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1.
The cationic complexes [(η6-arene)Ru(N,O-amino amide)X]Y (arene = p-cymene or indane; N,O-amino amide = (l)-proline amide or (l)-phenylalanine amide; X = Cl or I; Y = Cl, I or PF6) have been synthesised and fully characterized by spectroscopic and analytical methods. In several cases (1a, 3a, 4a, 4b, 5) the metal configuration has been definitively established by X-ray analysis on single crystal. The lability of the metal center in solution has been studied by 1H NMR and CD techniques. The highest configurational stability has been found in the complexes of the type [(η6-indane)Ru(N,O-proline amide)Cl]Y (4a,b). The complexes 1b, 2a-b, 3b, 4b and 5 are good precatalysts for the transfer hydrogenation of acetophenone in basic i-PrOH, with ee up to 76% at 30 °C. An ESI(+)-MS study of pre-catalytic solutions has provided useful information on the catalytic mechanism.  相似文献   

2.
The manganese cyclophane complex, [(η6-[32](1,3)cyclophane)Mn(CO)3][BF4] 2, was prepared by the reaction of [[32](1,3)cyclophane] 1 with Mn(CO)5FBF3. Reaction of 2 with NaBH3CN yielded the cyclohexadienyl manganese complex [(η5-6H-[32](1,3)cyclophane)Mn(CO)3] 3. Interestingly, treatment of 3 with Mn(CO)5FBF3 gave the bis-manganese complex (η65-6H-[32](1,3)cyclophane)[Mn(CO)3]2[BF4] 4. When NaBH3CN was treated with 4, [(η55-6H,6H-[32](1,3)cyclophane)Mn(CO)3] 5 was isolated as yellow crystals. The structure of compounds 2 and 3 were determined by single-crystal X-ray crystallography.  相似文献   

3.
The crystal structures of the two derivatives of aminomethane-1,1-diphosphonic acid with morpholinyl- (1) and thiomorpholinyl- (2) side chains were determined by single crystal X-ray diffraction and discussed with respect to molecular geometry and solid state organization. The protonation equilibria, solution behavior and complex-formation equilibria in solutions of 1 and 2 with the Zn(II), Mg(II) and Ca(II) ions were studied by means of NMR, pH-potentiometry and ESI-MS methods.As the pK(NH+) protonation constants of 1 and 2 are high (11.65 and 11.91, respectively) two different approaches were used to evaluate the pH-potentiometric data. The first approach disregarded the proton-dissociation from the NH+ group. In the second one, all the pKa values were considered in the M(II):ligand formation equilibria. For 1, the accuracy of the pK(NH+) determination was shown to be sufficient to calculate reliable stability constants of metal complexes with the use of both approaches. For 2, only approach neglecting the pK(NH+) protonation constant was shown to be correct.The studied acids form dinuclear, [M2L3Hx], [M2L2Hx] and mononuclear MLHx and ML2Hx complexes with different degree of ligand protonation. Tendency to undergo some oligomerization with the increase in the metal and ligand concentration was demonstrated for the [CaLH] complex of 1 and 2. As far as 1 and 2 remain protonated, the Zn(II), Mg(II) and Ca(II) ions are coordinated exclusively through oxygen atoms of the phosphonate groups. The metal promoted proton dissociation from the NH+ ring atom takes place in alkaline pH.  相似文献   

4.
Jian-Wei Xu  Yee-Hing Lai 《Tetrahedron》2005,61(9):2431-2440
The conformational behavior of a series of crown-fused dithia[n.3.3](1,2,6)cyclophanes (126-CPs) and dithia[n.3.3](1,3,5)cyclophanes (135-CPs) was investigated by variable-temperature 1H and 13C NMR spectroscopy, X-ray crystallography and density functional theory (DFT) calculations. Single crystal X-ray structure analysis showed that two thia-bridges in 126-CPs adopted a pseudochair-pseudochair (cc) conformation and the cyclophane decks underwent a ring-tilting motion in the case of [10.3.3](1,2,6)cyclophane (1a). In contrast, the thia-bridges in 135-CPs took both cc and pseudoboat-pseudochair (bc) conformations, and the ring-tilting process was also found in [10.3.3](1,3,5)cyclophane (2a). Variable temperature 1H NMR study revealed that there was no wobbling-motion for two thia-bridges in 126-CPs while thia-bridges in 135-CPs experienced a wobbling-process with a conformational barrier of 9.21 and 8.80 kcal mol−1, respectively, for 2a and [13.3.3](1,3,5)cyclophane (2b). DFT calculations for the two cyclophanes series revealed that 126-CPs preferred a cc conformation which was consistent with the experimental observation; similarly, 135-CPs took a preferential cc conformation, agreeing with 2a having a predominant cc conformer (cc:bc ratio=70:30), but not 2b having a predominant bc conformer (cc:bc ratio=15:85) in the solid state.  相似文献   

5.
Shin-ichi Naya 《Tetrahedron》2005,61(21):4919-4930
Novel photo-induced oxidative cyclization was accomplished to synthesize areno[b]pyrimido[5,4-e]pyran-2,4(1,3H)-dionylium ions 13a-c+·ClO4. Furthermore, 13a-c+·BF4 and their phenyl-substituted derivatives 19a,b+·BF4 were alternatively synthesized by the reaction of salicylaldehyde and its naphthyl derivatives with barbituric acids and subsequent treatment with aq. HBF4. Structural characteristics of 13a-c+ and 19a,b+ were clarified on inspection of the UV-vis and NMR spectral data as well as X-ray crystal analyses. The electrochemical properties were studied by the CV measurement. In a search for reactivity, reactions of 13a-c+·BF4 with some nucleophiles, hydride, benzylamine, and H2O, were also carried out. The photo-induced autorecycling oxidation reactions of 13a-c+·BF4 toward some amines under aerobic conditions were carried out to give the corresponding imines (isolated by converting to the corresponding 2,4-dinitrophenylhydrazones) in 643-3600% yield (recycling number of 13a-c+·BF4: 6.4-36.0).  相似文献   

6.
Bismuth(III) bis(trifluoromethanesulfonyl)amide (Bi(NTf2)3, 3) has been prepared from the reaction of protiodemetallation of tri-p-tolylbismuth by a stoichiometric amount of bis(trifluoromethanesulfonyl)amine (1). The intermediates BiPh3−n(NTf2)n (n=2 (4), 1 (5)) resulting from the reaction of 1 with triphenylbismuth have also been isolated. The amide 3 was able to catalyze the benzoylation and the benzenesulfonylation of toluene.  相似文献   

7.
The synthesis and binding properties of resorcinarene-based cavitands functionalized with N-acylthiourea moieties towards different cations are described. Extraction studies with metal (Pb2+, Cu2+, Ag+, Hg2+, Cd2+, Eu3+, Fe3+, K+, Na+, and Ca2+) picrates and the incorporation in ion selective electrodes (ISEs), show that there is more than a 40% increase of the Ag+ extraction for N-acylthiourea ionophores (2, 3, and 8) in comparison with N-benzoyl-N′-benzylthiourea (9). Ionophore 8, which has a C3 chain between the platform and the ionophore, extracts two times more Cu2+ than the more rigid one (2). Stoichiometry studies showed for ligand 2 a ligand/metal ratio of 1:1, while for model compound 9 a ratio of 1:2 was found. Potentiometric studies of electrodes revealed that cavitands 2, 3, and 8 induce a significantly different selectivity pattern compared to the cation-exchanger used, as well as model compound 9. Especially, a considerable enhancement of the selectivity towards Ag+ and Pb2+ over K+, Ca2+, and Na2+ ions was observed.  相似文献   

8.
The present work illustrates the versatile coordination modes of the amide-based ligands towards copper(II) ion. The reaction of the deprotonated form of the ligand, [L1]2− with CuCl2 affords a linear trinuclear complex, [Cu3(L1)2(Cl)2(H2O)] (1) which has been characterized thoroughly including single crystal structure analysis. The structure of 1 shows that one of the arm of the flexible ligand flips to coordinate second copper(II) centre, resulting in the formation of a trinuclear complex. On the other hand, ligand H2L2 in its deprotonated form reacts with Cu(II) ion to give complex 2 with general formula, [Cu(L2)]n (2). The crystal structure of the complex 2 shows that each copper is square-pyramidal with 5th coordination coming from the O-atom of the amide group from a neighbouring complex. This results in the generation of an one-dimensional zig-zag chain. The variable temperature magnetic measurements of the complexes, 1 and 2 show that while Cu ions in the former are antiferromagnetically coupled (J = −110.34 cm−1), a weak ferromagnetic interaction (J = +3.08 cm−1) exists in the later. A rationale, based on the orbital overlap from the copper ions and associated ligands, is provided for the observed magnetic coupling between the copper ions.  相似文献   

9.
A new series of DTPA-N,N″-bis(amide) ligands functionalized by alkyl carboxylates on the amide side-arms (1a1l) and their Gd(III) complexes of the type [Gd(1)(H2O)] · xH2O (2a2l) were synthesized and characterized by analytical and spectroscopic techniques. Potentiality of 2a2l as contrast agent for magnetic resonance imaging (MRI CA) was investigated by measuring some relevant physicochemical properties such as (i) the protonation constants of 1a1l, (ii) thermodynamic and conditional stability constants of 2a2l, (iii) the selectivity (pGd) of 1a1l for the Gd(III) ion over the endogenous metal ions such as Zn(II), Ca(II), and Cu(II), and (iv) the relaxivities (R1 and R2) of 2a2l in aqueous and aqueous HP-β-CD solutions. Comparative studies reveal that most of new Gd(III) complexes show enhanced thermodynamic stability and selectivity as compared with those of [Gd(DTPA-BMA)(H2O)] (DTPA-BMA = N,N″-di(methylcarbamoylmethyl)diethylenetriamine-N,N′,N″-triacetate). Also enhanced with 1a1l (except 1f and 1h) is affinity for Gd(III) as compared with [DTPA-BMA]3− under physiological conditions. The relaxivities (R1 and R2) of aqueous solutions of 2a2l, on the other hand, drop significantly as compared with [Gd(DTPA-BMA)(H2O)] although they increase dramatically (6–10 fold) in aqueous hydroxypropyl-β-cyclodextrin (HP-β-CD) solutions.  相似文献   

10.
Shin-ichi Naya 《Tetrahedron》2004,60(41):9139-9148
Ring transformation of 7,9-dimethylcyclohepta[b]pyrimido[5,4-d]furan- 8(7H),10(9H)-dionylium tetrafluoroborate 4+·BF4 to 7,9-dimethylcyclohepta[b]pyrimido[5,4-d]pyrrrole-8(7H),10(9H)-dionylium tetrafluoroborate 6a-d+·BF4 consists of the reaction of 4+·BF4 with amines and subsequent exchange of the counter-ion using aq. HBF4. Reactions of 4+·BF4 with aniline and 4-substituted anilines afforded the corresponding pyrrole derivatives 6a-c+·BF4 directly in good yields. On the other hand, reaction of 4+·BF4 with benzylamine gave the troponeimine intermediate 9, which was not converted to 6d+·BF4 and reverted to 4+·BF4 by adding HBF4; however, it was converted to 6d+·BF4 upon treatment with (COCl)2 or SOCl2, followed by exchange of the counter-ion. In a search for the characteristics of 9, inspection and comparison of the X-ray crystal analyses, NMR and UV-vis spectra, and CV measurement of 9 and N,N-disubstituted troponeimine derivatives 12 were carried out to suggest the remarkable structure of 12 having ionic C-O bonding between the imine-carbon atom and the oxygen atom of the barbituric acid moiety in the solid state. Thus, characteristics of 9 were ascribed to the sterically hindered and favorable conformation of N-protonated troponeimine intermediates. Furthermore, novel photo-induced oxidation reactions of a series of 4+·BF4, 5+·BF4, and 6a,e+·BF4 towards some amines under aerobic conditions were carried out to give the corresponding imines in 455-8362% yields [based on compounds 4+, 5+, and 6a,e+], suggesting the oxidation reaction occurs in an autorecycling process. Mechanistic aspects of the amine-oxidation reaction are also postulated.  相似文献   

11.
Yanlong Kang 《Tetrahedron》2004,60(49):11219-11225
The use of simple calix[4]arenes 1a,b for NO2/N2O4 sensing and conversion is demonstrated, both in solution and in the solid state. Upon reacting with these gases, compounds 1a,b encapsulate reactive NO+ cations within their cavities with the formation of deeply colored (λmax∼570 nm) charge-transfer complexes 2a,b. Further functionalization of the calix[4]arene platform is reported for attachment to solid supports. Polymer-supported calixarene material 3 was prepared, which reversibly traps NO2/N2O4 with the formation of nitrosonium storing polymer 4. Material 4 was effectively used for nitrosation of amides.  相似文献   

12.
Takashi Okitsu 《Tetrahedron》2005,61(38):9180-9187
Treatment of N-vinyl-α,β-unsaturated amides 1a-h with Bu3SnH and a catalytic amount of AIBN in boiling benzene caused 5-exo cyclization of allylic O-stannyl ketyl radicals generated by addition of Bu3Sn· on the amide-oxygen atoms to provide γ-lactams 2a-h after acidic workup. When enamide 1d was treated with Bu3SnH in the presence of AIBN followed by aldehydes 3a-d, sequential radical cyclization and aldol reactions occurred to afford anti-adducts 4a-d and syn-adducts 5a,b.  相似文献   

13.
Double O-H insertion reactions of cyclic diazo amides 1 and dihydroxy compounds 2 in the presence of rhodium(II) acetate catalyst have been achieved, which ultimately led to the facile synthesis of prototype bis(3-oxy-1,3-dihydro-2H-indol-2-one) systems. This facile double O-H insertion reaction protocol was successfully applied to synthesize several C2-symmetric macrocycles having oxindole units incorporated with complete diastereoselectivity.  相似文献   

14.
Synthesis of various bridged nicotinates 6 having [n](2,5)pyridinophane skeletons (n=8-14) was accomplished by the unique pyridine-formation reaction of methyl propiolate with a series of formyl-substituted (vinylimino)phosphoranes 5, which were prepared from the corresponding cycloalkanones 1 via Vilsmeier-Haack formylation giving chloro-substituted cycloalkenals 2, their thermal and photochemical transformation to formyl azirines 4, and the following ring-opening reactions with triphenylphosphine. The HPLC analysis of [11](2,5)pyridinophane derivatives, (Sp,S)-14 and (Rp,S)-14, showed that these diastereomers rapidly epimerize themselves at room temperature and that their planar-chirality was thermodynamically less stable as compared to the corresponding [11](2,5)cyclophane systems.  相似文献   

15.
The inhibition of hydrogen bond formation in the recognition of adipic acid by a new diamide receptor 1 having a pyridine-N-oxide and a simple pyridine ring adjacent to the amide moieties is observed. NMR studies show binding by the pyridine amide group in 1, which demonstrates the discrimination in hydrogen bonding between the carboxyls and an amide adjacent to pyridine versus another adjacent to the pyridine N-oxide. This specific inhibition of hydrogen bonding to a carboxyl group by the two different amides in 1 is corroborated by the NMR binding studies of 1 with propionic acid.  相似文献   

16.
Fluorescence of the phenolate anion (3(O)) and the amide anion (5(N)) of coelenteramide analogues in ion pairs with various counter cations was systematically investigated to elucidate the ionic structure of the light emitter in the bioluminescence of the calcium-activated photoproteins aequorin and obelin. The fluorescent properties of 3(O) in an ion pair with a conjugate acid of an organic base (BASE-H+) were varied depending on the structural variation of the ion pair and the solvent polarity. In particular, the fluorescence of 3(O) in the ion pair with the conjugate acid of n-butylamine (NBA-H+) indicates that the singlet-excited state of 3(O) (13(O)−∗) and NBA-H+ make a contact ion pair in which the fluorescence emission maxima of 3(O) is sensitive to the solvent polarity and the fluorescence quantum yields of 3(O) increase in a less polar solvent. The results also confirm that 13(O)−∗ is a twisted intramolecular charge transfer state. By contrast, the fluorescence of 5(N) in an ion pair depends little on the BASE-H+ or the solvent polarity. Based on these results, we conclude that the light emitter in aequorin and obelin bioluminescences is the singlet-excited state of coelenteramide phenolate anion 2(O) (12(O)−∗) in a contact ion pair with an imidazolium side chain of a histidine residue, which is located at the less polar active sites of the photoproteins. We also propose a mechanism for the bioluminescence reaction, including the chemiexcitation process to give 12(O)−∗.  相似文献   

17.
Oxa-bridged cyclophanes 4/6 and 8/10 featuring thieno[2,3-b]thiophene ring and binol or bis-naphthol have been synthesized. The structures are assigned by 2D NMR data and the identity of 4 is also independently established by a single X-ray crystallography. From dynamic NMR analysis, the Arrhenius energy of activation ΔG# for bridge inversions in 4 and 6 was calculated to be 15.3 and 12.9 kcal/mol, respectively. A higher ΔG# for 4, relative to the ester free 6 is attributable to the steric compression stemming from C2/C5 ester substituents to the bridge inversion processes. While the methylene bridges undergo inversion in 4 and 6, the naphthyl-naphthyl pseudo-rotation appears to be restricted even at higher temperatures. This is supported by retention of the optical purity of the chiral (−) 4 under thermal condition. For the case of bis-naphthol cyclophane 8, we observed the flipping of both the -OCH2- and the naphthyl-CH2-naphthyl bridges with ΔG# of ca. 11.4 kcal/mol. However, the ester free cyclophane 10 remained conformationally mobile even at −55 °C and its ΔG# was assumed to be <11.4 kcal/mol. The presence of an extra -CH2- linker in bis-naphthol cyclophanes 8/10 renders them relatively more conformationally mobile compared to binol cyclophanes 4/6, possessing a rigid naphthyl-naphthyl geometry.  相似文献   

18.
2-(N-aryliminomethyl)pyrrole precursors (2,6-R2-C6H3-NCH-2-C4H3NH) (R = Me, IH; R = iPr, IIH) were prepared and transformed into their corresponding sodium salts (Na+I and Na+II) by treatment with NaH. Both salts readily react with [NiBr2(DME)] (DME = 1,2-dimethoxyethane) to give the respective bis{2-(N-arylimino-κN-methyl)pyrrolide-κN}nickel(II) complexes (1, 2) in almost quantitative yields. The oxidative addition of IH to [Ni(COD)2] (COD = 1,5-cyclooctadiene) results in the formation of 3, which is a mono(iminomethylpyrrolide)-η3-(cyclic-allyl)-type organonickel(II) complex. The crystal structure of compound 1 has been established by X-ray diffraction studies.  相似文献   

19.
A new series of titanium(IV) and zirconium(IV) amides have been prepared from the reaction between M(NMe2)4 (M = Ti, Zr) and C2-symmetric ligands, (R)-2,2′-bis(pyridin-2-ylmethylamino)-6,6′-dimethyl-1,1′-biphenyl (2H2), (R)-2,2′-bis(pyrrol-2-ylmethyleneamino)-6,6′-dimethyl-1,1′-biphenyl (3H2), (R)-2,2′-bis(diphenylphosphinoylamino)-6,6′-dimethyl-1,1′-biphenyl (4H2), (R)-2,2′-bis(methanesulphonylamino)-6,6′-dimethyl-1,1′-biphenyl (5H2), (R)-2,2′-bis(p-toluenesulphonylamino)-6,6′-dimethyl-1,1′-biphenyl (6H2), and C1-symmetric ligands, (R)-2-(diphenylthiophosphoramino)-2′-(dimethylamino)-6,6′-dimethyl-1,1′-biphenyl (7H) and (R)-2-(pyridin-2-ylamino)-2′-(dimethylamino)-6,6′-dimethyl-1,1′-biphenyl (8H), which are derived from (R)-2,2′-diamino-6,6′-dimethyl-1,1′-biphenyl. Treatment of M(NMe2)4 with 1 equiv. of N4-ligand, 2H2 or 3H2 gives, after recrystallization from an n-hexane solution, the chiral zirconium amides (2)Zr(NMe2)2 (9), (3)Zr(NMe2)2 (11), and titanium amide (3)Ti(NMe2)2 (10), respectively, in good yields. Reaction of Zr(NMe2)4 with 1 equiv of diphenylphosphoramide 4H2 affords the chiral zirconium amide (4)Zr(NMe2)2 (12) in 85% yield. Under similar reaction conditions, treatment of Ti(NMe2)4 with 1 equiv. of sulphonylamide ligand, 5H2 or 6H2 gives, after recrystallization from a toluene solution, the chiral titanium amides (5)Ti(NMe2)2·0.5C7H8 (13·0.5C7H8) and (6)Ti(NMe2)2 (15), respectively, in good yields, while reaction of Zr(NMe2)4 with 1 equiv. of 5H2 or 6H2 gives the bis-ligated complexes, (5)2Zr (14) and (6)2Zr (16). Treatment of M(NMe2)4 with 2 equiv. of diphenylthiophosphoramide ligand 7H or N3-ligand 8H gives, after recrystallization from a benzene solution, the bis-ligated chiral zirconium amides (7)2Zr(NMe2)2 (17) and (8)2Zr(NMe2)2 (19), and bis-ligated chiral titanium amide (8)2Ti(NMe2)2 (18), respectively, in good yields. All new compounds have been characterized by various spectroscopic techniques, and elemental analyses. The solid-state structures of complexes 10, 12, 13, and 17-19 have further been confirmed by X-ray diffraction analyses. The zirconium amides are active catalysts for the asymmetric hydroamination/cyclization of aminoalkenes, affording cyclic amines in good to excellent yields with moderate ee values, while the titanium amides are not.  相似文献   

20.
For N-(thio)phosphorylthioureas of the common formula RC(S)NHP(X)(OiPr)2HLI (R = N-(4′-aminobenzo-15-crown-5), X = S), HLII (R = N-(4′-aminobenzo-15-crown-5), X = O), HLIII (R = PhNH, X = S), HLIV (R = PhNH, X = O), and (N,N′-bis-[C(S)NHP(S)(OiPr)2]2-1,10-diaza-18-crown-6) H2LV, salts LiLI,III,IV, NaLIIV, KLIIVM2LV (M = Li+, Na+, K+), Ba(LI,III,IV)2, and BaLV have been synthesized and investigated. Compounds NaLI,II quantitatively drop out as a deposit in ethanol medium, allowing the separation of Na+ and K+ cations. This effect is not displayed for the other compounds. The crystal structures of HLIII and the solvate of the composition [K(Me2CO)LIII] have been investigated by X-ray crystallography.  相似文献   

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