Reactions of dirhenium complexes with multidentate phosphine ligands

Michael John Siwajek, Purdue University

Abstract

The complexes (n-Bu4N)2Re 2Cl8 and cis-Re2(O2CCH 3)2Cl4L2 (L = H2O or py) react with dcpm (dcpm = Cy2PCH2PCy2) in refluxing ethanol to afford the complex Re2Cl4(μ-dcpm) 2. This complex is converted to the dirhenium(III) complex Re2 Cl6(μ-dcpm)2 via the oxidative addition of Cl2. The mixed-phosphine complex Re2Cl4(μ-dcpm)(PMe 3)2 is formed both by the reaction of Re2Cl 4(PMe3)4 with dcpm in refluxing 1-propanol, and by the reaction of (n-Bu4N)2Re 2C8 with excess dcpm and trimethylphosphine in refluxing 1-propanol. The reaction of Re2Cl4(μ-dcpm)2 with xylylNC in acetone affords the triplybonded dirhenium(II) complex Re 2Cl4(μ-dcpm)2(CNxylyl). Similarly, the triply-bonded dirhenium(II) bis-isocyanide complex, Re2Cl4(μ-dcpm) 2(CN-t-Bu)2 is formed by the reaction of Re2Cl4(μ-dcpm)2 with t-BuNC in acetone. The compounds Re2Cl4(μ-dcpm)2(CNxylyl) and Re2Cl4(μ-dcpm)2(CN-t-Bu) 2 both react with CO in dichloromethane in the presence of TlO 3SCF3 to form the compounds [Re2Cl3(μ-dcpm) 2(CNxylyl)(CO)2]O3SCF3 and [Re 2Cl3(μ-dcpm)2(CN-t-Bu) 2(CO)]O3SCF3, which are believed to possess edge-sharing bioctahedral geometries. In the absence of TlO3SCF3, Re2Cl4(μ-dcpm)2(CNxylyl) and Re2 Cl4(μ-dcpm)2(CN-t-Bu)2 react with CO in dichloromethane to afford the compounds [Re2Cl 3(μ-dcpm)2(CNxylyl)(CO)2]Cl and [Re2Cl 3(μ-dcpm)2(CN-t-Bu)2(CO)]Cl, which have different structures from those of the aforementioned triflate salts. The reactions of cis-Re2(O2CCH 3)2X4L2(X = Cl or Br; L = H2O or py) with triphos (triphos = CH3C(CH2PPh2) 3) in refluxing ethanol, followed by anion exchange reactions with TlO 3SCF3 in dichloromethane, afford the complexes [Re2 (μ-X)3(triphos)2]O3SCF3 (X = Cl or Br). These complexes react with cobaltocene in acetone to yield the dirhenium(II, I) complexes Re2(μ-X)3(triphos) 2(X = Cl or Br). The reaction of Re2Cl4(PMe3)4 with tripod (tripod = HC(PPh2)3) in refluxing ethanol affords the mixed-phosphine complex Re2Cl4(μ-dppm)(PMe 3)2 (dppm = Ph2PCH2PPh2). The complex cis-Re2(O2CCH3) 2Cl4(py)2 reacts with tripod to form the mononuclear rhenium(II) complex trans-ReC2[η2-HC(PPh 2)3]2.

Degree

Ph.D.

Advisors

Walton, Purdue University.

Subject Area

Chemistry

COinS