화학공학소재연구정보센터
Inorganic Chemistry, Vol.58, No.9, 5593-5602, 2019
Molecular Design of Cyclopentadienyl Tantalum Sulfide Complexes
Use of (Me3Si)(2)S and [Ta(eta(5)-C5Me5)Cl-4] (1) in a 4:3 ratio afforded the trimetallic sulfide cluster [Ta-3(eta(5)-C5Me5)(3)Cl-3(mu(3)-Cl)(mu(3)-S)(3)(mu(3)-S)] (2) with loss of SiClMe3. A similar reaction between 1, TaCl5, and (Me3Si)(2)S in a 2:1:4 ratio resulted in the analogous complex [Ta-3(eta(5)-C5Me5)(2)Cl-4(mu(3)-Cl)(mu-S)(3)(mu(3)-S)] (3). Single-crystal X-ray diffraction analyses of 2 and 3 showed in all cases trinuclear tantalum sulfide clusters. On the other hand, thermal treatment of 2 with SiH3Ph generated very cleanly the dinuclear tantalum(IV) sulfide complex [Ta-2(eta(5)-C5Me5)(2)Cl-2(mu-S)(2)] (4) in a quantitative way. Likewise, we found that 4 was synthesized more easily by a one-pot reaction of 1, (Me3Si)(2)S, and SiH3Ph in toluene. Reactions of 4 with a series of alkylating reagents rendered the dinuclear peralkylated sulfide complexes [Ta-2(eta(5)-C5Me5)(2)R-2(mu-S)(2)] (R = Me 5, Et 6, CH2SiMe3 7, C3H5 8, Ph 9). Single-crystal X-ray diffraction analyses of 4, 5, and 9 showed in all cases a trans disposition of the chloro or alkyl substituents. The short Ta-Ta distances (2.918(1)-2.951(1) angstrom) along with DFT calculations indicate a sigma-Ta-Ta interaction. Complexes 5, 6, and 8 undergo trans-cis isomerization, and mechanistic proposals are discussed based on DFT calculations.