Near IR region

Diverse series of diphenyl sulphoxide (DPSO) complexes of Mn(II), Fe(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Ca(II), Al(II) and Mg(II) with various large anions have been reported187-191. The complexes have the general formula M(DPSO)6(Anion) where M is the metal cation. The reflection spectra in the visible and near-IR region indicate an octahedral configuration around the metal ion surrounded by the DPSO molecules. Comparison with the spectra of DMSO complexes shows that they have almost identical structures. IR spectra indicate that the oxygen atom in the sulphinyl group is the donor atom in all these complexes. 

In contrast, when a THF-acetonitrile solution of [26+jClOj or [113+JC104 was added to the THF solution of K+[2 ], the deep green colour of carbanion [2 ] persisted. After evaporation of the solvent, purification of the residue yielded a dark green salt, [26+2 ] or [113+2 ] (Scheme 3), the IR spectra (KBr disk) of which consisted of the absorptions of [2 ] and [26+] or [113+] superimposed. The visible-near IR region... 

Due to the absorption band of the colored form of spiroindolinoben-zothiopyrans in the near IR region, they have been used in the optical erasable recording disks.89,100,101 The principle of optical erasable recording system using photochromic spirobenzothiopyran is explained as follows. 

The sensitizers display a crucial role in harvesting of sunlight. To trap solar radiation efficiently in the visible and the near IR region of the solar spectrum requires engineering of sensitizers at a molecular level (see Section 9.16.3).26 The electrochemical and photophysical properties of the ground and the excited states of the sensitizer have a significant influence on the charge transfer (CT) dynamics at the semiconductor interface (see Section 9.16.4). The open-circuit potential of the cell depends on the redox couple, which shuttles between the sensitizer and the counter electrode (for details see Section 9.16.5). 

The trarax-dichloro and dithiocyanate complexes show MLCT transitions in the entire visible and near IR region. The lowest energy MLCT transition band of the trara-dichloro complexes is around 700 nm in DMF solution, and the complexes show weak and broad emission signals above 950 nm. The absorption and emission maxima of the Zrarax-dithiocyanate complexes are blue shifted compared to its trarax-dichloro analogues due to the strong -k acceptor property of the NCS- ligands compared to Cl-, which is consistent with the electrochemical properties of these complexes. 

Pommeret, S., Antonetti, A. and Gauduel, Y. Electron hydration in pure liquid water. Existence of two nonequilibrium configuration in the near-IR region, JAm.Chem.Soc., 113 (1991). 9105-9111... 

Some transition metal cations have color in the visible or near IR region due to their unfilled d-orbitals, intrinsic sensing of these ions are possible. Such as the detection of Cu(II) in plating baths. 

Some commercially available instruments, in addition to visible spectrophotometers, can also perform measurements in the UV and near IR regions of the spectrum. 

For solutes of exceptionally high molecular weight there has been a discernible move towards conducting LS experiments in the near IR region (X0 1000 nm), which effectively reduces the relative size parameter (s2>1/2/X, even though very large for such materials. The associated problems of absorption and... 

Cyanine dyes are in principle capable of shifting the emission into the near-IR region [157], however, their ionic character makes it difficult to dope them into films by vacuum vapor evaporation. Other materials investigated for IR emission are complexes based on rare earth ions (Nd3+, Er3+), which are also used in inorganic amplifiers and lasers [158]. 

T. Imasaka, A. Yoshitake, and N. Ishibashi, Semiconductor laser fluorimetry in the near-IR region, Anal. Chem. 56, 1077-1079(1984). 

The binuclear unit also confers characteristic physical and spectroscopic properties to the complexes. Electronic spectra reveal a strong (e - 3000-4000 M-icm l) absorption band at 3(X)-400 nm with a characteristic low energy shoulder, both associated with the presence of an 0x0 bridge weaker (e 300-600 M lcm" ) features in the 400-550 nm region associated with the (p,-oxo)bis(p.-carboxylato)-diiron(in) core and d-d bands in the near IR region (Hgure 2a) (5,10). Laser excitation into the visible and near UV bands results in the observation of enhanced Raman features due to Fe-O-Fe vibrations (5,11) (see Chapter 3 for a more detailed discussion into the Raman spectra of these complexes). 

Optical and FTIR instrumentation. Absorption spectra were taken on three instruments. A Hewlett Packard 8450 UV/Vis Spectrophometer was used for the visible region of the spectrum. This instrument was computer control led and used to measure standard absorption spectra as well as absorption difference spectra. A Cary 14 Spectrophotometer was used for the near IR region, and an IBM IR/90 Series... 

Below 625 nm the reported absorption spectra consist of a series of intense LMCT excitations and their marked polarization dependence allows an unambiguous band assignment. In the red and near-IR region of the spectrum the highly structured d-d transitions are of low intensity. The vibrational progressions that are observed in the absorption and in the lumines-... 

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