Pressure Indicator With One-Dimensional d8 Complexes

金刚石顶砧压力传感器的发展使压力对各种材料的影响能够在现场直观地观察到。这对于多晶和晶体生长的研究尤其重要。当Ni^<2+>, Pd^<2_>和Pt^<2_>与1,2-二酮二肟（如二甲基乙肟）反应时，可形成各种d8配合物。这些配合物在化学上是稳定的，在大气压下具有美丽的颜色。配合物的颜色随吸收带的压力变化而变化。如果压力的半定量值能从材料的颜色随压力的变化而直观地确定出来，那将是很方便的。二（1,2-环己二酮二氧嘧啶）Pd(II), Pd(niox)_2的分子结构如图1所示。金刚石砧细胞内复合体的目视观察表明，随着压力的增加，颜色从黄色变为橙色（0.8至1.4 GPa），变为红色（1.4至2.3 GPa），变为紫色（2至3 GPa），变为蓝色（2.7至5.5 GPa），变为绿色（5.5至6.5 GPa），并变为淡黄色（高于7 GPa）。如果仔细研究颜色与压力的关系，可以用类似于ph试纸的比色法直观地观察颜色随压力的变化，从而得到压力的半定量值。在0 ~ 8gpa范围内，Pd(niox)_2是一个很好的压力指示器。二甲基乙氧嘧啶镍（II）的颜色最初是红色的，在1.7 GPa左右的压力下变为绿色。这是0到4gpa范围内的压力指示器。各种双（1,2-二酮二肟）M(II)（M: Ni, Pd， Pt等）可作为宽压力区的压力指示器。

The development of diamond-anvil pressure cells enables the effect of pressure on varrious matgerials to be observed, in situ, visually. This is especially importans for the study of polymorphs and crystal growth. Various d8 sauare complexes are formed when Ni^<2+>, Pd^<2_> and Pt^<2_> react withy 1,2-dionedioximes such as dimethylglyoxime. The complexes are chemicallyh stable, and have beautiful colours at atmo- spheric pressure. The colours of the complexes change with pressure shift of the absorption bands. It would be conve- nient if a semiguantitative value of pressure could be de- termined visuallyh from a change in the colour of a material with change in pressure. The molecular structure of bis(1,2- cyclohexanedionedioximato)Pd(II), Pd(niox)_2, is shown in Fig. 1. Visual observation of the comples in the diamond-anvil cell indicated that the colour turned from yellow to orange (at 0.8 to 1.4 GPa), to red(at 1.4 to 2.3 GPa), to purple(at 2 tro 3 GPa), to blue(at 2.7 to 5.5 GPa),to green(at 5.5 to 6.5 GPa) and to pale yellow(above 7 GPa) with increasing pressure. If the relationship between colour and pressure is studied in detail, a semiquantitative value of pressure could be ob- tained from the visual obsewrvation of the change in colour with pressure byh c colorimetric method similar to ph testing paper. Pd(niox)_2 is an excellent pressure indicator in the range 0 to 8 GPa. The colour of bis(dimethyhlglyoximato)Ni(II) which is initially red turns to green at pressure around 1.7 GPa. This is the pressure indicator in the range 0 to 4 GPa. Various bis(1,2-dionedioximato)M(II)(M: Ni, Pd, Pt, etc.) can be used as pressure indicators in the wide pressure region.