μ-Coordination chemistry of NO ligands: Adducts of trans-Mo(dmpe)2(H)(NO) with lithium salts

Four adducts were formed by the reaction of trans-Mo(dmpe)2(H)(NO) (1) (dmpe = bis(dimethylphosphino)ethane) and a respective lithium reagent to afford, [Mo(dmpe)2(H)(NO)LiHBEt3]2 (2), [Mo(dmpe)2(H)(NO)LiN(SiMe3)2]2 (3), [Mo(dmpe)2(H)(NO)]3(LiBH4)2 (4), and {[Mo(dmpe)2(H)(NO)]2[LiBH4]5}n (5). Structures 2–5 were characterized by crystal X-ray diffraction analyses. Structures 2 and 3 revealed to be dimers of the 1:1 adduct of 1 and the lithium salt. The two nitrosyl oxygen atoms in 2 are μ2-bridged connecting two separate LiHB(C2H5)3 moieties, whereas in 3 these oxygen atoms exhibit a terminal coordination mode binding to two lithium ions of the dimeric [LiN(SiMe3)2]2 unit. Structure 4 shows a discrete structure formed by two separate mononuclear LiBH4 units being bridged by the nitrosyl oxygen atoms of three Mo(dmpe)2(H)(NO) moieties. Structure 5 displays a complicated chain structure with differently coordinated lithium centers, various types of bridging BH4 and bridging nitrosyl groups.