Untitled

Paramagnetic 18-Valence-Electron Alkylcyclopentadienylnickel(II) Bromide Dimers

“…4 A view along the vector Ni1−Ni2 (Figure 2) shows that the bromo bridges use the space between the alkyl substituents of both five-membered rings, which is the reason for the eclipsed conformation of the two (tBu 3 C 5 H 2 )ligands. A similar but more pronounced behavior has been seen in the dicarbonyldimetal complexes [{(tBu 3 C 5 H 2 )M} 2 (μ-CO) 2 ] (M = Ni, 35 Co 36 ) with the same ring ligand set, where the short metal−metal distances of 2.396(4) Å (M = Ni) and 2.3538( 6) Å (M = Co) enhance steric strain and force both bridging carbonyl ligands in positions parallel to the two ring C−H vectors.…”

Structural Consequences of the Use of Hard and Soft Tripodal Ligands during Metathesis Reactions: Synthesis of the [Bis(hydrotris(methimazolyl)borato]bismuth(III) [Bis(hydrotris(pyrazolyl)borato]sodiate

“…In reactions with sodium, Cp can be induced to form the [Cp 2 Na] anion which is iso-structural with the [Tp 2 Na] anion, i.e., both species are sandwich complexes. In contrast, with the softer bismuth, substituted Cp ligands form species of general formula [CpBiCl 2 ] 2 16,17 and [Cp 2 Bi] + . These are highly comparable with the two TmBi complexes reported above.…”

Assigning Hapticity to Cyclopentadienyl Derivatives of Antimony and Bismuth

“…Sitzmann et al examined the hapticity of cyclopentadienylsubstituted bismuth dihalides, examining the position of the metal atom relative to the C(α) atom and the pattern of metal−carbon distances, rather than their absolute values. 33 Using these criteria, a bismuth atom located above the C(α)•••Z vector (Figure 10) with three shorter and two longer Bi•••C distances corresponds to η 3 coordination. In contrast, the metal shifted "to one side" with two shorter and three longer Bi•••C distances is designated as η 2 coordination.…”