Yi-Chou Tsai | PubMed Health

PubMed2006

A three-coordinate and quadruply bonded Mo-Mo complex.

Reaction of MoCl3(THF)3 with [Me2Si{NLi(Dipp)}2]2 (Dipp = 2,6-i-PrC6H3) afforded a triply bonded dimolybdenum complex 1,2-Mo2Cl2[Me2Si(NDipp)2]2 1, spanned by two Me2Si[N(Dipp)]2 ligands, thus resulting in a syn conformation. The air- and moisture-sensitive compound 1 was characterized by NMR spectroscopic, elemental, and single-crystal X-ray crystallographic analysis. Reduction of 1 by Na/Hg yielded the quadruply bonded dimeric complex Mo2[Me2Si(NDipp)2]2 2, which was also characterized by the aforementioned analytical methods. The Mo-Mo bond was determined to be 2.1784(12) A, which is considered a long quadruple bond. In addition, density functional theory (DFT) computations on compound 2 provided insight into the intriguing Mo-Mo quadruple bond.

Crystallography↗

PubMed1997

Syntheses and X-ray Structures of a Series of Chalcogen-Containing Manganese Carbonylates [E(2)Mn(3)(CO)(9)](-), [E(8)C(2)Mn(2)(CO)(6)](2-), and [E(2)Mn(4)(CO)(12)](2-) (E = Se, S).

The reaction of SeO(2) with Mn(2)(CO)(10)/KOH in methanol solution forms a trigonal bipyramid cluster anion [Se(2)Mn(3)(CO)(9)](-) (Ia). Cluster Ia can also be synthesized from the treatment of Se powder with Mn(2)(CO)(10)/KOH in 2:1 molar ratio in methanol solution. If Se is reacted with Mn(2)(CO)(10)/KOH in a molar ratio of 8:1, the deoxygenation occurs to produce a novel cluster [Se(8)C(2)Mn(2)(CO)(6)](2)(-) (IIa). Cluster IIa can readily transform into a new octahedral cluster [Se(2)Mn(4)(CO)(12)](2)(-) (IIIa) by further treatment with Mn(2)(CO)(10)/KOH in CH(2)Cl(2)/MeOH solutions, and the use of a molar ratio of 1:1 of Se powder to Mn(2)(CO)(10)/KOH in methanol also can yield complex IIIa. In the sulfur-manganese system, the synthesis of the analogous complexes [S(2)Mn(3)(CO)(9)](-) (Ib), [S(8)C(2)Mn(2)(CO)(6)](2)(-) (IIb), and [S(2)Mn(4)(CO)(12)](2)(-) (IIIb) also can be accomplished from the reactions of S powder with Mn(2)(CO)(10)/KOH in similar fashions. Clusters Ia-IIIa and Ib-IIIb are fully characterized by spectroscopic methods or/and X-ray analyses. The novel clusters [E(8)C(2)Mn(2)(CO)(6)](2)(-) (E = Se, IIa; E = S, IIb) each consist of two separate Mn(CO)(3) groups which are doubly bridged by two CE(4) fragments. Clusters Ia and Ib each display a trigonal bipyramid framework with two chalcogen atoms in the axial positions, while clusters IIIa and IIIb each exhibit an octahedral metal skeleton.

Journal Article↗