Three novel organometallic crown ethers with a general formula [Mo 2 Fe(µ 3 -S) (CO) . The crystal structure of 3 and one of the possible pathways for formation of 3-5 are briefly discussed.Since crown ethers were discovered in 1967, 1 a great variety of crown ethers, including those organometallic ones, have been synthesized and widely utilized in numerous fields, such as catalytic organic synthesis, molecular recognition, and chemical sensor technology. [2][3][4][5][6][7] However, although the first organometallic crown ether [η 5 -C 5 H 4 OCH 2 (CH 2 OCH 2 ) 3 CH 2 OC 5 H 4 -η 5 ]Fe appeared in 1986, 8 no organometallic crown ethers that contain metal cluster cores have been reported yet in the literature up to now. Fortunately, we recently found that the polyether chain-bridged dicyclopentadienylbis-(tricarbonylmolybdenumsodium) (1), 9 prepared from Mo(CO) 6 and NaC 5 H 4 CH 2 (CH 2 OCH 2 ) 3 CH 2 C 5 H 4 Na 9 in THF at reflux, reacted with the polyether chain-bridged dicyclopentadienyl double cluster [MoCoFe(µ 3 -S)(CO) 8 ] 2 -[η 5 -C 5 H 4 CH 2 (CH 2 OCH 2 ) 3 CH 2 C 5 H 4 -η 5 ] (2), 9 through an unexpected self-assembly cyclization reaction, to give three organometallic crown ethers containing a single, double, and triple tetrahedral [Mo 2 Fe(µ 3 -S)] cluster core with a general formula [Mo 2 Fe(µ 3 -S)(CO) 7 ] n [η 5 -C 5 H 4 -CH 2 (CH 2 OCH 2 ) 3 CH 2 C 5 H 4 -η 5 ] n in 53% total yield (3, n ) 1; 4, n ) 2; 5, n ) 3) (Scheme 1).The preparations of 3-5 were performed in a Schlenk flask under dry nitrogen. A mixture of Mo(CO) 6 (0.264

The reaction of M(CO) 3 (CH 3 CN) 3 (M ) Mo, W) with an equimolar quantity of 1,2-bis-(diphenylphosphino)benzene (dppb) results in formation of fac-M(CO) 3 (dppb) (CH 3 CN) (1, M ) Mo, 73%; 2, M ) W, 62%). Interaction of 1 or 2 with [60]fullerene in chlorobenzene at about 80 °C gives the isomerically pure isomers mer-M(CO) 3 (dppb)(η 2 -C 60 ) (3, M ) Mo, 76%; 4, M ) W, 66%). All the new compounds 1-4 have been characterized by elemental analysis and spectroscopic methods, as well as by single-crystal X-ray diffraction analysis for 3 and 4.

The bridging sulfido anions (μ-RS)(μ-S- )[Fe2(CO)6]2(μ4-S) (4a) react with succinyl chloride in THF to give double and quadruple butterfly Fe/S clusters (μ-RS)(μ-RSS)[Fe2(CO)6]2(μ4-S) (5a, R = Et; 6a, R = t-Bu) and [(μ-RS)Fe2(CO)6(μ4-S)Fe2(CO)6]2(μ-S−S-μ) (5b, R = Et; 6b, R = t-Bu), unexpectedly. Crystal structrues of 6a and 6b are described.

Reaction of complex salts [(μ-RE)(μ-CO)Fe2(CO)6][HNEt3] (1, E = S, Se) with phosphaalkene t-Bu(Me3SiO)CPSiMe3 (2) has been found to afford a series of new butterfly-shaped Fe2EP clusters of type [(μ-RE)[μ-t-Bu(Me3SiO)CHPH]Fe2(CO)6 (3, RE = EtS; 4, n-PrS; 5, n-BuS; 6, t-BuS; 7, PhSe; 8, p-MeC6H4Se) in quite high yields. This type of cluster may exist as three isomers, namely, e(R)e(H), e(R)a(H), and a(R)a(H), which differ in whether the R group and H atom are attached to E and P atoms with an axial or an equatorial bond. Clusters 3−8 have been characterized by elemental analysis and 1H, 31P, and 77Se NMR spectroscopy, as well as for isomers 3e(R)a(H), 6e(R)a(H), 8e(R)e(H), and 8a(R)a(H) by single-crystal X-ray diffraction analyses. In addition, a possible reaction mechanism has been preliminarily suggested.