ReV-Phthalocyaninate und ReV-Tetraphenylporphyrinate mit Oxo-Liganden: Synthese, Eigenschaften und Kristallstruktur

Hexa-coordinated Re-V phthalocyaninates (pc) and Re-V tetraphenylporphyrinates (tpp) of the type [Re(O)(X)p] (p: pc, tpp) with X=OCH3, ReO4, Cl/pc, F/pc, OH/tpp, [{Re(O)p}(2)(mu-O)] and (cat)(trans)[Re(O)(2p)] (cat: (Bu4N)-Bu-n, Et4N/ tpp) have been isolated and characterised by their UV-Vis-NIR, IR and resonance Raman (RR) spectra. In the RR spectra, the intensity of the (Re=O) and (Re-X) stretching vibrations (v(Re=O/-X)) in [Re(O)(X)p] and [{Re(O)(p)}(2)-(mu-O)] is selectively enhanced with excitation in coincidence with O --> Re-CT between ca 19000 and 22000 cm(-1). In accordance to selection rules, data of v(Re=O/-X) compare well with these of the complementary IR spectra. Because of the trans influence v(Re=O) depends on the axial ligand X, ranging from 940 to 1010cm(-1). The crystallographic characterization of [Re(O)(ReO4)tpp] . CHCl3 (1), [{Re(O)tpp}(2)(mu-O)] . py (2), ((Bu4N)-Bu-n)(trans)[Re(O),tpp](3), and (Et4N)(trans)[Re(O)(2)tpp] . 2H(2)O (4) is described. The tpp centered Re atom is in a distorted octahedron of four N atoms of the porphyrinate and two axial O atoms in a mutual trans position. Average Re-N distances are 2.062 Angstrom in 1, 2.086 Angstrom in 2, 2.089 Angstrom in 3, and 2.082/2.086 Angstrom in 4. The Re-O distance of the terminal rhenyl group varies from 1.64(1) Angstrom (1), 1.73(1)11.70(1) Angstrom (2) to 1.80(1) Angstrom (4), that of the monodentate rhenate(VII) from 1.70(1) to 1.75(1) Angstrom. The Re-O distances in the bridge of the linear O=Re-O-Re=O skeleton in 2 are 1.95(1)/1.89(1) Angstrom. In 1, with a bent O=Re-O similar or equal to ReO3 moiety (measured angle(Re-O similar or equal to ReO3)= 143(1)degrees) and a mostly ionic coordinated rhenate(VII), these distances differ significantly (2.20(1) Angstrom vs 1.75(1) Angstrom). The porphyrinate in 1 is saucer-shaped with a distal rhenate(VII), and the tpp centered Re atom is displaced by 0.31 Angstrom out of the (N)(4) plane towards the rhenyl-O atom. The distorted porphyrinates in 2 are rotated by 30.4(4)degrees, and the Re atoms are 0.1 Angstrom out of their (N)(4) planes towards the terminal O atoms. In 3 and 4 the porphyrinates are almost planar with the Re atom in their centre.