Benjamin E. Fener, Philipp Schüler, Phil Liebing, Helmar Görls and Matthias Westerhausen
{"title":"Syntheses and structures of dimesitylphosphinite complexes of alkali metals and their catalytic activity in hydrophosphorylation reactions†","authors":"Benjamin E. Fener, Philipp Schüler, Phil Liebing, Helmar Görls and Matthias Westerhausen","doi":"10.1039/D4DT02721C","DOIUrl":null,"url":null,"abstract":"<p >Metalation of dimesitylphosphane oxide, Mes<small><sub>2</sub></small>P(O)H (<strong>1</strong>), with alkali metal reagents (<em>n</em>BuLi, NaH, and A(hmds); A = K, Rb, and Cs) in THF yields the corresponding dimesitylphosphinites of lithium (<strong>2-thf</strong>), sodium (<strong>3-thf</strong>), potassium (<strong>4-thf</strong>), rubidium (<strong>5-thf</strong>), and caesium (<strong>6</strong>). Their molecular structures exhibit a broad and fascinating variety. Dinuclear compounds <strong>2-thf</strong>, <strong>3-thf</strong>, and <strong>5-thf</strong> have central four-membered A<small><sub>2</sub></small>O<small><sub>2</sub></small> rings, whereas the potassium congener crystallises as a tetranuclear complex with an inner A<small><sub>4</sub></small>O<small><sub>4</sub></small> heterocubane cage. The tetranuclear caesium congener precipitates without thf coligands and exhibits a quite unique structure in its crystalline state. Due to their catalytic activity in hydrophosphorylation reactions, we focus on the solvent–structure relationship of the potassium derivatives. In hydrocarbons, [K<small><sub>4</sub></small>(O-PMes<small><sub>2</sub></small>)<small><sub>4</sub></small>]<small><sub>2</sub></small> (<strong>4</strong>) is formed, and bidentate Lewis bases like dme and tmeda are unable to deaggregate this tetranuclear cage compound, but bases with a higher denticity (diglyme, triglyme, and pmdeta) split this cage compound into dinuclear complexes with central K<small><sub>2</sub></small>O<small><sub>2</sub></small> rings. In addition, very bulky <em>P</em>-bound aryl groups like 2,4,6-triisopropylphenyl in dinuclear <strong>8-thf</strong> hinder the formation of tetranuclear cage compounds, whereas 2-methylnaphthyl substituents are not bulky enough and the tetranuclear cage compound <strong>7-thf</strong> is stabilised. For the 2,4,6-triisopropylphenyl substituent, the rubidium and caesium congeners <strong>11</strong> and <strong>12</strong> crystallise with two central A<small><sub>2</sub></small>O<small><sub>2</sub></small> rings interconnected by π-interactions. A heteroleptic potassium complex <strong>9-hmds</strong>, containing hmds as well as phosphinite anions, represents a snapshot on the way from the starting K(hmds) to the phosphinite-based heterocubane congener. Finally, heterobimetallic [{(thf)K}<small><sub>2</sub></small>Mg(O-PMes<small><sub>2</sub></small>)<small><sub>4</sub></small>] (<strong>10-thf</strong>) with tetrahedrally coordinated Mg centres has been isolated.</p>","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":" 1","pages":" 181-197"},"PeriodicalIF":3.5000,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2025/dt/d4dt02721c?page=search","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Dalton Transactions","FirstCategoryId":"92","ListUrlMain":"https://pubs.rsc.org/en/content/articlelanding/2025/dt/d4dt02721c","RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"CHEMISTRY, INORGANIC & NUCLEAR","Score":null,"Total":0}
引用次数: 0
Abstract
Metalation of dimesitylphosphane oxide, Mes2P(O)H (1), with alkali metal reagents (nBuLi, NaH, and A(hmds); A = K, Rb, and Cs) in THF yields the corresponding dimesitylphosphinites of lithium (2-thf), sodium (3-thf), potassium (4-thf), rubidium (5-thf), and caesium (6). Their molecular structures exhibit a broad and fascinating variety. Dinuclear compounds 2-thf, 3-thf, and 5-thf have central four-membered A2O2 rings, whereas the potassium congener crystallises as a tetranuclear complex with an inner A4O4 heterocubane cage. The tetranuclear caesium congener precipitates without thf coligands and exhibits a quite unique structure in its crystalline state. Due to their catalytic activity in hydrophosphorylation reactions, we focus on the solvent–structure relationship of the potassium derivatives. In hydrocarbons, [K4(O-PMes2)4]2 (4) is formed, and bidentate Lewis bases like dme and tmeda are unable to deaggregate this tetranuclear cage compound, but bases with a higher denticity (diglyme, triglyme, and pmdeta) split this cage compound into dinuclear complexes with central K2O2 rings. In addition, very bulky P-bound aryl groups like 2,4,6-triisopropylphenyl in dinuclear 8-thf hinder the formation of tetranuclear cage compounds, whereas 2-methylnaphthyl substituents are not bulky enough and the tetranuclear cage compound 7-thf is stabilised. For the 2,4,6-triisopropylphenyl substituent, the rubidium and caesium congeners 11 and 12 crystallise with two central A2O2 rings interconnected by π-interactions. A heteroleptic potassium complex 9-hmds, containing hmds as well as phosphinite anions, represents a snapshot on the way from the starting K(hmds) to the phosphinite-based heterocubane congener. Finally, heterobimetallic [{(thf)K}2Mg(O-PMes2)4] (10-thf) with tetrahedrally coordinated Mg centres has been isolated.
期刊介绍:
Dalton Transactions is a journal for all areas of inorganic chemistry, which encompasses the organometallic, bioinorganic and materials chemistry of the elements, with applications including synthesis, catalysis, energy conversion/storage, electrical devices and medicine. Dalton Transactions welcomes high-quality, original submissions in all of these areas and more, where the advancement of knowledge in inorganic chemistry is significant.