Abstract
This thesis shows the synthesis of ditungsten complexes by the use of amidinate and α-diamino ligands. We could improve the yields of tungsten precursor, reduction of WCl4(DME) with Sn granules afforded pure W2Cl6(DME) (2). Treatment of 2 with 3 equiv. of [Li(THF)2][PhC(N-2,6-iPr2C6H3)2] (L1) produced a mix-valent ditungsten complex W2(μ-Cl)Cl2[μ-κ2-PhC(N-2,6-iPr2C6H3)2]2 (3). Upon reducing 3 with 1 equiv. of KC8 gave a quadruply bonded ditungsten species W2(μ-Cl)[Cl2Li(OEt2)][μ-κ2-PhC(N-2,6-iPr2C6H3)2]2 (4). Furthermore, complex 4 underwent 2 electron reduction with KC8 and produced a C-H bond activated ditungsten complex W2(μ-H)2[μ-κ2-PhC(N-2,6-iPr2C6H3)(N-2-iPr2-6-CH(κ1-CH2)CH3-C6H3)]2 (5). Surprisingly, complex 4 converted into 3 and 5 in hydrocarbon solvents via a disproportionation reaction. Reaction of WCl4(DME) with 2,6-iPr2C6H3-DAB (2,6-iPr2C6H3-DAB = 1,4-bis-(2,6-iPr2C6H3)-1,4-diaza-1,3-butadiene) (L2) afforded a mononuclear WCl4(κ2-2,6-iPr2C6H3-DAB) (6). Upon reduction of 6 with 1.5 equiv. of Na/Hg produced a ditungsten W2(μ-Cl)3Cl2(κ2-2,6-iPr2C6H3-DAB)2 (7), which is hard to be reduced further. Treatment of W2(μ-H)2(THF)[μ-κ2-HC(N-2,6-iPr2C6H3)(N-2-iPr2-6-CH(κ1-CH2)CH3-C6H3)]2 (1c) with 3 equiv. of CHCl3 in THF gave a THF ring opened ditungsten species W2(μ-Cl)Cl2[μ-(κ1;κ2)-C(CH2)3O][μ-κ2-HC(N-2,6-iPr2C6H3)2]2 (9), which features a bridging carbyne ligand moiety.