Preparation and properties of a triply bridged antiferromagnetically coupled binuclear copper(II) complex [Cu2L(OAc)2]ClO4 {L=2,6-bis[(N-methyl piperazin-1-yl) methyl]-4-bromo phenol}

Rajendiran, Thekkel M.; Kannappan, Ramu; Venkatesan, R.; Rao, P. Srinivasa; Kandaswamy, M.

doi:10.1016/s0277-5387(99)00222-3

Cited by 24 publications

(4 citation statements)

References 31 publications

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“…From Table 3, the K con > 4, which indicate that the Cu II Cu I mixed valence species is stable with respect to disproportionation. This situation is the most common and has been observed in several binuclear systems [34,35]. A coulometric experiment conducted at 100 mV more negative than the second reduction peak consumed two electrons per molecule.…”

Section: Redox Propertiesmentioning

confidence: 69%

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Rajendiran

Kannappan

Mahalakshmy

et al. 2003

Transition Metal Chemistry

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A series of binuclear Cu II complexes [Cu 2 XL] nþ having two copper(II) ions bridged by different motifs (X = OH À , MeCO À 2 , or Cl À) have been prepared using the ligands: H 2 L 1 ¼ 4-methyl-2-[N-(2-{dimethylamino}ethyl-N¢methyl)aminomethyl]-6-[(prolin-1-yl)methyl]phenol, H 2 L 2 ¼ 4-nitro-2-[N-(2-{dimethylamino}ethyl-N¢-methyl)aminomethyl]-6-[(prolin-1-yl)methyl]phenol, H 2 L 3 ¼ 4-methyl-2-[N-(2-{diethylamino}ethyl-N¢-ethyl)aminomethyl]-6-[(prolin-1-yl)methyl]phenol and H 2 L 4 ¼ 4-nitro-2-[N-(2-{diethylamino}ethyl-N¢-ethyl)aminomethyl]-6-[(prolin-1-yl)methyl]phenol. The complexes have been characterized by spectroscopic, analytical, magnetic and electrochemical measurements. Cryomagnetic investigations (80-300 K) revealed anti-ferromagnetic exchange between the Cu II ions (À2J in the range)50 to)182 cm À1). The strength of anti-ferromagnetic coupling lies in the order: OAc > OH > Cl. Cyclic voltammetry revealed the presence of two redox couples, assigned to Cu

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Section: Redox Propertiesmentioning

confidence: 69%

Untitled

Rajendiran

Kannappan

Mahalakshmy

et al. 2003

Transition Metal Chemistry

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“…The acetate bridging in syn-syn bidentate mode is common in diiron and dimanganese complexes [24] and also found in dicopper(ii/iii) complexes. [25,26] The dinucleating μ-bis(tetradentate) ligand shows a nonhelical binding mode for the dicopper(ii/iii) complex as against the double helical binding of two parent hexadentate ligands for a tetracopper[(ii) 4 ] complex reported recently by us. [11] Two nitrogen atoms, one terminal and one bridging phenolate oxygen atom from one-half of the ligand are coordinated to one metal center forming one five-membered (N-Cu-N) and two six-membered (N-Cu-O) terminal and bridging chelate rings.…”

Section: Syntheses and Spectroscopic Characterization Studiesmentioning

confidence: 92%

μ‐η¹:η¹‐N,N'‐Imidazolidine‐Bridged Dicopper(II/III) Complexes of a New Dinucleating μ‐Bis(tetradentate) Schiff Base Ligand: Synthesis, Structural Characterization, ¹H NMR Spectroscopy, and Magnetic Coupling

et al. 2005

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The copper coordination chemistry of a new imidazolidine‐based doubly bridging μ‐bis(tetradentate) ligand, H3mhbai is studied. A new family of pentacoordinate dinuclear complexes of formula [CuII2(‐mhbai)(‐X)]·2 H2O (1–4) [X = OAc, NO3, Cl, S2COMe], where H3mhbai stands for 2‐(2‐hydroxyphenyl)‐1,3‐bis[4‐(2‐hydroxyphenyl)‐4‐methyl‐3‐aza‐but‐3‐enyl]‐2‐methyl‐1,3‐imidazolidine, were synthesized from the ligand, H3mhbai in air. The complex 1 was structurally characterized by X‐ray crystallography. The μ‐η1:η1‐N,N'‐imidazolidine bridging mode between two copper(II) ions has been identified in this complex along with a nonhelical binding mode of the μ‐bis(tetradentate) ligand. Variable temperature (2–300 K) magnetic susceptibility data of 1 show the presence of a weak antiferromagnetic exchange interaction between the two triply bridged magnetically isolated copper(II) (S = 1/2) ions. The χmT values start to drop at temperature below 50 K, to reach a value of 0.55 cm3 K mol–1 at 2 K for a coupling constant value of J = –2.2 cm–1. The 1H NMR spectrum of the weakly coupled complex 1 shows a total of seventeen hyperfine shifted peaks, as expected from the idealized Cs symmetry of the compound, spread over a very large window of chemical shift, spanning about 130 ppm. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

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“…This is due to the monomer impurity present in the complex. Generally, the signal intensity of monomeric impurities is larger than that of dimeric complexes since the monomeric complexes are more soluble [19] and the spectral linewidths for these complexes are narrower than those for dimeric complexes. The calculated isotropic g and A values are g iso = 2.16 and A iso /g e β e = 4.96 mT.…”

Section: Epr Studiesmentioning

confidence: 99%

“…To understand the nature of the metal ions in the enzymes mentioned above, a series of bimetallic copper and nickel complexes with various bridging moieties have been prepared in our laboratory [19][20][21]. Single-crystal EPR studies of the bimetallic nickel complexes at room temperature have indicated that the zero-field splitting (D/g e β e ) parameters are −9.7, −4.2 and 13.9 mT.…”

Section: Introductionmentioning

confidence: 99%

Single‐crystal EPR studies of a perchlorate‐bridged dimeric copper(II) complex with 2‐[(4‐methyl‐pyridin‐2‐ylimino)‐methyl]‐phenol

Srinivasan

Sougandi

Velavan

et al. 2007

Physica Status Solidi (b)

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A new dimeric perchlorate-bridged copper(II) complex with the Schiff's base ligand 2-[(4-methylpyridin-2-ylimino)-methyl]-phenol has been synthesized. The complex has been characterized using elemental analysis, ultraviolet -visible and infrared spectroscopy, conductivity, magnetic studies and EPR techniques. Single-crystal EPR studies indicate that zero-field splitting (D) is relatively small, and that the half-field transition is not observed due to its low intensity. An interesting observation in the frozen solution is that the low-field side of the zero-field splitting line splits into seven lines, due to interaction between the two copper ions. The magnetic susceptibility data indicate a weak ferromagnetic property and that the complex is a 1 : 2 electrolyte. Another set of EPR resonances corresponding to higher D and g values, compared to the system reported, are noticed, whose origin is not yet known.

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Preparation and properties of a triply bridged antiferromagnetically coupled binuclear copper(II) complex [Cu2L(OAc)2]ClO4 {L=2,6-bis[(N-methyl piperazin-1-yl) methyl]-4-bromo phenol}

Cited by 24 publications

References 31 publications

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μ‐η¹:η¹‐N,N'‐Imidazolidine‐Bridged Dicopper(II/III) Complexes of a New Dinucleating μ‐Bis(tetradentate) Schiff Base Ligand: Synthesis, Structural Characterization, ¹H NMR Spectroscopy, and Magnetic Coupling

Single‐crystal EPR studies of a perchlorate‐bridged dimeric copper(II) complex with 2‐[(4‐methyl‐pyridin‐2‐ylimino)‐methyl]‐phenol

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Preparation and properties of a triply bridged antiferromagnetically coupled binuclear copper(II) complex [Cu2L(OAc)2]ClO4 {L=2,6-bis[(N-methyl piperazin-1-yl) methyl]-4-bromo phenol}

Cited by 24 publications

References 31 publications

Untitled

Untitled

μ‐η1:η1‐N,N'‐Imidazolidine‐Bridged Dicopper(II/III) Complexes of a New Dinucleating μ‐Bis(tetradentate) Schiff Base Ligand: Synthesis, Structural Characterization, 1H NMR Spectroscopy, and Magnetic Coupling

Single‐crystal EPR studies of a perchlorate‐bridged dimeric copper(II) complex with 2‐[(4‐methyl‐pyridin‐2‐ylimino)‐methyl]‐phenol

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μ‐η¹:η¹‐N,N'‐Imidazolidine‐Bridged Dicopper(II/III) Complexes of a New Dinucleating μ‐Bis(tetradentate) Schiff Base Ligand: Synthesis, Structural Characterization, ¹H NMR Spectroscopy, and Magnetic Coupling