First structural characterisation of 1,2,4-selenadiphosphole and 1,2,4-telluradiphosphole ring systems. Crystal and molecular structures of the η1-complexes [M(CO)5(P2SeC2But2)] (M=Cr,W) and [W(CO)5(P2TeC2But2)]

Isolation of a Kinetically Stabilized 1,3,6-Triphosphafulvene

“…The WÀP2 distance is 2.480(2) , while the P1ÀC1 and P2ÀC2 distances (1.689(7) and 1.703 (7) , respectively) are close to the P C lengths of tungsten-complexed 1,2,4-telluradiphosphole 11 (1.695(7) and 1.702 (7) ). [14] The P3ÀC3 distance is 1.710 (6) , which is close to the PC length in p-phosphaquinone 12 (1.705 (2) ). [15] The C2ÀC3 distance (1.447(8) ) is similar to the CÀC length in the 1,4-diphospha-1,3-butadiene system.…”

“…The C1-P1-C3 and C1-P2-C2 angles are 96.6(3) and 100.2(3)8, respectively, which are smaller than those found in 11 (101.7(3) and 106.3(3)8). [14] Compound 3 is regarded as a trimer of the phosphanylidene carbene. As depicted in Scheme 2, phosphaalkyne 7 is first generated from 4 through elimination of LiBr, followed by a [1,2] Fritsch ± Buttenberg ± Wiechell-type migration.…”

New pathways in the reaction between the 1,2,4-triphosphole P3C2But2CH(SiMe3)2 and selenium: Crystal and molecular structures of three new cage compounds, P3Se4C2But2CH(SiMe3)2, P3Se3C2But2 H2CH(SiMe3)2 and P5Se2C4But4(CHSiMe3But)

“…Regitz and coworker reported [12,14] the high yield synthesis of the 1,2,4-selenadiphosphole P 2 C 2 Bu t 2 Se (5) by treatment of selenium with the phospha-alkyne, Bu t CP, in the presence of NEt 3 and subsequently its structure was established by single crystal X-ray studies on sigma bonded metal pentacarbonyl complexes [15].…”

A Novel Approach to 1,2,4-Thiadiphospholes and Functionalized 1,2-Thiaphospholes

“…A similar tendency was observed for an analogous tungsten complex of a 1,2,4-selenadiphosphole, the constitution of which was confirmed by X-ray crystallography. [17] Practically no change in the chemical shift of the P(2) signal of 7a was observed. In comparison to 7b, however, the signal of phosphorus atom P(4) experienced a larger shift to lower field of around 10 ppm.…”

“…The analogous chromium complex of a 1,2,4-selenadiphosphole, the structure of which was also confirmed by X-ray crystallography, showed comparable changes in its 31 P NMR signals. [17] The 2 J P,C coupling constants of the signals of the carbonyl ligand carbon atoms at δ ϭ 215 (7a) or 199 (7b) (CO ax ) and at δ ϭ 221 (7a) or 195 (7b) (CO eq ) were characteristic for the η 1 complexation. In accord with literature data, the axial carbonyl ligands gave rise to appreciably larger 2 J P,C couplings [13.3 (7a) or 34.5 Hz (7b)] than the equatorial carbonyl ligands (2.4 Hz for 7a, 8.0 Hz for 7b).…”