Metal-metal multiple bonds. 5. Molecular structure and fluxional behavior of tetraethylammonium .mu.-cyano-bis(cyclopentadienyldicarbonylmolybdate)(Mo-Mo) and the question of semibridging carbonyls

Synthesis and characterization of the cluster complexes containing tetrahedral FeCrCo(μ3-S) cluster cores generated by isolobal displacement reactions. Crystal structures of (η5-RC5H4)FeCrCo(μ3-S)(CO)8 (R=H, CO2Et) and FeCo2(μ3-S)2(CO)9

“…This is because, as shown in Table 4, the asymmetry parameters a for the two carbonyls attached to Cr in 4 and 6 fall within the range 0:1 6 a 6 0:6 [14].…”

“…Cr(1)-C(2) 1.858 Co(1) Á Á Á C(2) 2.581 0.39 a An asymmetric parameter a is defined as a ¼ ðd 2 À d 1 Þ=d 1 , where d 1 and d 2 are the short and long distances of M-(CO), respectively [14].…”

“…Calc. for C 30 H 16 (14) The same procedure as that for 13 was followed, but 1.0 mmol of [g 5 -C 5 H 4 CH 2 (CH 2 OCH 2 ) 2 CH 2 C 5 H 4 -g 5 ]Na 2 was used in place of (g 5 (15) The same procedure as that for 13 was followed, but 1.0 mmol of [g 5 -C 5 H 4 CH 2 (CH 2 OCH 2 ) 3 CH 2 C 5 H 4 -g 5 ]Na 2 was used in stead of (g 5 (17) and FeCo 2 (l 3 -S) 2 (CO) 9 (9) The same procedure as that for 13 was followed, but 0.220 g (1.00 mmol) of Cr(CO) 6 , 0.50 mmol of [g 5 -C 5 H 4 C(O)CH 2 ] 2 Na 2 , and 0.458 g (1.00 mmol) of FeCo 2 (l 3 -S)(CO) 9 Further separation with 1:1 (v/v) of acetone/light petroleum ether as eluent gave a main brown red band, from which 0.203 g (42%) of 9 was obtained.…”

A Cyclic Hexanuclear Heterometalladithiolene Cluster [{(Cp*Rh)2Mo(μ‐CO)2(CO)}2(S2C6H2S2)2] with Two π‐Conjugated S2C6S2 Bridges: Synthesis, Crystal Structure, and Properties

“…The Rh1Mo bond length (2.8983(7) Å) is 0.1577 Å longer than the Rh2Mo bond length (2.7406(9) Å), with an Rh2‐Mo‐Rh1 angle of 150.18(2)°. The carbonyl C9O3 can be regarded as semi‐bridging because the asymmetric parameter α is 0.24 5. The quasi‐aromatic systems of the dinuclear rhodadithiolene heterocycle 2 are changed in 4 ; the dihedral angles at the S⋅⋅⋅S vector in the Rh1S 2 C 2 and Rh2S 2 C 2 rings are 14.0° and 129.8°, respectively.…”

Selenium-capped trimolybdenum and tritungsten carbonyl clusters [Se2M3(CO)10]2− (M=Mo, W)

“…As known, chalcogen-capped homonuclear group 6 trimetallic carbonyl complexes are rare [4][5][6], and 1 and 4 present the first seleniumcapped trimolybdenum and tritungsten carbonyl clusters. According to CurtisÕ suggestion [11], clusters 1, 2, and 4 each possesses two semibridging carbonyls for the metal coordinated with four CO ligands, which are evidenced by the shorter distances for Mo(2)Á Á ÁC(2), Cr(1)Á Á ÁC(1), and W(1)Á Á ÁC(3) (2.91(1), 2.85(2), and 2.93(2) Å ) and the slightly bending of the carbonyls (Mo (1)…”