N,O versus O,O coordination in β-imino diketonato complexes: Role of the metal center and of the imino substituent

Basato, Marino; Bortolussi, Marzio; Faggin, Elena; Tubaro, Cristina; Veronese, Augusto C.

doi:10.1016/j.ica.2008.05.003

Cited by 17 publications

(3 citation statements)

References 19 publications

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“…In case of M ¼ Ni 2þ , the spectrum displays bands at 17,500, 14,650, and 20,900 cm À1 . The higher energy band is characteristic of distorted square planar copper(II) complexes while the other two bands are consistent with distorted square planar nickel(II) complexes [13,[19][20][21][22]. The spectrum of [Cu(H 2 L)Co(OAc) 2 ] displays bands at 12,200, 16,500, 17,000, and 17,950 cm À1 .…”

Section: Magnetic and Electronic Spectral Studiesmentioning

confidence: 84%

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Synthesis, characterization, and biological activity studies of copper(II)–metal(II) binuclear complexes of dipyridylglyoxal bis(2-hydroxybenzoyl hydrazone)

El‐Dissouky

Al-Fulaij

Awad

et al. 2009

Journal of Coordination Chemistry

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2010) Synthesis, characterization, and biological activity studies of copper(II)-metal(II) binuclear complexes of dipyridylglyoxal bis(2-hydroxybenzoyl hydrazoneA new series of copper(II) mononuclear and copper(II)-metal(II) binuclear complexes [(H 2 L)Cu] Á H 2 O, [CuLM] Á nH 2 O, and [Cu(H 2 L)M(OAc) 2 ] Á nH 2 O, n ¼ 1-2, M ¼ Co(II), Ni(II), Cu(II), or Zn(II), and L is the anion of dipyridylglyoxal bis(2-hydroxybenzoyl hydrazone), H 4 L, were synthesized and characterized. Elemental analyses, molar conductivities, and FT-IR spectra support the formulation of these complexes. IR data suggest that H 4 L is dibasic tetradentate in [(H 2 L)Cu] Á H 2 O and [Cu(H 2 L)M(OAc) 2 ] Á nH 2 O but tetrabasic hexadentate in [CuLM] Á nH 2 O (n ¼ 1-2). Thermal studies indicate that waters are of crystallization and the complexes are thermally stable to 347-402 C depending upon the nature of the complex. Magnetic moment values indicate magnetic exchange interaction between Cu(II) and M(II) centers in binuclear complexes. The electronic spectral data show that d-d transitions of CuN 2 O 2 in the mononuclear complex are blue shifted in binuclear complexes in the sequences: Cu-Cu 4 Cu-Ni 4 Cu-Co 4 Cu-Zn, suggesting that the binuclear complexes [CuLM] Á nH 2 O are more planar than the mononuclear complex. The structures of complexes were optimized through molecular mechanics applying MM þ force field coupled with molecular dynamics simulation. [(H 2 L)Cu] Á nH 2 O, [CuLM] Á nH 2 O, and the free ligand were screened for antimicrobial activities on some Gram-positive and Gramnegative bacterial species. The free ligand is inactive against all studied bacteria. The screening data showed that [CuLCu] Á H 2 O 4 [(H 2 L)Cu] Á H 2 O 4 [CuLZn] Á H 2 O 4 [CuLNi] Á 2H 2 O % [CuLCo] Á H 2 O in order of biological activity. The data are discussed in terms of their compositions and structures.

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Section: Magnetic and Electronic Spectral Studiesmentioning

confidence: 84%

“…This is supported by the appearance of a new band at 25,285 cm À1 assigned to O (p ) ! Ni (d ) [13,[19][20][21].…”

Section: Magnetic and Electronic Spectral Studiesmentioning

confidence: 99%

Synthesis, characterization, and biological activity studies of copper(II)–metal(II) binuclear complexes of dipyridylglyoxal bis(2-hydroxybenzoyl hydrazone)

El‐Dissouky

Al-Fulaij

Awad

et al. 2009

Journal of Coordination Chemistry

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“…Secondly, there is a greater geometric constraint in the transition state of the N H‐enamine 8 than N ‐substituted enamine 4 as the nitrogen atom in 8 is not pre‐substituted with any group or functionality acting as a cyclization auxillary . Thirdly, a free N H‐group in an enamine can bind to a Cu(I)‐catalyst to form an inactive Cu(I)‐ N H complex causing the loss of catalyst‐redox activity essential to perform the radical reactions . Despite all these challenges, a single step synthesis of a N H‐pyrrole from a N H‐enamine is advantageous over multisteps N ‐preprotection post deprotection dependent protocols usually suffering with the loss of the yields …”

Section: Introductionmentioning

confidence: 99%

β,β,β‐Trichloroethyl‐NH‐Enamine as Viable System for 5‐Endo‐trig Radical Cyclization via Multifaceted Cu^I−Cu^II Redox Catalysis: Single Step Synthesis of Multi‐Functionalized NH‐Pyrroles

2019

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Here we report a mild and regioselective copper-catalyzed direct synthesis of multi-substituted and functionalized NH-pyrroles in high yields from diverse β,β,β-trichloroethyl-NH-enamines via a novel 5-endo-trig radical cyclization mode, previously known to be unviable in the enamine system. An approach to transform a geometrically 'disfavored to favored' 5-endo-trig radical cyclization mode in NH-enamine systems via multifaceted Cu I À Cu II redox catalysis generating radicals, preventing dehalogenative reduction of radical precursors and dehydrohalogenating the 5-endo-trig cyclized products have been demonstrated experimentally. With wider substrate scope, this method incorporates halo-, NH-and carbonyl functionalities besides alkyl, aryl and heteroaryl substituents in the pyrrole unit easily. These difficult to prepare 3-halo-NH-pyrroles are potential sources for natural products, agrochemicals, pharmaceuticals and organometallic chemistry. Scheme 1. a) Viable 5-endo-trig radical cyclizations in N-substituted enamide, b) unviable 5-endo-trig radical cyclizations in Nsubstituted enamine and c) transformation of unviable to viable mode in present work. UPDATES asc.wiley-vch.de Scheme 2. Synthesis of 3-chloro-NH-pyrroles 21 by Cu(I)/PMDETA-catalyzed 5-endo-trig radical cyclization-aromatization of NHenamines 20.Scheme 4. Study of the conformational role of substituents and functionalities of NH-enamines in the 5-endo-trig radical cyclization process.

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Magnetic properties of iron(II) complex with β-iminodiketone

Pardasani¹,

Pardasani²

2023

Magnetic Properties of Paramagnetic Compounds, Magnetic Susceptibility Data, Volume 7

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N,O versus O,O coordination in β-imino diketonato complexes: Role of the metal center and of the imino substituent

Cited by 17 publications

References 19 publications

Synthesis, characterization, and biological activity studies of copper(II)–metal(II) binuclear complexes of dipyridylglyoxal bis(2-hydroxybenzoyl hydrazone)

Synthesis, characterization, and biological activity studies of copper(II)–metal(II) binuclear complexes of dipyridylglyoxal bis(2-hydroxybenzoyl hydrazone)

β,β,β‐Trichloroethyl‐NH‐Enamine as Viable System for 5‐Endo‐trig Radical Cyclization via Multifaceted Cu^I−Cu^II Redox Catalysis: Single Step Synthesis of Multi‐Functionalized NH‐Pyrroles

Magnetic properties of iron(II) complex with β-iminodiketone

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N,O versus O,O coordination in β-imino diketonato complexes: Role of the metal center and of the imino substituent

Cited by 17 publications

References 19 publications

Synthesis, characterization, and biological activity studies of copper(II)–metal(II) binuclear complexes of dipyridylglyoxal bis(2-hydroxybenzoyl hydrazone)

Synthesis, characterization, and biological activity studies of copper(II)–metal(II) binuclear complexes of dipyridylglyoxal bis(2-hydroxybenzoyl hydrazone)

β,β,β‐Trichloroethyl‐NH‐Enamine as Viable System for 5‐Endo‐trig Radical Cyclization via Multifaceted CuI−CuII Redox Catalysis: Single Step Synthesis of Multi‐Functionalized NH‐Pyrroles

Magnetic properties of iron(II) complex with β-iminodiketone

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β,β,β‐Trichloroethyl‐NH‐Enamine as Viable System for 5‐Endo‐trig Radical Cyclization via Multifaceted Cu^I−Cu^II Redox Catalysis: Single Step Synthesis of Multi‐Functionalized NH‐Pyrroles