1H NMR and Calorimetric Studies of the Inclusion of Trimethylammonium Cations into Water Soluble Calixresorcinarenes

Abstract

The complexation of tetramethylammonium (TEMA), benzyltrimethylammonium (BTMA), p-nitrobenzyltrimethylammonium (BTMAN) and N, N, N-trimethylanilinium (TMA) by the tetrasulphonate derivative of the resorcinol cyclic tetramer (1), was studied in aqueous solution by ¹H NMR and calorimetry. Host 1 specifically recognizes the—N⁺ (CH₃)₃ group of TEMA, BTMA and BTMAN, whereas it binds TMA unselectively; TMA is included both via the charged group and the aromatic moiety. The binding constants of all four guests with 1, as determined by both ¹H NMR and calorimetric titrations, show that all inclusion processes are almost equally stabilised.

ΔHΔ and ΔSΔ values, determined by direct calorimetry, reveal specific interactions that are not expressed in the ΔGΔ terms and indicate that we are dealing with “non-classical hydrophobic effects”. The effects of the structural, conformational and electronic properties of the guests on the forces driving the inclusion processes are discussed.     

Inclusion complexes of 2-phenoxyethanol and alkoxyethanols in cyclodextrins: an 1H NMR study

The association in aqueous solutions of small amphiphilic molecules [2-phenoxyethanol, PhE₁, and some α-n-alkyl-ω-hydroxyoligo(oxiethylenes], C₄E₁, C₄E₂ and C₆E₂) with β-cyclodextrin (βCD), heptakis(2,6-di-O-methyl)-β-cyclodextrin (DIMEB) and heptakis(2,3,6-tri-O-methyl)-β-cyclodextrin (TRIMEB) was investigated by ¹H NMR spectroscopy. The upfield shifts observed for the H3 and H5 NMR signals due to anisotropic shielding confirm that the host–guest associations are of inclusion type. The stoichiometries and the apparent inclusion constants, K _app, were determined by ¹H NMR spectroscopy using the H5 and H3 signals. The relative differences in the K _app values for βCD inclusion complexes seem to reflect the hydrophobic/hydrophilic balance of the guests. The K _app values for the PhE₁ inclusion complexes can be related to the degree of methylation and hydrophobicity variation within the considered hosts. In addition, a comparative study between βCD and TRIMEB inclusion complexes using 2D ROESY (Rotating-frame Overhauser Enhancement SpectroscopY) NMR spectra provides structural features for these complexes which are inaccessible by other experimental methods.     

Spectroscopic characterization and <Emphasis Type="Italic">Ab initio</Emphasis> calculations of new diazaphosphole and diazaphosphorinane

Phosphoryl chloride is used as a starting material to synthesize new diazaphosphole, (1) and diazaphosphorinane, (2). The products are characterized by ¹H, ¹³C, ³¹P NMR, and IR spectroscopy. A high value ² J(PNH) = 17.0 Hz, 17.2 Hz is measured for two non-equivalent NH protons of endocyclic nitrogen atoms in compound 1, while it greatly decreases to 4.5 Hz in 2. Also, great amounts are obtained for two ² J(P,C) as well as two ³ J(P,C) in the ¹³C NMR spectrum of 1, but they are zero in 2. Here, the effect of ring strain and ring size on the structural and spectroscopic parameters is observed. The ³¹P NMR spectra reveal that δ(³¹P) of compound 1 is far much more downfield (12.63 ppm) relative to that of compound 2 (−10.39 ppm). Furthermore, ab initio quantum chemical calculations are performed to optimize the structures of these molecules by density functional theory (B3LYP) and Hartree-Fock (HF) methods, using the standard 6−31+G** basis set. The stabilization energies are calculated by the equation ΔE _{stabilization} = E _molecule − ΣE _i , where i = atom. To obtain the atomic hybridizations, NBO computations are made at the B3LYP/6−31+G** level. Also, by NMR calculations the ¹H, ¹³C, ³¹P chemical shifts are obtained and compared with the experimental ones.     

Cooperative molecular recognition of dyes by two bis(β-cyclodextrin)s with aromatic,sulfur-containing,diamine tethers

The molecular binding behavior of two bis(β-cyclodextrin (CD))s, that is, 4,4′-diaminodiphenylsulfone-bridged bis(β-CD) 2 and 4,4′-diaminodiphenyldisulfide-bridged bis(β-CD) 3 with some representative organic dyes, i.e., acridine red (AR), neutral red (NR), ammonium 8-anilino-1-naphthalenesulfonate (ANS), sodium 2-(p-toluidinyl)naphthalenesulfonate (TNS), rhodamine B (RhB), and brilliant green (BG), has been investigated at 25 °C in phosphate buffer (pH 7.20) by ultraviolet, fluorescence and 2D NMR spectroscopy. The fluorescence of ANS, TNS, AR, and NR are enhanced, whereas that of RhB is quenched, by inclusion complexation with both host compounds. The results obtained show bridged bis(β-CD)s 2 and 3 with dye guests give higher complex stability constants (K _S) than those of the native β-CD 1, through cooperative binding of two hydrophobic CD cavities with one guest. In addition, the K _S values of all guests with host 3 are much larger than those with 2 except for NR as guest. The 2D ¹H NOESY spectrum of host 3 and RhB was acquired to confirm the cooperative binding mode. The molecular binding ability of dyes by hosts 1–3 are discussed from the viewpoint of the size and shape-fitting relationship between host and guest.     

Geometric Isomers of Cobalt(II) and Cobalt(III) Picolinates in Solution

Cobalt complexes with picolinic acid (HPic), namely, [Co^II(Pic)₂(H₂O)₂] · 2H₂O (I) and [Co^III(Pic)₃] · H₂O (II) are studied using ¹H and ¹³C NMR spectroscopy. Compound Iexists in solution as three geometric isomers, namely, trans-trans-trans, cis-trans-cis, and trans-cis-cis(molar ratio 4 : 2 : 1, respectively). According to ¹³C NMR data, compound IIexists in solution as a mer-isomer. The relative energy stability of the isomers was estimated using the molecular mechanics method.     

Preparation,Structure and Thermal Decomposition of Cu(II) Complexes with 2-Chloro- and 2,3-Dichlorobenzoic Acids and Imidazole

The reaction products of Cu(II) 2-chlorobenzoate and imidazole (1), and of Cu(II) 2,3-dichlorobenzoate and imidazole (2) formulated as CuL'₂·3imd and CuL"·3imd (L' = C₇H₄ClO₂, L" = C₇H₄Cl₂O₂ ^?, imd = imidazole), were prepared and characterized by means of structural and spectroscopic measurements and thermochemical properties. The blue (1) and green (2) compounds crystallize in the monoclinic system with space group C2/c, cell parameters a = 20.753(4), b = 8.414(2), c = 14.429(3) Å, β = 90.15(3)°, V = 2519.5(9) &Aringsup3;, Z = 4 for (1) and a = 21.335(4), b = 8.417(2), c = 15.030(3) Å, β = 94.11(3)°, V = 2692.1(10) &Aringsup3;, Z = 4 for (2). The complexes decompose at 483 K.     

Synthesis, Structure, and 31P NMR of Sulfur/Oxygen-Bridged Incomplete Cubane-Type Molybdenum and Tungsten Clusters with Triphenylphosphine Ligands

Sulfur/oxygen-bridged incomplete cubane-type triphenylphosphine molybdenum and tungsten-clusters [Mo₃S₄Cl₄(H₂O)₂(PPh₃)₃]·3THF (1A), [Mo₃S₄Cl₄(H₂O)₂(PPh₃)₃]·2THF (2A), [Mo₃OS₃Cl₄(H₂O)₂(PPh₃)₃]·2THF (1B), and [W₃S₄Cl₄(H₂O)₂(PPh₃)₃]·2THF (1C) were prepared from the corresponding aqua clusters and PPh₃ in THF/MeOH. On recrystallization from THF, procedures with and without addition of hexane to the solution gave 1A and 2A, respectively, while the procedures gave no effect on the formation of 1B and 1C. Crystallographic results obtained are as follows: 1A: monoclinic, P2₁/n, a=17.141(4) Å, b=22.579(5) Å, c=19.069(4) Å, =96.18(2)°, V=7337(3) ų, Z=4, R(R _w)=0.078(0.102); 1C: monoclinic, P2 ₁/c, a=12.635(1) Å, b=20.216(4) Å, c=27.815(3) Å, =96.16(1)°, V=7062(2) ų, Z=4, R(R _w)=0.071(0.083). If the phenyl groups are ignored, the molecule [Mo₃S₄Cl₄(H₂O)₂(PPh₃)₃] in 2A has idealized CS symmetry with the mirror plane perpendicular to the plane determined by the metal atoms, while the molecule in 1A does not have the symmetry. The tungsten compound 1C is isomorphous with the molybdenum compound 2A. ³¹P NMR spectra of 1A, 2A, and 1C were obtained and compared with similar clusters with dmpe (1,2-bis(dimethylphosphino)ethane) ligands.     

Chlorodiphenyltin(IV) and triphenyltin(IV) complexes of N-alkylated 2-amino-1-cyclopentene-1-carbodithioic acids: synthesis, spectroscopic characterization and X-ray studies

Four new complexes, [Ph₃Sn(isopropylACDA)] (1), [Ph₂SnCl(isopropylACDA)] (2), [Ph₃Sn(secbutylACDA)] (3), and [Ph₂SnCl(secbutylACDA)] (4), have been prepared from reaction between N-alkylated 2-amino-1-cyclopentene-1-carbodithioic acids (ACDA) with Ph₂SnCl₂ and Ph₃SnCl in 1:1 ratio. All complexes are characterized by FTIR, multinuclear NMR (¹H, ¹³C, and ¹¹⁹Sn) and mass spectrometry. In all complexes, the S–H proton has been removed and coordination takes place through the carbodithioate moiety. The ¹¹⁹Sn NMR data are consistent with five coordination of tin atom in solution. Complexes 2, 3, and 4 have also been confirmed by single X-ray crystallography. All three crystals are triclinic with space group P − 1. In complexes 2 and 4, the geometry around tin atom is distorted trigonal bipyramidal while in 3 the geometry is in between distorted tetrahedral and trigonal bipyramid. In all three structures, ligands are asymmetrically coordinated to tin atom. In addition, crystal structures are further stabilized by N–H···S hydrogen bonding.     

Structural studies of seven homoisoflavonoids, six thiohomoisoflavonoids, and four structurally related compounds

¹H and ¹³C NMR chemical shifts have been determined and assigned based on PFG ¹H, ¹³C HMQC, and HMBC experiments for 3-(4′-X-benzyl)-4-chromenones (Ia, X = CN and Ib, X = NO₂), 3-(4′-X-benzyl)-4-thiochromenones (IIa, X = Cl and IIb, X = Br), (E)-3-(4′-X-benzylidene)-4-chromanones (IIIa–IIIe, X = OCH₃, CH₃, Cl, N(CH₃)₂, Br), (Z)-3-(4′-X-benzylidene)4-thiochromanones (IVa–IVd, X = Cl, Br, F, OCH₃), 2-benzyl-1,2,3,4-tetrahydro-1-naphthol (V), 2-benzyl- and (E)-2-benzylidene-1-tetralones (VI and VII), and (E)-2-benzylidene-1-benzosuberol (VIII). The crystal structures have been determined for the following seven compounds: derivatives of 4-chromanones (IIIa–IIId), 1-tetrahydronaphtol (V), and 1-tetralones (VI and VII). The molecular features and intermolecular interactions in crystal state have been discussed.     

Ruthenium Tris-pyrazolylborate Complexes XVII [1]. Structure and Bonding in a Series of Ruthenium Hydrido-tris-(pyrazolyl)-borate Cyclooctadiene Complexes

Summary.  The complexes RuTp(cod)X (X = Br⁻ (2), I⁻ (3), CN⁻ (4)) have been obtained by the reaction of RuTp(cod)Cl (1) with KX in boiling MeOH in high yields. The cationic complexes [RuTp(cod)(py)]⁺ (5), [RuTp(cod)(dmso)]⁺ (6), and [RuTp(cod)(CH₃CN)]⁺ (7) were prepared as the CF₃SO₃ ⁻ salts by reacting 1 with 1 equivalent of AgCF₃SO₃ in the presence of the respective co-ligand in CH₂Cl₂. The crystal structures of 1, 3, 4, 5, 6, and 7 are reported. Structural features are discussed in conjunction with ¹H, ¹³C, and ¹⁵N NMR spectroscopic data revealing a linear correlation of ¹⁵N chemical shifts and Ru-N (trans to X(L)) bond distances. Received August 31, 2000. Accepted (revised) October 23, 2000     

p-tert-Butyldihomooxacalix[4]arene/p-tert-Butylcalix[4]arene: Transition and Heavy Metal Cation Extraction and Transport Studies by Ketone and Ester Derivatives

The binding properties of two phenylketones (2a and 3a) and two ethylesters (2b and {3b) derived from p-tert-butyldihomooxacalix[4]arene or from p-tert-butylcalix[4]arene, in the cone conformation, towards transition (Ag⁺, Ni²⁺, Cu²⁺, Co²⁺, Zn²⁺, Fe²⁺ and Mn²⁺) and heavy (Cd²⁺, Hg²⁺ and Pb²⁺) metal cations have been determined by extraction studies with metal picrates and liquid membrane transport experiments with the same salts. The affinity of these ligands for Ag⁺ has also been investigated by ¹H NMR spectroscopy. Both ketones are better extractants than the esters, and show a strong preference for Ag⁺, while Cu²⁺ is the most extracted cation with the esters. ¹H NMR titrations with AgSO₃CF₃ indicate 1 : 1 complexes for all ligands, those with ketones are more stable, on the NMR time scale, than those with esters. Both esters are good carriers for Ag⁺, and 2b exhibits the highest transport rate (4.7 mol h^-1) found until now with dihomooxacalix[4]arene derivatives.     

Inclusion compounds of thiourea and peralkylated ammonium salts. Part II. Hydrogen-bonded host lattices built of thiourea and cyclic dimeric bicarbonate moieties

New inclusion complexes R₄N⁺HCO ₃ ^– ·x(NH₂)₂CS·yH₂O (1, R=C₂H₅,x=1,y=1;2, R=n–C₃H₇,x=2,y=0;3, R=n–C₄H₉,x=3,y=0) have been prepared and characterized by X-ray crystallography. Crystal data, MoK radiation:1, space groupPbca,Z=8,a=8.839(2),b=14.930(3),c=24.852(5) Å, andR _F=0.063 for 1419 observed data;2, space groupC222₁,Z=8,a=8.521(3),b=16.941(4),c=32.022(7) Å,R _F=0.054 for 1689 observed data;3, space group ,Z=2,a=9.553(2),b=12.313(3),c=14.228(4) Å, =90.44(2),=103.11(2), =110.12(2)°,R _F=0.044 for 3925 observed data. In the crystal structure of1, the thiourea molecules form hydrogen-bonded zigzag ribbons running parallel to thea axis, and the cyclic dimeric bicarbonate moieties (HCO ₃ ^– )₂ together with water molecules behave likewise. A puckered layer is formed by further lateral hydrogen bonding between these two types of ribbons, and the (C₂H₅)₄N⁺ cations occupy the space between adjacent layers. In the crystal structure of2, the thiourea ribbons are cross-linked orthogonally by (HCO ₃ ^– )₂ unitsvia N–H...O hydrogen bonds to form a composite double layer. Half of the cations are enclosed within and the other half sandwiched between these double layers. In the crystal structure of3, the thiourea molecules form puckered double ribbons running in the [110] direction. The host framework is constructed by cross-linking the double ribbons with bridging bicarbonate dimers, yielding two channel systems aligned parallel to [100] and [111] that accommodate the cationic guests. The structural relationship between the present complexes and the classical thiourea channel adducts is discussed. Supplementary Data relating to this article have been deposited with the British Library as Supplementary Publication No. SUP 82178 (44 pages).     

基于多羧酸烟酸配体的镝、钬、铒和铥配合物的合成及荧光、磁学性质的表征

以5-(4-羧基苯氧基)烟酸配体(H₂cpna)和稀土金属离子Dy³⁺、Ho³⁺、Er³⁺和Tm³⁺为原料,采用水热法合成了4种稀土金属配合物[M(Hcpna)(cpna)(H₂O)₃]_n,其中M=Dy(1)、Ho (2)、Er (3)、Tm (4)。单晶X射线衍射分析表明配合物1、2、3和4为同构配合物,均为一维链状结构。通过红外、元素分析以及粉末X射线衍射对所得配合物进行了表征,同时对配合物的荧光和磁学性质开展了研究。荧光测试结果表明,配合物1～4的荧光强度均低于配体H2cpna的荧光强度。在2～300 K温度范围内1 kOe直流电场下测试了配合物1～4的磁性,结果表明配合物1、2、3和4的χ_mT值分别为14.04、14.15、11.08和6.83 cm³·mol^-1·K,与文献理论值相符合。     

Iron Pentacarbonyl Promoted Addition of CO and MeOH to 1,4-Disubstituted-1,3-butadiyne and Formation of Vinylallyl and Butatriene Ligand Systems

Abstract  Photochemical reaction of methanol solution containing 1,4-diferrocenyl- or 1,4-diphenyl-1,3-butadiynes and iron pentacarbonyl into which CO was constantly bubbled, yielded diiron hexacarbonyl complexes of cumulene ligand systems, [η¹: η³-{RCHC₂CR(COOMe)}Fe₂(CO)₆] (1; E, R = Fc, 2; Z, R = Fc, 5; E, R = Ph, 6; Z, R = Ph) and [η³: η³-{RCHC₂CR(COOMe)}Fe₂(CO)₆] (3; E, R = Fc, 7; E, R = Ph), formed by 1,4-addition of –COOMe and –H to the butadiynes. Additionally, diferrole, [Fe(CO)₄{C(O)CC(Fc)C(O)}₂],4 was obtained in minor quantity. Compounds 1, 2, 5 and 6 contain vinylallyl carbon framework which is stabilized by MeOC=O → Fe bond along with η¹: η³ coordinated Fe₂(CO)₆ unit. Compounds 3 and 7 contain butatriene units which are stabilized by η³: η³ coordinated Fe₂(CO)₆ unit. Characterization of the new compounds was carried out by IR and ¹H and ¹³C NMR spectroscopy and by mass spectrometry. Molecular structures of 2–7 were established by single crystal X-ray diffraction methods. Graphical Abstract  Diiron hexacarbonyl complexes of cumulene ligand systems, [η¹: η³ {RCHC₂CR(COOMe)}] (1; E, R = Fc, 2; Z, R = Fc, 5; E, R = Ph, 6; Z, R = Ph) and [η³: η³-{RCHC₂CR(COOMe)}] (3; E, R = Fc, 7; E, R = Ph) were obtained from photochemical reactions between Fe(CO)₅, CO and methanol. Yield of the minor product, the diferrole, 4, was improved when the photoreaction was carried out in hexane in place of methanol      

Palladium(II)-dppe-arylazoimidazole complexes: Synthesis,and spectroscopic characterization

Reaction of [Pd(dppe)Cl₂/Br₂] with AgOTf in a dichloromethane medium followed by ligand addition led to [Pd(dppe)(OSO₂CF₃)₂] and then [Pd(dppe)(RaaiR)](OSO₂CF₃)₂ [RaaiR′ = p-R-C₆H₄-N=N-C₃H₂-NN-1-R′, (1–3), abbreviated as a N,N′-chelator, where N(imidazole) and N(azo) are represented by N and N′, respectively; R = H (a), Me (b), Cl (c) and R′ = Me (1), CH₂CH₃ (2), CH₂Ph (3), OSO₂CF₃ is the triflate anion, dppe = 1,2-bis-(diphenylphosphinoethane)]. ³¹P “¹H” NMR confirmed that due to the two phosphorus atom interaction in the azoimine symmetrical environment one sharp peak was formed. The ¹H NMR spectral measurements suggest that azo-imine link with lot of phenyl protons in the aromatic region. ¹³C (¹H) NMR spectrum, ¹H, ¹H COSY and ¹H, ¹³C HMQC spectrum assign the solution structure and stereo-retentive conformation in each complex.     

Synthesis and structures of fulvene-bridged diruthenium complexes

Three diruthenium carbonyl complexes, namely (η ³:η ⁵-C₅H₄C(CH₂)₂)Ru₂(CO)₅ (1), (η ³:η ⁵-C₅H₄C(CHCH₂)(C₂H₅))Ru₂(CO)₅ (2), and (η ¹:η ⁵-C₅H₄C₅H₈)Ru₂(CO)₆ (3), were obtained from the reactions of C₅H₄C(Me)₂, C₅H₄C(Et)₂, and C₅H₄C(CH₂)₄, respectively, with Ru₃(CO)₁₂ in refluxing xylene. The complexes were characterized by elemental analysis, IR and ¹H NMR spectra. Single-crystal X-ray diffraction analysis for complexes 1 and 2 revealed that the fulvene ligands bridge two ruthenium atoms in η ³:η ⁵ fashion.     

Synthesis and carboxylate anion binding studies on cyclic sugar-amino acid hybrids

Abstract

Here in, the condensation of boc-glycine with 2,6-anhydro-3,4,5-tri-O-benzyl-D-gluco-heptitol followed by its boc-deprotection to form 2,6-anhydro-3,4,5-tri-O-benzyl-D-gluco-heptitolyl bis-glycinate, which in turn on condensation with succinic acid/pyridine-2,6-dicarboxylic acid led to the formation of sugar-amino acid hybrid macrocyclic compounds 4, 6 and debenzylated marocyclic compound 5, having amide bonds that function as efficient host for polar, hydrogen bond acceptors and carboxylate ions. The anion inclusion capability of synthesized macrocylic hosts has been evaluated by the study of their binding with boc-GlyCOOˉ anion as guest through 1H NMR titration studies in CDCl₃. The binding constant (K_a) of boc-GlyCOOˉ guest with macrocyclic hosts 4 and 6 involving succinate and pyridine-2,6-dicarboxylate linkers was found to be 9.201?×?10³ and 1.437?×?10⁴ M^?1, respectively. The higher binding constant was observed in the complex of boc-GlyCOOˉ with pyridine-dicarboxylate containing host may be due to the extra rigidity & suitable conformation attained by the presence of rigid-aromatic dicarboxylate linker.     

Regioselective synthesis and structures of anti-cancer 20(R)-ginsenoside Rg3 derivatives

Abstract

Regioselective synthesis of three novel palmitates of 20(R)-ginsenoside Rg₃ was accomplished via a facile strategy, along with complete assignment of their ¹H and ¹³C NMR resonances by 1D and 2D NMR (¹H-¹H COSY, DEPT 135, HSQC, HMBC, and NOESY) techniques. The derivatives were tested for in vitro anti-proliferative activities against pancreatic cancer PANC-1 cells. Compounds 2, 3, and 4 exhibited more potent activity than did 20(R)-ginsenoside Rg₃.