IR band around

The presence of a thiocyanate group can be very easily deduced from the IR spectrum, which contains a sharp, but weaker in intensity, IR band around 2150 cm-1 and an NMR carbon resonance between 112 and 115 ppm. In the case of psamaplin B (172), C-NMR additivity effects applied to the methylene carbon linked to the thiocyanate were used to distinguish between a thio- and isothiocyanate group [142]. Chemical proof can be provided by LAH reduction of the thiocyanate, which gives a thiol rather than a methylamine group as the reaction product of the reduction of the isothiocyanate [195]. 

There are, however, conflicting interpretations advanced in the literature regarding the appearance of these bands in the IR spectra (cf. [323-327] see also Volume 1, Chapter 7, pages 198-199, of the present series). The situation is even more complicated by the fact that so-called hydroxyl nests in the siHcalite-1 structure, [(-0-)3Si-0H]4, give rise to an IR band around 960 cm as weU. There-... 

The most commonly employed titania modification in catalysis is anatase, whereas there are fewer applications of rutile. In many reports, mixed ana-tase-rutile samples were investigated. In sum, at least 12 types of OH groups on the anatase surface have been proposed by different authors (115). The most frequently reported hydroxyls are characterized by IR bands around 3720-3715 and 3675 cm (27,28,115,269,272-274,330,357,504,651, 678,679). These two bands are well discemable after evacuation at a temperature of 673 K. A band around 3640 cm is also often reported and characterizes less stable hydroxyls (230,273,356,504,651). For a Degussa P25 sample (containing rutile), an additional band at 3662 cm was reported (273). An increase in the evacuation temperature results in a complex spectrum containing a set of low-intensity bands. 

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