Synthesis and structures of the multinuclear rhenium nitrido complexes [Re2N2Cl4(PMe2Ph)4(MeCN)] and [Re4N3Cl9(PMe2Ph)6]

The binuclear rhenium complex [Re2N2Cl4-(PMe2Ph)(4)(MeCN)] (1) is obtained as a byproduct of the synthesis of [(Me2PhP)(3)(MeCN)ClReNZrCl5] from [Re-NCl2(PMe2Ph)(3)] and [ZrCl4(MeCN)(2)] in toluene. It crystallizes as 1 2 toluene in the monoclinic space group P2(1)/n with a=1517.0(3); b=1847.7(2); c=1952.3(6)pm; beta= 106.44(1)degrees and Z = 4. The two Re atoms are connected by an asymmetric nitrido bridge Re drop N-Re with distances Re-N of 169.9(5) and 208.7(5) pm. In course of the reaction of [ReNCl2(PMe2Ph)(3)] with [ZrCl4(THF)(2)] in CH2Cl2 hydrochloric acid is formed by acting of the Lewis acid on the solvent. HCl protonates and eliminates phosphine ligands of the educt [ReNCl2(PMe2Ph)(3)] to form the phosphonium salt [PMe2PhH](2)[ZrCl6] (2). It crystallizes in the monoclinic space group C2/c with a=15.36.9(3): b=1148.8(1); c= 1402.2(3) pm, beta=100.70(2)degrees and Z = 4. The remaining fragments of the rhenium complex combine to yield the tetranuclear mixed valent complex [Re4N3Cl9(PMe2Ph)(6)] (3), crystallizing as 3 CH2Cl2 in the triclinic space group P (1) over bar with a=1312.9(19); b=1661.4(2); 1897.1(2) pm; alpha= 78.62(1)degrees; beta= 86.77(1)degrees; gamma = 68.25(1)degrees and Z = 2. The four Re atoms occupy the corners of a tetrahedron. Its edges are formed by three nitrido and three chloro bridges. The asymmetric nitrido bridges Re drop N-Re are characterized by short distances in the range of 172(2) to 176(3) pm and long distances of 194(3) to 203(2) pm. The angles Re-N-Re are between 154(1) and 160(1)degrees.