The CN Stretching Vibration

Figure 9.40 shows the IgSg band of HCN involving one quantum of Vi, the CN stretching vibration, and six quanta of V3, the CH stretching vibration. This extremely weak band was observed using a cavity length of 1.3 m. 

Figure 1 illustrates the IR spectra of NBR and HNBR samples with different concentrations of residual double bonds [11]. The CN stretching vibration is observed at 2222 cm in NBR and HNBR. The peak at 1440 cm is for C—H deformation of —CH2— groups. The =C—H out of plane deformations of trans, vinyl, and cis double bonds are observed at 970 cm", 920 cm", and 730 cm", respectively. These peak absorbances decrease gradually, and a new peak at 723 cm" appears on the spectrum of HNBR for—CH2— rocking vibration [when (CH2)n n > 4] [11,78]. The CN stretching vibration is taken as an internal standard and the... 

The given value of the CN stretching vibration in the original paper [37] is incorrect... 

In aqueous solution it was found that the binding of the sulfur atoms to the silver nucleus was not strong enough to give the complexes a character of independent units which could be detected by spectroscopic means. The displacements observed in the CN stretching vibration were directly dependent upon the amount of silver present per thiocyanate group.144... 

Some weak features attributed to the BEDO-TTF intramolecular vibrations are observed below 1600 cm-1 and a narrow double band near 2100 cm 1 is assigned to the CN stretching vibration of the anion. Below 200 K the qualitative change in the reflectivity spectra for E L is accompanied by the appearance of new vibrational features at 862 and 1012 cm 1. 

For NaY zeolite stirred with cyanide or Fe(CN)e solutions no bands for the CN stretching vibration in the IR... 

Fig. 10. ATR spectra of the CN stretching vibration of thiocyanate at an Ag/electrolyte interface measured at indicated electrode potentials (V) vs. Ag/AgCl. The angle of incidence of radiation is 70°. Electrolyte (a), (b) 0.1 M NaC104 + 0.01 M NaSCN (c) 0.1 M NaCl + 0.01 M NaSCN. Thickness of Ag electrode (a), (c) 18 nm (b) 17 nm. Measurement order is top to bottom in each case.

Summary. Surface-enhanced Raman spectrsocopy (SERS) can be used as an in-situ method for monitoring the development of surface morphology, nucleus formation, and crystal growth. The correlation between the true surface area and the Raman intensity was investigated. The splitting of the CN stretch vibration is interpreted as a representation of a surface cluster distribution. 

Fig. 2. Development of the SER signal of the CN stretch vibration during silver deposition on platinum, electrolyte HI.

Fig. 5. SER spectrum of the CN" stretch vibration after silver deposition on platinum obtained by applying the potential pulse programming of Fig. 1(b) electrolyte I.

Fig. 8. SER spectra of the CN" stretch vibration for different silver concentrations ( n = 3 s) (a) electrolyte I (b) electrolyte HI.

Fig. 10. Relation between the frequency of the CN" stretch vibration in the different Ag(CN) complexes and the partial (positive) charge per CN" ligand Va cn and vcn" were excluded.

Silver is an example of a metal that shows the surface-enhanced Raman effect. After a special surface treatment, the signal of a molecular group on the surface of the metal is enhanced by several orders of magnitude. One successful surface treatment is deposition of silver. So, after starting silver deposition from a cyanide electrolyte on a platinum electrode, a Raman signal of the CN-stretch vibration develops and reaches a limiting value (Figure 7.28). ... 

The different complexes in a silver cyanide electrolyte show different Raman signals of the CN-stretch vibration. The peak observed in Figure 7.28 is usually explained as the Ag(CN)3 peak. The peak around 2110 cm (2080-2140 cm" ) was observed at -0.7 Vg ,g. Switching to 0 a shift to 2140 cm (2110-2175 cm" ) was observed, which is the frequency of Ag(CN)2. Compared to the deposition mechanism (Section 7.5.2) one has to conclude that the Ag(CN)3 complex dominates even on the surface. 

Figure 7.28 Development of the Raman spectrum of the CN-stretch vibration in the Ag(CN) complex after switching to a deposition potential of silver, 0.4 mol dm" KNOj, 0.028 mol dm KCN, 0.005 mol dm AgN03, A = 514.5 cm , 30 mW cm , and deposition on a Pt electrode. After switching to an anodic potential of dissolution, the Raman signal is observed (even increases) until the silver deposit has dissolved.

Fig. 51 Development of the SERS signal of the CN stretch vibration during deposition on platinum in 0.027 mol l KCN, 0.003 mol 1 AgNOs and 0.36 mol KNO3. Excitation line 514.5 nm. (Reproduced with permission from Ref [80].)...

Huang CY, Wang T, Gai E (2003) Temperature dependence of the CN stretching vibration of a nitrile-derivatized phenylalanine in water. Chem. Phys. Lett. 371 731-738... 

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