Search results for "Moiety"
showing 10 items of 621 documents
Self-Immolative Linkers as Caps for the Design of Gated Silica Mesoporous Supports
2016
A new hybrid material based on sulforhodamine-B dye-loaded silica mesoporous nanoparticles capped with a self-immolative gate has been synthesized and characterized. The gated material's controlled release behavior is monitored under different pH conditions. Under acidic and neutral conditions, a low level of dye release is detected. However, at slightly basic pH, significant dye release occurs owing to deprotonation of the phenol moiety in the capping molecule, which results in its disassembly.
Fluorescent organometallic rhodium(I) and ruthenium(II) metallodrugs with 4-ethylthio-1,8-naphthalimide ligands: Antiproliferative effects, cellular …
2018
Fluorescent 4-ethylthio-1,8-naphthalimides containing rhodium(I) N-heterocyclic carbene (NHC) and ruthenium (II) NHC fragments were synthesised and evaluated for their antiproliferative effects, cellular uptake and DNA-binding activity. Both types of organometallics triggered ligand dependent efficient cytotoxic effects against tumor cells with the rhodium(I) NHC derivatives causing stronger effects than the ruthenium (II) NHC analogues. Antiproliferative effects could also be observed against several pathogenic Gram-positive bacterial strains, whereas the growth of Gram-negative bacteria was not substantially affected. Cellular uptake was confirmed by atomic absorption spectroscopy as well…
Heterocyclic photorearrangements. Photoinduced rearrangement of 3-styryl-1,2,4-oxadiazoles
1990
The photochemical behaviour of 3-styryl-5-phenyl-(5-methyl)-1,2,4-oxadiazoles in methanol at 254 nm has been investigated. A photoinduced rearrangement to the quinoline system has been pointed out and explained as proceeding through an initial photolysis of the ring ON bond, followed by a six membered ring closure reaction involving the styryl moiety.
Langmuir films and Langmuir-Blodgett multilayers incorporating mechanically-threaded molecules-pseudorotaxanes
1996
This paper describes the synthesis of a π-electron rich aromatic lipid containing a polyether thread intercepted by a 1,5-dioxynaphthalene moiety. The terminus of one end of the polyether is a methoxyl group and the other a glycerol unit linked via the 2-oxo position, while the 1,3-oxo functions are covalently attached to octadecyl chains. This compound, when cospread at the air-water interface with the tetracationic cyclophane, cyclobis(paraquat-p-phenylene), and the phospholipid, dimyristoylphosphatidic acid, as its monoanion, forms self-assembled pseudorotaxanes which are self-organized into a two-dimensional supramolecular array at the interface. The electrostatic interactions between t…
Cs3UP2S8, a Coordination Polymer Containing the Unprecedented [U=S]2+Sulfidouranium(2+) Moiety
2013
Although terminal chalcogeno ligands are well known for the group 5 and 6 transition metals, they are highly unusual for the oxophilic group 4 metals and unknown so far for the lanthanides or actinides. Cs3UP2S8, is the first actinide compound containing a terminal M=S group. It was synthesized by reacting uranium metal, Cs2S, S, and P2S5 in a 4:1:8:3 ratio at 700 °C in an eutectic LiCl/CsCl mixture. The crystal structure was determined by single-crystal X-ray diffraction techniques. Cs3UP2S8 crystallizes in the rhombohedral space group R [a = 15.5217(8) A; c = 35.132(2) A, V = 8305.0(8) A3, Z = 18]. The crystal structure is based on a tetrahedral network type, wherein the uranium atoms are…
Comparative G2(MP2) Molecular Orbital Study of B3H7XH3 and H3BXH3 Donor−Acceptor Complexes (X = N, P, and As)
2002
B3H7XH3 and H3BXH3 (X = N, P, and As) have been studied as donor−acceptor complex type at the G2(MP2) level of theory. Both single- and double-bridged structures of B3H7 Lewis acid are taken into account. Although the double-bridged structure is energetically favored in the isolated state, the coordination prefers the single-bridged one. The monoborane adducts adopt the staggered arrangement with C3v symmetry. The energetic analysis by natural bond orbital theory shows that the decrease of hyperconjugative contribution upon complexation in the B3H7 moiety has, as consequence, a loss of symmetry for B3H7XH3 (X= P and As) complexes. In the two series, the coordination is the result of two opp…
Optically Active Titanium Complexes Containing Linked Amido‐cyclopentadienyl Ligands: Their Use as Asymmetric Hydrogenation Catalysts
1996
Optically active titanium complexes of the formula Ti(η5:η1−C5R4SiMe2NCHMePh)Cl2 (R = H, Me), containing the cyclopentadienyl ligand linked to a chiral 1-phenylethylamido moiety, were synthesized and characterized in both enantiomerically pure forms. A single-crystal X-ray structural analysis of (S)()Ti(η5:η1−C5H4SiMe2NCHMePh)Cl2 shows a conformation in which the phenyl group is turned away from the metal center. NOE measurements suggest that a related structure is retained in solution. Upon activation with n-butyllithium, these complexes show hydrogenation activity toward imines with slight enantioselectivity.
UV photostability of metal phthalocyanines in organic solvents
2003
Kinetic studies of photochemical reactions induced by UV radiation in solutions of metal phthalocyanines have been carried out to determine the factors which might have influenced the stability of photosensitized phthalocyanines. Complexes of the molecular type Mpc, M'(2)pc, and Lnpc(2) (where M = Li, Mg, Fe, Co, Zn, Pb; M'= Tl; Ln = rare earth; pc = phthalocyanine ligand, C(32)H(16)N(8)(2-)) were investigated in DMF, DMSO, and pyridine. Progressive decay of the phthalocyanine macrocycle due to absorption of UV light was observed. Phthalimide found in the final photolysis product may indicate some chemically bonded oxygen involved in the solid phthalocyanine material. Fluorescence lifetimes…
Ligand mediated structural diversity of copper(II)-azido moiety: Synthesis, structure and magnetic study
2022
Abstract Two copper azido complexes [Cu4(L1)4(µ1,1-N3)3(N3)] (1) and [{Cu2(L2)(N-benzylen)(µ1,1-N3)3(µ1,1,3-N3(N3)]n (2) have been synthesized by the reaction of aqueous solution of sodium azide to a methanolic solution of copper perchlorate hexahydrate and corresponding Schiff-base ligands. Schiff bases HL1 and HL2 act as blocking coligands are derived from the 1:1 condensation of N-benzyl ethylenediamine with Salicyldehyde and 2-hydroxy-5-chloroacetophenone respectively (N-benzylen is the N-benzyl ethylenediamine). These two complexes are characterized by the elemental analysis, FT-IR, single crystal X-ray diffraction, powder XRD and also TGA. Single crystal X-ray structural study reveals…
In situ synthesis of lipopeptides as versatile receptors for the specific binding of nanoparticles and liposomes to solid-supported membranes.
2008
A detailed study of the in situ coupling of small peptides such as CGGH6 (H6) and CGWK8 (K8) to maleimide functionalized phospholipid bilayers is presented. Individually addressable microstructured membranes are employed to unequivocally probe the conjugation. The in situ coupling of peptides via a terminal cysteine moiety to maleimide functionalized phospholipids is shown to be a convenient and versatile way to selectively fabricate peptide-modified phospholipid bilayers serving as specific receptor platforms for functionalized vesicles and nanoparticles. Specific binding of functional vesicles to the peptide-modified bilayers is achieved by either histidine complexation with Ni-NTA-DOGS c…