| Popis: |
The crystal structures of three MoCuS cubane-like cluster compounds are reported. They were synthesized by the reaction of the trinuclear molybdenum cluster [Mo 3 S 4 ][S 2 P(OCH 2 CH 3 ) 2 ] 4 ·H 2 O with CuI in suitable solvents. Including two other clusters reported earlier with the same cubane-like cores, the structural characters of the five compounds with different bridging carboxylate and loosely coordinated ligands, which are formulated as [Mo 3 CuS 4 ][S 2 P(OCH 2 CH 3 ) 2 ] 3 ·I·(μ 2 -OOCR)·L (R=CH 3 , L=H 2 O, ( I ); R=CH 3 , L=(CH 3 ) 2 SO, ( II ); R=C 6 H 5 , L=C 5 H 5 N, ( III ); R=CH 3 , L=(CH 3 ) 2 NCHO, ( IV ); R=CCl 3 , L=CH 3 CN, ( V )), are discussed. Cluster compounds I, II and IV have different loosely coordinated ligands L (H 2 O for I , (CH 3 ) 2 SO (DMSO) for II , (CH 3 ) 2 NCHO (DMF) for IV ) but the same bridging carboxylate OOCCH 3 ; the MoO L bonds are 2.295 A ( I ), 2.215 A ( II ), 2.214 A ( IV ), respectively. On the other hand, in comparing the MoO b (O b atom from the bridging carboxylate OOCR) bonds, the sequence is MoO (O atom of OOCCCl 3 )> MoO (O atom of OOC 6 H 5 )> MoO (O atom of OOCCH 3 ), which is consistent with the acidity of HOOCCCl 3 >HOOCC 6 H 5 >HOOCCH 3 . The average Mo(μ 2 -S) bond of the trinuclear molybdenum cluster is 2.28 A, but it changes to 2.33 A in the cubane-like cluster as the Mo(μ 3 -S) bonds. This implies charge displacement from μ 2 -S to the Cu atom. |
