학술논문

Synthesis of a chelating hexadentate ligand with a P3N3donor set. Crystal and molecular structure of [OC-6-22]-[Co{(RP*,RP*,RP*)-CH3C(CH2PPhC6H4NH2-2)3}](PF6)3
Document Type
Article
Source
Dalton Transactions; 2006, Vol. 2006 Issue: 38 p4614-4622, 9p
Subject
Language
ISSN
14779226; 13645447
Abstract
The first structurally authenticated example of a hexadentate chelating tertiary phosphine in which all six donors are bound to a single metal centre is described. The multidentate ligand (RP*,RP*,RP*)- and (RP*,RP*,SP*)-CH3C(CH2PPhC6H4NH2-2)3has been prepared in 80% yield viathe reaction of five equivalents of sodium (2-aminophenyl)phenylphosphide (generated in situfrom (2-aminophenyl)phenylphosphine and sodium in thf) with 1,1,1-tri(bromomethyl)ethane in thf. The diastereomeric mixture has been complexed to cobalt(iii) and the resulting pair of complexes, viz.[Co{(RP*,RP*,RP*)-CH3C(CH2PPhC6H4NH2-2)3}]Cl3and [CoCl{(RP*,RP*,SP*)-CH3C(CH2PPhC6H4NH2-2)3}]Cl2, separated by ion exchange chromatography. The structure of the former (as the corresponding hexafluorophosphate salt) has been confirmed by X-ray crystallography and clearly shows all six donors of the P3N3ligand coordinated to a single cobalt(iii) centre. The related hexadentate ligand with internal N donors and terminal diphenylphosphino groups, viz.CH3C(CH2NHC6H4PPh2-2)3, has also been synthesised, albeit in low yield, viathe reaction of [Li(tmeda)][2-NHC6H4PPh2] (generated in situfrom (2-aminophenyl)diphenylphosphine, n-butyllithium and tmeda in diethyl ether) with 1,1,1-tri(iodomethyl)ethane in thf. No formation of a P3N3ligand has been observed when either Na[2-PPhC6H4NH2] or [Li(tmeda)][2-NHC6H4PPh2] is reacted with the related tripodal substrate 1,1,1-tris(tolyl-4-sulfonyloxymethyl)ethane in thf. Rather the P-methyloxetane (±)-[3-{(2-aminophenyl)phenylphosphinomethyl}]-3-methyloxetane and the sulfonamide 2-(4-CH3C6H4SO2)NHC6H4PPh2and the corresponding N-methyloxetane [3-{(2-diphenylphosphinophenyl)aminomethyl}]-3-methyloxetane have been isolated from the respective reactions. The structure of the sulfonamide has been confirmed by an X-ray analysis of the platinum(ii) complex trans-[PtCl(CH3){2-PPh2C6H4NH(SO2C6H4CH3-4)}2].