Tellurium complexes with new, large-bite dithio ligands. The crystal structures of cis- and trans- [Te{Ph2P(S)-N-P(S)(OPh)(2)}(2)] and [(4-MeOC6H4TeCl3)(2){mu-(Pr2P)-Pr-i(S)-Fc-P(S)Pr-i(2)}]
| Authors | |
|---|---|
| Year of publication | 2001 |
| Type | Article in Periodical |
| Magazine / Source | Journal of Organometallic Chemistry |
| MU Faculty or unit | |
| Citation | |
| Field | Inorganic chemistry |
| Keywords | tellurium(II) and (IV) complexes; new dithio ligands; crystal structures |
| Description | Reaction of the protonated large-bite bidentate ligand Ph2P(S)-NH-P(S)(OPh)(2) with [Te{NH2)(2)CS}(4)]Cl-2 resulted in the complex [Te(L-L)(2)] (1a), where (L-L)(-) = Ph2P(S)-N-P(S)(OPh)(2). When (L-L)(-) reacted with 4-MeOC6H4TeCl3, an isomeric complex, 1b. resulted. Reaction between the less basic ligand 'Pr2P(S)-Fc-P(S)'Pr-2 (Fc = ferrocene) and 4-MeOC6H4TeCl3 yielded the complex [(4-MeOC6H4TeCl3)(2) {mu-'Pr2P(S)-Fc-P(S)'Pr-2}], (2). X-ray crystallographic studies show that 1a and 1b both are square planar complexes of Te(II), 1a being asymmetric and 'cis' with two short Te-S bonds trans to two long Te-S bonds (average bond lengths being 2.5415 and 2.9050 Angstrom). Isomer Ib is centrosymmetric, 'trans', with nearly equal Te-S bond lengths averaging 2.6805 Angstrom. Complex 2 is an addition compound where the large dithio ligand bridges two 4-MeOC6H4TeCl3 units through weak Te-S bonds. The resulting coordination around each Te(IV) atom is psi -octahedral with the lone pair of electrons and aryl in axial positions relative to the TeCl3S equatorial plane. Here the Te-S bond lengths are 2.7560(16) and 2.6910(12) Angstrom. The trans influence of the dithio ligand in 2 is smaller than that of Cl-, resulting in an average Te-Cl bond length trans to sulfur of only 2.4196 Angstrom, while the other Te-Cl bond lengths average 2.4959 Angstrom. The reason for the lower basic nature of the ligand with a P-Fc-P backbone compared to those with PN-P backbones, is that it lacks a central charge donating group like N-. |
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