Hexaarylcyclotriplumbane:  A Molecule with a Homonuclear Ring System of Lead

Abstract

The reaction of lead(II) bromide with RMgBr, R = 2,4,6-Et3C6H2, furnishes black crystals of hexakis(2,4,6-triethylphenyl)cyclotriplumbane (1) as the first molecule with a homonuclear lead ring. 1 adopts a skewed structure with highly stretched Pb-Pb bond lengths of 3.185 A (average), which indicate that the three-membered ring is formed by weak interactions of 3 singlet plumbylene molecules.

Dispersion Energy Enforced Dimerization of a Cyclic Disilylated Plumbylene

“…A somewhat similar situation is found in distannene (Mebp 2 Sn) 2 (Mebp = 2,3,4-methyl-6- tert -butylphenyl) 24 and, in particular, in Weidenbruch’s cyclotriplumbane (Tep 2 Pb) 3 (Tep =2,4,6-triethylphenyl), where each lead atom acts as an electron pair acceptor for one of its neighbors and as a donor to the other one. 25 As the geometry of the core in Weidenbruch’s compounds depends on subtle changes in the steric bulk of the ligands, plumbylene 6 might adopt an intermediate position. 25−27 The electronic situation would favor trimerization, while the silyl ligands employed do not allow higher aggregates than a dimer for steric reasons.…”

“…25 As the geometry of the core in Weidenbruch’s compounds depends on subtle changes in the steric bulk of the ligands, plumbylene 6 might adopt an intermediate position. 25−27 The electronic situation would favor trimerization, while the silyl ligands employed do not allow higher aggregates than a dimer for steric reasons.…”

Theory and Calculations of Molecules Containing Heavier Main Group Elements and Fullerenes Encaging Transition Metals: Interplay with Experiment

“…It is interesting that the skewed structure was verified by the synthesis and X-ray crystal analysis of c-Pb 3 R 6 (R = 2,4,6-triethylphenyl). 18 The linear HE¸EH and planar H 2 E=EH 2 structures have significantly shorter EE bond distances upon geometry optimization than the trans-bent structures. However, "short bond = strong bond" is not necessarily satisfied, 9 which has been established for second row atoms.…”

A Mixed‐Anion System Consisting of a Germyl Anion and Anions Delocalized on Conjugated Carbon Ring Skeletons

“…Compound 5 can be expected to have a higher germylene character 5B as compared to germabenzenylpotassium caused by the extension of conjugation, which may result in the formation of a three‐membered ring, cyclotrigermane 6 . The formation of a three‐membered ring of Group 14 elements, such as cyclotristannane or cyclotriplumbane, through the trimerization of the corresponding stannylenes or plumbylenes has been previously reported. In addition, the reduction of some dihalogermanes are known to give cyclotrigermanes, although the involvement of a germylene intermediate is unclear .…”