SYNTHESIS OF SELENOPHOSPHINIC AND TELLUROPHOSPHINIC AMIDES AND AMIDATO COMPLEXES - CRYSTAL-STRUCTURES OF BU(2)(T)P(TE)NH(C6H11), [TI(ETA-C5H5)CL-2(BU(2)(T)P(SE)NPRI)] AND [TICL2(BU(T)(2)P(SE)N(C6H11))(2)].C7H8

The reaction of Bu(2)(t)PNHR' with selenium or tellurium affords the c halcogenophosphinic amides Bu(2)(t)P(E)NHR' (E = Se or Te; R' = Pr-i o r cyclo-C6H11). The compounds [Bu(2)(t)P(E)NHCH2](2) were prepared sim ilarly. The crystal structure of Bu(2)(t)P(Te)NH(C6H11) was determined ; it shows a short P-Te bond of 2.371(1) Angstrom and a rather long P- N bond of 1.781(4) Angstrom. The lithium salts Li[Bu(2)(t)P(Se)NR'] re act with [TiCl3(cp)] (cp = eta-C5H5) to give [TiCl2(cp){Bu(2)(t)P(Se)N R'}]. The reaction of Li[Bu(2)(t)P(Se)NPri] with [TiCl4(thf)(2)] (thf = tetrahydrofuran) affords [TiCl3{Bu(2)(t)P(Se)NPri)]. while a similar reaction with Li[Bu(2)(t)P(Se)N(C6H11)] leads to the isolation of [Ti Cl2{Bu(2)(t)P(Se)N(C6H11}(2)]. The structures of [TiCl2(cp){Bu(2)(t)P( Se)NPri}] and [TiCl2{Bu(2)(t)P(Se)N(C6H11)}(2)]. C7H8 have been determ ined by X-ray crystallography. The selenophosphinic amidato ligands ar e bidentate in ail cases. The former complex adopts a distorted square -pyramidal geometry with apical cp, while the latter is octahedral wit h cis-CI ligands and trans stereochemistry for the nitrogen donors.