Complexation Reaction and Applications of Chloroplatinic acid hexahydrate

Chloroplatinic acid hexahydrate appears as an orange‑yellow powder or reddish‑brown crystalline solid under ambient temperature and pressure. It exhibits notable hygroscopicity and is readily deliquescent, soluble in water, ethanol, and acetone. Chloroplatinic acid hexahydrate serves as a metal‑separating reagent, primarily used for the preparation of noble‑metal catalysts and noble‑metal plating. Additionally, chloroplatinic acid hexahydrate can be employed to precipitate potassium, gallium, ammonium, cesium, and thallium for their separation from sodium.

Figure1: Picture of Chloroplatinic acid hexahydrate

Complexation Reaction

Method 1

The reaction was performed by treating dimethyldi(4‑N,N‑dimethylaminophenyl)silane (1) with chloroplatinic acid hexahydrate in acetone (ace), yielding the complex salt [H(dma)]₂(PtCl₆)·0.5ace (2·0.5ace) (dma = N,N‑dimethylphenylamine), which was characterized by single‑crystal X‑ray diffraction. Simultaneously, the byproducts (4‑dimethylaminophenyl)dimethylsilanol (3), dma, 4‑(dimethylphenylsilyl)‑N,N‑dimethylaniline (4), and 1,3‑bis(4‑(dimethylamino)phenyl)‑1,1,3,3‑tetramethyldisiloxane (5) were isolated. Their structures were confirmed by FT‑IR, ¹H NMR, ¹³C NMR, ²⁹Si NMR, and ESI‑MS analyses. The formation of these byproducts indicates that cleavage of both the Si–C and C–N bonds in compound 1 occurred during the reaction. Possible reaction mechanisms were also discussed. [1]

Method 2

A solution of 22 mg (0.2 mmol) diethylammonium chloride in 4 mL of acetonitrile was poured into a solution of 50 mg (0.1 mmol) of hexachloroplatinic acid hexahydrate in 4 mL of acetonitrile. The resulting solution was concentrated to a volume of 0.5 mL, and the precipitated crystals were fi ltered out and dried. Yield 44 mg (82%), orange crystals, mp 218°С. [2]

Chemical Applications

Chloroplatinic acid hexahydrate can be used for the precipitation of alkaloids, electroplating, catalysis, and the preparation of platinum‑asbestos materials. In the synthesis of cerium‑loaded platinum catalysts, TiO₂/Pt nanocomposites, platinum‑nanoparticle‑impregnated porous carbon films, and cadmium sulfide‑platinum colloidal systems, chloroplatinic acid hexahydrate serves as a platinum precursor. Furthermore, studies have reported that chloroplatinic acid hexahydrate has been applied in the following research areas: the preparation of Pd nanocubes (width ~150 nm) and Pt nanospheres (diameter ~150 nm); the formulation of plating solutions for the electrodeposition of Pt nanoparticles on multilayer graphene‑petal nanosheets (MGPNs); and the synthesis of Pt‑nanocarbon (NC) nanocomposites.

Synthesis of Modified Polysiloxanes

Under the catalysis of chloroplatinic acid hexahydrate, allyl‑epoxy polyether and terminal hydride‑containing silicone oil underwent a hydrosilylation reaction to give the intermediate epoxy‑polyether‑modified polysiloxane. Subsequently, terminal amino‑polyether was added to carry out an amino‑mediated ring‑opening reaction with the intermediate, yielding polyether‑amino‑modified polysiloxane (MPEAS). The structure of the product was characterized by FT‑IR spectroscopy, and the synthesis conditions as well as the application process were optimized. The optimized synthetic procedure was as follows: for the hydrosilylation step, chloroplatinic acid hexahydrate was used at 0.03 wt%, with a reaction temperature of 90 °C and a reaction time of 8 h; for the amino‑ring‑opening step, the temperature was maintained at 65–75 °C for 6 h. The optimized application conditions included pre‑drying at 100 °C for 10 min, followed by curing at 150 °C for 50 s. Fabrics treated with the resulting product exhibited improved softness, nearly unchanged whiteness, and a static water absorption time of only 3.4 s. [3]

Preparation of Pt/TiO₂ Photocatalytic Materials

Using tetrabutyl titanate as the titanium source and chloroplatinic acid hexahydrate as the platinum source, a high‑performance visible‑light Pt/TiO₂ photocatalytic material was prepared by a sol‑gel method. The synthesized samples were characterized by XRD and UV‑Vis spectroscopy. XRD results indicated that the TiO₂ possessed an anatase crystal structure; the addition of Pt did not alter the phase of TiO₂, and no distinct diffraction peaks corresponding to Pt were detected. UV‑Vis measurements showed that the 0.6% Pt/TiO₂ sample exhibited enhanced absorption in the visible region. Under visible‑light irradiation, the photocatalytic performance of Pt/TiO₂ was evaluated using methylene blue solution as a model pollutant. Experimental results demonstrated that with increasing Pt doping, the degradation rate constant of methylene blue initially increased and then leveled off, with the 0.6% Pt/TiO₂ sample displaying the highest photocatalytic efficiency. XPS analysis was further employed to elucidate the mechanism behind the visible‑light photocatalytic activity of the Pt/TiO₂ samples. [4]

Reference

[1] Wang P, Yue Z, Zhang J, et al. Reactions and mechanisms of chloroplatinic acid hexahydrate with dimethyldi (4-N, N-dimethylaminophenyl) silane[J]. Inorganic Chemistry Communications, 2011, 14(6): 1027-1031.

[2] Tkacheva A R, Sharutin V V, Sharutina O K, et al. Tetravalent platinum complexes: synthesis, structure, and antimicrobial activity[J]. Russian Journal of General Chemistry, 2020, 90: 655-659.

[3] Zhao, H., Ma, F., Zhao, Q., et al. Synthesis and application of polyether?amino?modified polysiloxane [J]. Textile Auxiliaries, 2014, 31(5): 4.

[4] Wu, W., Li, Y., Zheng, M., Hu, Y., He, D., Di, L., & Zhang, X. Preparation and properties of high?performance visible?light Pt/TiO? photocatalytic materials [J]. Journal of Functional Materials, 2015, 46(5): 5.

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