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Synthetic, structural, NMR and catalytic studies of phosphinic amide-phosphoryl chalcogenides (chalcogen = O, S, Se) as mixed-donor bidentate ligands in zinc chemistry.

Synthetic, structural, NMR and catalytic studies of phosphinic amide-phosphoryl chalcogenides (chalcogen = O, S, Se) as mixed-donor bidentate ligands in zinc chemistry.

Authors :
del Águila-Sánchez MA
Santos-Bastos NM
Ramalho-Freitas MC
García López J
Costa de Souza M
Camargos-Resende JA
Casimiro M
Alves-Romeiro G
Iglesias MJ
López Ortiz F
Source :
Dalton transactions (Cambridge, England : 2003) [Dalton Trans] 2014 Oct 07; Vol. 43 (37), pp. 14079-91. Date of Electronic Publication: 2014 Aug 14.
Publication Year :
2014

Abstract

ortho Substituted (diphenylphosphoryl)-, (diphenylphosphorothioyl)- and (diphenylphosphoroselenoyl)-phosphinic amides o-C6H4(P(X)Ph2)(P(O)N(i)Pr2) (X = O (20a), S (20b), Se (20c)) were synthesized by ortho directed lithiation of N,N-diisopropyl-P,P-diphenylphosphinic amide (Ph2P(O)N(i)Pr2) followed by trapping with Ph2PCl and subsequent oxidation of the o-(diphenylphosphine)phosphinic amide (19) with H2O2, S8 and Se. The reaction of the new mixed-donor bidentate ligands with zinc dichloride afforded the corresponding complexes [ZnCl2(P(X)Ph2)o-C6H4(P(O)N(i)Pr2)] (21a-c). The new compounds were structurally characterized in solution by nuclear magnetic resonance spectroscopy and in the solid-state by X-ray diffraction analysis of the ligand (20b) and the three complexes (21a-c). The X-ray crystal structure of 20b suggests the existence of a P[double bond, length as m-dash]O→P(S)-C intramolecular nonbonded interaction. The natural bond orbital (NBO) analysis using DFT methods showed that the stabilization effect provided by a nO→σ*P-C orbital interaction was negligible. The molecular structure of the complexes consisted of seven-membered chelates formed by O,X-coordination of the ligands to the zinc cation. The metal is four-coordinated by binding to the two chlorine atoms showing a distorted tetrahedral geometry. Applications in catalysis revealed that hemilabile ligands 20a-c act as significant promoters of the addition of diethylzinc to aldehydes, with 20a showing the highest activity. Chelation of Et2Zn with 20a was evidenced by NMR spectroscopy.

Details

Language :
English
ISSN :
1477-9234
Volume :
43
Issue :
37
Database :
MEDLINE
Journal :
Dalton transactions (Cambridge, England : 2003)
Publication Type :
Academic Journal
Accession number :
25121963
Full Text :
https://doi.org/10.1039/c4dt01789g