First syntheses, structural and theoretical studies of η5-1,2,4-triphosphole metal tricarbonyl complexes of Cr, Mo and W

The Homoleptic Sandwich Anion [Co(P2C2tBu2)2]−: A Versatile Building Block for Phosphaorganometallic Chemistry

“…Similar cationic ligands have been reported in [CpMoCl(CO){h 3 -P 2 C 2 tBu 2 H(OR)}] (R = H, Me) [16] and [Fe(h 4 -P 3 C 2 tBu 2 nBuMe)(C 5 R 5 )] (R = H, Me), [17] which were prepared by addition of water or methanol to [CpMoCl(CO)(h 4 -P 2 C 2 tBu 2 )] and by lithiation/alkylation of [Fe(h 5 -P 3 C 2 tBu 2 )- (C 5 R 5 )], respectively. [16,18] The distances between the atoms P3, C3, P4, and C4 in 4 (1.776(2)-1.799(2) ) indicate delocalized p-bonding within the P 3 C 2 tBu 2 Ph 2 ligand. The P5ÀC4 distance of 1.776 (2) is also short, while the remaining bonds within the P 3 C 2 ring are in the usual range for single bonds (P3 À P5 = 2.1364(5), P5 À C51,C61 = 1.845(2) and 1.821 (2) ).…”

Triphospholes as2e and4e donors: Synthesis and structural characterization of the 1,2,4-triphosphole complexes ?1-trans-[PtCl2(PEt3)(P3C2But2CH(SiMe3)2] and ?1-?1-trans-[PtCl2(PEt3)2}2(?-P3C2But2CH(SiMe3)2]

“…However, the metal-ring Pt-P(3) bond distance is significantly longer than the Pt-P(4) bond distance of the PEt 3 ligand, reflecting that this is the weaker Pt-P bond. 2 H} NMR spectra of (2) and (3) are quite similar, and a comparison of their chemical shift and coupling constant data is summarized in Table 1.…”

“…31 P{ 1 H} NMR spectroscopy was employed to monitor the course of the reaction, and the mode of attachment of the 1,2,4-triphosphole ring to platinum in (2) 2 ] complexes (R ‫ס‬ alkyl, aryl). This resonance is split into a doublet of doublets of doublets arising from couplings to the three types of phosphorus atoms.…”

“…The ring [P(1)P(2)C(1)P(3)C (2)] is planar in (3), while in (1) and (2) only the atoms from the diene system [P(2)C(1)P(3)C (2)] lie in the same plane. The P(1) to plane distance is 0.232 Å for (1) and 0.170 Å for (2), and the bond angles around this phosphorus, excluding Pt, are typical for a sp …”

“…[1]. Of special interest is the greatly enhanced aromatic behavior of the 1,2,4-triphosphole ring system (1) compared with phospholes themselves, and in its complexes with both [M(CO) 3 ] fragments (M ‫ס‬ Cr, Mo, W) and with [Ru(0) (cyclooctadiene)], it is also a 6e donor, but now the ring is essentially planar [2,3]. In a preliminary report [1], we also described the ligating behavior of the 1,2,4-triphosphole as a 2e donor in trans-[PtCl 2 (PEt 3 ){P 3 C 2 CH(SiMe 3 ) 2 }] (2).…”