PHOTOCHEMISTRY OF OSMIUM(II) AMMINE COMPLEXES. THE DINITROGEN SPECIES DINITROGENPENTAAMMINEOSMIUM(2+) AND CIS-(BIS)(DINITROGEN)TETRAAMMINEOSMIUM(2+)
PHOTOCHEMISTRY OF OSMIUM(II) AMMINE COMPLEXES. THE DINITROGEN SPECIES DINITROGENPENTAAMMINEOSMIUM(2+) AND CIS-(BIS)(DINITROGEN)TETRAAMMINEOSMIUM(2+)
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锇(II) 胺络合物的光化学。
DOI：
10.1002/chin.197835032
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发表时间：
1978
期刊：
影响因子：
--
通讯作者：
P. Ford
中科院分区：
文献类型：
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作者：
T. Matsubara;M. A. Bergkamp;P. Ford
报告了锇 (II) 二氮配合物 Os (NH3) 5N22+ 和 cU-Os (NH3) 4 (N2) 22+ 在氯化物水溶液中光解的量子产率。间二氮离子仅在 365-214 nm 波长范围内发生光水化，生成 0s (NH3) 4 (H2O) N22+。金属到配体电荷转移 (MLCT) 波段 (Xmax 223 nm) 的直接激发比较长波长激发产生更小的量子产率。这表明从 MLCT 态直接到基态的失活与内部转换到较低能态的竞争，后者是配体取代途径的前体，Os (NH3) 5N22+ 离子仅产生 Os (III) 物质作为最终光解产物，但产物分布分析表明，在 365-229 nm 激发波长范围内发生显着的光水化，产生 0s (NH3) 5H2O2+。 Os (II) 物质被溶剂热氧化产生 Os (III) 最终产物。在此波长范围内，直接光氧化为 Os (III) 可能与光水化竞争，但在 214 nm 处，光氧化是压倒性的主导光反应途径。与钌 (II) 光化学类似，有人认为电荷转移到溶剂态可能是初级光氧化的前体，而配体场态可能是初级光水化的前体。
Reported are quantum yields for photolysis of the osmium (II) dinitrogen complexes Os (NH3) 5N22+ and cU-Os (NH3) 4 (N2) 22+ in aqueous chloride solution. The m-dinitrogen ion undergoes photoaquation only over the wavelength range 365-214 nm to give 0s (NH3) 4 (H20) N22+. Direct excitation of the metal-to-ligand charge-transfer (MLCT) band (Xmax 223 nm) gave smallerquantum yields than longer wavelength excitation. This indicates deactivation from the MLCT state (s) directly to the ground state competitive with internalconversion to lower energy state (s) which are precursors to ligand substitution pathways, The Os (NH3) 5N22+ ion gives only Os (III) species as final photolysis products but analysis of the productdistributions indicates that significant photoaquation to give 0s (NH3) 5H202+ is occurring over the excitation wavelength range 365-229 nm. Thermal oxidation of Os (II) species by solvent accounts for the Os (III) final products. Photooxidation directly to Os (III) may be competitive with photoaquation over this wavelength range, but at 214 nm photooxidation is the overwhelmingly dominant photoreaction pathway. In analogy to ruthenium (II) photochemistry, it is argued that a charge-transfer to solvent state is a likely precursorto primary photooxidation while ligand field states are the likely precursors to primary photoaquation.