ORGANOMETAL CHEMISTRY OF TECHNETIUM .12. PHOTOLYTIC CO-SUBSTITUTION REACTIONS OF TECHNETIUM-TRICARBONYL COMPOUNDS - SYNTHESIS AND X-RAY STRUCTURAL-ANALYSIS OF (C5H5)TC(CO)(2)(PPH(3)), (C(5)ME(5))TC(CO)(2)(PPH(3)) AND [HB(3,5-ME(2)PZ)(3)TC(CO)(2)[P(OME)(3)] IN COMPARISON WITH ITSHOMOLOGS

Photochemical reactions of technetiumtricarbonyl compounds with neutra l phosphorous donor ligands are reported. (C(5)Me(5))Tc(CO)(3) and (C5 H5)Tc(CO)(3) react with triphenylphosphane to yield (C(5)Me(5))Tc(CO)( 2)(PPh(3)) (3) and (C5H5)Tc(CO)(2)(PPh(3)) (4) respectively. 3 and 4 h ave been isolated and their molecular and crystal structures were dete rmined by single-crystal X-ray diffraction. The crystal structures of the yellow compounds 3 (monoclinic) and 4 (triclinic) are dicussed tog ether with their spectroscopic data and are compared with the also det ermined structure of the homologous rhenium compound (C(5)Me(5))Re(CO) (2)(PPh(3)) (3a). Thermal in-situ reaction of irradiated HB(3,5-Me(2)C (3)HN(2))Tc(CO)(3) with trimethylphosphite (TMP) yields HB(3,5-Me(2)C( 3)HN(2))Tc(CO)(2)(TMP) (7). The crystal and molecular structure of 7 w as determined and and is discussed in comparison with the determined s tructures of the homologous compounds HB(3,5-Me(2)C(3)HN(2))Re(Co)(2)( TMP) (7a), and HB(3,5-Me(2)C(3)HN(2))Mn(CO)(2)(TMP) (7b). The intermed iate Re-compound HB(3,5-Me(2)C(3)HN(2))Re(CO)(2)(THF) (8a) has been al so isolated and characterized.