Search results for "Molecule"
showing 10 items of 5162 documents
Single-molecule magnet properties of a monometallic dysprosium pentalene complex
2018
The pentalene-ligated dysprosium complex [(η8-Pn†)Dy(Cp*)] (1Dy) (Pn† = [1,4-(iPr3Si)2C8H4]2−) and its magnetically dilute analogue are single-molecule magnets, with energy barriers of 245 cm−1. Whilst the [Cp*]− ligand in 1Dy provides a strong axial crystal field, the overall axiality of this system is attenuated by the unusual folded structure of the [Pn†]2− ligand. peerReviewed
Rare‐earth cyclobutadienyl sandwich complexes: Synthesis, structure and dynamic magnetic properties
2018
The potassium cyclobutadienyl [K2{η4‐C4(SiMe3)4}] (1) reacts with MCl3(THF)3.5 (M=Y, Dy) to give the first rare‐earth cyclobutadienyl complexes, that is, the complex anions [M{η4‐C4(SiMe3)4}{η4‐C4(SiMe3)3‐κ‐(CH2SiMe2}]2−, (2M), as their dipotassium salts. The tuck‐in alkyl ligand in 2M is thought to form through deprotonation of the “squarocene” complexes [M{η4‐C4(SiMe3)4}2]− by 1. Complex 2Dy is a single‐molecule magnet, but with prominent quantum tunneling. An anisotropy barrier of 323(22) cm−1 was determined for 2Dy in an applied field of 1 kOe, and magnetic hysteresis loops were observed up to 7 K. nonPeerReviewed
Asymmetric Ring Opening in Tetrazine‐based Ligand Affording a Tetranuclear Opto‐Magnetic Ytterbium Complex
2021
We report the formation of a tetranuclear lanthanide cluster, [Yb 4 (bpzch) 2 (fod) 10 ] ( 1 ), which occurs from a serendipitous ring opening of the functionalized tetrazine bridging ligand, bpztz (3,6‐dipyrazin‐2‐yl‐1,2,4,5‐tetrazine) upon reacting with Yb(fod) 3 (fod ‐ = 6,6,7,7,8,8,8‐heptafluoro‐2,2‐dimethyl‐3,5‐octandionate). Compound 1 was structurally elucidated via single‐crystal X‐ray crystallography and subsequently magnetically and spectroscopically characterized to analyse its magnetisation dynamics and its luminescence behaviour. Computational studies validate the observed M J energy levels attained by spectroscopy and provides a clearer picture of the slow relaxation of the ma…
Triplet-State Position and Crystal-Field Tuning in Opto‐Magnetic Lanthanide Complexes : Two Sides of the Same Coin
2019
Lanthanide complex‐based luminescence thermometry and single‐molecule magnetism are two effervescent research fields, owing to the great promise they hold from an application standpoint. The high thermal sensitivity achievable, their contactless nature, along with sub‐micrometric spatial resolution make these luminescent thermometers appealing for accurate temperature probing in miniaturized electronics. To that end, single‐molecule magnets (SMMs) are expected to revolutionize the field of spintronics, thanks to the improvements made in terms of their working temperature – now surpassing that of liquid nitrogen – and manipulation of their spin state. Hence, the combination of such opto‐magn…
Three-dimensional bimetallic octacyanidometalates $[M^{IV}{(\mu-CN)_{4}Mn^{II}(H_{2}O)_2}_2 \cdot 4H_{2}O]_{n}$ (M=Nb,Mo,W) : synthesis, single-cryst…
2008
Abstract We report the synthesis, the single-crystal X-ray crystallographic structures and the magnetic properties of three new isostructural cyanido-bridged networks: [M IV {(μ-CN) 4 Mn II (H 2 O) 2 } 2 ·4H 2 O] n [M IV = Nb IV ( 1 ), Mo IV ( 2 ), W IV ( 3 )]. For compound 1 , the magnetic properties reveal a ferrimagnetic phase below 50 K. In contrast, compounds 2 and 3 show a paramagnetic behaviour with no magnetic ordering down to 2 K. The only electronic difference between the two kinds of compounds is the presence of two paired electrons on Mo IV ( 2 ) and W IV ( 3 ) (d 2 electronic configuration, S = 0) with no possible exchange interactions with Mn II ions (d 5 electronic configur…
Squaric Acid-Based Radiopharmaceuticals for Tumor Imaging and Therapy.
2021
Targeting vectors bound to a chelator represent a significant fraction of radiopharmaceuticals used nowadays for diagnostic and therapeutic purposes in nuclear medicine. The use of squaramides as coupling units for chelator and targeting vector helps to circumvent the disadvantages of several common coupling methods. This review gives an overview of the use of squaric acid diesters (SADE) as linking agents. It focuses on the conjugation of cyclic chelators, e.g., DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid), as well as hybrid chelators like AAZTA5 (6-pentanoic acid-6-amino-1,4-diazepine tetracetic acid) or DATA5m (6-pentanoic acid-6-amino-1,4-diazapine-triacetate) to diff…
Theoretical prediction of the photoinduced chemiluminescence of pesticides
2007
Although it is relatively easy to find chemiluminescent (CL) molecules working on the field of direct liquid phase (especially employing strong oxidants), the molecules found as chemiluminescent are normally very weak CL compounds for developing suitable analytical CL-procedures. Therefore, it is mandatory to develop new strategies to enhance in a simple way the native chemiluminescence of such a compounds, and even to increase the number of compounds to be determined by direct chemiluminescence. Photoinduced chemiluminescence (Ph-CL) results in a simple and easily on-line accessible strategy to solve these disadvantages. In the present paper, molecular connectivity, a topological method wh…
Monoclonal antibodies to polysialic acid reveal epitope sharing between invasive pathogenic bacteria, differentiating cells and tumor cells
1987
Monoclonal antibodies (mAb) for rapid diagnosis and detection of invasive bacteria and identification of pathogenic factors in infectious disease are equally important in medical microbiology and clinical pathology and may even provide a breakthrough in basic medical and cell biology research. Such a situation evolved from the application of a unique mAb against the poorly immunogenic homopolymers of alpha 2,8-linked sialic acid of Escherichia coli K1 and meningococci group B capsules which could be derived from immune-hyperreactive NZB-autoimmune mice. The cross-reactivity of this mAb with identical polysialic acid (polySA) units of the neural cell adhesion molecule (N-CAM) revealed antige…
Non-covalent interactions of N-phenyl-1,5-dimethyl-1H-imidazole-4-carboxamide 3-oxide derivatives—a case of intramolecular N-oxide hydrogen bonds
2017
The crystal structures of new N-phenyl-1,5-dimethyl-1H-imidazole-4-carboxamide 3-oxide derivatives are reported. The results of X-ray diffraction showed the existence of intramolecular hydrogen bonding between carboxamide nitrogen donors and N-oxide oxygen acceptors. The use of Quantum Theory of Atoms in Molecules allowed its classification as a strong interaction, with energy about 10 kcal/mol, and of intermediate character between closed shell and shared bonds. Comparison of experimental data and quantum theoretical calculations indicated that a substituent attached to the phenyl ring in the para position influences the strength and geometry of the title hydrogen bonding. Stronger π-elect…
Antibodies to cell surface ganglioside GD3 perturb inductive epithelial-mesenchymal interactions
1988
Abstract Most epithelial sheets emerge during embryogenesis by a branching and growth of the epithelium. The surrounding mesenchyme is crucial for this process. We report that branching morphogenesis and the formation of a new epithelium from the mesenchyme in the embryonic kidney can be blocked by a monoclonal antibody reacting with a surface glycolipid, disialoganglioside G D3 . In contrast, a more than 10-fold excess of antibodies to adhesive glycoproteins (N-CAM, L -CAM, fibronectin) fails to inhibit morphogenesis. Although the anti-G D3 antibody affected epithelial development, the disialoganglioside G D3 was expressed not in the epithelium, but in the mesenchyme surrounding the develo…