Syntheses and Structures of Four New Tellurium(II) Complexes

Abstract

The four Te II complexes, cis-[TeCl 2 {( i PrNH) 2 CS} 2 ] (1), cis-[TeCl 2 {( i BuNH) 2 CS} 2 ] (2), trans-[TeCl 2 {(PhNMe) 2 CS} 2 ] (3), and trans-[TeCl 2 {(Et 2 N) 2 CS} 2 ] (4), have been synthesised and their molecular structures solved by means of X-ray crystallography. All four complexes are square planar, those with disubstituted thiourea ligands have a cis configuration, those with tetrasubstituted thioureas have a trans configuration. The Te±S bond lengths in 1 and 2 average 2.4994 and 2.5213 A Ê , respectively. The Te±Cl bonds trans to the Te±S bonds have average lengths of 2.8754 and 2.8334 A Ê , reflecting the trans influence of the two disubstituted thioureas. In 3 and 4 with identical ligands trans to each other, the average Te±S and Te±Cl bond lengths are 2.6834 and 2.5964 A Ê , respectively. Cis-trans-Isomerie in quadratisch-planaren [TeCl 2 (stu) 2 ]-Komplexen mit substituierten, volumino È sen Thioharnstoff(stu)-Liganden. Synthesen und Strukturen von vier neuen Tellur(II)-Komplexen Inhaltsu È bersicht. Die vier Te II -Komplexe cis-[TeCl 2 -{( i PrNH) 2 CS} 2 ] (1), cis-[TeCl 2 {( i BuNH) 2 CS} 2 ] (2), trans-[TeCl 2 ((PhNMe) 2 CS} 2 ] (3) und trans-[TeCl 2 {(Et 2 N) 2 CS} 2 ] (4) wurden synthetisiert und ihre Strukturen durch Ro È ntgenkristallstrukturanalysen bestimmt. Die vier Komplexe sind quadratisch-planar, wobei die mit disubstituierten Thioharnstoffliganden eine cis-Konfiguration und die vierfachsubstituierten eine trans-Konfiguration haben. Die Bindungsla Èn-gen Te±S in 1 bzw. 2 betragen im Mittel 2,4994 bzw. 2,5213 A Ê . Die Te±Cl-Bindungen in trans-Stellung zu den Te±S-Bindungen betragen im Mittel 2,8754 bzw. 2,8334 A Ê , was den trans-Einfluû der zwei disubstituierten Thioharnstoffeinheiten widerspiegelt. In 3 und 4 mit identischen Liganden in trans-Stellung zueinander betragen die mittleren Bindungsla È ngen Te±S bzw. Te±Cl 2,6834 bzw. 2,5964 A Ê .

Redox Chemistry of Tellurium Bis(tert-butylamido)cyclodiphosph(V)azane Disulfide and Diselenide Systems: A Spectroscopic and Structural Study

“…Adoption of the trans configuration is likely preferred in 5a and 5b in order to minimize steric repulsion. 40 Further, the longer Te-S bond distance in 5a compared to that in trans-TeCl 2 (tmtu) 2 [2.7280(7) vs 2.684 Å av, respectively] suggests that the ligand 2a is a poorer donor than tmtu toward TeCl 2 ; this may account for the relative instability of 5a. The absence of any structural information on trans-TeCl 2 (selenourea) 2 adducts precludes a direct comparison for 5b.…”

Chlorotris(N,N′-dicyclohexylthiourea-S)tellurium(II) chloride, a tellurium complex with a TeClS3coordination sphere

“…The interplanar SCN 2 /SCN 2 angle is 54.69 (6) for the two trans-related thioureas. This is a rather large angle compared with the values in the trans complexes mentioned above, which are around 13 (Husebye et al, 2001). An analogous bromide, [TeBr(stu) 3 ]Br, has been synthesized and its structure reported by Kumar et al (1990).…”

“…The TeÐS2 bond length in (I) is 2.6211 (4) A Ê and it is positioned trans to TeÐCl1, which has a bond length of 2.6485 (4) A Ê , indicating a weak trans in¯uence of the N,N H -dicyclohexylthiourea ligand. However, this in¯uence is still greater than that of the Cl À ligand, indicated by the shortening of the TeÐS bond at the expense of the TeÐCl bond, which lengthens relative to the average found in ClÐTeÐCl 3c-4e systems (Husebye et al, 2001).…”

“…The remaining thiourea assumes a corresponding angle of 74.31 (3) . Angles around 70 seem to be common for trans-[TeCl 2 (stu) 2 ] complexes (Husebye et al, 2001).…”

Reactivity of the metalloligand [Pt2(µ-S)2(PPh3)4] toward tellurium(II) thiourea complexes: synthesis and structural characterization of the ditellurium(I) derivative [{Pt2(µ-S)2(PPh3)4}2Te2]2+

“…[ 34 ] NaBPh4 (Aldrich), NH4PF6(Aldrich) and Li[N(SO2C2F5)2] (3M) were used as obtained. Other chemicals were at least of reagent grade.…”