26082-96-2Relevant articles and documents
Monooxygenation of an appended phenol in a model system of tyrosinase: Implications on the enzymatic reaction mechanism
Hamann, Jessica Nadine,Rolff, Malte,Tuczek, Felix
, p. 3251 - 3258 (2015)
A new tridentate N-donor ligand and its corresponding copper(i) complex have been synthesized to investigate the tyrosinase-like aromatic hydroxylation of an attached phenol. The results of the oxygenation reactions are compared to related systems having attached phenyl and catechol groups, respectively. The title complex is the first system mediating the monooxygenation of a phenol in the absence of an external base. This journal is
Towards polymer diagnostic agents - Copolymers of N-(2-hydroxypropyl)- methacrylamide and bis(2-pyridylmethyl)-4-vinylbenzylamine: Synthesis, characterisation and Re(CO)3-labelling
Kunz, Peter C.,Brueckmann, Nadine E.,Spingler, Bernhard
, p. 394 - 399 (2007)
Diagnosis of early stage angiogenic tumours is fundamental for cancer therapy. In this study we present the synthesis and characterisation of functionalised HPMA-copolymers with optimal molecular weights that meet the demands of the enhanced permeability and retention (EPR) effect. Rhenium tricarbonyl complexes of the tripodal ligands bis(2-pyridylmethyl)benzylamine (1a) and bis(2-pyridylmethyl)-4-vinylbenzylamine (1b) were prepared and characterised by 1H NMR and IR spectroscopy, mass spectrometry and X-ray diffraction. Ligand 1b was copolymerised with N-(2-hydroxypropyl) methacrylamide (HPMA), and the resulting copolymer was treated with (nBu 4N)2[Re(CO)3Br3] to yield a Re(CO)3-labelled copolymer. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
Highly selective hydroxylation of alkanes catalyzed by (μ-oxo)bis(μ- carboxylato)-bridged diiron(iii) complexes: Involvement of mononuclear iron(iii) species in catalysis
Visvaganesan, Kusalendiran,Suresh, Eringathodi,Palaniandavar, Mallayan
, p. 3814 - 3823 (2009)
A few diiron(iii) complexes [Fe2(O)(OAc)2(L1) 2](ClO4)21, [Fe2(O)(OBz) 2(L1)2](ClO4)22, [Fe 2(O)(OAc)2(L2)2](ClO4)23 and [Fe2(O)(OBz)2(L2)2](ClO4) 24, where L1 = N,N-bis(pyrid-2-ylmethyl)-iso-butylamine, L2 = N,N-bis(pyrid-2-ylmethyl)benzylamine, AcO = acetate and BzO = benzoate, have been isolated and characterized by means of elemental analysis and spectral and electrochemical methods. The molecular structures of the complexes 2 and 4 have been determined by single-crystal X-ray diffraction analysis and they possess a distorted bioctahedral geometry in which each iron atom is coordinated to the oxygen atom of the μ-oxo bridge, two oxygen atoms of the μ-benzoato bridges and three nitrogen atoms of L1 and L2 ligands capping the two ends of the diiron(iii) cluster. The ESI-MS spectral data of the complexes reveal that the complexes remain intact in dichloromethane (DCM) solution. Upon adding one equivalent of Et3N to a mixture of one equivalent of the diiron(iii) complexes and excess of m-chloroperbenzoic acid (m-CPBA) in DCM, an intense absorption band (λmax, 670-700 nm) appears, which corresponds to the species [Fe2(O)(OAc)(m-CPBA)(L)2]2+ (ESI-MS, m/z 466) suggested as the intermediate involved in the oxygenation reactions. All the present complexes show efficient alkane hydroxylation with 300-400 turn over numbers and good selectivities for cyclohexane (A/K, 10-14) and adamantane (3°/2°, 9-11). Interestingly, the formation of monoiron(iii) species has been discerned in the alkane hydroxylation reactions beyond ～50 turnovers. The mononuclear 1: 1 iron(iii) complexes of L1 and L2 ligands generated in situ are also found to catalyze the oxygenation reactions with high selectivity and efficiency for cyclohexane (A/K, 10-14). Upon their reaction with m-CPBA in DCM, a characteristic absorption band (λmax, 600 nm, εmax, 355 M-1 cm-1) appears and decays at room temperature. This spectral feature is consistent with the mononuclear high-valent iron-oxo species suggested as an intermediate in the oxygenation reactions.
Solvent induced cooperativity of Zn(ii) complexes cleaving a phosphate diester RNA analog in methanol
Mohamed, Mark F.,Sánchez-Lombardo, Irma,Neverov, Alexei A.,Brown, R. Stan
experimental part, p. 631 - 639 (2012/02/05)
The kinetics of cyclization of 2-hydroxypropyl p-nitrophenyl phosphate (1) promoted by two mononuclear Zn(ii) catalytic complexes of bis(2-pyridylmethyl) benzylamine (4) and bis(2-methyl 6-pyridylmethyl)benzylamine (5) in methanol were studied under sspH-controlled conditions (where sspH refers to [H +] activity in methanol). Potentiometric titrations of the ligands in the absence and presence of Zn2+ and a non-reactive model for 1 (2-hydroxylpropyl isopropyl phosphate (HPIPP, 6)) indicate that the phosphate is bound tightly to the 4:Zn(ii) and 5:Zn(ii) complexes as L:Zn(ii):6-, and that each of these undergoes an additional ionization to produce L:Zn(ii):6-:(-OCH3) or a bound deprotonated form of the phosphate, L:Zn(ii):62-. Kinetic studies as a function of [L:Zn(ii)] indicate that the rate is linear in [L:Zn(ii)] at concentrations well above those required for complete binding of the substrate. Plots of the second order rate constants (defined as the gradient of the rate constant vs. [complex] plot) vs.sspH in methanol are bell-shaped with rate maxima of 23 dm mol-1 s-1 and 146 dm mol-1 s-1 for 4:Zn(ii) and 5:Zn(ii), respectively, at their sspH maxima of 10.5 and 10. A mechanism is proposed that involves binding of one molecule of complex to the phosphate to yield a poorly reactive 1:1 complex, which associates with a second molecule of complex to produce a transient cooperative 2:1 complex within which the cyclization of 1 is rapid. The observations support an effect of the reduced polarity solvent that encourages the cooperative association of phosphate and two independent mononuclear complexes to give a reactive entity.
