Bis(phosphinoselenoic amides) as versatile chelating ligands for alkaline earth metal (Mg, Ca, Sr and Ba) complexes: syntheses, structure and ε-caprolactone polymerisation

Kottalanka, R K and Adimulam, H and Bhattacharjee, J and H, Vignesh Babu and Panda, Tarun K (2014) Bis(phosphinoselenoic amides) as versatile chelating ligands for alkaline earth metal (Mg, Ca, Sr and Ba) complexes: syntheses, structure and ε-caprolactone polymerisation. Dalton Transactions, 43. pp. 8757-8755. ISSN 1477-9226

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Abstract

We report here a series of heavier alkaline earth metal complexes with N,N′-(ethane-1,2-diyl)bis(P,P-diphenylphosphinoselenoic amide) using two synthetic routes. In the first route, the heavier alkaline earth metal bis(trimethylsilyl)amides [M{N(SiMe3)2}2(THF)n] (M = Ca, Sr, Ba), when treated with phosphinoselenoic amine [Ph2P(Se)NHCH2CH2NHPPh2(Se)] (1), afforded the corresponding alkaline earth metal complexes of the composition [(THF)3M{Ph2P(Se)NCH2CH2NPPh2(Se)}] [M = Ca (2), Sr (3), Ba (4)]. The metal complexes 2–4 were also obtained from a one-pot reaction, where potassium phosphinoselenoic amide was generated in situ by the reaction of compound 1 and [KN(SiMe3)2], followed by the addition of the respective metal diiodides in THF at room temperature. The magnesium complex [(THF)3Mg{Ph2P(Se)NCH2CH2NPPh2(Se)}] (5) was also prepared. The solid-state structures of alkaline earth metal complexes 2–5 were established by single crystal X-ray diffraction analysis. In the solid state, all the metal complexes are monomeric but in complexes 2–4, ligand 1 is chelated in a tetra-dentate fashion to each metal ion but in complex 5, ligand 1 behaves as a bidentate ligand. Complexes 2–4 were tested as catalysts for the ring-opening polymerisation of ε-caprolactone and a high level of activity for the barium complex 4 was observed, with narrow polydispersity. We also report the synthesis and structure of the bis(amidophosphino borane) ligand [Ph2P(BH3)NHCH2CH2NHPPh2(BH3)] (6) and the corresponding barium complex [(THF)2Ba{Ph2P(BH3)NCH2CH2NPPh2(BH3)}]2 (7).

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IITH Creators:

IITH Creators	ORCiD
Panda, Tarun K	http://orcid.org/0000-0003-0975-0118

Item Type:

Article

Additional Information:

†Electronic supplementary information (ESI) available: For crystallographic details in CIF. CCDC 987282–987289. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c4dt00669k

Subjects:

Chemistry

Divisions:

Department of Chemistry

Depositing User:

Users 3 not found.

Date Deposited:

30 Sep 2014 10:24

Last Modified:

07 Sep 2017 11:04

URI:

http://raiithold.iith.ac.in/id/eprint/163