The solid state and solution structure of 2,3-dicyano-5,6-di(2-thienyl)-1, 4-pyrazines [(CN)(2)Th(2)Pyz], and its pd(II) derivative, [(CN)(2)Th(2)Pyz(PdCl2)2]center dot H2O, formed by reaction of [(CN)(2)Th(2)Pyz] with [(C6H5CN)(2)Pdcl(2)] were characterized by X-ray, UV-visible, H-1 and C-13 NMR, and extended X-ray absorption fine structure (EXAFS) spectral measurements. The X-ray crystal structure of [(CN)(2)Th(2)Pyz] shows the presence of one thienyl ring positioned orthogonal to the rest of the molecule, with the two vicinal thienyl rings lying orthogonal to each other in a rare arrangement. NMR studies of [(CN)(2)Th(2)Pyz] in the solid state and in solutions of dimethylformamide or dimethyl sulfoxide confirm a nonequivalence of the thienyl rings in the solid state and also in solution. EXAFS results indicate that two distinct Pd-II coordination sites are formed at the di(2-thienyl)pyrazino moiety of [(CN)(2)Th(2)Pyz(PdCl2)(2)]center dot H2O, with identical Pd-N-pyz (2.03(3) angstrom) and Pd-Cl (2.36(3) angstrom) bond lengths but with different Pd-Sl (2.25(4) angstrom) and Pd-S2 (3.21(5) angstrom) bond distances in an overall asymmetric molecular framework. Density functional theory (DFT) and time-dependent DFT (TDDFT) theoretical studies also provide information about the structure and spectral behavior of the precursor and its metalated Pd-II derivative. H-1/C-13 NMR and UV-visible spectral measurements were also carried out on two heteropentametallic porphyrazine macrocycles which were prepared by a reaction of PdCl2 with [Th(8)TPyzPzM] where Th(8)TPyzPz = tetrakis-2,345,6-di-(2-thienyl)-pyrazino]porphyrazinato dianion and M = Mg-II(H2O) or Zn-II. Spectroscopic data on the newly synthesized [(PdCl2)(4)Th(8)TPyzPzM] compounds suggest that the binding of PdCl2 involves coordination sites of the type S2(th)PdCl2 with the two thienyl rings of each di(2-thienyl)pyrazino fragment bound to Pd-II in an equivalent manner ("th-th" coordination). This is similar to what was found for the corresponding octapyridinated analogues ("py-py" coordination).

Structural Flexibility and Role of Vicinal 2-Thienyl Rings in 2,3-Dicyano-5,6-di(2-thienyl)-1,4-pyrazine, [(CN)2Th2Pyz], Its Palladium(II) Complex [(CN)2Th2Pyz(PdCl2)2], and the Related Pentametallic Pyrazinoporphyrazines [(PdCl2)4Th8TPyzPzM] (M = MgII(H2O), ZnII) / M. P., Donzello; G., De Mori; E., Viola; C., Ercolani; E., Bodo; L., Mannina; D., Capitani; Rizzoli, Corrado; L., Gontrani; G., Aquilanti; K. M., Kadish; P., D’Angelo. - In: INORGANIC CHEMISTRY. - ISSN 0020-1669. - 50:(2011), pp. 12116-12125. [10.1021/ic201678p]

Structural Flexibility and Role of Vicinal 2-Thienyl Rings in 2,3-Dicyano-5,6-di(2-thienyl)-1,4-pyrazine, [(CN)2Th2Pyz], Its Palladium(II) Complex [(CN)2Th2Pyz(PdCl2)2], and the Related Pentametallic Pyrazinoporphyrazines [(PdCl2)4Th8TPyzPzM] (M = MgII(H2O), ZnII)

RIZZOLI, Corrado;
2011-01-01

Abstract

The solid state and solution structure of 2,3-dicyano-5,6-di(2-thienyl)-1, 4-pyrazines [(CN)(2)Th(2)Pyz], and its pd(II) derivative, [(CN)(2)Th(2)Pyz(PdCl2)2]center dot H2O, formed by reaction of [(CN)(2)Th(2)Pyz] with [(C6H5CN)(2)Pdcl(2)] were characterized by X-ray, UV-visible, H-1 and C-13 NMR, and extended X-ray absorption fine structure (EXAFS) spectral measurements. The X-ray crystal structure of [(CN)(2)Th(2)Pyz] shows the presence of one thienyl ring positioned orthogonal to the rest of the molecule, with the two vicinal thienyl rings lying orthogonal to each other in a rare arrangement. NMR studies of [(CN)(2)Th(2)Pyz] in the solid state and in solutions of dimethylformamide or dimethyl sulfoxide confirm a nonequivalence of the thienyl rings in the solid state and also in solution. EXAFS results indicate that two distinct Pd-II coordination sites are formed at the di(2-thienyl)pyrazino moiety of [(CN)(2)Th(2)Pyz(PdCl2)(2)]center dot H2O, with identical Pd-N-pyz (2.03(3) angstrom) and Pd-Cl (2.36(3) angstrom) bond lengths but with different Pd-Sl (2.25(4) angstrom) and Pd-S2 (3.21(5) angstrom) bond distances in an overall asymmetric molecular framework. Density functional theory (DFT) and time-dependent DFT (TDDFT) theoretical studies also provide information about the structure and spectral behavior of the precursor and its metalated Pd-II derivative. H-1/C-13 NMR and UV-visible spectral measurements were also carried out on two heteropentametallic porphyrazine macrocycles which were prepared by a reaction of PdCl2 with [Th(8)TPyzPzM] where Th(8)TPyzPz = tetrakis-2,345,6-di-(2-thienyl)-pyrazino]porphyrazinato dianion and M = Mg-II(H2O) or Zn-II. Spectroscopic data on the newly synthesized [(PdCl2)(4)Th(8)TPyzPzM] compounds suggest that the binding of PdCl2 involves coordination sites of the type S2(th)PdCl2 with the two thienyl rings of each di(2-thienyl)pyrazino fragment bound to Pd-II in an equivalent manner ("th-th" coordination). This is similar to what was found for the corresponding octapyridinated analogues ("py-py" coordination).
2011
Structural Flexibility and Role of Vicinal 2-Thienyl Rings in 2,3-Dicyano-5,6-di(2-thienyl)-1,4-pyrazine, [(CN)2Th2Pyz], Its Palladium(II) Complex [(CN)2Th2Pyz(PdCl2)2], and the Related Pentametallic Pyrazinoporphyrazines [(PdCl2)4Th8TPyzPzM] (M = MgII(H2O), ZnII) / M. P., Donzello; G., De Mori; E., Viola; C., Ercolani; E., Bodo; L., Mannina; D., Capitani; Rizzoli, Corrado; L., Gontrani; G., Aquilanti; K. M., Kadish; P., D’Angelo. - In: INORGANIC CHEMISTRY. - ISSN 0020-1669. - 50:(2011), pp. 12116-12125. [10.1021/ic201678p]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11381/2378735
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