INORGANIC SULFUR CYCLE ON DINUCLEAR RHODIUM COMPLEX

通过二硫配合物[(rhcp^*)_2(μ-CH_2)_2(μ-S_2)](1)与O_2在空气中的氧化反应，分离出氧化态在-2~+6之间的无机硫物种作为配体。分离得到的硫磺配合物为：硫磺配合物[(rhcp^*)_2(μ-CH_2)_2(μ-SSO)](2)，硫磺酸盐配合物[(rhcp^*)_2(μ-CH_2)_2(μ-SS(O)_2)](3)，α-二硫氧配合物顺-[(rhcp^*)_2(μ-CH_2)_2(μ-S(O)SO)](4)，和陷阱-[(rhcp^*)_2(μ-CH_2)_2(μ-S(O)SO)](5).利用m-CPBA，配合物1以及2和3得到了α-二磺酸配合物[(rhcp^*)_2(μ-CH_2)_2(μ-S(O)_2SO_2)](6).这些双核配合物具有一个二硫杂环骨架，其中S-S部分以侧向配位方式与Rh-Rh基团配位.Cp^*Rh-RHcp^*的强给电子基允许α-二磺酮的高级含氧硫物种通过两个S原子仍然作为配位配体工作。在这项研究中，我们探索了分离的硫氧络合物对亲电性和亲核性的反应性。络合物6很容易被NaBH_4还原为3，而不是1。虽然我们还没有成功地将3还原为1，但我们发现3与I_2或ICH_2CH_2I反应生成了1的前体[{(RhCp^*)_2(μ-CH_2)_2}_2(μ_4-S_4)]^&lt；2+&gt；.Rh-Rh键上的人工硫循环完成。

Inorganic sulfur species with oxidation states between -2 and +6 have been isolated as the ligands in the rhodium dinuclear complexes from the oxygenation of disulfido complex [(RhCp^*)_2(μ-CH_2)_2(μ-S_2)] (1)with O_2 in the air. The isolated oxysulfur complexes are the thiolsulfinato complex [(RhCp^*)_2(μ-CH_2)_2(μ-SSO)] (2),thiolsulfonato complex [(RhCp^*)_2(μ-CH_2)_2(μ-SS(O)_2)] (3),α-disulfoxido complex cis-[(RhCp^*)_2(μ-CH_2)_2(μ-S(O)SO)] (4),and traps-[(RhCp^*)_2(μ-CH_2)_2(μ-S(O)SO)] (5).Using peroxides such as m-CPBA, complex 1 as well as 2 and 3 gave the α-disulfone complex [(RhCp^*)_2(μ-CH_2)_2(μ-S(O)_2SO_2)] (6).These dinuclear complexes have a dithiodirhodium metalacycle framework where the S-S moiety coordinates to the Rh-Rh group in a side-on fashion. The strong electron donation group of Cp^*Rh-RhCp^* allows the high grade oxygenated sulfur species of α-disulfone to work still as the didentate ligand through both S atoms. In this research the reactivity of the isolated oxysulfur complexes towards electrophiles and nucleophiles has been explored. Complex 6 is readily reduced to 3 by NaBH_4, not to 1. Although we did not succeed yet in the reduction of 3 to 1, but found that the reaction of 3 with I_2 or ICH_2CH_2I produces the precursor of 1, [{(RhCp^*)_2(μ-CH_2)_2}_2(μ_4-S_4)]^<2+>. The artificial sulfur cycle on the Rh-Rh bond is completed.