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rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
2005-5-9
pubmed:abstractText
The reaction of [Mo(3)S(4)(H(2)O)(9)](4+) (1) with [(CpRhCl(2))(2)] afforded a novel rhodium-molybdenum cluster, [{Mo(3)RhCpS(4)(H(2)O)(7)(O)}(2)](8+) (2). X-ray structure analysis of [2](pts)(8).14H(2)O (pts(-) = CH(3)C(6)H(4)SO(3)(-)) has revealed the existence of a new oxo-bridged twin cubane-type core, (Mo(3)RhCpS(4))(2)(O)(2). The high affinity of the CpRh group for sulfur atoms in 1 seems to be the main driving force for this reaction. The strong Lewis acidity of the CpRh group in intermediate A, [Mo(3)RhCpS(4)(H(2)O)(9)](6+), caused a release of proton from one of the water molecules attached to the molybdenum atoms to give intermediate B, [Mo(3)RhCpS(4)(H(2)O)(8)(OH)](5+). The elimination of two water molecules from two intermediate B molecules, followed by the deprotonation reaction of hydroxo bridges, generated the twin cubane-type cluster 2. The formal oxidation states of rhodium and molybdenum atoms are the same before and after the reaction (i.e., Mo(IV)(3), Rh(III)). The Mo-O-Mo moieties in [2](pts)(8).14H(2)O are nearly linear with a bond angle of 164.3(3) degrees, and the basicity of the bridging oxygen atoms seems to be weak. For this reason, protonation at the bridging oxygen atoms does not occur even in a strongly acidic aqueous solution. The binding energy values of Mo 3d(5/2), Rh 3d(5/2), and C 1s obtained from X-ray photoelectron spectroscopy measurements for [2](pts)(8).14H(2)O are 229.8, 309.3, and 285 eV, respectively. The XPS measurements on the Rh 3d(5/2) binding energy indicate that the oxidation state of Rh is 3+. The binding energy of Mo 3d(5/2) (229.8 eV) compares with that observed for [1](pts)(4).7H(2)O (230.7 eV, Mo 3d(5/2)). A lower energy shift (0.9 eV) is observed in the binding energy of Mo 3d(5/2) for [2](pts)(8).14H(2)O. This energy shift may correspond to the coordination of an oxygen atom having a negative charge to the molybdenum atom.
pubmed:language
eng
pubmed:journal
pubmed:status
PubMed-not-MEDLINE
pubmed:month
May
pubmed:issn
0020-1669
pubmed:author
pubmed:issnType
Print
pubmed:day
16
pubmed:volume
44
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3494-8
pubmed:year
2005
pubmed:articleTitle
Synthesis and characterization of a twin Cubane-type molybdenum-rhodium-sulfur cluster, [{Mo3RhCp*S4(H2O)7(O)}2]8+. X-ray structure of [{Mo3RhCpS4(H2O7O}2](CH3C6H4SO3)(8).14H2O.
pubmed:affiliation
Research Institute of Natural Sciences, Okayama University of Science, Ridai-cho, Japan. akashi@high.ous.ac.jp
pubmed:publicationType
Journal Article