Search results for "stereo"

Synthesis, crystal structure and magnetic properties of a cyanide-bridged heterometallic {CoIIMnIII} chain

2017

The assembly reaction between the low-spin [CoII(dmphen)(CN)3]- metalloligand and the [MnIII(salen)(H2O)]+ complex cation yielded the one-dimensional compound {[MnIII(salen)(μ-NC)2CoII(dmphen)(CN)]·2H2O}n (1), which behaves as a ferrimagnetic chain, the intrachain magnetic coupling being J = -1.71(1) cm-1.

Synthesis and in vitro biological evaluation of novel diaminothiophene scaffolds as antitumor and anti-influenza virus agents. Part 2

2017

On the basis of high-throughput screening, fragment-based drug discovery, structure–activity relationships and building block analysis methods, herein we report the synthesis and biological evaluation of a novel series of diethyl 2,5-diaminothiophene-3,4-dicarboxylate derivatives. All of the prepared Schiff bases (with mono-, di- and poly-substituents at the aromatic portion), mono- and bis-amides of diethyl 2,5-diaminothiophene-3,4-dicarboxylate, were evaluated against various human cancer and non-cancerous (only for active compounds) cell lines, as well as influenza A (subtypes FM/1/47/H1N1, hanfang/359/95/H3N2) and B (subtype jifang/13/97) viruses. The obtained results suggest that some …

Electrochemical and spectroscopic studies of poly(diethoxyphosphoryl)porphyrins

2011

Abstract The synthesis and electrochemical characterization of two related series of porphyrins bearing diethoxyphosphoryl groups are reported. One group of compounds is represented as (T( p -R)PP)M where R = phos = P(O)(OEt) 2 and M = Zn(II) or H 2 while the other is represented as (di( p -R)Pdi(phos)P)M where R = P(O)(OEt) 2 , H or CH 3 and M = Zn(II) or H 2 . Each porphyrin was investigated by electrochemistry and thin-layer spectroelectrochemistry in CH 2 Cl 2 , CDCl 3 , CHCl 3 or PhCN containing tetra- n -butylammonium perchlorate (TBAP) as supporting electrolyte. The highly electron-withdrawing P(O)(OEt) 2 groups lead to easier reductions and harder oxidations than the two comparison …

Molecular materials based upon organic π-donors and magnetic anions

2000

Electrochemical combination of the magnetic dinuclear anion [MM'(C 2 O 4 )(NCS) 8 ] 4- (MM' = CrCr, CrFe) or paramagnetic mononuclear anion [Cr(NCS) 6 ] 3- with the ET organic π-donor (ET = BEDT-TTF = bis(ethylenedithio)tetrathiafulvalene) gives rise to two new series of molecular hybrid salts formulated (ET) 5 [MM'(C 2 O 4 )(NCS) 8 (MM' = CrCr (1), CrFe (2)), (ET) 8 [MM'(C 2 O 4 )(NCS) 8 ] (3), (ET) 5.5 f Cr(NCS) 6 ] (4) and (ET) 5 [(C 2 H 5 ) 4 N] [Cr(NCS) 6 ](THF) (5) (THF = tetrahydrofuran). The crystal structures consist of alternating organic and inorganic layers. The organic part does not produce any detectable effect on the magnetic properties coming from the inorganic sublattice. T…

Determining Factors for the Unfolding Pathway of Peptides, Peptoids, and Peptidic Foldamers.

2016

We present a study of the mechanical unfolding pathway of five different oligomers (α-peptide, β-peptide, δ-aromatic-peptides, α/γ-peptides, and β-peptoids), adopting stable helix conformations. Using force-probe molecular dynamics, we identify the determining structural factors for the unfolding pathways and reveal the interplay between the hydrogen bond strength and the backbone rigidity in the stabilization of their helix conformations. On the basis of their behavior, we classify the oligomers in four groups and deduce a set of rules for the prediction of the unfolding pathways of small foldamers.

Synthesis, crystal structure and magnetic properties of two oxalato-bridged dimetallic trinuclear complexes combined with a polar cation

2010

Two isostructural heterometallic trinuclear oxalato-bridged complexes of formula C(4)[MCr(2)(ox)(6)(H(2)O)(2)]·nH(2)O (C(+) = 4-aminopyridinium; ox(2-) = oxalate dianion; M(2+) = Mn(2+), n = 3, 1; M(2+) = Co(2+), n = 3.25, 2) have been synthesized by using direct self-assembly methods combining C(3)[Cr(ox)(3)] and the chloride salts of the corresponding metal ion. The crystal structures of both compounds have been resolved by single-crystal X-ray diffraction. They crystallize in the C2/c space group [a = 11.5113(15) Å, b = 20.250(3) Å, c = 21.810(4) Å, beta = 100.447(10) degrees, V = 5161.6(3) Å(3), and Z = 4 for 1, and a = 11.4334(16) Å, b = 20.243(2) Å, c = 21.805(3) Å, beta = 101.113(9) …

2016

The title compound, C32H48O8P2S2, was prepared by the nickel-catalyzed reaction of bis(5-bromothienyl)dipropoxybenzene and triisopropyl phosphite. The thiophene rings are inclined to the benzene ring by 14.6 (2) and 25.3 (3)°. One propyloxy group is disordered. Four hydrogen bonds connect the molecules, which are arranged in ribbons parallel to thebcplane.

Thiourea-Catalyzed Domino Michael–Mannich [3+2] Cycloadditions: A Strategy for the Asymmetric Synthesis of 3,3′-Pyrrolidinyl-dispirooxindoles

2017

The asymmetric synthesis of trifluoromethylated 3,3′-pyrrolidinyl-dispirooxindole derivatives with four contiguous stereogenic centers, including two vicinal spiro-stereocenters, is described. Employing a bifunctional thiourea catalyst, a domino Michael–Mannich [3+2] cycloaddition occurs readily between isatin ketimines and isatin-derived enoates with good yields and very high stereoselectivities, providing a direct entry to the title compounds of potential medical value.

Organocatalytic Asymmetric Synthesis of 2,3′-Connected Bis-Indolinones by Mannich Reactions of N-Acetylindolin-3-ones with Isatin N-Boc Ketimines

2017

A highly diastereo- and enantioselective Mannich reaction of N-acetylindolin-3-ones with isatin N-Boc ketimines to form 2,3′-connected bis-indolinones is developed employing a low loading of a readily available bifunctional thiourea catalyst. The asymmetric synthesis connects two indolinones via a vic-diamine unit and generates two neighboring stereocenters.

Solution, structural and photophysical aspects of substituent effects in the N^N ligand in [Ir(C^N)2(N^N)]+ complexes

2013

The syntheses and properties of a series of eleven new [Ir(ppy)2(N^N)][PF6] complexes (Hppy = 2-phenylpyridine) are reported. The N^N ligands are based on 2,2-bipyridine (bpy), substituted in the 6- or 5-positions with groups that are structurally and electronically diverse. All but two of the N^N ligands incorporate an aromatic ring, designed to facilitate intra-cation face-to-face π-interactions between the N^N and one [ppy](-) ligand. Within the set of ligands, 6-(3-tolyl)-2,2'-bipyridine (5), 4,6-bis(4-nitrophenyl)-2,2'-bipyridine (9), and 4,6-bis(3,4,5-trimethoxyphenyl)-2,2'-bipyridine (10) are new and their characterization includes single crystal structures of 9, and two polymorphs o…