Coordination Structure Conversion of Hydrazone鈥揚alladium(II) Complexes in the Solid State and in Solution

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• 作者：Fumi Kitamura ; Kana Sawaguchi ; Asami Mori ; Shoji Takagi ; Takayoshi Suzuki ; Atsushi Kobayashi ; Masako Kato ; Kiyohiko Nakajima
• 刊名：Inorganic Chemistry
• 出版年：2015
• 出版时间：September 8, 2015
• 年：2015
• 卷：54
• 期：17
• 页码：8436-8448
• 全文大小：639K
• ISSN：1520-510X

文摘

We prepared hydrazone鈥損alladium(II) complexes of [PdCl₂(HLⁿ)] and [PdCl(Lⁿ)] (n = 1鈥?) by the reaction of [PdCl₂(cod)] or [PdCl₂(PhCN)₂] and the hydrazone ligands of HLⁿ {N鈥?(pyridin-2-ylmethylene)picolinohydrazide (HL¹), N鈥?[1-(pyridin-2-yl)ethylidene]picolinohydrazide (HL²), and N鈥?[(6-methylpyridin-2-yl)methylene]picolinohydrazide (HL³)}. The structures of the complexes were determined by X-ray analysis. The hydrazone ligands had 魏N(py1),魏N(imine) and 魏N(amidate),魏N(py2) bidentate coordination modes in [PdCl₂(HLⁿ)] (1, n = 1; 2, n = 2) and in [PdCl₂(HL³)] (3), respectively. In contrast, tridentate coordination modes of 魏N(py1),魏N(imine),魏N(py2) and 魏N(py1),魏N(amidate),魏N(py2) were observed in [PdCl(Lⁿ)] (4, n = 1; 5, n = 2) and in [PdCl(Lⁿ)] (6, n = 1; 7, n = 2; 8, n = 3). Thermal conversion of complexes 1鈥?b>3 to complexes 6鈥?b>8 proceeded in acetonitrile. Complexes 4 and 5 were obtained from complexes 1 and 2, respectively, in a basic acetonitrile solution under dark conditions. Complex 4 reverted immediately to complex 1 in an acidic acetonitrile solution that included hydrochloric acid. However, under room light, in the basic acetonitrile solution that included trimethylamine, complex 4 converted photochemically to complex 6. The thermochromic or vapochromic structure conversion of these complexes also occurred in the solid state. On heating at 180 掳C, the color of the crystals of complexes 1, 2, and 3 changed from yellow to orange in the solid state. ¹H NMR and/or UV鈥搗is absorption spectroscopy confirmed that the orange complexes 6鈥?b>8 were produced. The reddish-orange crystals of complexes 4 and 5 were exposed to hydrogen chloride vapor to yield the yellow products of complexes 1 and 2, respectively.