Synthesis, structure, and photolysis of isocyanato complexes of rhenium

The Re-III isocyanato complex Re(NCO)(3)(PMe2Ph)(3) yields from the reaction of ReCl3(PMe2Ph)(3) with an excess of NaOCN in EtOH. It crystallizes in the triclinic space group <P(1)over bar> with a = 991.8(6), b = 1180.7(6), c = 1348.8(5) pm, alpha=89.85(1)degrees, beta=94.12(1), gamma=121.56(1)degrees, Z = 2. In the mononuclear complex with an octahedral coordination of the Re atoms the phosphine and isocyanato ligands exhibit a meridional arrangement. By using a deficient amount of NaOCN the mono isocyanato complex Re(NCO)Cl-2(PMe2Ph)(3) is formed, and part of the educt is transformed to its isomer [(Me2PhP)(3)Re(mu-Cl)(3)Re(PMe2Ph)(3)]Cl-3. The mono isocyanato complex forms monoclinic crystals with the space group P2(1)/n and a=1467.5(7), b=1310.6(7), c=1603.2(8)pm, beta=112.08(1)degrees, Z = 4. The isocyanato ligand is in trans position to a CI atom, and the phosphine ligands are coordinated in a meridional arrangement. [(Me2PhP)(3)Re(mu-Cl)(3)Re(PMe2Ph)(3)]Cl-3 . 2EtOH crystallizes in the hexagonal space group P6(3)/m with a = 1332.6(2), c = 2300.1(7) pm, Z = 2. The dinuclear complex cation occupies with its center a special position with the symmetry C-3h Photolysis of Re(NCO)Cl-2(PMe2Ph)(3) results in the cleavage of the isocyanato Ligand with release of CO and formation of the nitrido complex ReNCl2(PMe2Ph)(3). The reaction of ReNCl2(PMe2Ph)(3) with NaOCN affords the complex ReN(NCO)2(PMe2Ph)(3). It crystallizes in the space group P2(1)/n with a = 943.0(3), b = 2635.2(4), c = 1212.6(5) pm, beta=109.88(1)degrees Z = 4. In this nitrido complex, like in the educt, the phosphine ligands form a meridional arrangement. The nitrido ligand is in trans position to an isocyanato group. The distance Re=N is 165.9(6) pm.