Search results for "Complex."
showing 10 items of 5824 documents
Coordination polymers based on bridging cyanocarbanions and bis-tridentate p-phenylenediamine ligands
2017
Two new Cu(II) coordination polymeric neutral chains of formula [Cu 2 (1,4-tpbd)(μ-A) 2 (H 2 O) 2 ](A) 2 with A = tcnoet − ( 1 ) and tcnopr − ( 2 ) (1,4-tpbd = N,N,N′N′ -tetrakis(2-pyridylmethyl)benzene-1,4-diamine, tcnoet − = 1,1,3,3-tetracyano-2-ethoxypropenide and tcnopr − = 1,1,3,3-tetracyano-2-propoxypropenide) have been synthesized and characterized by infrared spectroscopy, X-ray diffraction and magnetic measurements. 1 and 2 show alternating chains where the 1,4-tpbd and the cyanocarbanion units (tcnoet − for 1 and tcnopr − for 2 ) alternate as bridging ligands. The molecular structure can be viewed as [Cu 2 (μ-tpbd)] 4+ dinuclear units (with Cu⋯Cu distances of 8.2233(3) for 1 …
Zn(II)-alloferon complexes - Similar sequence, different coordination modes, no antibacterial activity.
2020
Often, in the search for a highly defined scientific phenomenon, a different one becomes apparent. This was also the case of this work, in the scope of which we planned to search for metal-enhanced, novel antibacterial/ antifungal compounds. Instead, we denied the existence of such and revealed the details of the bioinorganic chemistry of Zn(II)-alloferon complexes. Zinc(II) complexes of alloferon 1 and 2, ligands with a sequential difference of one amino acid only, show a substantially different coordination pattern at physiological pH. In the case of Zn(II)-alloferon 1 species, a histamine-like binding mode is observed (N-terminal amine and imidazole of His-1) and the coordination sphere …
C−C Cross-Couplings from a Cyclometalated Au(III) C∧ N Complex: Mechanistic Insights and Synthetic Developments
2021
Abstract In recent years, the reactivity of gold complexes was shown to extend well beyond π‐activation and to hold promises to achieve selective cross‐couplings in several C−C and C−E (E=heteroatom) bond forming reactions. Here, with the aim of exploiting new organometallic species for cross‐coupling reactions, we report on the Au(III)‐mediated C(sp2)−C(sp) occurring upon reaction of the cyclometalated complex [Au(CCH2N)Cl2] (1, CCH2N=2‐benzylpyridine) with AgPhCC. The reaction progress has been monitored by NMR spectroscopy, demonstrating the involvement of a number of key intermediates, whose structures have been unambiguously ascertained through 1D and 2D NMR analyses (1H, 13C, 1H‐1H CO…
Organoplatinum(II) Complexes Self-Assemble and Recognize AT-Rich Duplex DNA Sequences
2021
The specific recognition of AT-rich DNA sequences opens up the door to promising diagnostic and/or therapeutic strategies against gene-related diseases. Here, we demonstrate that amphiphilic PtII complexes of the type [Pt(dmba)(N∧N)]NO3 (dmba = N,N-dimethylbenzylamine-κN, κC; N∧N = dpq (3), dppz (4), and dppn (5)) recognize AT-rich oligonucleotides over other types of DNA, RNA, and model proteins. The crystal structure of 4 shows the presence of significant π-stacking interactions and a distorted coordination sphere of the d8 PtII atom. Complex 5, containing the largest π-conjugated ligand, forms supramolecular assemblies at high concentrations under aqueous environment. However, its aggreg…
Interplay between spin-crossover and luminescence in a multifunctional single crystal iron( ii ) complex: towards a new generation of molecular senso…
2019
Multifunctional mononuclear iron( ) complex coordinated with six phosphorescent ligands exhibiting correlated spin-crossover transition and enhanced fluorescence.
Photomagnetic properties of an Iron(II) low-spin complex with an unusually long-lived metastable LIESST state
2007
A comprehensive study of the photomagnetic behavior of the [Fe(L222N5)(CN)2].H2O complex has been carried out. This complex is characterized by a low-spin (LS) iron(II)-metal center up to 400 K and exhibits at 10 K the well-known Light-Induced Excited Spin State Trapping (LIESST) effect. The critical LIESST temperature (T(LIESST)) has been measured to be 105 K. The kinetics of the transition from the metastable high-spin (HS) state to the low-spin state have been determined and used for reproducing the experimental T(LIESST) curve. This study represents a second example of a fully low-spin iron(II)-metal complex up to 400 K, which can be photoexcited at low temperature with an atypical long…
Ammonia Activation by a Nickel NCN-Pincer Complex featuring a Non-Innocent N-Heterocyclic Carbene: Ammine and Amido Complexes in Equilibrium
2015
A Ni0-NCN pincer complex featuring a six-membered N-heterocyclic carbene (NHC) central platform and amidine pendant arms was synthesized by deprotonation of its NiII precursor. It retained chloride in the square-planar coordination sphere of nickel and was expected to be highly susceptible to oxidative addition reactions. The Ni0 complex rapidly activated ammonia at room temperature, in a ligand-assisted process where the carbene carbon atom played the unprecedented role of proton acceptor. For the first time, the coordinated (ammine) and activated (amido) species were observed together in solution, in a solvent-dependent equilibrium. A structural analysis of the Ni complexes provided insig…
Self-Representation of Children Suffering from Congenital Heart Disease and Maternal Competence
2013
Background: Child development may be subject to forms of motor, physical, cognitive and self-representation impairments when complex congenital heart disease (CHD) occurs. In some cases, inadequacy of both self-representation as well as the family system are displayed. It seems to be important to search the likely internal and external resources of the CHD child, and the possible connections among such resources, which may help him/her to manage his/her own risk condition. Design and Methods: The research project inquires the possible resources related to the self-representation and self-esteem levels of the CHD child, and those related to maternal self-perception as competent mothers. A gr…
Responses of microbial activity and decomposer organisms to contamination in microcosms containing coniferous forest soil.
2002
Soil respiration from microcosms contaminated with pentachlorophenol, 2-ethanolhexanoate, creosote, CuSO4, and benomyl was measured in order to evaluate usefulness of soil microcosms and microbial respiration rate monitoring as a toxicity test in soils with high organic matter content. Coniferous forest soil and its organisms were used as test objects. In addition, how a short-term low temperature period including frost affects respiration dynamics in stressed soils was studied, i.e., whether contaminants reduce resistance of the community to other (also natural) stresses. In addition, at the end of the experiment, effects of contaminants on faunal and microbial community structures were an…
One-dimensional oxalato-bridged copper(II) complex possessing two structurally different metallic centres
2001
Abstract The crystal structure of the oxalato-bridged copper(II) compound [Cu2(μ-ox)2(ampy)3]n 1 (ox=oxalate dianion, ampy=2-amino-3-methylpyridine) consists of infinite corrugated one-dimensional chains in which two types of copper(II) centres, five- and six-coordinated, are bridged sequentially by asymmetric bis-bidentate oxalato ligands. Magnetic susceptibility measurements show the occurrence of a significant intrachain antiferromagnetic coupling (J=−22.9 cm −1 ) .