Double Betaine Research Articles

Effects of pH on the Stimuli-Responsive Characteristics of Double Betaine Hydrophilic Block Copolymer PGLBT-b-PSPE.

We investigated the pH-responsive behavior of the carboxybetaine-sulfobetaine diblock copolymer poly(2-(2-(methacryloyloxy)ethyl)dimethylammonio)acetate-block-3-((2-(methacryloyloxy)ethyl)dimethylammonio)propane-1-sulfonate (PGLBT-b-PSPE) in aqueous solution under varying temperatures. Alongside the temperature-responsive PSPE block which induces self-assembly of polymer micelles under the upper critical solution temperature, the PGLBT motifs having protonation sites caused additional changes in the phase behaviors. In acidic conditions where the pH is lower than the pKa of PGLBT-b-PSPE, the transmittance of polymer solutions more abruptly dropped and became cloudy at higher temperatures compared to the case of salt-free solutions. There were two simultaneous diffusive modes in the turbid solutions equivalent to unimers or micelles and large aggregates over a few hundred nanometers. Unlike in neutral and basic conditions, those large aggregates did not disappear after the emergence of the polymer micelles. The trend of the temperature-responsive behavior hardly changed in the alkaline solutions; however, the critical temperature significantly decreased. The surface charge of the unimers and self-assembled objects determined by zeta potential measurement varied from neutral or negative to positive with proton addition and further positively increased below the micelle formation temperature. This indicates the cationization of PGLBT moieties and their arrangement in the outer layer of the polymer micelle surface. In spite of the positively charged outer surface, two fast and slow diffusive modes representing micelles and large clusters were repeatedly observed in acidic solutions, and to some extent, size-grown particles eventually precipitated.

Syntheses, Characterization, and Fluorescence Properties of Four Coordination Polymers based on Double Betaine Ligands

Four novel In3+ and Cd2+ based 1D coordination compounds constructed by double betaine ligands were synthesized and characterized structurally and optically. They assemble into 3D supra‐molecular architectures via different stacking or entanglement of 1D zigzag shaped chains, in which C–H···Cl and C–H···O hydrogen bonding interactions play a dramatic impact. Compound 1 displays a 1D + 1D → 3D four‐connect lvt net with 42·84 topology. Compound 2 assembles into a 3D architecture by inclined stacking of the adjacent zigzag chains. Compound 3 displays a 2D + 2D → 3D inclined polycatenation based on the resulting 2D (6, 3) layers that constructed by 1D chains. Compound 4 displays a 3D supra‐molecular architecture based on 1D chains, which were connected via the hydrogen bonding. Meanwhile, four compounds emit in the range of visible region owing to the intra‐ligand π*→π and/or π*→n electron transition induced florescence.

Two novel Cd(II)-based coordination polymers constructed from isomeric double betaine ligands: Syntheses, structures and fluorescent properties

Two novel Cd2+ based coordination compounds based on two isomeric double betaine ligands (1,4-Bis(4-carboxylatopyridinium-1-methylene)benzene (H2L1Cl2) and 1,4-Bis(3-carboxylatopyridinium-1-methylene)benzene (H2L2Cl2)) were synthesized, structurally and optically characterized. Both compounds show two dimensional sheet architectures with different features depending on structural motifs that ranging from helical chain to linear chain, and the spatial arrangements of coordinated ligands as well as their unlike coordination modes. They further exhibit the way how three dimensional supramolecular isomers form via weak interactions. Meanwhile, two compounds exhibit intense fluorescence attributing to the ligands' emissions with stokes shift.

Dichloro(ethylenediamine-N,N-di-3-propionato)zinc: Synthesis and crystal structure

Dichloro(ethylenediamine-N,N-di-3-propionato)zinc (I) has been synthesized for the first time by the reaction between acrylic acid and ethylenediamine coordinated with ZnCl2 in an aqueous medium. Complex I has been characterized by IR, Raman, and 1H,13C NMR spectroscopy, mass spectrometry, and elemental analysis. The X-ray diffraction analysis of complex I has also been performed. Crystals are monoclinic, а = 9.7792(4) A, b = 9.9805(4) A, c = 13.1130(5) A, β = 101.5620(10)°, space group Р21/c, Z = 4, V = 1253.88(9) A3, ρcalc = 1.804 g/cm3. The coordination polyhedra of Zn atoms in complex I are slightly distorted {ZnCl2O2} tetrahedra, each of which are built of two chlorine atoms and the carboxyl oxygen atoms of the two propionic groups of two ligand molecules and form a polymeric layer parallel to crystallographic plant (100). Bond lengths are Zn–О 1.970(1) and 1.976(1); Zn–Cl 2.2600(4) and 2.2693(4) A. The ligand molecule in complex I has a double betaine structure.

Crystal and molecular structure of the “asymmetric” ethylenediamine-N,N-di-3-propionic acid monohydrate

A new complexing agent the “asymmetric” ethylenediamine-N,N-di-3-propionic acid (as.EDDP) is obtained. The crystal structure of the new compound is determined by single-crystal X-ray diffraction. C8H16N2O4·H2O crystals are monoclinic; space group P21/c, a = 12.7416(4) A, b = 6.5470(2) A, c = 12.1908(4) A, β = 93.100(1)°, Z = 4, ρ x = 1.454 mg/m3, and R 1 (I > 2.0σ(I)) = 0.0326. In the solid form, the as.EDDP molecule has a double betaine structure: The intramolecular hydrogen bonds with the betaine proton of the tertiary nitrogen atom are formed with the participation of one oxygen atom of the carboxyl group of each 3-propionic fragment, which forms two N(1)-H(1N)-bonded six-membered H-cycles. The intermolecular hydrogen bonds are formed between the three hydrogen atoms of the protonated primary nitrogen atom and the oxygen atoms of the 3-propionic fragments of three other as.EDDP molecules. The water molecule participates in the formation of intermolecular hydrogen bonds with the oxygen atom of one carboxyl group of the molecule.

Catena-Poly[[[tetraaquacadmium(II)]-μ-3,3′-[p-phenylenebis(oxymethylene)]bis(1-pyridinioacetate)] dinitrate hemihydrate

In the title polymeric coordination complex, {[Cd(C22H20N2O6)(H2O)4](NO3)2·0.5H2O}n, obtained from the self-assembly of the flexible double betaine 3,3′-[p-phenyl­enebis(oxymethyl­ene)]bis­(1-pyridinioacetate) with cadmium nitrate, both the octa­hedrally coordinated CdII cation and the substituted betaine ligand lie on inversion centres. The chains constructed through the trans-related acetate groups of the ligand are inter-connected via O—H⋯O hydrogen bonds involving coordinated aqua ligands, the nitrate anions and the partial-occupancy (0.25) water mol­ecule of solvation, forming a three-dimensional structure.

Catena-Poly[[[diaquacopper(II)]-μ-2,2′-{[p-phenylenebis(oxymethylene)]bis(pyridinium-3,1-diyl)}diacetate] dibromide

The title centrosymmetric coordination polymer, {[Cu(C22H20N2O6)(H2O)2]Br2}n, formed by the reaction of the flexible double betaine ligand 2,2′-{[p-phenyl­enebis(oxymethyl­ene)]bis­(pyridine-3,1-di­yl)}diacetic acid with CuBr2, contains a Cu(II) atom ( symmetry) which is surrounded by two water molecules and bridged by two anions in a square-planar coordination. In the crystal, polymeric zigzag chains are linked via O—H⋯Br inter­actions, forming a two-dimensional network extending parallel to (011).

Two novel anion-directed Cu(II) double betaine coordination polymers with different open frameworks: Inorganic chains [Cu 3(μ 3–OH) 2(μ 2–H 2O) 2] n as secondary building units with unusual chair-like [Cu 3O 4] cores

The reaction of double betaine ligand L 1 (L 1 = 1,3-bis(pyridinio-4-carboxylato)-propane) with Cu(ClO 4) 2 and Cu(NO 3) 2, respectively, afforded two novel anion-directed coordination polymers with different open frameworks. The structure of [Cu 3(L 1) 2(OH) 2(H 2O) 2](ClO 4) 4·2H 2O 1 is a unique 3-D open-framework with large S-shape channels, while [Cu 3(L 1) 2(OH) 2(H 2O) 2](NO 3) 4·2H 2O 2 has a 2-D tubular structure. There exist inorganic copper-oxo chains [Cu 3(μ 3–OH) 2(μ 2–H 2O) 2] n in both 1 and 2 as secondary building units, in which the [Cu 3O 4] cores exhibit a rarely observed chair-like configuration. The anion template of ClO 4 - and NO 3 - , and labile coordination orientation of L 1 ligand prompt the formation of different polymeric networks in 1 and 2.

A unique 3-D 3d–4f heterometallic coordination polymer with double betaine ligand: Crystal structure and magnetic properties

A unique 3d–4f heterometallic coordination polymer with double betaine ligand, [GdCu 2(L 1) 4(H 2O) 2](ClO 4) 7 · 6H 2O 1 (L 1 = 1,3-bis(pyridinio-4-carboxylato)-propane), has been synthesized by the self-assembly of Cu(ClO 4) 2 and Gd(ClO 4) 3 with flexible double betaine ligand L 1, and structurally characterized by single-crystal X-ray diffraction. The structure of 1 can be regarded as being constructed by the cross-linkage of the vertex-sharing double-paddle-wheel-like trinuclear [Cu(COO) 4Gd(COO) 4Cu] units and L 1 ligands to produce an interesting cationic NaCl-like framework with a 4 126 3 topology, which is counter-balanced by the perchlorate ions located in the interspaces of the framework. Variable-temperature magnetic susceptibilities of 1 show there is no magnetic interaction between the Cu(II) and Gd(III) ions.

Two Cu(II) double betaine coordination polymers with different metal-organic frameworks

Two new Cu(II) coordination polymers with double betaine ligands have been prepared, and their structures have been characterized by single-crystal X-ray diffraction techniques. The structure of [Cu(L 1) 2](ClO 4) 2·2H 2O 1 (L 1 = 1,3-bis(pyridinio-4-carboxylato)-propane) contains 1-D cationic chains, in which the adjacent Cu(II) atoms are doubly bridged by L 1 ligands in the syn- syn bis-monodentate mode. In [Cu(L 2) 2](ClO 4) 2·4H 2O 2 (L 2 = 1,4-bis(pyridinio-4-carboxylato)-1,4-dimenthylbenzene), the Cu(II) atoms are joined by the L 2 ligands in the same coordination mode as 1 in two directions to form a 2-D grid-like framework. The crystal packing in 1 and 2 is controlled mainly by face-to-face π–π stacking interactions between pyridine rings. The thermal stability of 1 has also been investigated.

Different Molecular Frameworks of Zinc(II) and Cadmium(II) Coordination Polymers Constructed by Flexible Double Betaine Ligands

A series of six novel Zn(Cd)-double betaine coordination polymers have been obtained by the mild reactions of the respective metal nitrate with three flexible double betaine ligands. Single-crystal X-ray structural analyses reveal that the six complexes possess different molecular frameworks derived from various coordination modes and flexibilities of double betaine ligands, which indicates that the nature of the ligands has a great influence on the structural topologies of the metal−organic molecular architectures. Extensive hydrogen bonds play important roles in crystal packing and supramolecular frameworks. It is noteworthy that the different one-dimensional water chains with “arm-chair” and “zigzag” characteristics are presented in the complexes Zn(L2)(H2O)(NO3)](NO3)·2H2O (3) and [Cd(L2)(H2O)(NO3)]NO3·3H2O (4) [L2 = 1,3-bis(pyridinio-4-acetato)-propane], respectively .

Crystalline hydrates and polymeric Ag(I) complexes of isomeric flexible double betaines 1,4-bis( n-picolyloxyl)benzene- N, N′-diacetate ( n = 2,3,4)

The isomeric flexible double betaines 1,4-bis(2-picolyloxyl)benzene- N, N′-diacetate (L 1), 1,4-bis(3-picolyloxyl)benzene- N, N′-diacetate (L 2) and 1,4-bis(4-picolyloxyl)benzene- N, N′-diacetate (L 3) were used to react with AgNO 3, affording coordination polymeric complexes {[Ag 2L 1](NO 3) 2 · 3.5H 2O} n ( 1), {[Ag 2L 1](NO 3) 2 · 6H 2O} n ( 2) and {[Ag 3L 3](NO 3) 3 · 3H 2O} n ( 3). The crystal structures of the betaine hydrates L 1 · 8H 2O, L 2 · 6H 2O, L 3 · 5H 2O and the silver(I) complexes have been determined. L 1 · 8H 2O consists of a hydrogen-bonded three-dimensional network, whereas both L 2 · 6H 2O and L 3 · 5H 2O feature hydrogen bonded two-dimensional frameworks. In complex 1, the Ag(I) ions in the dimeric unit have different coordination environments; through the linkage of L 1 ligands and nitrates, the dimeric units are extended into a polymeric double chain. In complex 2, each Ag(I) ion of the centrosymmetric dimeric unit adopts a severely distorted tetrahedral coordination geometry; the dimeric subunits are connected by the L 2 ligands, giving an infinite one-dimensional chain, and the chains are further connected through hydrogen bonding to generate an infinite three-dimensional network. In complex 3, three Ag(I) ions constitute an isosceles triangle consolidated by weak Ag⋯Ag interactions, and such trinuclear subunits are further connected by the L 3 ligands, nitrate ions and water molecules through coordination and hydrogen bonding, yielding a three-dimensional network.

Crystal and molecular structures of 1:2 crystalline salts of two isomeric double betaines with hydrobromic acid and nitric acid

Four 1:2 crystalline salts of the isomeric flexible double betaines 1,4-bis(2-picolyloxyl)benzene- N, N′-diacetate (L 1) and 1,4-bis(3-picolyloxyl)benzene- N, N′-diacetate (L 2) with HBr and HNO 3, [H 2L 1Br 2] 1, [H 2L 1(NO 3) 2] 2, [H 2L 2Br 2] 3 and [H 2L 2(NO 3) 2]·2H 2O 4, have been synthesized and characterized by single-crystal X-ray analysis. They are all hydrogen-bonded networks consolidated by strong intermolecular interactions involving the bromide or nitrate ion, together with π–π stacking between the betaine molecules. The isostructural bromide–nitrate pair of compounds 1 and 2 provide an interesting corollary to the well-known methyl-chloro and benzene–thiophene exchange rules in crystal engineering.

Structural diversity in lanthanum(III) coordination polymers constructed with the isomeric flexible double betaines 1,4-bis( n-picolyloxyl)benzene- N, N′-diacetate ( n=2, 3)

Six coordination polymers: {[La(H 2O) 6L 1] 2Cl 6·12H 2O} ∞ ( 1), [La(H 2O) 2L 1(NO 3) 3] ∞ ( 2), {[La(H 2O) 4(L 1) 2](CF 3SO 3) 3·H 2O} ∞ ( 3), {[La(H 2O) 7(L 2) 0.5]Cl 3} ∞ ( 4), {[La(H 2O) 2L 2(NO 3) 2]NO 3·0.5H 2O} ∞ ( 5) and {[La(H 2O) 3(L 2) 2](CF 3SO 3) 3·6H 2O} ∞ ( 6) have been synthesized by the reaction between lanthanum(III) salts and the isomeric double betaines 1,4-bis(2-picolyloxyl)benzene- N, N′-diacetate (L 1) and 1,4-bis(3-picolyloxyl)benzene- N, N′-diacetate (L 2). Compound 1, 2 and 3 are all mononuclear: 1 shows a double-layer network constructed by ML 1 coordination bonds together with hydrogen bonds, while 2 and 3 are 3D frameworks. In compound 4, 5 and 6, dinuclear units are linked by one, two and four L 2 ligands, respectively, leading to different kinds of polymeric chains; in each compound the chains are further connected through intermolecular hydrogen bonding and π–π stacking to generate a 2D network.

Coordination networks generated from transition metal chlorides and a flexible double betaine

The new flexible double betaine 1,4-bis(2-picolyloxyl)benzene- N, N′-diacetate (L) has been synthesized and used to generate five complexes with divalent metal chlorides: [M(H 2O) 6]Cl 2·L·2H 2O (M=Mn ( 1), Co ( 2)), [Cu(μ-L)Cl 2] ∞ ( 3), {[Zn(μ-L)Cl 2]·2H 2O} ∞ ( 4), and {[Cd 2(μ-Cl) 2(μ-L)Cl 2(H 2O) 2]·2H 2O} ∞ ( 5). Isomorphous compounds 1 and 2 have a hydrogen-bonded three-dimensional network in which adjacent L ligands overlap through π–π stacking of the pyridine and benzene rings. Compounds 3, 4, and 5 display three different types of one-dimensional polymeric structures. Bridged by L acting in the anti mode, compound 3 exhibits an infinite zigzag chain in which consecutive, approximately planar L ligands are arranged in a crossed manner when viewed along the chain direction, the distance between adjacent copper(II) ions being about 13 Å. In contrast, compound 4 features a spring-like infinite helical chain with zinc ions lying on the axis and bridged by L acting in the syn fashion, and the Zn(II)⋯Zn(II) separation is approximately 9 Å. In compound 5, the building unit is a centrosymmetric Cd 2Cl 2 moiety, and adjacent dimeric units are linked by the centrosymmetric L ligand acting in the anti mode to give an infinite zigzag chain running along the c axis; such chains are further connected through hydrogen bonds to form a three-dimensional network.

Self-assembly of silver(i) coordination polymers with novel layered open network structures based on a flexible double betaine ligand

Three coordination polymers, [Ag4(L1)2(NO3)4]·H2O (1), [Ag(L1)](BF4)·2H2O (2) and [Ag2(L1)(H2O)](ClO4)2 (3), were obtained from self-assembly of AgX (X = NO3−, BF4−, or ClO4−) with a new flexible double betaine L1 (L1 = 1,3-bis(pyridinio-4-carboxylato)propane). Single crystal X-ray diffraction studies for complexes 1–3 reveal layered open network structures containing novel cavities and channels. Complex 1 consists of an unprecedented rhombic tetrameric Ag4O2 subunit, in which a μ3-η1 coordination mode of the carboxylate group is found for the first time among silver(I) carboxylates. Complex 2 is constructed from a bis(carboxylate-O,O′)-bridged centrosymmetric dimeric subunit, in which the coordination sphere of each silver(I) atom is completed by a monodentate carboxylate group at each axial site. In complex 3, the [Ag2(carboxylate-O,O′)2] dimeric subunits are extended into a polymeric chain through the linkage of each metal centre to carboxylate groups of an adjacent dimer, and such infinite chains are extended into a plane wave-like layer structure by the cross-linkage of the molecular skeletons of the flexible double betaine ligands.

Lanthanide coordination polymers with dicarboxylate-like ligands: crystal structures of polymeric lanthanum(III) and terbium(III) complexes with flexible double betaines

Four novel polymeric lanthanide(III) complexes of two new double betaine derivatives have been synthesized and structurally determined. In [{La 2(L 1) 2(H 2O) 9} n ]Cl 6 n ·2 nH 2O ( 1) and [{Tb(L 1)(H 2O) 4} n ]Cl 3 n · nH 2O ( 2) (L 1=4,4′-trimethylenedipyridinio- N, N′-diacetate), the lanthanide(III) ions form a two-dimensional layer in which each pair of lanthanide(III) ions is bridged by two syn–anti μ-carboxylato- O, O′ groups. Adjacent layers are cross-linked through hydrogen bonds among aqua ligands, lattice water molecules and chloride ions, to form a three-dimensional network. Isomorphous [{Ln(L 2)(H 2O) 4} n ]Cl 3 n ·5 nH 2O (Ln=La, 3; Ln=Tb, 4; L 2=1,3 bis(pyridinio-4-carboxylato)-propane) each contain a centrosymmetric paddle-wheel-like dimeric unit in which each pair of adjacent metal atoms is bridged by four syn–syn μ-carboxylato- O, O′ groups that are oriented nearly perpendicular to each other about the metal–metal axis. Neighboring dimeric subunits are bridged by a pair of flexible L 2 ligands into a polymeric chain. Adjacent chains are inter-linked by hydrogen bonds among aqua ligands, lattice water molecules and chloride ions into a three-dimensional network.

SYNTHESIS, CRYSTAL STRUCTURE AND LUMINESCENCE STUDIES OF A LANTHANIDE COORDINATION POLYMER WITH A NEW DOUBLE BETAINE LIGAND

A novel europium(III) coordination polymer with a new double betaine derivative. {[Eu(L1)(NO3)(H2O)3](NO3)2 3.5H2O}n (L= l,3-bis(pyridinio-4-carboxylato)-propane) has been synthesized and its structure determined. Its luminescence properties have also been studied. The title metal carboxylate coordination polymer contains centrosymmetric dimeric units in which each pair of metal ions is linked by a pair of syn-anti carboxylato-O.O' groups, and each pair of such dimeric units is bridged by the backbones of L1 ligands to form infinite double chains in the b direction. These metal carboxylate chains are further cross-linked by hydrogen bonds among both coordinated and discrete nitrate anions, aqua ligands and lattice water molecules to form a three-dimensional network. Luminescent data show that the L1 ligand is a good energy donor and the complex has a relatively long luminescent lifetime.

Generation of coordination networks with dicarboxylate-like ligands: Synthesis and crystal structures of polymeric complexes of gadolinium(III) perchlorate with flexible double betaines

Three novel gadolinium(III) co-ordination polymers containing three flexible double betaines with different numbers of metahylene bridges and a rigid tris(ethylene) bridge between two quaternary ntirogen atoms, namely [ sGd( L 1) 2(H 2O 2 s n ](ClO 4) 3 n · nH 2O ( 1),[ sGd( L 2) 2(H 2O) 2 s n ](ClO 4) 3 n · nH 2O ( 2) and [ sGd(L 3) 2 (H 2O) 2 s n ](ClO 4) 3 n · 8 nH 2O ( 3) (L 1 = N, N′-dicarboxymethyl- N, N, N′, N′-tetramethyl-1,3-propanediammonium, −O 2CCH 2N +Me 2-(CH 2) 3-N +Me 2CH 2CO 2 −; L 2 = N, N′-dicarboxymethyl- N, N′-dicarboxymethyl- N, N, N′, N′-tetramethyl-1,4-butanediammonium, −O 2CCH 2N +Me 2-(CH 2) 4-N +Me 2CH 2CO 2 −; L 3 = 1,4-diazoniabicyclo[2.2.2]octane-1,4- diacetate, −O 2CCH 2N +(CH 2CH 2) 3N +CH 2CO 2 −), have been prepared and characterized by X-ray crystallography. Each complex contains paddlewheel-like dimeric subunits in which each pair of adjacent metal atoms is bridged by four μ-carboxylato- O, O′ groups that are orientated nearly perpendicular to each other about the metal-metal axis. The dimeric subunits are extended into a polymeric chain through the linkage of each metal center to the carboxylato groups of an adjacent dimer. Such infinite chains are extended into a plane wave-like layer structure in ( 1) and ( 2), and a three-dimensional framework in ( 3) by the cross-linkage of the molecular skeletons of double betaine ligands. The formation of hydrogen bonds further leads to a three-dimensional network in ( 1). The gadolinium(III) atom in each complex is surrounded in a distorted square-antiprismatic geometry by six carboxylato oxygen atoms and two aqua ligands. The carboxylato groups in the dimeric subunits adopt the common syn-syn bidentate bridging and unidentate co-ordination modes in ( 1), ( 2) and ( 3). In addition, the carboxylato groups in ( 1) and ( 2) also coordinate the metal atoms in an unusual syn-skew μ- O, O′ bridging mode.

Synthesis and structural characterization of a novel polymeric praseodymium(III) complex with a new flexible double betaine

A novel polymeric Pr(III) complex with a new double betaine, namely [{Pr(L-1)(1.5)(H2O)(2)}(n)] [ClOli4]3(n). nH(2)O (1) (L-1= 1,4-diazoniobicyclo[2,2,2]octane- 1,4-dipropionate), has been synthesized and characterized by X-ray analysis. In the title complex, the Pr(III) atom is nine-coordinated by seven oxygen atoms from five L-1 ligands and two aqua ligands. Each pair of adjacent praseodymium(III) atoms is linked by a pair of mu(3) chelating and bridging carboxylate groups, thus forming an infinite metal metal chain running parallel to the a direction, and such chains are cross-linked by flexible backbones of L-1 ligands into a three-dimensional network with the perchlorate anions and lattice water molecules accommodated in the interstitial space. The title complex crystallizes in the monoclinic space group P2(1)/n with a = 8.085(2), b = 14.316(3), c = 29.775(6) Angstrom, beta = 103.04(3)degrees and Z = 4.