کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1336425 | 1500221 | 2016 | 6 صفحه PDF | دانلود رایگان |
Two solid state forms of the {(bpymH2)2+,[WIV(CN)8]4−} charge-transfer ion pair have been obtained in the reaction between 2,2′-bipyrimidine (bpym) and octacyanotungstate(IV) in acidic solution and characterised in terms of structure and spectroscopic properties: (bpymH2)2[WIV(CN)8]·4H2O (1) and (PPh4)2(bpymH2)[WIV(CN)8]·10H2O (2). In contrast to the yellow potassium salt, compound 1 is red and shows an outer-sphere charge-transfer (IPCT) band in the visible range of the electronic spectrum. In addition, due to thermal electron transfer ca. 0.3% of the diamagnetic WIV centres is oxidised to paramagnetic WV, as shown by the EPR spectra. In the yellow compound 2 the extent of the thermal charge separation increases to 16%, which can be rationalised by charge delocalisation through the π–π interactions between bpym and the phenyl rings of the additional PPh4+ cations.
Graphical AbstractThermal electron transfer in the {(bpymH2)2+,[WIV(CN)8]4−} (bpym = 2,2′-bipyrimidine) ion pair is enhanced by the presence of π–π interactions between bpym and the additional PPh4+ cations.Figure optionsDownload as PowerPoint slide
Journal: Polyhedron - Volume 119, 24 November 2016, Pages 1–6