Reactions of [Nb2(µ-S2)2(dtc)4] 1 (dtc = diethyldithiocarbamate, S2CNEt2) with chalcogen-transfer reagents PEt3Y (Y = Se or Te) were investigated. With PEt3Se, fully substituted [Nb2(µ-Se2)2(dtc)4] 2 forms if a catalytic amount of free PEt3 is present. However PEt3Te gives [Nb2(S)(Te2)(dtc)4] 3 which has a new core with two different chalcogens acting as bridges. The structures of both 2 and 3 were determined by X-ray analysis [2: Nb–Nb 2.974(2), Se–Se 2.303(2). 3: Nb–Nb 2.920(4), Te–Te 2.648(3) Å]. Electrochemistry of 2 and 3 was studied and a reversible one-electron oxidation was found for 2, giving a blue ESR-active (19-plet, g = 2.0489, A = 52.5 G) species [Nb2(µ-Se2)2(dtc)4]+ at 638 mV vs. NHE. By contrast in the reaction of [Nb2(µ-S2)2(acac)4] 4 (Hacac = acetylacetone) with PEt3Te only the sulfur abstraction product [Nb2(µ-S)2(acac)4] 5 formed, which could be more directly prepared from 4 and PEt3. Crystal structures of 4 and 5 were determined.
Fetching data from CrossRef. This may take some time to load.
Journal of the Chemical Society, Dalton Transactions
- Information Point