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This article describes the construction of a novel optically transparent thin-layer electrochemical (OTTLE) cell for IR and UV-Vis spectroelectrochemical experiments at variable temperature. The cell has a three-electrode set melt-sealed into a smooth polyethylene spacer which is sandwiched between two CaF2 windows. The width of this spacer (0.18–0.20 mm) defines the thickness of the thin solution layer. The whole electrode assembly is housed in a thermostated Cu block of the OTTLE cell which fits into a double-walled nitrogen-bath cryostat. The experimental setup permits relatively fast electrolysis within the tested temperature range of 295 to 173 K under strictly anaerobic conditions and protection of light-sensitive compounds. Other important merits of the cell design include lack of leakage, facile cleaning, almost negligible variation of the preset temperature, and facile manipulation in the course of the experiments. The applicability of the variable-temperature IR/UV-Vis OTTLE cell is demonstrated by stabilization of a few electrogenerated carbonyl complexes of Mn(I) and Ru(II) with 3,5-di- tert. butyl-1,2-benzo(semi)quinone (DB(S)Q) and N, N′-diisopropyl-1,4-diaza-1,3-butadiene (iPr-DAB) ligands, respectively, at appropriately low temperatures.

Complexes of the type [Ru(X)(R)(CO)2(L)] (X = halide, CF3S03; R = alkyl; L = N,N '-diisopropyl-1,4-diaza-1,3-butadiene, pyridine-2-carbaldehyde TV-isopropylimine, 2,2,-bipyridine) experience significant influences of X and R on the energies and relative intensities of their lowest-energy electronic transitions. The halide complexes show two absorption bands in the visible region, which are assigned to two sets of charge transfer transitions from mixed metal-halide orbitals. Variation of the halide from Cl to I gives rise to a change in character of the lowestenergy band from MLCT to XLCT, as evidenced by resonance Raman spectra. These spectra show enhancement of Raman intensity for both ys(CN) and vs(CO) in the case of the Cl complex, but only for vs(CN) for the corresponding I complex. Variation of the alkyl ligand from Me to iPr leads to a shift of both absorption bands to lower energy with a concomitant change of their relative intensities. The latter effect is again ascribed to a change of charge transfer character of the electronic transitions.

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Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. [6312][6313][6314][6315][6316][6317][6318] Photochemistry of the Clusters OS~(CO)~O(L) (L = 2,2'-Bipyridine, 2,2'-Bipyrimidine, 2,3-Dipyrid-2-ylpyrazine, 2,3-Dipyrid-2-ylbenzoquinoxaline). The complexes OS~(CO)IO(L) (L = 2,2'-bipyridine (bpy), 2,2'-bipyrimidine (bpym), 2,3-dipyrid-2-ylpyraine (dpp), and 2,3-dipyrid-2-ylbenzoquinoxaline (dpb)) were synthesized, and their low-energy Os -L (MLCT) transitions were characterized with resonance Raman spectroscopy. Continuous wave excitation into the MLCT transitions does not lead to product formation. However, rapid-scan IR and nano-and picosecond time-resolved absorption spectra show the formation of a transient species (for L = bpy, bpym, and dpp) which reacts back to give the parent complex. In toluene the transient has a lifetime of less than 10 ns and is assigned to an MLCT state of the cluster. In coordinating solvents a different transient species is observed with a lifetime that strongly depends