Self-assembly preparation, structure and magnetic studies of a novel dinuclear copper(II) complex: [Cu2(μ-OH)(μ-OAc)(μ-L)][BF4]2 [L = bis-1,3-(cis,cis-1,3,5-triaminocyclohexane)xylylidiene]

Boxwell, Clive J.; Bhalla, Rajiv; Cronin, Leroy; Turner, Scott S.; Walton, Paul H.

doi:10.1039/a803796e

Cited by 35 publications

(15 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Hydrogen atoms were placed at calculated positions and those of lattice water molecules were located on the Fourier map and refined. In compound 1 the carbon atoms of the -CH 2 -N(3)(Me) 2 group was found disordered and refined over two conformations with occupancies of 0.610(13)/ 0.390 (13) and the same disorder was found in 7 both the 5-membered chelate rings (refined occupancies of 0.629(10)/ 0.371 (10) and 0.562(9)/0.438( 9)). In 3, 4 and 5 the tert-butyl group was successfully split over two positions (refined occupancies of 0.516(18)/0.484 (18), 0.505(10)/0.495 (10) and 0.875(9)/0.125 (9), respectively).…”

Section: X-ray Crystallographymentioning

confidence: 79%

“…For the last few years our laboratory has been actively engaged to access the mechanistic pathway of catechol oxidase, a less well known member of type-III copper proteins. 1 It is now well established from the reports of several distinguished research groups [1][2][3][4][5][6][7][8][9][10][11] around the world, including us, 12,13 that in the case of Cu II and Mn III model compounds, metal-centered redox participation rather than a radical pathway is most probably responsible for the catecholase activity induced by these species. On the other hand, by using redox innocent Zn II complexes with the "end-off" compartmental ligand, 14 more recently we established that a radical pathway (instead of metal-centered redox contribution) is most probably instrumental in the oxidation of 3,5-di-tert-butylcatechol (3,5-DTBC) to 3,5-di-tert-butylbenzoquinone (3,.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A radical pathway in catecholase activity with nickel(ii) complexes of phenol based “end-off” compartmental ligands

et al. 2014

View full text Add to dashboard Cite

Seven dinuclear and one dinuclear based dicyanamide bridged polymeric Ni(II) complexes of phenol based compartmental ligands (HL(1)-HL(4)) have been synthesized with the aim to investigate their catecholase-like activity and to evaluate the most probable mechanistic pathway involved in this process. The complexes have been characterized by routine physicochemical studies as well as by X-ray single crystal structure analyses namely [Ni2(L(2))(SCN)3(H2O)(CH3OH)] (), [Ni2(L(4))(SCN)3(CH3OH)2] (), [Ni2(L(2))(SCN)2(AcO)(H2O)] (), [Ni2(L(4))(SCN)(AcO)2] (), [Ni2(L(2))(N3)3(H2O)2] (), [Ni2(L(4))(N3)3(H2O)2] (), [Ni2(L(1))(AcO)2(N(CN)2)]n () and [Ni2(L(3))(AcO)2(N(CN)2)] (), [SCN = isothiocyanate, AcO = acetate, N3 = azide, and N(CN)2 = dicyanamide anion; L(1-4) = 2,6-bis(R2-iminomethyl)-4-R1-phenolato, where R1 = methyl and tert-butyl, R2 = N,N-dimethyl ethylene for L(1-2) and R1 = methyl and tert-butyl, R2 = 2-(N-ethyl) pyridine for L(3-4)]. A UV-vis spectrophotometric study using 3,5-di-tert butylcatechol (3,5-DTBC) reveals that all the complexes are highly active in catalyzing the aerobic oxidation of (3,5-DTBC) to 3,5-di-tert-butylbenzoquinone (3,5-DTBQ) in methanol medium with the formation of hydrogen peroxide. An EPR study confirms the generation of radicals during the catalysis. Cyclic voltammetric studies of the complexes in the presence and absence of 3,5-DTBC have been performed. Reduction of Ni(II) to Ni(I) and that of the imine bond of the ligand system have been detected at ∼-1.0 V and ∼-1.5 V, respectively. Coulometric separation of the species at -1.5 V followed by the EPR study at 77 K confirms the species as an organic radical and thus most probably reduced imine species. Spectroelectrochemical analysis at -1.5 V clearly indicates the oxidation of 3,5-DTBC and thus suggests that the radical pathway is supposed to be responsible for the catecholase-like activity exhibited by the nickel complexes. The ligand centred radical generation has further been verified by density functional theory calculation.

show abstract

Section: X-ray Crystallographymentioning

confidence: 79%

Section: Introductionmentioning

confidence: 99%

A radical pathway in catecholase activity with nickel(ii) complexes of phenol based “end-off” compartmental ligands

et al. 2014

View full text Add to dashboard Cite

show abstract

“…In each case, the geometry around the copper ion is square pyramidal distorted along the apical Cu-N bond of one of three amino nitrogens of TACH. The apical Cu-N distance is 2.232 (3) [53,54,55]. GlyGly is coordinated through the terminal NH 2 group and the peptide carbonyl oxygen atom from the same glycine residue with a Cu-N4 distance of 2.024(2) Å and a Cu-O(1) distance of 2.037(2) Å .…”

Section: Crystal Structurementioning

confidence: 99%

Copper(II)-cis,cis-1,3,5-triaminocyclohexane complex-promoted hydrolysis of dipeptides: kinetic, speciation and structural studies

et al. 2002

View full text Add to dashboard Cite

The hydrolysis of glycylglycine (GylGly), glycyl-L-leucine (GlyLeu), L-leucylglycine (LeuGly) and glycyl-DL-serine (GlySer) promoted by a copper(II)- cis, cis-1,3,5-triaminocyclohexane complex [Cu(II)TACH] was investigated at 70 degrees C and pH 7-10, using HPLC. The observed pseudo-first-order rate constants (k(obs)) and rate enhancing factors (REF) were as follows: 4.1x10(-3 )h(-1)(REF=23) for GylGly, 1.6x10(-3 )h(-1)(REF=21) for GlyLeu, 5.1x10(-3 )h(-1)(REF=64) for LeuGly and 9.2x10(-2 )h(-1)(REF=47) for GlySer [pH 8.1, dipeptide 2 mM, copper(II) 2 mM and TACH 2 mM]. Based on the pH dependence and dipeptide concentration dependence of the initial rates and speciation of the Cu(II)-TACH-dipeptide system at 25 degrees C and I=0.1, the reactions proceed via the formation of a ternary complex [Cu(TACH)(dipeptide)](+) as an intermediate followed by OH(-)-dependent and OH(-)-independent paths to give amino acid(s). GylGly, GlyLeu and LeuGly preferred the OH(-)-dependent path, while GlySer preferred the OH(-)-independent path. The latter can be explained by the intramolecular attack of the amide carbonyl group coordinated with its oxygen atom by the OH group in the serine residue. The X-ray crystal structure of [Cu(TACH)(GlyGly)]BPh(4).MeOH confirmed that GlyGly coordinates to copper(II) ion with its terminal amino N and amide O atoms. The crystal structures of [Cu(TACH)(Gly)]BPh(4) and [Cu(2)(TACH)(2)(OH)(2)](ClO(4))(2).NaClO(4).H(2)O are also reported.

show abstract

“…Found: C, 37.08; H, 2.92; N, 5.79; Br, 22. 35; Cu,18.05%. Single crystals of 1 were prepared by diffusion a methanol into a dmf solution of the green crystalline compound.…”

mentioning

confidence: 98%

“…Heterobridged ligands, l-hydroxo/alkoxo-l-X and [10][11][12][13][14][15][16][17][18][19] (X ¼ N À 3 ; NO À 2 , pyrazolate, carboxylate, etc.) and their metallic compounds can be considered as a special class of exchange-coupled systems where the magnetic properties are more dependent on the second bridging ligand (X); e.g., they are strongly antiferromagnetic for X ¼ N À 3 , moderately antiferromagnetic for X ¼ NO À 2 , weakly to strongly antiferromagnetic for X = pyrazolate and weakly antiferromagnetic to weakly ferromagnetic for X ¼ RCO À 2 .…”

mentioning

confidence: 99%

Ferromagnetic exchange in μ-alkoxo-μ-dicarboxylato double bridged tetranuclear copper(II) complexes: [Cu4(L-X)2(μ-C4H4O4)(dmf)2] (L=1,3-bis(5-X-salicylideneamino)-2-propanol, X=Br, Cl)

Lee

Cheng

Lin

et al. 2005

Inorganic Chemistry Communications

View full text Add to dashboard Cite

Self-assembly preparation, structure and magnetic studies of a novel dinuclear copper(II) complex: [Cu2(μ-OH)(μ-OAc)(μ-L)][BF4]2 [L = bis-1,3-(cis,cis-1,3,5-triaminocyclohexane)xylylidiene]

Cited by 35 publications

References 13 publications

A radical pathway in catecholase activity with nickel(ii) complexes of phenol based “end-off” compartmental ligands

A radical pathway in catecholase activity with nickel(ii) complexes of phenol based “end-off” compartmental ligands

Copper(II)-cis,cis-1,3,5-triaminocyclohexane complex-promoted hydrolysis of dipeptides: kinetic, speciation and structural studies

Ferromagnetic exchange in μ-alkoxo-μ-dicarboxylato double bridged tetranuclear copper(II) complexes: [Cu4(L-X)2(μ-C4H4O4)(dmf)2] (L=1,3-bis(5-X-salicylideneamino)-2-propanol, X=Br, Cl)

Contact Info

Product

Resources

About