1-(N,N-Dimethylferrocenylmethylamine)-2-methyl-3-(trimethylsilyl)-2,3-dicarba-1-plumba-closo-heptaborane(6)

Abstract

The title compound, 1-Pb[(r/s-CsHs)Fe{r/5-CsH4 -was crystallized in the monoclinic space group P2~/n. (1) and (2) the dihedral angles between the C5H5 and C2B3 planes in (3) are about 91°. This is the result of a slight rotation of the ferrocenyl ligand about the C(11)--C(21) bond making the Pb--C(12) bond a distance of closest approach and thus establishing the existence of secondary metal-CsHs (Tr) interactions in the stabilization of these donor-acceptor complexes.

Chemistry ofC-Trimethylsilyl-Substituted Heterocarboranes. 27. Synthetic, Spectroscopic, Structural, and Reactivity Studies on d0Hafnacarboranes of 2,3-C2B4-Carborane Ligands

“…A comparison of these values with those listed in Table 3 shows that the Hf-Cl bond distances are slightly smaller than the corre- sponding distances in the zirconacarboranes; this is in agreement with the results found in the metallocene sandwich complexes of the two metals. 21 The solution 1 H, 13 C, and 11 B NMR spectra of compounds I-V are listed in Table 1. They all show peaks that are consistent with the formulations given in the Experimental Section and, in the case of compounds I-III, with the structures shown in Figures 1-3 Conclusions.…”

“…Three standard reflections, monitored after every 150 reflections for compounds II and III, did not show any significant change in intensity during the data collection. However, a similar monitoring of compound I revealed significant decay; a C6D6 was used as solvent and as an internal standard of δ 7.15 ppm (in the 1 H NMR spectra) and δ 128.0 ppm (in the 13 C NMR spectra) for compounds, with a positive sign indicating a downfield shift. Legend: s ) singlet, d ) doublet, t ) triplet, q ) quartet, v ) very, br ) broad.…”

“…Similar steric effects were also thought to be important in determining the metal coordination in a number of SiMe 3 -substituted titanacarboranes. 12 Other than our preliminary report on the synthesis and structure of the full-sandwich complex 1-Cl-1(THF)-2,2′- 13 very little has been reported on the small-cage hafnacarboranes. Preparatory to a systematic study of the reactivity of the structures and chemistry of these potentially useful d 0 systems, several full-sandwich, half-sandwich, and mixed-ligand sandwich hafnacarboranes were prepared and characterized.…”