Electronic Thesis and Dissertation Repository

Degree

Doctor of Philosophy

Program

Chemistry

Supervisor

John F. Corrigan

Abstract

The reaction of M[ESiMe3] (M = Li/Na; E = S, Se) with polyorganobromides, has afforded polychalcogenotrimethylsilane complexes Ar(CH2ESiMe3)n: 1,4-(Me3SiECH2)2(C6Me4) (E = S, 1; E = Se, 2), 1,3,5-(Me3SiECH2)3(C6Me3) (E = S, 3; E = Se, 4) and 1,2,4,5-(Me3SiECH2)4(C6H2)(E = S, 5; E = Se, 6). The powerful potential of these complexes as precursor to combine with other organic reagents such as acyl halides (here ferrocenoyl chloride) lead to polyferrocenylchalcogenoesters: [1,4-{FcC(O)ECH2}2(C6Me4)] (E = S, 7; E = Se, 8), [1,3,5-{FcC(O)ECH2}3(C6Me3)] (E = S, 9; E = Se, 10) and [1,2,4,5-{FcC(O)ECH2}4(C6H2)] (E = S, 11; E = Se, 12).

Two new dichalcogenotrimethylsilane reagents 1,2-(Me3SiSCH2)2(C6H4), 13 and 1,2-(Me3SiSeCH2)2(C6H4), 14 were prepared to further expand the series above. These two new reagents were prepared from 1,2-(BrCH2)2(C6H4) and Li[ESiMe3]. Their reactivity towards metal salts and M-E bond formation was demonstrated when 13 and 14 were reacted with [PdCl2(dppp)] to give two analogous dinuclear organochalcogenolate-bridged complexes [(dppp)2Pd2-μ-κ2S-{1,2-(SCH2)2C6H4}]X2, [15]X2 and [(dppp)2Pd2-μ-κ2Se-{1,2-(SeCH2)2C6H4}]X2, [16]X2 (X = Cl, Br) respectively. To expand this methodology, the tetranuclear palladium complex [(dppp)4Pd4-μ-κ4S-{1,2,4,5-(SCH2)4C6H2}]X4, [17]X4 (X = Cl, Br) was isolated when complex 5 was reacted with a suspension of [PdCl2(dppp)] in the presence of LiBr, as a source of counter ion.

The reactivity of the polychalcogenotrimethylsilanes was developed with a different coordination chemistry system, namely the addition of [(IPr)CuOAc] (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) to solutions of 1, 2, 3, 4 and 6 and the previously reported 1,1´-fc(CH2ESiMe3)2 to yield the poly(NHC)-copper-chalcogenolate complexes, 1,4-[{(IPr)CuECH2}2(C6Me4)] (E = S 18, E = Se 19), 1,1’-[fc{CH2ECu(IPr)}2] (E = S 20, E = Se 21), 1,3,5-[{(IPr)CuECH2}3(C6Me3)] (E = S 22, E = Se 23) and 1,2,4,5-[{(IPr)CuSeCH2}4(C6H2)] (24).

The copper-chalcogenolate [(IPr)Cu-ESiMe3] (E = S 25, Se 26, Te 27) have been prepared from [(IPr)CuOAc] and E(SiMe3)2. Single crystal X-ray analysis illustrates that the structures of complexes 25-27 exhibit a pendant –SiMe3 group bonded to a chalcogen atom with a near linear coordination geometry about the copper centre. Reaction of Hg(OAc)2 with freshly prepared 25 [(IPr)Cu-SSiMe3] yielded the ternary cluster [{(IPr)CuS}2Hg], 28 via activation of the S-Si bonds.

This straightforward approach has also been extended by i) substituting copper(I) with silver(I) and ii) by using the smaller NHC iPr2-bimy (1,3-diisopropylbenzimidazolin-2-ylidene) instead of IPr.

The reaction of [(IPr)AgOAc] with one equivalent of E(SiMe3)2 (E = S, Se) yielded [(IPr)Ag-ESiMe3] (E = S 29, Se 30). The addition of two equivalents of [(IPr)Ag-SSiMe3] to a solution of one equivalent of Hg(OAc)2 in THF led to the first example of a Ag-Hg-sulfide cluster [{(IPr)CuS}2Hg], 31, which is isostructural with 28.

Similar reactions between [(iPr2-bimy)CuOAc] and E(SiMe3)2 (E = S, Se) led to the formation of two new metal-chalcogen complexes, [(iPr2-bimy)Cu-ESiMe3] (E = S 32, Se 33). Unlike the IPr containing complexes 25-27, 29 and 30, [(iPr2-bimy)Cu-ESiMe3] exist as dimers in the solid state; this can be attributed to the smaller size of the coordinated iPr2-bimy compared to IPr. One consequence of the varying ligand size is demonstrated with the reaction between [(iPr2-bimy)Cu-SSiMe3] and Hg(OAc)2 which leads to the formation of a ternary cluster with a Cu10S8Hg3 core surrounded by six iPr2-bimy ligands, [(iPr2-bimy)6Cu10S8Hg3], 34.


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