INORGANIC SULFUR CYCLE ON DINUCLEAR RHODIUM COMPLEX

在二硫键配合物[（RhCp^*）_2（μ-CH_2）_2（μ-S_2）]（1）与O_2的氧化反应中，分离出了氧化态在-2 ~+6之间的无机硫物种。硫氧化合物为硫代亚磺酸根配合物[（RhCp^*）_2（μ-CH_2）_2（μ-SSO）]（2），硫代磺酸根配合物[（RhCp^*）_2（μ-CH_2）_2（μ-SS（O）_2）]（3），α-二亚砜配合物cis-[（RhCp^*）_2（μ-CH_2）_2（μ-S（O）SO）]（4），和捕获剂-[（RhCp^*）_2（μ-CH_2）_2（μ-S（O）SO）]（5）。配合物1、配合物2和配合物3得到了α-二砜配合物[（RhCp^*）_2（μ-CH_2）_2（μ-S（O）_2SO_2）]（6）。S部分以侧面方式与Rh-Rh基团配位。Cp^*Rh-RhCp^* 的强给电子基团允许α-二砜的高级氧化硫物质通过两个S原子仍然作为二齿配体起作用。在这项研究中，探索了分离的氧硫配合物对亲电试剂和亲核试剂的反应性。配合物6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，但发现3与I_2或ICH_2CH_2I反应生成1的前体[{（RhCp^*）_2（μ-CH_2）_2}_2（μ_4-S_4）]^<2+>。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.