Search results
Search for "coordination" in Full Text gives 560 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
Halide metathesis in overdrive: mechanochemical synthesis of a heterometallic group 1 allyl complex
Beilstein J. Org. Chem. 2019, 15, 1856–1863, doi:10.3762/bjoc.15.181
- ]∞ in low yield, which was crystallographically characterized as a coordination polymer that displays site disorder of the K+ and Cs+ ions. The entropic benefits of mixed Cs/K metal centers, but more importantly, the generation of multiple intermolecular K…CH3 and Cs…CH3 interactions in [CsKA'2
- coordination polymer. Within these experimental parameters, the general reaction in Equation 5 was examined. When n = 1, a reaction carried to completion would result in full metal exchange, with partial exchange the outcome for any larger values of n. The experimental protocol involved grinding various ratios
- noted that both [KA'] and CsI are insoluble in hexanes, and the grinding clearly initiated a reaction that occurred before the first hexanes extraction. Structure of [CsKA'2] Small blocks grown from hexanes were identified from a single crystal X-ray study as the coordination polymer [CsKA'2]∞. A
Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage
Beilstein J. Org. Chem. 2019, 15, 1612–1704, doi:10.3762/bjoc.15.165
- ash-supported Sc(OTf)3 for Friedal–Crafts acylation reaction, also the group of Fukuzawa has exploited Sc(OTf)3 in the synthesis of N-substituted 1,4-DHPs [26][82]. Enhancement in reactivity and selectivity of many reactions, ability to polarize bonds upon coordination and thus altering their
- aliphatic alkynes gave an optimal yield of the final product in the range of 50–78%. Successful formation of the product on application of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO: a radical scavenger) has nullified the probability of radical pathway. It was thought to be initiated by the coordination of
- dimethylamino- or nitro-substituted aldehydes did not result in the target compound that might be due to the deactivation caused by coordination of these groups with the catalyst. Metal–carbene complexes attracted the attention of organic chemists and have become an important branch of organometallic chemistry
Water inside β-cyclodextrin cavity: amount, stability and mechanism of binding
Beilstein J. Org. Chem. 2019, 15, 1592–1600, doi:10.3762/bjoc.15.163
- ), there is no consensus regarding the number of bound water molecules and the location of their coordination. A number of intriguing questions remain: (1) Which localities of the host’s macrocycle are the strongest attractors for the guest water molecules? (2) What are the stabilizing factors for the
- cyclodextrins. The results conflict mostly on the number of bound water molecules and the location of their coordination (inside/outside the host cavity). For β-CD, the experimentally established water content varies between 9 and 12 molecules: Sabadini et al. [9] have found 9.6 H2O/β-CD, Specogna 10 H2O [10
- the host molecule interior were modelled and energetically optimized (Figure 2). The hydration mechanism involving sequential binding of individual water molecules to α-CD [19] had been found to be the preferred fashion of coordination (as opposed to the bulk hydration by pre-formed water clusters
Different reactivity of phosphorylallenes under the action of Brønsted or Lewis acids: a crucial role of involvement of the P=O group in intra- or intermolecular interactions at the formation of cationic intermediates
Beilstein J. Org. Chem. 2019, 15, 1491–1504, doi:10.3762/bjoc.15.151
- calculations. Hydrolysis of these species resulted in the formation of phosphoryl-substituted allyl alcohols and 1,3-butadienes. A strong coordination of the oxygen of the P=O group with AlCl3 prevented the formation of cyclic 1,2-oxaphospholium ions and played a crucial role in the different reactivity of
- under the action of Brønsted or Lewis acids can be explained by involvement of the P=O group in intra- or intermolecular interactions at the formation of cationic intermediates. Strong coordination of Lewis acid AlCl3 with the P=O group completely deactivates it for further intramolecular reactions
2,3-Dibutoxynaphthalene-based tetralactam macrocycles for recognizing precious metal chloride complexes
Beilstein J. Org. Chem. 2019, 15, 1460–1467, doi:10.3762/bjoc.15.146
- sidewalls have been synthesized and characterized. The macrocycle containing isophthalamide bridges can bind square-planar chloride coordination complexes of gold(III), platinum(II), and palladium(II) in CDCl3, while the macrocycle with 2,6-pyridine dicarboxamide bridging units cannot. This may be due to
- macrocycle, which make it conformationally adaptive to maximize the binding affinities. In addition, the macrocycle shows fluorescent quenching when adding the chloride metal complexes in its solution and may be used as a fluorescent sensor for the detection of these coordination complexes. Keywords: host
- a pair of new tetralactam macrocycles with 2,3-dibutoxynaphthalene as the sidewalls. The tetralactam macrocycle with 2,6-pyridine dicarboxamide cannot bind square-planar chloride coordination complexes of gold(III), platinum(II), and palladium(II) in CDCl3, while the macrocycle containing
Introduction of an isoxazoline unit to the β-position of porphyrin via regioselective 1,3-dipolar cycloaddition reaction
Beilstein J. Org. Chem. 2019, 15, 1434–1440, doi:10.3762/bjoc.15.143
- confirmed the basic features of the NMR-derived structure. Furthermore, a pair of enantiomers of 3a presented in the crystal, which formed a dimeric complex through intermolecular coordination between the Zn2+ center and the carbonyl group of the second molecule. Keywords: dipolar cycloaddition
- nitrile oxide to approach the double bond from outside the macrocycle. In addition, a pair of enantiomers is revealed which formed a dimeric fashion with the help of the fifth coordination to the Zn2+ by the carbonyl group from the other molecule. The distance of Zn–O is found to be 2.37 Å, which is
Selective detection of DABCO using a supramolecular interconversion as fluorescence reporter
Beilstein J. Org. Chem. 2019, 15, 1371–1378, doi:10.3762/bjoc.15.137
- for supramolecular transformations [10], but rarely exploited strategically for specific functions. Elegant examples for the utility of dynamic interactions, in particular metal–ligand coordination, are thermally driven supramolecular devices, such as ball bearings [11][12], crank engines [13], rotors
- equipped with a trimethoxyphenyl group to furnish a fourth coordination to the copper(I) center and a sterically crowded duryl group to prevent homoleptic complexation, while lutidine 9 was selected to strengthen the HETPYP-I [33] (HETeroleptic PYridine and Phenanthroline complexation) coordination. In
- phenanthroline and very similar to the one experienced by the methyl protons (f2’-H) that are diagnostically shifted upfield to −0.63 ppm. Proton h-H is equally split into two sets reflecting the strong coordination of one methoxy group at an unsymmetrically coordinated copper(I) center. Similar to model system
Synthesis of dipolar molecular rotors as linkers for metal-organic frameworks
Beilstein J. Org. Chem. 2019, 15, 1331–1338, doi:10.3762/bjoc.15.132
- eventually also interfere with the coordination chemistry of MOF formation. We therefore considered benzoannelation with 1,3-dioxole (4) and 1,4-dioxane (5) units as electron-donating substituents instead of amino units and substitution with fluorine (1 and 2) to replace the cyano units. Almost free rotation
- benzodioxole and benzodioxane groups show an even stronger electron-donating effect than two methoxy substituents while simultaneously being less sterically demanding as rotors in coordination networks. According to our calculations dioxane derivative 5 exhibits a dipole moment exceeding 10 Debye, which is, to
Host–guest interactions between p-sulfonatocalix[4]arene and p-sulfonatothiacalix[4]arene and group IA, IIA and f-block metal cations: a DFT/SMD study
Beilstein J. Org. Chem. 2019, 15, 1321–1330, doi:10.3762/bjoc.15.131
- cations (La3+) a supramolecular approach with explicit solvent treatment has been applied in the study of the effect of metal hydration on the complexation process. The La3+ binding to the p-sulfonatocalix[4]arene host molecule (now in the metal’s second coordination shell) is still exergonic as evidenced
- of p-sulfonatocalix[4]arene and some inorganic and organic cations in aqueous solution [32]. The predicted ΔG value (relative Gibbs energy) of the complexation between the host calixarene molecule and hydrated La3+ cation (with an average coordination number of water molecules in the first hydration
- distorted for all metal cations hosted. The coordination number of Na+ and Rb+ cations in the complex is equal to 2; that of Mg2+, La3+, Sr2+ and Lu3+ is 4. In the [C[4]A−Na]3− and [C[4]A−Rb]3− complexes the metal is bound to one oxygen atom from 2 opposite SO3− groups. The Mg2+ ion also coordinates to 2
Synthesis of non-racemic 4-nitro-2-sulfonylbutan-1-ones via Ni(II)-catalyzed asymmetric Michael reaction of β-ketosulfones
Beilstein J. Org. Chem. 2019, 15, 1289–1297, doi:10.3762/bjoc.15.127
- by the coordination of β-ketosulfones through the oxygen atom of the sulfonyl group with Ni. For example, sulfoxide complexes with O-coordination of the corresponding ligands are widely known [57]. Although the donor properties of sulfones are lower than those of sulfoxides. Results and Discussion
- coordination to Ni. The complex B regenerates after the conjugate addition via transition state C and coordination of a new β-ketosulfone molecule to Ni. TS1 and TS2 are proposed by analogy with 1,3-dicarbonyl compounds [47] to rationalize the asymmetric induction. As illustrated in Scheme 2, β-ketosulfone is
Robust perfluorophenylboronic acid-catalyzed stereoselective synthesis of 2,3-unsaturated O-, C-, N- and S-linked glycosides
Beilstein J. Org. Chem. 2019, 15, 1275–1280, doi:10.3762/bjoc.15.125
- complete α-anomeric selectivity. The reactions using rhamnal 6a was completed at a much faster rate within 2 h at room temperature in comparison to glucals 1a and 4a which required ≈6 h at 40 °C to give the products. A plausible pathway of the reaction is proposed in Figure 4. Coordination of
Mechanochemical amorphization of chitin: impact of apparatus material on performance and contamination
Beilstein J. Org. Chem. 2019, 15, 1217–1225, doi:10.3762/bjoc.15.119
- doping effects in coordination polymers [40][41]. Yet a systematic study of quantitative contamination as a function of the medium has not been reported. Mechanochemistry is a promising strategy towards the activation, functionalization and deconstruction of biomass. Mechanochemical activation can
Self-assembly behaviors of perylene- and naphthalene-crown macrocycle conjugates in aqueous medium
Beilstein J. Org. Chem. 2019, 15, 1203–1209, doi:10.3762/bjoc.15.117
- through hydrogen bonding and metal ion coordination in nonpolar solvents [66][67][68]. Compared with NDI, PDI has more aromatic rings to generate stronger intermolecular π−π stacking, leading to molecular aggregates more easily, and these aggregates or supramolecular assemblies can give rise to desirable
Unexpected polymorphism during a catalyzed mechanochemical Knoevenagel condensation
Beilstein J. Org. Chem. 2019, 15, 1141–1148, doi:10.3762/bjoc.15.110
- materials [1]. Interest in these methods stems largely from the fact that they are efficient and more environmentally friendly as compared to traditional approaches [2][3]. Mechanochemistry is a well-established method for the synthesis of coordination polymers, the formation of cocrystals, and in C–C
Design of a double-decker coordination cage revisited to make new cages and exemplify ligand isomerism
Beilstein J. Org. Chem. 2019, 15, 1129–1140, doi:10.3762/bjoc.15.109
- of Pd(NO3)2 with L1 at a 1:2 or 3:4 ratios afforded [Pd(L1)2](NO3)2 (3a) and [(NO3)2@Pd3(L1)4](NO3)4 (4a), respectively. The encapsulated NO3– ions of 4a undergo anion exchange with halides (F–, Cl– and Br– but not with I–) to form [(X)2@Pd3(L1)4](NO3)4 5a–7a. The coordination behaviour of ligand L1
- : anion binding; double-decker cage; ligand isomerism; macrocycles; palladium; self-assembly; supramolecular; Introduction Coordination-driven self-assembly is a convenient strategy for the construction of supramolecules of desired dimensions via simple synthetic procedures. Well-defined metal–ligand
- coordination bonds enable the construction of designer targeted molecules with ease. The use of a palladium(II) component for complexation with a non-chelating bi- or polydentate ligand (usually N-donor ligands) is particularly advantageous for the construction of a variety of metallocages [1][2][3][4][5
Precious metal-free molecular machines for solar thermal energy storage
Beilstein J. Org. Chem. 2019, 15, 1096–1106, doi:10.3762/bjoc.15.106
- an additional intramolecular coordination bond between the “crowned” cation and the alkylsulfonate anchoring group which is only possible for the cis form [19]. The further studies by the same group of authors indicated that benzothiazolium styryl monoazacrown ether dyes have several main advantages
Halogen bonding and host–guest chemistry between N-alkylammonium resorcinarene halides, diiodoperfluorobutane and neutral guests
Beilstein J. Org. Chem. 2019, 15, 947–954, doi:10.3762/bjoc.15.91
- groups. Halides such as chloride and bromides can have high coordination numbers and as such can simultaneously be involved in both HB and XB to form ordered assemblies [32][33]. When the already hydrogen-bonded halides in NARXs are involved in XB, changes in the 1H NMR chemical shifts of the –OH and
Mechanochemistry of supramolecules
Beilstein J. Org. Chem. 2019, 15, 881–900, doi:10.3762/bjoc.15.86
- conditions through covalent approaches. By using common synthetic methodologies chemists are able to proficiently synthesize a variety of both natural and unnatural molecular scaffolds [4][5][6]. The era of supramolecular chemistry began with the introduction of coordination theory by Alfred Werner in 1893
- ][42]. Review Self-assembly During a metal-directed self-assembly process, the coordination geometry and coordination number at the metal center plays a central role in creating a self-assembled system. In 1962, Busch and coworker first demonstrated the concept of the template effect by choosing a
- supramolecular mechanochemistry is still in its infancy and needs significant improvement towards understanding and development of suitable methods [116][117][118]. A generalized overview of coordination-driven self-assembly. Examples of self-assembly or self-sorting and subsequent substitution. Synthesis of
Coordination chemistry and photoswitching of dinuclear macrocyclic cadmium-, nickel-, and zinc complexes containing azobenzene carboxylato co-ligands
Beilstein J. Org. Chem. 2019, 15, 840–851, doi:10.3762/bjoc.15.81
- each case two strong bands, one between 1620–1590 cm−1 and the other in the 1419–1395 cm−1 range. These bands can be assigned to the asymmetric (νas(RCO2−)) and symmetric stretching vibrations (νs(RCO2−)) of the carboxylato co-ligands [1]. Coordination is implied by the fact that the νas(RCO2
- groups dictate the coordination mode of the carboxylato ligand [13]. The average Cd–S, Cd–N and Cd–O distances at 2.670, 2.429, and 2.258 Å, respectively, are all very similar to those in 6. The Cd···Cd distance is at 3.405 Å. Again, π–π stacking of the azo-carboxylato co-ligand occurs, the shortest
- -H appears as a shoulder around 325 nm in 1. The slight red-shift may be a consequence of deprotonation and coordination to the Cd2+ ions. The spectrum of the deprotonated azoH– ion, for comparison, absorbs at 329 nm. The absorption bands above 310 nm can thus be attributed to the π–π* and n–π
Strong hyperconjugative interactions limit solvent and substituent influence on conformational equilibrium: the case of cis-2-halocyclohexylamines
Beilstein J. Org. Chem. 2019, 15, 818–829, doi:10.3762/bjoc.15.79
- to E.A.B. and R.R., and for the scholarship to C.S.F.; and the Coordination for the Improvement of Higher Education Personnel (CAPES) for the scholarships to C.B.F. and U.Z.M. Thanks also go to the São Paulo Research Foundation (FAPESP) (Grant 2016/24109-0) for the financial assistance and to the
Hoveyda–Grubbs catalysts with an N→Ru coordinate bond in a six-membered ring. Synthesis of stable, industrially scalable, highly efficient ruthenium metathesis catalysts and 2-vinylbenzylamine ligands as their precursors
Beilstein J. Org. Chem. 2019, 15, 769–779, doi:10.3762/bjoc.15.73
- catalysts 11a–c (Figure 3). In spite of the fact that we do not have the X-ray analysis for catalyst 11d, it is possible to assume that this complex should exhibit the longest coordination N→Ru bond (at least more than 2.30 Å). Interestingly, lower yields of stilbene from styrene in CH2Cl2 were obtained in
Selective benzylic C–H monooxygenation mediated by iodine oxides
Beilstein J. Org. Chem. 2019, 15, 602–609, doi:10.3762/bjoc.15.55
- substrate containing benzylic C–H bonds with acidic sodium dichromate or basic potassium permanganate [3][4][5]. More recent examples have used metal coordination complexes as catalysts for oxidation [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. Additionally, transition metal-based complexes are
Intramolecular cascade annulation triggered by rhodium(III)-catalyzed sequential C(sp2)–H activation and C(sp3)–H amination
Beilstein J. Org. Chem. 2019, 15, 571–576, doi:10.3762/bjoc.15.52
- pathways, and the one from 2a is the minor pathway. The main pathway is directly from 1a. Based on the above results, a plausible mechanism is proposed in Scheme 4 [31]. C(sp2)–H activation of acrylamide 1a, followed by subsequent intramolecular coordination of the alkyne gives intermediate B. Subsequent
Dirhodium(II)-catalyzed [3 + 2] cycloaddition of N-arylaminocyclopropane with alkyne derivatives
Beilstein J. Org. Chem. 2019, 15, 542–550, doi:10.3762/bjoc.15.48
- , entries 11–15). DCE was the best solvent, leading to a 67% yield of 3a. Due to axial coordination of dirhodium(II) for a strong coordination solvent, the yield of the resulting cycloaddition product in N,N-dimethylformamide decreased to only 33% (Table 1, entry 16). Regrettably, though Rh2(5S,R-MenPY)4 is
- yield of 40% (Table 3, entry 11). In addition, we also examined some alkynes containing heterocycles, such as 3-ethynylpyridine and 2-ethynylthiophene. Because the heteroatoms were axially tightly coordinated to the dirhodium(II) catalyst, coordination of the cyclopropylamine with the dirhodium(II
Synthesis and fluorescent properties of N(9)-alkylated 2-amino-6-triazolylpurines and 7-deazapurines
Beilstein J. Org. Chem. 2019, 15, 474–489, doi:10.3762/bjoc.15.41
- as cell imaging tools [31][32], biosensors and sensors for detection of heavy metals [33]. The tendency of these structures to form hydrogen bonds, to respond to medium effects (solvatochromism) [34] and to certain impurities (e.g., coordination complexes with metal ions) make these compound classes
Other Beilstein-Institut Open Science Activities
