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| 1.
論文 |
論文
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Ihara, Yoshinori ; Satake, Yasuhiro ; Suzuki, Masatatsu ; Uehara, Akira
概要:
The thermochemical changes in coordination structure of diaquabis(N,N- or N,N′,-dialkylethylenediamine)nickel(II) comple
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xes ([Ni(H2O)2(diamine)2]X2·nH2O) were reinvestigated by means of TG-DTA and electronic spectroscopy at room and elevated temperatures, where diamine is N,N (or N,N′-dimethylethylenediamine (NN- or NN′-dmen) or N,N-(or N,N′)-diethylethylenediamine (NN- or NN′-deen); X is Cl−, Br−, I−, or NO3−; n is 0, 1, 2, or 3. The diaqua complexes prepared were all trans except for cis-[Ni(H2O)2(NN-dmen)2]I2. The trans complexes with the symmetric (N,N′-dialkylsubstituted) diamines brought about a deaquation-anation upon heating, retaining the original trans configuration, while those with the asymmetric (N,N-dialkylsubstituted) diamines transformed into the cis complexes. In the case of the NN-dmen complexes, cis-halogenoaqua species were isolated as a stable intermediate during the thermal reactions. The complex nitrates changed to trans-dinitrato or cis-mononitrato species depending upon the diamines. The effects of the N-substituents in the diamines and of the anions on the patterns of thermal reactions were also discussed.
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| 2.
論文 |
論文
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Ihara, Yoshinori ; Satake, Yasuhiro ; Fujimoto, Yumi ; Senda, Hitoshi ; Suzuki, Masatatsu ; Uehara, Akira
概要:
The structures of two diaquabis(N,N-dialkylethylenediamine)nickel(II) chlorides ([Ni(H2O)2(diamine)2]Cl2·nH2O) were dete
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rmined by X-ray crystallographic studies, where diamine is N,N-dimethylethylenediamine(NN-dmen) or N,N-diethylethylenediamine (NN-deen). Both complexes are trans and crystallize in the monoclinic space group P21⁄n. The unit cell parameters of the NN-dmen complex, NiCl2C8N4O2H32, are a=7.531(1), b=13.092(1), c=9.591 Å, β=107.76(1)°, and Z=2, and those of the NN-deen complex, NiCl2C12N4O2H36, are a=9.154(1), b=8.692(1), c=12.395(2) Å, β=104.46(1)°, and Z=2. In trans-[Ni(H2O)2(NN-dmen)2]Cl2·2H2O and trans-[Ni(H2O)2(NN-deen)2]Cl2, the Ni–NMe2 and Ni–NEt2 bond distances (2.183 and 2.271 Å) are much longer than the Ni–NH2 distances (2.078 and 2.064 Å), forming tetragonally distorted octahedrons with four close in-plane neighbors(N2O2) and two remote axial ones(N2). It is apparent that this distortion originates from the steric requirement of N-substituted groups. Such a distortion significantly affects the electronic spectra of these complexes.
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