Synthesis and characterization of new soluble and thermally stable aromatic poly(amide-imide)s based on N-[3,5-bis(N-trimellitoyl)phenyl]phthalimide

A new dicarboxylic acid, N-[3,5-bis(N-trimellitoyl)phenyl]phthalimide (1a), bearing three preformed imide rings was synthesized from the condensation of N-(3,5-diaminophenyl)phthalimide and trimellitic anhydride in glacial acetic acid at 1:2 molar ratio. For study of structure-properties relationship 1,3-bis(N-trimellitoyl)benzene (1b, as a reference) was also synthesized in a similar manner. 1a and 1b were characterized by spectroscopic methods and elemental analyses.A series of wholly aromatic poly(amide-imide)s with inherent viscosities of 0.63-1.09 dl g⁻¹ was prepared by triphenyl phosphite-activated polycondensation from the triimide-dicarboxylic acid 1a and the reference monomer 1b with various aromatic diamines. All of the polymers were fully characterized by FT-IR and ¹H NMR spectroscopy. The effects of the phthalimide pendent group on the polymers properties such as solubility, crystallinity, and thermal stability were investigated by comparison of the polymers. The polymers obtained from triimide-dicarboxylic acid 1a exhibited excellent solubility in a variety of solvents such as N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, and dimethylsulfoxide. These poly(amide-imide)s possessed glass-transition temperatures from 334 to 403 °C and exhibited excellent thermal stabilities and had 10% weight losses from 541 to 568 °C under a nitrogen atmosphere. Poly(amide-imide)s containing phthalimide pendent groups showed higher solubility, higher T_g and T_d10% values than those having no phthalimide pendent groups.     

Synthesis and characterization of new soluble and thermally stable poly(ester-imide)s derived from N-[3,5-bis(N-trimellitoyl)phenyl]phthalimide and various bisphenols

A new dicarboxylic acid chloride (2) bearing three preformed imide rings was synthesized by treating N-(3,5-diaminophenyl)phthalimide with trimellitic anhydride followed by refluxing with thionyl chloride. A novel family of aromatic poly(ester-imide)s with inherent viscosities of 0.27-0.35 dl g⁻¹ were prepared from 2 with various bisphenols such as resorcinol (3a), hydroquinone (3b), 2,2′-dihydroxybiphenyl (3c), 4,4′-dihydroxybiphenyl (3d), bisphenol-A (3e), 2,2′-dimethyl-4,4′-dihydroxybiphenyl (3f), 1,5-dihydroxynaphthalene (3g), 2,7-dihydroxynaphthalene (3h), and 2,2′-dihydroxy-1,1′-binaphthyl (3i) by high-temperature solution polycondensation in nitrobenzene using pyridine as hydrogen chloride quencher. All of the resulted polymers were fully characterized by FT-IR and NMR spectroscopy and elemental analyses. The poly(ester-imide)s exhibited excellent solubility in some polar organic solvents. From differential scanning calorimetry, the polymers showed glass-transition temperatures between 259 and 353 °C. Thermal behaviors of the obtained polymers were characterized by thermogravimetric analysis and the 10% weight loss temperatures of the poly(ester-imide)s were found to be in the range between 451 and 482 °C in nitrogen. Furthermore, crystallinity of the polymers was estimated by means of wide-angle X-ray diffraction.     

Synthesis, photoluminescent and electrochromic properties of new aromatic poly(amine-hydrazide)s and poly(amine-1,3,4-oxadiazole)s derived from 4,4′-dicarboxy-4″-methyltriphenylamine

A series of new poly(amine-hydrazide)s I were prepared from the dicarboxylic acid 4,4′-dicarboxy-4″-methyltriphenylamine with terephthalic dihydrazide (TPH) and isophthalic dihydrazide (IPH), respectively, via the Yamazaki phosphorylation reaction. Polymers I were readily soluble in many common organic solvents, and could be solution cast into transparent, tough, and flexible films with good mechanical properties. Differential scanning calorimetry (DSC) indicated that the hydrazide polymers had T_g’s in the range of 222-223 °C and could be thermally cyclodehydrated into the corresponding oxadiazole polymers in the range of 300-400 °C. The resulting poly(amine-1,3,4-oxadiazole)s II exhibited T_g’s in the range of 269-283 °C, 10% weight-loss temperatures in excess of 511 °C, and char yield at 800 °C in nitrogen higher than 63%. These poly(amine-hydrazide)s I exhibited strong UV-Vis absorption bands at 351-355 nm in NMP solution. Their photoluminescence spectra in NMP solution and film showed maximum bands around 459-461 nm in the blue region for I series. The hole-transporting and electrochromic properties are examined by electrochemical and spectroelectrochemical methods. Cyclic voltammograms of the poly(amine-hydrazide)s I prepared by casting polymer solution onto an indium-tin oxide (ITO)-coated glass substrate exhibited one reversible oxidation redox couples at 1.32-1.33 V vs. Ag/AgCl in acetonitrile solution. All obtained poly(amine-hydrazide)s I revealed excellent stability of electrochromic characteristics, changing color from original pale yellowish to blue.     

Novel non-chelated cobalt(II) benzimidazole complex catalysts: Synthesis, crystal structures and cocatalyst effect in vinyl polymerization of norbornene

The novel non-chelated monodentate benzimidazole (BI) complexes CoCl₂(BI)₂ (1)-(3), where BI = 1-(2-methoxybenzyl)- 2-(2-methoxyphenyl)-1H-benzimidazole (1), BI = 2-(2,6-difluorophenyl)-1H-benzimidazole (2) and 2-methyl-1H-benzimidazole (3) were synthesized and characterized by single X-ray crystallography. Unexpectedly, in solid state these complexes show similar coordination behavior to their analogue nickel(II) benzimidazole complexes such as inter-molecular H-bonding pattern and presence of acetonitrile solvent molecules per unit of complex molecule. Moreover, among these cobalt catalysts 1-3, similar trend to that of nickel catalysts is observed for metal-to-nitrogen (M-X) coordination bond length and halogen-metal-halogen (X-M-X) bond angle. But unlike nickel(II) benzimidazole complexes, these catalysts show very low activity for vinyl polymerization of norbornene (NB) upon activation with methylaluminoxane (MAO); however, the activity abruptly increased in modified methylaluminoxane (MMAO). The presence of a small amount of toluene strongly hampered the activity, and the use of dry methylaluminoxane (dMAO) as a cocatalyst did not result in a high activity. The use of toluene-free solid modified methylaluminoxane (sMMAO) is found to be the best cocatalyst, where the highest activity of value 3.9 × 10⁷ g of PNB mol_Co⁻¹ h⁻¹ was achieved for 3/sMMAO at 30 °C.     

Novel organosoluble and colorless poly(ether imide)s based on 1,1-bis[4-(3,4-dicarboxyphenoxy)phenyl]cyclohexane dianhydride and trifluoromethyl-substituted aromatic bis(ether amine)s

A series of novel fluorinated poly(ether imide)s (IV) having inherent viscosities of 0.70-1.08 dL/g were prepared from 1,1-bis[4-(3,4-dicarboxyphenoxy)phenyl]cyclohexane dianhydride (I) and various trifluoromethyl (CF₃)-substituted aromatic bis(ether amine)s II_a-g by a standard two-step process with thermal and chemical imidization of poly(amic acid) precursors. These poly(ether imide)s showed excellent solubility in many organic solvents and could be solution-cast into transparent, flexible, and tough films. These films were essentially colorless, with an ultraviolet-visible absorption edge of 375-380 nm and a very low b^∗ value (a yellowness index) of 5.5-7.3. They also showed good thermal stability with glass-transition temperatures of 207-269 °C, 10% weight loss temperatures in excess of 474 °C, and char yields at 800 °C in nitrogen more than 62%. In comparison with analogous V series poly(ether imide)s without the -CF₃ substituents, the IV series polymers showed better solubility, lower color intensity, and lower dielectric constants.     

Colorless poly(ether-imide)s deriving from 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride(BPADA) and aromatic bis(ether amine)s bearing pendent trifluoromethyl groups

A series of poly(ether-imide)s (III) characterized by colorless, highly solubility was synthesized from 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride(BPADA) and various fluorinated aromatic diamines (I_a-h) in DMAc via polycondensation to form poly(amic acid) (II), followed by chemical (C) and thermal (H) imidization. These polymers had inherent viscosities ranging from 0.60 to 1.3 dL/g. These polyimides were highly soluble in a variety of organic solvent such as amide-type, ether-type and chlorinated solvents. Moreover, these poly(ether-imide) films were almost colorless, with an ultraviolet-visible absorption cutoff wavelength below 390 nm and low b* value (a yellowness index) of 4.6-18.0. The III series showed strength tensile of 72-101 MPa, elongation at break of 11-25%, initial modulus of 1.5-2.0 GPa. The glass transition temperature (T_g) of III_a-h were in the range of 202-267 °C, and the decomposition temperature above 493 °C and left 40-65% char yield at 800 °C in nitrogen. They had the lower dielectric constants of 3.39-3.72 (1 MHz) and moisture absorptions in the range of 0.11-0.40%.     

Synthesis and properties of thermally stable and optically active novel wholly aromatic polyesters containing a chiral pendent group

5-(2-Phthalimidyl-3-methyl butanoylamino)isophthalic acid (5), as a novel diacid monomer containing phthalimide and flexible chiral groups, was prepared by the reaction of 2-phthalimidyl-3-methyl butyric acid chloride (4) with 5-aminoisophthalic acid (5AIPA) in dry N,N-dimethylacetamide (DMAc). A series of novel polyesters (PE)s containing phthalimide group was prepared by the reaction of diacid monomer 5 with several aromatic diols via direct polyesterification with the tosyl chloride/pyridine/dimethylformamide (DMF) system as a condensing agent. The resulting new polymers were obtained in good yields with inherent viscosities ranging between 0.37 and 0.61 dL g⁻¹ and were characterized with FT-IR, ¹H NMR, elemental and thermogravimetric analysis techniques. These polymers are readily soluble in amide type solvents such as DMAc, DMF, 1-methyl-2-pyrrolidone, hexamethyl triaminophosphine, dimethyl sulfoxide and protic solvents such as sulfuric acid. Thermogravimetric analysis showed that the 10% weight loss temperature in a nitrogen atmosphere was more than 345 °C, which indicates that the resulting PEs have a good thermal stability as well as excellent solubility.     

Synthesis and properties of soluble and light-colored poly(amide-imide-imide)s based on tetraimide-dicarboxylic acid (TIDA) and various aromatic diamines: TIDA from 4,4′-oxydiphthalic anhydride, 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene, and 3-aminobenzoic acid

A new tetraimide-dicarboxylic acid (TIDA) I was synthesized starting from 3-aminobenzoic acid (m-ABA), 4,4′-oxydiphthalic anhydride (ODPA), and 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene (BAFPB) at a 2:2:1 molar ratio in N-methyl-2-pyrrolidone (NMP). A series of organosoluble, light-colored poly(amide-imide-imide)s (PAII, III_a-j) was prepared by triphenyl phosphite-activated polycondensation from the tetraimide-diacid I with various aromatic diamines (II_a-j). All the polymers were readily soluble in a variety of organic solvents such as NMP, N,N-dimethyl acetamide (DMAc), dimethyl sulfoxide, and even in less polar m-cresol and pyridine. Polymer films cast from DMAc had the cutoff wavelengths between 374 and 384 nm and had the b^∗ values in the range of 14.8-30.2. Polymers III_a-j afforded tough, transparent, and flexible films, which had tensile strengths ranging from 87 to 103 MPa, elongations at break from 11% to 37%, and initial moduli from 1.9 to 2.3 GPa. The glass transition temperatures of these polymers were in the range of 242-274 °C. They had 10% weight loss temperature above 526 °C and showed the char yield more than 55% residue at 800 °C in nitrogen.     

Regularly alternating poly(amideimide)s containing pendent pentadecyl chains: Synthesis and characterization

Two new aromatic diamines containing preformed amide linkages, viz., N,N′-(4-pentadecyl-1,3-phenylene)bis(4-aminobenzamide) I and N,N′-(4-pentadecyl-1,3-phenylene)bis(3-aminobenzamide) II, were synthesized by reaction of 4-pentadecylbenzene-1,3-diamine with 4-nitrobenzoylchloride and 3-nitrobenzoylchloride, followed by reduction of the respective dinitro derivatives. A series of new poly(amideimide)s was synthesized by polycondensation of I and II with four commercially available aromatic dianhydrides, viz., pyromellitic dianhydride (PMDA), 4,4′-biphenyltetracarboxylic dianhydride (BPDA), 4,4′-oxydiphthalic anhydride (ODPA), and 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6-FDA) in N,N-dimethylacetamide (DMAc) employing conventional two step method via poly(amic acid) intermediate followed by thermal imidization. Reference poly(amideimide)s were synthesized by polycondensation of N,N′-(1,3-phenylene)bis(4-aminobenzamide) and N,N′-(1,3-phenylene)bis(3-aminobenzamide) with the same aromatic dianhydrides. Inherent viscosities of poly(amideimide)s containing pendent pentadecyl chains were in the range 0.37-1.23 dL/g in N,N-dimethylacetamide at 30 ± 0.1 °C indicating the formation of medium to high molecular weight polymers. The poly(amideimide)s containing pendent pentadecyl chains were found to be soluble in N,N-dimethylacetamide, N,N-dimethylformamide, 1-methyl-2-pyrrolidinone and pyridine and could be cast into transparent, flexible and tough films from their N,N-dimethylacetamide solution. Wide angle X-ray diffraction patterns exhibited broad halo indicating that the polymers were essentially amorphous in nature. X-ray diffractograms also displayed sharp reflection in the small angle region (2θ ≈ 3°) for poly(amideimide)s containing pentadecyl chains indicating the formation of layered structure arising from packing of flexible pentadecyl chains. The glass transition temperatures observed for reference poly(amideimide)s were in the range 331-275 °C and those for poly(amideimide)s containing pendent pentadecyl chains were in the range 185-286 °C indicating a large drop in T_g owing to the “internal plasticization” effect of pentadecyl chains. The temperature at 10% weight loss (T₁₀), determined by TGA in nitrogen atmosphere, were in the range 460-480 °C indicating their good thermal stability.     

Fluorescent detection of amidinium-carboxylate and amidinium formation using a 1,8-diphenylnaphthalene-based diamidine: dicarboxylic acid recognition with high fluorescence efficiency

A 1,8-diphenylnaphthalene-based diamidine (1) ‘turn-on’ fluorescent probe for the detection of dicarboxylic acids has been designed and synthesized. The fluorescence spectra of the diamidine 1 with carboxylic acids that showed two different fluorescence bands, which corresponded to the amidinium-carboxylate (λ_em=410–430 nm) and amidinium (λ_em=440–470 nm as a broad band, which consisted from two peaks) formation, were confirmed by DOSY NMR and TD-DFT calculations. The complexation of diamidine 1 with dicarboxylic acids, which have sufficient distances between the two carboxylic groups for binding to the diamidine 1 (dicarboxylic acids 3, 4, and α,ω-dicarboxylic acids 6 (C₆–C₂₀)), showed the formation of 1:1 complexes (i.e., amidinium-carboxylate formation). On the other hand, for the complexation with monocarboxylic acids and dicarboxylic acids having insufficient distances between the two carboxylic groups (benzoic acid 5, acetic acid 7, and α,ω-dicarboxylic acids 6 (C₃–C₅)), formation of the amidinium (1·2H⁺) was observed. Relatively similar binding constants (10⁻⁵) for the complexation of the diamidine 1 with dicarboxylic acids 6, which depend on their chain length (strain), were observed due to the flexibility of the 1,8-diphenylnaphthalene unit. Additionally, for the complexation of the diamidine 1 with dicarboxylic acids, higher fluorescence quantum yields (Φ_fl: up to 80%) were observed when compared to the binding of the diamidine 2 (Φ_fl: up to 35%).     

Preparation and properties of aromatic poly(amide-imide)s derived from N-[3,5-bis(3,4-dicarboxybenzamido)phenyl]phthalimide dianhydride

An imide ring-containing diamide-dianhydride, N-[3,5-bis(3,4-dicarboxybenzamido)phenyl]phthalimide dianhydride (1) was prepared by the reaction of trimellitic anhydride chloride with N-(3,5-diaminophenyl)phthalimide in a medium consisting of methylene chloride and pyridine. A series of new alternating aromatic poly(amide-imide)s having inherent viscosities of 0.26-0.37 dl/g was synthesized using a two-step poly(amic-acid) precursor method. A reference monomer, 1,3-bis(3,4-dicarboxybenzamido)benzene dianhydride (2) without the phthalimido pendant group attached to the polymer main chain was prepared in order to study the structure-property relationship. In this case, the structure effects on some properties of the resulting poly(amide-imide)s including crystallinity, solubility, thermal stability, and film flexibility could be easily clarified. A diamide-triimide (3) as a model compound was also synthesized by the reaction of new dianhydride 1 with aniline to compare the characterization data as well as to optimize the polymerization conditions. The resulting polymers were fully characterized by FT-IR, UV-visible and ¹H NMR spectroscopy. Most of the polymers showed an amorphous nature and were readily soluble in a variety of organic solvents such as N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N-methyl-2-pyrrolidone (NMP), and pyridine. The glass-transition temperatures of these polymers were recorded between 301 and 371 °C. All polymers showed no significant weight loss below 500 °C in nitrogen, and the decomposition temperatures at 10 wt.% loss range from 506 to 543 °C. The films of the resulting poly(amide-imide)s could be cast from their NMP solutions, and the transparency and flexibility of them were investigated.     

Pyrenyl-appended imidazolium receptor for selective fluorescence sensing of oxalic acid

A new fluorescent imidazolium-based cholestane receptor 4 bearing a pyrene moiety was synthesized. The binding ability of 4 toward various dicarboxylic acids was examined by UV-vis and fluorescence spectroscopy. Receptor 4 showed the highest binding constant for oxalic acid among all the tested dicarboxylic acids (K_a = 5.06 × 10⁴ M⁻¹). Oxalic acid formed a complex with 4 with a 1:2 ratio in ethanol.     

Synthesis and electronic structures of D2h-symmetry tetrabenzoporphyrins

A novel low-symmetry tetrabenzoporphine with D_2h symmetry (1) and its zinc complex (2) were prepared via mixed condensation reaction of 5,6-dimethyl phthalimide and 4,5,6,7-tetraphenyl phthalimide with sodium acetate in the presence of zinc acetate. The zinc complex 2 exhibited a split Q band at 640 and 623 nm and a single Soret band at 435 nm. The absorption spectra of 1 and 2 were calculated and analyzed using Hartree-Fock theory based on INDO/S Hamiltonian.     

Aqueous syntheses of [(Cp-R)M(CO)3] type complexes (Cp = cyclopentadienyl, M = Mn, Tc, Re) with bioactive functionalities

We describe reactions of [^99mTc(H₂O)₃(CO)₃)]⁺ (1) with Diels-Alder products of cyclopentadiene such as “Thiele’s acid” (HCp-COOH)₂ (2) and derivatives thereof in which the corresponding [(Cp-COOH)^99mTc(CO)₃)] (3) complex did form in water. We propose a metal mediated Diels-Alder reaction mechanism. To show that this reaction was not limited to carboxylate groups, we synthesized conjugates of 2 (HCp-CONHR)₂ (4a-c) (4a, R = benzyl amine; 4b, R = N_α-Boc-l-2,3-diaminopropionic acid and 4c, R = glycine). The corresponding ^99mTc complexes [(4a)^99mTc(CO)₃)] 6a, [(4b)^99mTc(CO)₃)] 6b and [(4c)^99mTc(CO)₃)] 6c have been prepared along the same route as for Thiele’s acid in aqueous media demonstrating the general applicability of this synthetic strategy. The authenticity of the ^99mTc complexes on the no carrier added level have been confirmed by chromatographic comparison with the structurally characterized manganese or rhenium complexes.Studies of the reaction of 1 with Thiele’s acid bound to a solid phase resin demonstrated the formation of [(Cp-COOH)^99mTc(CO)₃)] 3 in a heterogeneous reaction. This is the first evidence for the formation of no carrier added ^99mTc radiopharmaceuticals containing cyclopentadienyl ligands via solid phase syntheses. Macroscopically, the manganese analogue 5a and the rhenium complexes 5b-c have been prepared and characterized by IR, NMR, ESI-MS and X-ray crystallography for 5a (monoclinic, P2₁/c, a = 9.8696(2) Å, b = 25.8533(4) Å, c = 11.8414(2) Å, β = 98.7322(17)°) in order to unambiguously assign the authenticity of the corresponding ^99mTc complexes.     

Synthesis and characterization of novel optically active poly(amide-imide)s via direct amidation

N,N′-Pyromelliticdiimido-di-l-methionine (3) was prepared from the reaction of pyromellitic dianhydride (1) with l-methionine (2) in glacial acetic acid and pyridine solution at refluxing temperature. The direct polycondensation reaction of the monomer diimide-diacid (3) with 1,3-phenylenediamine (4a), 1,4-phenylenediamine (4b), 2,6-diaminopyridine (4c), 3,5-diaminopyridine (4d), 4,4′-diaminodiphenylether (4e) and 4,4′-diaminodiphenylsulfone (4f) was carried out in a medium consisting of triphenyl phosphate, N-methyl-2-pyrolidone, pyridine and calcium chloride. The resulting poly(amide-imide)s having inherent viscosities 0.45-0.53 dl g⁻¹ were obtained in high yields and are optically active and thermally stable. All of the above compounds were fully characterized by IR spectroscopy, elemental analyses and specific rotation. Some structural characterization and physical properties of these new optically active poly(amide-imide)s are reported.     

Rational design and syntheses of 0-D, 1-D, and 2-D metal-organic frameworks (MOFs) from ferrocenedicarboxylate tetrametallic macrocyclic building units and subsidiary ligands

We have designed and synthesized three new metal-1,1′-ferrocenedicarboxylate complexes containing tetrametallic macrocyclic building units, namely, [Cd₂(η²-O₂CFcCO₂-η²)₂(phen)₂(H₂O)₂] · 4CH₃OH (1) (Fc = (η⁵-C₅H₄)Fe(C₅H₄-η⁵), phen = 1,10-phenanthroline), {[Cd(η²-O₂CFcCO₂)(pebbm)(H₂O)] · 2H₂O}_n (2) (pebbm = 1,1′-(1,5-pentanediyl)bis-1H-benzimidazole) and {[Cd(η²-O₂CFcCO₂-η²)(prbbm)(H₂O)] · 3H₂O}_n (3) (prbbm = 1,1′-(1,3-propanediyl)bis-1H-benzimidazole). Compound 1 is a 0-D discrete tetrametallic macrocyclic framework. Compound 2 features an infinite 1-D ribbon of rings structure constructed by the subsidiary ligands pebbm connecting tetrametallic macrocyclic building units. For 3, its tetrametallic macrocyclic building units are linked by the subsidiary ligands prbbm to form a 2-D network structure. The structural features of these complexes indicate that the ferrocenedicarboxylate tetrametallic macrocycle can be used as a successful molecular building unit and the shapes and conformational flexibility of subsidiary ligands play a crucial role in the manipulation of the configuration of the resultant MOFs. Their fluorescence spectra in solid state at room temperature suggest that the fluorescence emissions of 1-3 are ruled by 1,1′-ferrocenedicarboxylate ligand.     

Control of molecular weight distribution in polycondensation polymers 2. Poly(ether ketone) synthesis

Synthesis of aromatic poly(ether ketone) (3) with a narrow molecular weight distribution (M_w/M_n) was investigated via polycondensation. M_ns of 3 could be controlled varying the feed ratio of monomer (1) and initiator (2) maintaining relatively narrow M_w/M_ns (<1.3). The kinetics of polycondensation obeyed a first-order relationship between polycondensation time and -(1/[2]₀) ln([1]/[1]₀), and the rate of polycondensation was estimated as 2.57 mol⁻¹ L h⁻¹. MALDI-TOF mass analysis of 3 indicated that polycondensation should proceed via chain growth manner to give 3 having an initiator unit in each chain end.     

Structural diversity of di and triorganotin complexes with 4-sulfanylbenzoic acid: Supramolecular structures involving intermolecular Sn?O, O-H?O or C-H?X (X = O or S) interactions

Twelve new organotin complexes with 4-sulfanylbenzoic acid of two types: R_nSn[S(C₆H₄COOH)]_4−n (I) (n = 3: R = Me 1, n-Bu 2, Ph 3; PhCH₂4; n = 2: R = Me 5; n-Bu 6, Ph 7, PhCH₂8) and R₃Sn(SC₆H₄COO)SnR₃ · mEtOH (II) (m = 0: R = Me 9, n-Bu 10, PhCH₂12; m = 2: R = Ph 11), along with the 4,4′-bipy adduct of 9, [Me₃Sn(SC₆H₄COO)SnMe₃]₂(4,4-bipy) 13, have been synthesized. The coordination behavior of 4-sulfanylbenzoic acid is monodentate in 1-8 by thiol S atom but not carboxylic oxygen atom. While, in 9-13 it behaves as multidenate by both thiol S atom and carboxylic oxygen atoms. The supramolecular structures of 6, 11 and 13 have been found to consist of 1D molecular chains built up by intermolecular O-H?O, C-H?O or C-H?S hydrogen bonds. The supramolecular aggregation of 7 is 2D network determined by two C-H?O hydrogen bonds. Extended intermolecular C-H?O interactions in the crystal lattice of 9 link the molecules into a 2D network.     

Synthesis and properties of new poly(ether-ester)s containing aliphatic diol based on isosorbide. Effects of the microwave-assisted polycondensation

Microwave irradiation was applied to synthesize to the bulk synthesis of novel poly(ether-ester)s based on diol-ether of isosorbide (1) and adipoyl chloride (2) or terephthaloyl chloride (3). Thus, the poly(ether-ester)s (4 and 5) consist partially of isosorbide. In order to check the influence of microwaves and possible specific non-thermal microwave effects, the reactions were comparatively performed inside a thermostated oil bath under similar conditions. The reaction conditions were varied to optimize both yields and molecular weights of poly(ether-ester)s. The reaction proceeded roughly five times faster under microwave irradiation, the polycondensation being almost completed (yields upto approximately 95%) within 5 min to afford a series of novel poly(ether-ester)s based with relatively high average molecular weights (M_w upto approximately 8000). The resulting poly(ether-ester)s were characterized by NMR (¹H and ¹³C), FT-IR spectrometry, SEC measurements and MALDI-TOF mass spectrometry. Thermal properties of the poly(ether-ester)s (4 and 5) were investigated by means of differential scanning calorimetry (DSC).     

Supramolecular assemblies in the crystals of carboxylate salts prepared from a ferrocene β-aminoalcohol

(Ferrocenylmethyl)(2-hydroxyethyl)amine (1) reacts with mono- (CH₃CO₂H and PhCO₂H) and dicarboxylic acids (HO₂C(CH₂)_nCO₂H (n = 0-2), (E)- and (Z)-HO₂CCHCHCO₂H) to give the respective carboxylates, viz [1H](RCO₂) (2, R = CH₃; 3, R = Ph), [1H]₂(O₂C(CH₂)_nCO₂) (4, n = 0; 5, n = 1; 6, n = 2), [1H]₂((E)-O₂CCHCHCO₂) (7) and [1H]₂((Z)-HO₂CCHCHCO₂) (8), as defined crystalline solids. Crystal structures of 2-8 have been determined by single-crystal X-ray diffraction analysis, revealing extensive hydrogen bonding interactions based predominantly on charge-supported N⁺-H···O⁻ and O-H···O⁻ hydrogen bonds, and on C-H···O contacts. Whereas the crystal assemblies of the monocarboxylate salts propagate preferentially in one dimension (2: cross-linked chains, 3: columnar stacks), those of the salts prepared from the dicarboxylic acids (including hydrogenmaleate 8) are best described as layered composite arrays resulting via alternation of polar, hydrogen-bonded layers and of non-polar sheets constituted by the ferrocenyl substituents.