Synthesis and Characterization of a Twin Cubane-Type Molybdenum-Rhodium-Sulfur Cluster, [{Mo3RhCp*S4(H2O)7(O)}2]8+. X-ray Structure of
详细信息 查看全文
- 作者：Haruo Akashi ; Kiyoshi Isobe ; and Takashi Shibahara
- 刊名：Inorganic Chemistry
- 出版年：2005
- 出版时间：May 16, 2005
- 年：2005
- 卷：44
- 期：10
- 页码：3494 - 3498
- 全文大小：93K
- 年卷期：v.44,no.10(May 16, 2005)
- ISSN：1520-510X
文摘
The reaction of [Mo3S4(H2O)9]4+ (1) with [(Cp*RhCl2)2] afforded a novel rhodium-molybdenum cluster, [{Mo3RhCp*S4(H2O)7(O)}2]8+ (2). X-ray structure analysis of [2](pts)8·14H2O (pts- = CH3C6H4SO3-) has revealed the existenceof a new oxo-bridged twin cubane-type core, (Mo3RhCp*S4)2(O)2. The high affinity of the Cp*Rh group for sulfuratoms in 1 seems to be the main driving force for this reaction. The strong Lewis acidity of the Cp*Rh group inintermediate A, [Mo3RhCp*S4(H2O)9]6+, caused a release of proton from one of the water molecules attached tothe molybdenum atoms to give intermediate B, [Mo3RhCp*S4(H2O)8(OH)]5+. The elimination of two water moleculesfrom two intermediate B molecules, followed by the deprotonation reaction of hydroxo bridges, generated the twincubane-type cluster 2. The formal oxidation states of rhodium and molybdenum atoms are the same before andafter the reaction (i.e., Mo(IV)3, Rh(III)). The Mo-O-Mo moieties in [2](pts)8·14H2O are nearly linear with a bondangle of 164.3(3)
, and the basicity of the bridging oxygen atoms seems to be weak. For this reason, protonationat the bridging oxygen atoms does not occur even in a strongly acidic aqueous solution. The binding energy valuesof Mo 3d5/2, Rh 3d5/2, and C 1s obtained from X-ray photoelectron spectroscopy measurements for [2](pts)8·14H2Oare 229.8, 309.3, and 285 eV, respectively. The XPS measurements on the Rh 3d5/2 binding energy indicate thatthe oxidation state of Rh is 3+. The binding energy of Mo 3d5/2 (229.8 eV) compares with that observed for[1](pts)4·7H2O (230.7 eV, Mo 3d5/2). A lower energy shift (0.9 eV) is observed in the binding energy of Mo 3d5/2 for[2](pts)8·14H2O. This energy shift may correspond to the coordination of an oxygen atom having a negative chargeto the molybdenum atom.
, and the basicity of the bridging oxygen atoms seems to be weak. For this reason, protonationat the bridging oxygen atoms does not occur even in a strongly acidic aqueous solution. The binding energy valuesof Mo 3d5/2, Rh 3d5/2, and C 1s obtained from X-ray photoelectron spectroscopy measurements for [2](pts)8·14H2Oare 229.8, 309.3, and 285 eV, respectively. The XPS measurements on the Rh 3d5/2 binding energy indicate thatthe oxidation state of Rh is 3+. The binding energy of Mo 3d5/2 (229.8 eV) compares with that observed for[1](pts)4·7H2O (230.7 eV, Mo 3d5/2). A lower energy shift (0.9 eV) is observed in the binding energy of Mo 3d5/2 for[2](pts)8·14H2O. This energy shift may correspond to the coordination of an oxygen atom having a negative chargeto the molybdenum atom.