Mono- and Dinuclear High-Spin Half-Sandwich Manganese(II) Complexes Containing Acetylide and TMEDA Ligands

The d5 high‐spin MnII half‐sandwich complexes [Mn(C≡CR)(MeC5H4)(tmeda)] (R = SiMe3 2; Ph 3; tBu 4; C≡CSiMe3 5; C≡CPh 6; tmeda = N,N,N′,N′‐tetramethylethylenediamine) were prepared by the reaction of [Mn(MeC5H4)2(tmeda)] (1) with 1 equiv. of the corresponding acetylene or the trimethyltin acetylide. The dinuclear complexes [Mn(C≡C−C≡CSiMe3)2(tmeda)]2 (7) and [Mn2(MeCp)2(μ1‐tBuC≡C)2(μ1‐tmeda)] (8), which contain Mn−Mn bonds, were synthesized by treating 1 with an excess of HC≡C−C≡CSiMe3 or HC≡CtBu, respectively. Dinuclear complexes of the type [(MeC5H4)(tmeda)MnC≡C− X−C≡CMn(tmeda)(C5H4Me)] [X = 1,3‐C6H4 9; 1,4‐C6H4 10; 4,4′‐(C6H4)2 11] were obtained by treatment of 1 with 0.5 equiv. of the corresponding acetylides 1,3‐C6H4(C≡CSnMe3)2, 1,4‐C6H4(C≡CSnMe3)2 and 4,4′‐(C6H4)2(C≡CSnMe3)2 in benzene for 24 h to yield the corresponding dinuclear complexes in very good yields. All the mono‐ and dinuclear compounds have been characterized by NMR, IR, Raman spectroscopy and elemental analyses. X‐ray diffraction studies have been performed on complexes 3 and 5−11. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)