NDLI: Group 1 and group 2 metal complexes supported by a bidentate bulky iminopyrrolyl ligand: synthesis, structural diversity, and ε-caprolactone polymerization study

Content Provider	World Health Organization (WHO)-Global Index Medicus
Author	Kottalanka, Ravi K. Panda, Tarun K. Harinath, A. Rej, Supriya
Description	Author Affiliation: Kottalanka RK ( Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi - 502 285, Sangareddy, Telangana, India. tpanda@iith.ac.in.); Harinath A ( Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi - 502 285, Sangareddy, Telangana, India. tpanda@iith.ac.in.); Rej S ( Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi - 502 285, Sangareddy, Telangana, India. tpanda@iith.ac.in.); Panda TK ( Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi - 502 285, Sangareddy, Telangana, India. tpanda@iith.ac.in.)
Abstract	We report here a series of alkali and alkaline earth metal complexes, each with a bulky iminopyrrolyl ligand $[2-(Ph_{3}CN=CH)C_{4}H_{3}NH]$ (1-H) moiety in their coordination sphere, synthesized using either alkane elimination or silylamine elimination methods or the salt metathesis route. The lithium salt of molecular composition $[Li(2-(Ph_{3}CN=CH)C_{4}H_{3}N)(THF)_{2}]$ (2) was prepared using the alkane elimination method, and the silylamine elimination method was used to synthesize the dimeric sodium and tetra-nuclear potassium salts of composition $[(2-(Ph_{3}CN=CH)C_{4}H_{3}N)Na(THF)]_{2}$ (3) and $[(2-(Ph_{3}CN=CH)C_{4}H_{3}N)K(THF)_{0.5}]_{4}$ (4) respectively. The magnesium complex of composition $[(THF)_{2}Mg(CH_{2}Ph)\{2-(Ph_{3}CN=CH)C_{4}H_{3}N\}]$ (5) was synthesized through the alkane elimination method, in which $[Mg(CH_{2}Ph)_{2}(OEt_{2})_{2}]$ was treated with the bulky iminopyrrole ligand 1-H in 1:1 molar ratio, whereas the bis(iminopyrrolyl)magnesium complex $[(THF)_{2}Mg\{2-(Ph_{3}CN=CH)C_{4}H_{3}N\}_{2}]$ (6) was isolated using the salt metathesis route. The heavier alkaline earth metal complexes of the general formula $\{(THF)_{n}M(2-(Ph_{3}CN=CH)C_{4}H_{3}N)_{2}\}$ [M = Ca (7), Sr (8), and n = 2; M = Ba (9), n = 3] were prepared in pure form using two synthetic methods: in the first method, the bulky iminopyrrole ligand 1-H was directly treated with the alkaline earth metal precursor $[M\{N(SiMe_{3})_{2}\}_{2}(THF)_{n}]$ (where M = Ca, Sr and Ba) in 2:1 molar ratio in THF solvent at ambient temperature. The complexes 7–9 were also obtained using the salt metathesis reaction, which involves the treatment of the potassium salt (4) with the corresponding metal diiodides $MI_{2}$ (M = Ca, Sr and Ba) in 2:1 molar ratio in THF solvent. The molecular structures of all the metal complexes (1-H, 2–9) in the solid state were established through single-crystal X-ray diffraction analysis. The complexes 5–9 were tested as catalysts for the ring-opening polymerization of ε-caprolactone. High activity was observed in the heavier alkaline earth metal complexes 7–9, with a very narrow polydispersity index in comparison to that of magnesium complexes 5 and 6.
ISSN	14779226
Issue Number	46
Volume Number	44
e-ISSN	13645447
Journal	Dalton Trans.
Language	English
Publisher	Royal Society of Chemistry
Publisher Date	2015-12-14
Publisher Place	Great Britain (UK)
Access Restriction	Subscribed
Subject Keyword	Caproates Chemistry Coordination Complexes Lactones Metals, Alkaline Earth Pyrroles Chemical Synthesis Imines Ligands Models, Molecular Polymerization Journal Article Research Support, Non-U.S. Gov't
Content Type	Text
Resource Type	Article
Subject	Inorganic Chemistry

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