Transition-Metal-Stabilised Heavy Tetraphospholide Anions

02 August 2022, Version 1
This content is a preprint and has not undergone peer review at the time of posting.

Abstract

Phosphorus analogues of the ubiquitous cyclopentadienyl (Cp) are a rich and diverse family of compounds, which have found widespread use as ligands in organometallic complexes. By contrast, phospholes incorporating heaviear group 14 elements (Si, Ge, Sn, and Pb) are hardly known. Here, we demonstrate the isolation of the first metal complexes featuring heavy cyclopen-tadienyl anions (SnP4)2─ and (PbP4)2─. The complexes [(η4-tBu2C2P2)2Co2(μ,η5:η5-P4Tt)] [Tt = Sn (6), Pb (7)] are formed by reaction of white phosphorus (P4) with cyclooctadiene cobalt complexes [Ar′TtCo(η4-P2C2tBu2)(η4-COD)] [Sn (2), Pb (3), Ar′ = C6H3-2,6{C6H3¬-2,6-iPr2}2, COD = cycloocta-1,5-diene] and Tt{Co(η4-P2C2tBu2)(COD)}2 [Tt = Sn (4), Pb (5)]. While the (SnP4)2− complex 6 was isolated as a pure and stable compound, compound 7 eliminates Pb(0) below room temper-ature to afford [(η4-tBu2C2P2)2Co2(μ,η4:η4-P4) (8), which is a rare example of a tripledecker complex with a (P4)2─ middle deck. The electronic structures of 6-8 are analysed using theoretical methods, including an analysis of intrinsic bond orbitals and magnetic response theory. Thereby the aromatic nature of (P5)− and (SnP4)2− was confirmed, while for (P4)2− a specific type of symmetry-induced weak paramagnetism was found which is distinct from conventional antiaromatic species.

Keywords

coordination chemistry
cobalt
phosphorus
germanium
tin
lead
phospholes
white phosphorus

Supplementary materials

Title
Description
Actions
Title
Supporting Information
Description
Details on the synthesis and characterization of compounds 1-8, X-ray crystallographic data, NMR and UV-vis spectroscopic data, and results of quantum chemical calculations
Actions

Comments

Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.