Search results for "Monomer"
showing 10 items of 857 documents
Expanding the Size of Catecholesters - Modified Ligands for the Hierarchical Assembly of Dinuclear Titanium(IV) Helicates
2015
Five 2,3-dihydroxybenzoic acid derivatives 1 – 5 were used as starting materials to obtain the corresponding methyl and ethyl esters. Those were applied as ligands in the hierarchical self-assembly of lithium-bridged dinuclear titanium(IV) complexes 1a–4a, 1b–3b, and 5b. The equilibria between the mononuclear triscatecholate complexes (monomer) and the dinuclear helicates (dimer) were observed by 1H NMR spectroscopy in [D6]DMSO and [D4]MeOH at room temperature.
pH‐Controlled Assemblies of Dimethyltin‐Functionalized 9‐Tungstophosphates with Guanidinium as Structure‐Directing Cation
2010
Aqueous reaction of (CH 3 ) 2 SnCl 2 with Na 9 [A-α-PW 9 O 34 ] in a 3:1 ratio with [C(NH 2 ) 3 ] + as structure-directing agent resulted in three distinct assemblies of dimethyltin-functionalized tungstophosphates depending on the pH: [{(CH 3 ) 2 -Sn(H 2 O)}{(CH 3 ) 2 Sn}(A-α-PW 9 O 34 )] 5- ( 1 ) at pH = 4.5; [{(CH 3 ) 2 -Sn(H 2 O) 2 }{(CH 3 ) 2 Sn(H 2 O)} 2 (A-α-PW 9 O 34 )] 3- (2) at pH = 3.0; and [{(CH 3 ) 2 Sn(H 2 O)} 3 (A-α-PW 9 O 34 )] 3- (3) at pH = 2.0. All three compounds have been characterized in the solid-state by elemental and thermal analyses, infrared spectroscopy and single-crystal X-ray diffraction. The [A-α-PW 9 O 34 ] 9- trilacunary fragments have three {(CH 3 ) 2 Sn} 2…
Synthesis, Crystal Structure, Thermal Analysis and Magnetic Behavior of a Novel One‐Dimensional Polymeric Pyridinium Chlorocuprate( II ): (Hpy) 2 [Cu…
2003
A one-dimensional polymeric pyridinium chlorocuprate (HPy)2[Cu3Cl8(H2O)2], an intermediate between (HPy)CuCl3 and CuCl2·2H2O, has been synthesized and characterized by X-ray analysis [monoclinic, P21/c, a = 7.8950(10), b = 14.144(2), c = 9.921(10) A, β = 99.20(2)°]. The structure contains [Cu3Cl8(H2O)2]n2n− chains in which both square-pyramidal and octahedral CuII exist. The chains are composed of linked [Cu2Cl6]2− dimers and CuCl2(H2O)2 monomeric units. On being heated in the solid state the compound undergoes dehydration followed by dehydrohalogenation to produce a pyridine complex of CuII: [Cu3Py2Cl6]. Other compounds, (HPy)2[CuCl4], CuPyCl2 and CuPy2Cl2, also produce [Cu3Py2Cl6] as an i…
2D and 3D Anilato-Based Heterometallic M(I)M(III) Lattices: The Missing Link
2015
The similar bis-bidentate coordination mode of oxalato and anilato-based ligands is exploited here to create the first examples of 2D and 3D heterometallic lattices based on anilato ligands combining M(I) and a M(III) ions, phases already observed with oxalato but unknown with anilato-type ligands. These lattices are prepared with alkaline metal ions and magnetic chiral tris(anilato)metalate molecular building blocks: [M(III)(C6O4X2)3](3-) (M(III) = Fe and Cr; X = Cl and Br; (C6O4X2)(2-) = dianion of the 3,6-disubstituted derivatives of 2,5-dihydroxy-1,4-benzoquinone, H4C6O4). The new compounds include two very similar 2D lattices formulated as (PBu3Me)2[NaCr(C6O4Br2)3] (1) and (PPh3Et)2[KF…
A Nonconventional Approach toward Multihydroxy Functional Polystyrenes Relying on a Simple Grignard Reagent
2020
Capitalizing on the inertness of styrene toward Grignard reagents, 4-vinylphenylmagnesium bromide was utilized for the rapid and convenient preparation of the protected monomer 2,2-dimethyl-4-(4-vi...
Oxotungsten(VI) complexes with amino(phenolate)alcoholate ligand
2009
Abstract The reaction between tungsten(VI) complex [W(eg)3] (eg = 1,2-ethanediolato dianion) and a phenolic ligand precursor 2,4-di-tert-butyl-6-(((2-hydroxyethyl)(methyl)amino)methyl)phenol (H2L) affords a monomeric oxotungsten complex [WO(eg)(L)]. This complex reacts further with Me3SiCl, which leads to the displacement of ethanediolato ligand from the complex unit and formation of cis- and trans-isomers of corresponding dichloro complex [WOCl2(L)]. Identical dichloro complexes were also prepared by the reaction between H2L and WOCl4. Molecular structure of [WO(eg)(L)] was verified by X-ray crystallography.
Synthesis and characterization of molybdenum(VI)-dioxo complexes containing both coordinated thiolate and carboxylate groups. Reactions with their ow…
1998
Abstract The synthesis, characterization and spectroscopic properties of a group of Mo(VI) complexes having thiocarboxylate ligands of type [MoVIO2(O2CC(S)MePh-X)2]2 have been reported (X = H, p-Me, p-Cl). The peak potential for the Mo(VI) reduction increasing according to the electron-donor ability of X (Me > H > Cl). Reaction of these Mo(VI) complexes with their own free ligands has been studied by ESR and UV-Vis spectroscopy, yielding the monomeric [MoVO(O2CC(S)MePh-X)2]− as unique complex products. The kinetic study of this oxidation reaction has also been investigated.
Electrochemically Induced Reversible and Irreversible Coupling of Triarylamines
2011
The electrochemical coupling and dimerization behavior of the low molecular compounds triphenylamine (TPA) and 9-phenylcarbazole (PHC) in comparison to tri-p-tolylamine (p-TTA) with para-blocked methyl groups has been investigated in detail. In contrast to the unsubstituted radical cations of TPA and PHC, the radical cations of p-TTA are stable in the radical cation state and do not undergo any further coupling reactions. However, we found that the dicationic state of p-TTA does undergo two different competitive reaction pathways: (1) an irreversible intramolecular coupling reaction which leads to phenylcarbazole moieties and (2) a reversible intermolecular dimerization leading to charged σ…
Bridging rigidity and flexibility : modulation of supramolecular hydrogels by metal complexation
2021
The combination of complementary, noncovalent interactions is a key principle for the design of multistimuli responsive hydrogels. In this work, an amphiphilic peptide, supramacromolecular hydrogelator which combines metal-ligand coordination induced gelation and thermoresponsive toughening is reported. Following a modular approach, the incorporation of the triphenylalanine sequence FFF into a structural (C3EG ) and a terpyridine-functionalized (C3Tpy ) C3 -symmetric monomer enables their statistical copolymerization into self-assembled, 1D nanorods in water, as investigated by circular dichroism (CD) spectroscopy and transmission electron microscopy (TEM). In the presence of a terpyridine …
Kinetic treatment of slow initiation in living carbocationic polymerization and investigation of benzyl halides as initiators for the polymerization …
1998
In contrast to earlier conclusions it is demonstrated that kinetic analysis of incremental monomer addition (IMA) experiments for living carbocationic polymerizations with slow initiation leads only to the ratio of apparent rate constants of initiation and propagation. The apparent rate constants depend on the true (bimolecular) rate constants and on the positions of the equilibria between dormant and active states of initiator and polymer chain ends, respectively. The same considerations are true for other living processes involving dormant species, e.g., group transfer polymerization or controlled radical polymerization. Slow initiation of living carbocationic polymerization of isobutylen…