摘要
Reaction of Mo(CO) 6 with excess N,N′-di(3-methoxyphenyl)formamidine (HDmAniF) in o-dichlorobenzene afforded the yellow complex Mo 2 (DmAniF) 4 , 1. The structure of 1 reveals that the ligands bridge the two metal centers through the two nitrogen atoms, forming two s-cis, s-trans and two s-trans, s-trans conformations. Reaction of 1 with Me 3 OBF 4 in CH 3 CN gave cis-[Mo 2 (DmAniF) 2 (CH 3 CN) 4 ][BF 4 ] 2 , 2, which crystallized in two different forms. The first form, 2·CH 2 Cl 2 ·CH 3 CN, 2a, showing one BF 4 - anion coordinating to the axial positions of the Mo-Mo bond [Mo⋯F = 2.685(4) Å], contains two cis DmAniF - ligands which adopt the same s-cis, s-trans conformation. The other form, 2·0.5CH 2 Cl 2 · 0.5CH 3 CN, 2b, involves two independent molecules. While one [Mo-Mo = 2.1432(8) Å] of the two molecules shows axial interaction by CH 3 CN [Mo⋯N = 2.692(8) Å] and the two cis DmAniF - ligands adopt the same s-cis, s-trans conformation, the other one [Mo-Mo = 2.1317(9) Å] shows no axial interaction and the two cis DmAniF - ligands adopt different conformations, which are s-cis, s-trans and s-cis, s-cis, respectively. The Mo-Mo distance of 2a, 2.1281(6) Å, is the shortest among the compounds having Mo 2 (μ 2 -L) 2 (CH 3 CN) 4 core, where L is the anionic, cationic or neutral form of a formamidine ligand. Reaction of 2 with NaOCH 3 in CH 3 OH produced the tetranuclear complex cis-[Mo 2 (DmAniF) 2 ] 2 (μ-OCH 3 ) 4 , 3. The molecule of 3 bears four bridging CH 3 O - groups that link two quadruply bonded moieties and the ligands adopts the s-trans, s-trans conformation. © 2008.