Synthesis, properties, and ligating behavior of the first facultative tritelluroethers, Te(CH2CH2CH2TeR)2 (R = Me or Ph)

The first examples of linear tritelluroether ligands, Te(CH2CH2CH2TeR)(2) [L, R = Me (LI) or Ph (L-2)], have been prepared from Na2Te and RTeCH2CH2CH2Cl and fully characterized spectroscopically and by quaternization with MeI to the corresponding telluronium. salts, MeITe(CH2CH2CH2TeRMeI)(2). A series of metal complexes have been prepared, the metal substrate being chosen to illustrate the ligating modes available to these ligands and to permit comparison with literature data on complexes of Se(CH2CH2CH2SeMe)(2) and MeC(CH2TeR)(3), In fac-[Mn(CO)3(L)] CF3SO3 the ligands bind as tridentates facially to the metal center, whereas in [PtCl(L)]PF6 the ligands occupy three positions on the square-planar metal center. The [{eta (5)-C5Me5}Rh(L)](PF6)(2) contain tridentate L bound to one triangular face of the octahedron. The X-ray crystal structure of [{eta (5)-C5Me5}Rh(L-2)](PF6)(2). MeOH shows tridentate telluroether coordination with the ligand adopting the DL configuration, giving a distorted pseudo-octahedral environment at Rh(III). A short contact between one C-H group in one of the phenyl rings and the centroid of the other phenyl ring (2.56 Angstrom) helps to stabilize the adopted configuration. The metal complexes have been characterized by analysis, ES+ or FAB mass spectrometry, and IR and multinuclear NMR (H-1, C-13{H-1}, Te-125) spectroscopy. The invertomers present in coordinated L have been established by the multinuclear NMR studies.