6′,2″-terpyridine) were isolated and their crystal structures determined by single-crystal X-ray diffraction. The compounds are tricl...
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todo:paper_02775387_v79_n_p178_Sartoris2023-10-03T15:16:11Z Structural and EPR studies of pyrophosphate-bridged dinuclear Cu II complexes Sartoris, R.P. Calvo, R. Santana, R.C. Nascimento, O.R. Perec, M. Baggio, R.F. Copper EPR Magnetic interactions Pyrophosphates Structure Two new pyrophosphate-bridged copperII complexes, [Cu(dpa)(H2O7P2)]2 1 and [Cu 2(terpy)2(HO7P2)·(H 2O4P)·(H3O4P)·(H 2O)] 2 (dpa = 2,2′-dipyridylamine and terpy = 2,2′:6′,2″-terpyridine) were isolated and their crystal structures determined by single-crystal X-ray diffraction. The compounds are triclinic and contain dinuclear copperII units bridged by pyrophosphate anions. The EPR spectra observed in three planes of single crystal samples as a function of field orientation at 293 K for compounds 1 and 2, and also for two other pyrophosphate compounds already reported, [Cu(bipy)(cis-H2O7P2)]2· 3(H2O) 3 and [Cu(bipy)(trans-H2P2O 7)]2 4 display a single resonance for any field orientation and temperatures T between 4 and 293 K, as in mononuclear spin systems, without hyperfine structure, and their g-factors and line widths were measured. The relations between the principal directions of the g-matrices and the molecular structures are discussed and compared with related compounds. The temperature dependences of the intensity of the EPR signals observed for 1-4 above 4 K indicate a paramagnetic Curie behavior, with no indication of intradinuclear exchange interactions (so, |J| < 2 K). The absence of dinuclear splitting and of hyperfine structure of the dinuclear units is explained in terms of averaging out by the interdinuclear interactions, allowing to set a lower limit of their magnitudes. © 2014 Elsevier Ltd. All rights reserved. Fil:Perec, M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_02775387_v79_n_p178_Sartoris |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Copper EPR Magnetic interactions Pyrophosphates Structure |
| spellingShingle |
Copper EPR Magnetic interactions Pyrophosphates Structure Sartoris, R.P. Calvo, R. Santana, R.C. Nascimento, O.R. Perec, M. Baggio, R.F. Structural and EPR studies of pyrophosphate-bridged dinuclear Cu II complexes |
| topic_facet |
Copper EPR Magnetic interactions Pyrophosphates Structure |
| description |
Two new pyrophosphate-bridged copperII complexes, [Cu(dpa)(H2O7P2)]2 1 and [Cu 2(terpy)2(HO7P2)·(H 2O4P)·(H3O4P)·(H 2O)] 2 (dpa = 2,2′-dipyridylamine and terpy = 2,2′:6′,2″-terpyridine) were isolated and their crystal structures determined by single-crystal X-ray diffraction. The compounds are triclinic and contain dinuclear copperII units bridged by pyrophosphate anions. The EPR spectra observed in three planes of single crystal samples as a function of field orientation at 293 K for compounds 1 and 2, and also for two other pyrophosphate compounds already reported, [Cu(bipy)(cis-H2O7P2)]2· 3(H2O) 3 and [Cu(bipy)(trans-H2P2O 7)]2 4 display a single resonance for any field orientation and temperatures T between 4 and 293 K, as in mononuclear spin systems, without hyperfine structure, and their g-factors and line widths were measured. The relations between the principal directions of the g-matrices and the molecular structures are discussed and compared with related compounds. The temperature dependences of the intensity of the EPR signals observed for 1-4 above 4 K indicate a paramagnetic Curie behavior, with no indication of intradinuclear exchange interactions (so, |J| < 2 K). The absence of dinuclear splitting and of hyperfine structure of the dinuclear units is explained in terms of averaging out by the interdinuclear interactions, allowing to set a lower limit of their magnitudes. © 2014 Elsevier Ltd. All rights reserved. |
| format |
JOUR |
| author |
Sartoris, R.P. Calvo, R. Santana, R.C. Nascimento, O.R. Perec, M. Baggio, R.F. |
| author_facet |
Sartoris, R.P. Calvo, R. Santana, R.C. Nascimento, O.R. Perec, M. Baggio, R.F. |
| author_sort |
Sartoris, R.P. |
| title |
Structural and EPR studies of pyrophosphate-bridged dinuclear Cu II complexes |
| title_short |
Structural and EPR studies of pyrophosphate-bridged dinuclear Cu II complexes |
| title_full |
Structural and EPR studies of pyrophosphate-bridged dinuclear Cu II complexes |
| title_fullStr |
Structural and EPR studies of pyrophosphate-bridged dinuclear Cu II complexes |
| title_full_unstemmed |
Structural and EPR studies of pyrophosphate-bridged dinuclear Cu II complexes |
| title_sort |
structural and epr studies of pyrophosphate-bridged dinuclear cu ii complexes |
| url |
http://hdl.handle.net/20.500.12110/paper_02775387_v79_n_p178_Sartoris |
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