Pressure Indicator With One-Dimensional d8 Complexes

金刚石顶锤压力室的发展使人们能够在现场、直观地观察到压力对各种材料的影响。这对于晶型和晶体生长的研究尤其重要。当Ni^-lt；2+-gt；，Pd^-lt；2-gt；和Pt2--lt；2-gt；与1，2-二酮肟(如丁二酮肟)反应时，形成各种d8苏拉尔络合物。该络合物化学稳定，常压下颜色鲜艳。络合物的颜色随吸收带压力的变化而变化。如果能从物质的颜色随压力的变化来直观地确定压力的半量值，那将是很方便的。双(1，2-环己二酮)Pd(II)Pd(Niox)_2的分子结构如图1所示。对钻石顶压室中络合物的目测观察表明，随着压力的增加，颜色从黄色变为橙色(在0.8~1.4 Gpa)，到红色(在1.4~2.3 Gpa)，到紫色(在2 tro 3 Gpa)，到蓝色(在2.7~5.5 Gpa)，到绿色(在5.5~6.5 Gpa)和淡黄色(在7 Gpa以上)。如果仔细研究颜色与压力的关系，用类似于pH试纸的比色法，目测颜色随压力的变化，可得到半定量的压力值。Pd(Niox)2在0~8 Gpa范围内是一种很好的压力指示剂。二(二甲基乙二酮亚胺)镍(II)的颜色最初是红色的，在1.7 Gpa左右的压力下变成绿色。这是0到4 Gpa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)可在较宽的压力范围内用作压力指示器。

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.