Synthesis and Characterization of the Metalloplumbylenes (η⁵-C₅H₅)(CO)₃M-P̈b-C₆H₃-2,6-Trip₂(M = Cr, Mo, or W; Trip = −C₆H₂-2,4,6-i-Pr₃)

Abstract

The reaction of Pb(Br)C6H3-2,6-Trip2 (Trip = C6H2-2,4,6-i-Pr3), generated in situ, with the salts Na[M(η5-C5H5)(CO)3]·DME (M = Cr, Mo, or W; DME = 1,2-dimethoxyethane) affords the novel green, crystalline metalloplumbylenes (η5-C5H5)(CO)3M-P̈b-C6H3-2,6-Trip2 (M = Cr, 1; Mo, 2; W, 3) in moderate yield. The compounds were characterized spectroscopically (1H, 13C, and 207Pb NMR, IR, and UV−vis) and by combustion analysis. In addition the X-ray crystal structures of 1−3 were determined. The compounds feature strongly bent geometries at lead (M−Pb−C = 108.6(2)−113.58(9)°) and relatively long M−Pb distances (2.9092(9) Å, Cr; 2.9845(7) Å, Mo; 2.9809(10) Å, 3.0055(6) Å W), which are consistent with single M−Pb bonding. The stability of the complexes, which melt with decomposition in the range 210−226 °C, is attributed to steric protection of the metal centers by the very large −C6H3-2,6-Trip2 substituent. The compounds are the first examples of metalloplumbylenes that feature a bent two-coordinate lead geometry.

Theoretical Investigation of Triple Bonding between Transition Metal and Main Group Elements in (η5-C5H5)(CO)2M≡ER (M = Cr, Mo, W; E = Si, Ge, Sn, Pb; R = Terphenyl Groups)

“…It is noteworthy that the MPb distances of 2.383 Å for M = Cr, 2.513 Å for M = Mo, and 2.516 Å for M = W are much shorter than the corresponding single bond distances of 2.909Å for M = Cr, 2.985 Å for M = Mo, and 2.981 Å for M = W observed for (η 5 -C5H5)(CO)3M-PbAr**. 17 In addition, the M-Pb-Ar** angles of 176.8-179.2° for (η 5 -C5H5)(CO)2M≡PbAr** are very close to 180°. These results suggest that Pb is able to form a strong triple bond in (η 5 -C5H5)(CO)2M≡PbAr**.…”

Tungsten–Lead Triple Bonds: Syntheses, Structures, and Coordination Chemistry of the Plumbylidyne Complexes trans‐[X(PMe3)4WPb(2,6‐Trip2C6H3)]

“…15 The isostructural, trans ‐configured octahedral complexes have approximate C 2 point group symmetry,20 and display almost linear W‐Pb‐C aryl linkages ( 2 ‐Br, 177.5(2)°; 2 ‐I, 175.79(8)°) and the shortest WPb bonds ( 2 ‐Br, 2.5464(5) Å; 2 ‐I, 2.5477(3) Å) reported to date 21. In fact, the WPb bond lengths of 2 ‐Br and 2 ‐I are 0.20 Å shorter than those of the bridged plumbylidyne complex [{W(CO) 4 } 2 (μ‐Br){μ‐Pb(2,6‐Trip 2 C 6 H 3 )}] (2.7423(3) and 2.7517(3) Å), which contains a three‐coordinate lead center with trigonal‐planar geometry,14 and approximately 0.45 Å shorter than the WPb single bonds of the V‐shaped tungstenoplumbylene [Pb(2,6‐Trip 2 C 6 H 3 ){W(η 5 ‐C 5 H 5 )(CO) 3 }] (2.9809(10) and 3.0055(6) Å) 21d. The PbC aryl bonds of 2 ‐Br (2.254(6) Å) and 2 ‐I (2.258(3) Å) are shorter than those of 1 ‐Br and 1 ‐I (Figure 1), or those reported for the plumbylenes [Pb(2,6‐Trip 2 C 6 H 3 )R] (R=Me, t Bu, Ph: PbC aryl 2.272(9)–2.321(3) Å)14 and metalloplumbylenes [Pb(2,6‐Trip 2 C 6 H 3 ){M(η 5 ‐C 5 H 5 )(CO) 3 }] (M=Cr, Mo, W: PbC aryl 2.278(9)–2.294(4) Å),21d and indicate that the triply bonded lead atom uses sp‐hybrid orbitals for σ bonding.…”

Synthesis, Characterization, and CO Elimination of Ferrio-Substituted Two-Coordinate Germylenes and Stannylenes

“…6 We were also able to extend our results to the preparation of metallostannylenes (η 5 -C 5 H 5 )(CO) 3 M−SnAr (M = Cr, Mo, W; Ar = Ar Me 6 , Ar Pri 6 ) 7 and metalloplumbylenes (η 5 -C 5 H 5 )(CO) 3 M-PbAr Pri 6 (M = Cr, Mo, W). 8 In these singly bonded species, the Ge, Sn, Pb atoms are two-coordinate with bent C−E−M (M = Cr, Mo, W; E = Ge, Sn, Pb) geometry. More recently, two Ge(II) compounds containing Ge−Fe σ bonds, (Piso)GeFe(η 5 -C 5 H 5 )(CO) 2 (Piso − = [ArNC( t Bu)-NAr] − , Ar = −C 6 H 3 -2,6-i Pr 2 ) 9 and LGeFe(η 5 -C 5 H 5 )(CO) 2 (L = CH{CMe(NAr)} 2 , Ar = −C 6 H 3 -2,6-i Pr 2 ), 10 were synthesized by using bidentate amidinate or diketiminate ligands at germanium.…”