The synthesis, electrochemistry, and reactivities of a complex cation,
trans-dioxo-N,N¢-dimethyl-N,N¢-bis(pyridine-2-ylmethyl)propane-1,3-diamineruthenium(VI)(trans-[Ru(LMe2)O2] 2+ ), have been reported. 1 It can oxidize tetrahydrofuran and aromatic hydrocarbons under mild conditions. Its pyridine functional group increases both the redox potential and the reactivity of the ruthenium oxo oxidant. It is considered that its reactivity would also depend on the geometry of the pyridine functional group on the structure of the complex cation. The redox behaviors of [Cu(LMe2) N¢-dimethyl-N,N¢-bis(pyridine-2-ylmethyl)ethane-1,2-diamine (L¢Me2) and perchlorate ions has been also reported. 6 Only one perchlorate ion in [Cu(ClO4)(L¢Me2)]ClO4 coordinates to the Cu 2+ ion. Each N-methyl group of the [Cu(ClO4)(L¢Me2)]ClO4 is placed at a cis configuration. The crystal structures of manganese(II) and copper(II) with its L¢Me2 included in these binuclear complexes have been reported. 5,7 The pyridine functional group on the complex cation with an ethylene group between two N-pyridine-2-ylmethylamines would have a more rigid geometry than that with the propylene group. 8 The Cu-N4 square-planar geometry of [Cu(ClO4)2(LMe2)] is distorted more than that of N, N¢-bis(pyridine-2-ylmethyl) The complex of an isothiocyanato-N,N¢-dimethyl-N,N¢-bis(pyridine-2-ylmethyl)propane-1,3-diaminecopper(II) perchlorate ([Cu(NCS)(LMe2)]ClO4) was prepared. Its crystal structure was determined by X-ray diffractometry. [Cu(NCS)(LMe2)]ClO4 crystallized in a triclinic system, and was characterized thus: P1, a = 9.257(3), b = 9.883(4), c = 11.806(5)Å, a = 89.638(12), b = 81.053(10), g = 88.841(12)˚, Z = 2, V = 1066.7(7)Å 3 . The crystal structure was solved by direct methods and refined by full-matrix least squares on F 2 to final values of R1 = 0.058.
Crystal structures of N, N¢-dimethyl-N,N¢-bis(pyridine-2-ylmethyl)propanediaminecopper(II) perchlorate ([Cu(LMe2)]-(ClO4)2) 1 and isothiocyanato-N,N¢-dimethyl-N,N¢-bis(pyridine-2-ylmethyl)propanediaminecopper(II) perchlorate ([Cu(NCS)-(LMe2)]ClO4) 2 have been reported. Each of the N-methyl groups is placed at a trans-and a cis-configuration for [Cu(LMe2)](ClO4)2 and [Cu(NCS)(LMe2)]ClO4, respectively. This would be a reason why a distortion of the complex cation was released to re-bind LMe2 with Cu(II) after the dissociation of LMe2 from [Cu(LMe2)] 2+ ; as a result, the isothiocyanate ion strongly coordinated to [Cu(LMe2)] 2+ . When the two N-methyl groups were replaced at two N-ethyl groups, which might make a large steric hindrance in a peripheral ligand of Cu(II), it is interesting to investigate the configuration of the N-ethyl groups for N, N¢-diethyl-N,N¢-bis(pyridine-2-ylmethyl)propanediaminecopper(II) ([Cu(LEt2)] 2+ ). Its crystal structure and preparation have not yet been reported. Therefore, the [Cu(LEt2)] 2+ complex was prepared, and its crystal structure was determined in this work.
N,N¢-Bis(pyridine-2-ylmethyl)propanediamine (LH2) was
The crystal structures of N, N¢-dimethyl-N,N¢-bis(pyridin-2-ylmethyl)propane-1,3-diaminecopper(II) perchlorate ([Cu(ClO4)2(LMe2)]) 1 and isothiocyanato-N,N¢-dimethyl-N,N¢-bis(pyridin-2-ylmethyl)propane-1,3-diaminecopper(II) perchlorate ([Cu(NCS)(LMe2)]ClO4) 2 have been reported. Each of the N-methyl groups is placed at a trans-and a cisconfiguration for [Cu(ClO4)2(LMe2)] and [Cu(NCS)(LMe2)]ClO4, respectively. When the two N-methyl groups were replaced at two N-ethyl groups, each of the N-ethyl groups for isothiocyanato-N,N¢-diethyl-N,N¢-bis(pyridin-2-ylmethyl)propane-1,3-diaminecopper(II) perchlorate ([Cu(NCS)(LEt2)] ClO4) was placed at the cis-configuration. 3 This would be one reason why a small distortion of the complex coordinated LMe2 or LEt2 and isothiocyanate or perchlorate ion to Cu(II) is more preferable to a large one. Therefore, the different configuration of N-alkyl groups, such as N-methyl and N-ethyl groups, depending on the distortion for analogous Cu(II) complexes, is interesting. The strong coordinating isothiocyanate ion to those Cu(II) complexes might cause the cis-configuration for the N-alkyl groups, while the weak coordinating perchlorate ion might cause the trans-configuration for them. Therefore, a crystal structure of the analogous Cu(II) complex, catena-(m2-
Complex formations of copper(II) with some analogous ligands of N,N¢-bis(pyrdin-2-ylmethyl)propane-1,3-diamine and their crystal structures have been reported. 1-4 In a research of the complex formation of CuSO4•5H2O with N,N¢-bis(pyridin-2ylmethyl)propane-1,3-diamine, which was prepared, according to a published method, 5 a green product was accidentally found. It is interesting to identify the unknown green product, because it sometimes leads to finding unexpected compounds. 6,7 Since the green product gave single-crystals in a methanolic solution, the crystal structure was determined. The green product was a copper(II)-2-Py complex ([Cu2(2-Py)2(H2O)(OH)2(SO4)]), where 2-Py is 2-pyrdinecarboxylic acid anhydride. When 0.08 mol of 2-pyridinecarbaldehyde (Wako,
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