Synthesis,structural characterization,and photocatalytic study of transition metal coordination polymers constructed from mixed ligands

Three 3-D coordination polymers, [Cu(cca)(4,4′-bipy)]_n (1), [Co₃(pda)₃(1,10′-phen)₂]_n (2), and [Co(pda)(1,10′-phen)]_n (3), have been synthesized from 4-carboxycinnamic acid (cca), 1,4′-phenylenediacrylic acid (pda), 4,4′-bipyridine (4,4′-bipy), 1,10′-phenanthroline (1,10′-phen), and Cu and Co salts under different conditions. The X-ray crystal structures of these three complexes are presented. Complex 1 exhibits a threefold 3-D α-Po interpenetration network. Complex 2 with a 3-D framework with six-connected single α-Po framework constructed from Co₃ unit has been synthesized and characterized. Complex 3 shows a 3-D framework with bcu topology composed of 1-D rod-shaped secondary building units. Furthermore, the photocatalytic properties of 2 were studied. When excited by UV light, 2 exhibits photocatalytic activity, in 300?min, about 71% Rhodamine B decomposes.     

Ancillary ligand-controlled assembly of three coordination polymers: synthesis,characterization, luminescent,and catalytic properties

Abstract

By changing the ancillary ligands, three new zinc-based coordination polymers (CPs), {[Zn(4,4′-bpy)(H₂O)₄]·(TDC)·(H₂O)}_n (1), [Zn(2,2′-dmbpy)(TDC)]_n (2), and [Zn₂(3,3′-dmbpy)(TDC)₂]_n (3) (H₂TDC =2,5-thiophenedicarboxylic acid, 4,4′-bpy =4,4′-bipyridine, 2,2′-dmbpy =2,2′-dimethyl-4,4′-bipyridine, 3,3′-dmbpy =3,3′-dimethyl-4,4′-bipyridine) have been synthesized under the same reaction conditions (H₂O, pH =7–8, and 140°C) and were structurally characterized. 1 is a linear chain structure and further connected into a 3-D structure through hydrogen bonds. 2 shows a 2-D (4,4) network when the dinuclear [Zn₂(COO)₄N₂] building unit is regarded as a six-connected node. 3 has a twofold-interpenetrating 3-D zinc-organic framework pcu topology. Furthermore, 1–3 show strong photoluminescence at room temperature in the solid state, and the catalytic activities of 1–3 for degradation of methyl orange in a Fenton-like process have been investigated. The results suggest that the ancillary ligands influence the final resulting CPs.     

SYNTHESIS AND CHEMISTRY OF SOME NEW 2-MERCAPTOIMIDAZOLE DERIVATIVES OF POSSIBLE ANTIMICROBIAL ACTIVITY

4,5-Diaryl-2,3-dihydro-2-mercaptoimidazoles (2a–e) were synthesized. They reacted with chloroacetic acid in gl. acetic acid/Ac ₂ O in presence of anhyd. sodium acetate afforded 5,6-diaryl-2,3-dihydro-imidazo[2,1-b]thiazol-3-ones (3a–d). Also these compounds were prepared by the action of chloroacetyl chloride on compounds (2) in pyridine. Compounds (3a–d) on condensation with aromatic aldehydes yield 2-arylmethylene-5,6-diaryl-2,3-dihydroimidazo[2,1-b]-thiazol-3-ones (4a–q). The latter compounds were prepared directly by the reaction of (2) with chloroacetic acid and the aromatic aldehydes. Compounds (3a–d) coupled with aryldiazonium salts in pyridine to give 2-arylhydrazono-5,6-diaryl-2,3-dihydroimidazo[2,1-b]thiazol-3-ones (5a–r). Also compounds (2) when reacted with 2 or 3-bromopropionic acid afford 2,3-di-hydro-5,6-diaryl-2-methylimidazo[2,1-b]thiazol-3-ones (6a–d) and 2,3-di-hydro-6,7-diaryl imidazo-[2,1-b]-1,3-thiazin-4-ones (7a–d), respectively. Compounds (3, 6, and 7) have been cleaved by aromatic amines to give the corresponding 2-(4′,5′-diaryl-2′,3′-dihydroimidazol-2′-yl)thioacetanilide (8a–f), 2-(2′,3′-dihydro-4′,5′-diaryl imidazol-2′-yl)thiopropionamide (9a–c), and 3-(2′,3′-dihydro-4′,5′-diaryl-imidazol-2′-yl)thiopropionamide (10a–d) respectively. All the prepared compounds show considerable antimicrobial activity against bacteria, yeast, and fungi.     

SYNTHESIS OF NEW 8-METHOXY-4-METHYL-3-(N-[2′-AMINO-(1′,3′,4′)THIA/OXA-DIAZOL-5′-YL]-SUBSTITUTED METHYL)-AMINO THIOCOUMARINS

8-Methoxy-4-methyl-3-(N-[2′-amino-(1′, 3′,4′)thia/oxa-diazol-5′-yl] substituted methyl)-amino thiocoumarins 6(a–f) and 7(a–f), were synthesized by using the unreported 8-methoxy-4-methyl-3-[N-(2′-oxo-2′-methoxy-1′-substituted ethan-1′-yl) amino thiocoumarins as key intermediates.     

Studies on Flavans. III. The Total Synthesis of (±)-7,4′-Dihydroxy-3′-methoxyflavan, (±)-7,3′-Dihydroxy-4′-methoxyflavan,and (±)-7,4′-Dihydroxyflavan

Abstract

The first total synthesis of (±)-7,3′-dihydroxy-4′-methoxyflavan (1) and (±)-7,4′-dihydroxy-3′-methoxyflavan (2), along with the synthesis of (±)-7,4′-dihydroxyflavan (3), three naturally occurring flavans, were described. The key step is the cyclization of 1,3-diaryl-1-propanol by BF₃·Et₂O.     

Self-assembly and crystal structures of coordination polymers constructed by 4′-hydroxyisoflavone-3′-sulfonates with Cs(I) and Rb(I)

Four coordination polymers, [CsL1(H₂O)₂]·H₂O (1), [CsL2(H₂O)₂]·H₂O (2), [Rb₂(L2)₂(H₂O)₂]·2H₂O (3) and [RbL3(H₂O)] (4), were synthesized by Cs(I), Rb(I) and 4′-hydroxyisoflavone-3′-sulfonates L1–L3 [L1 = 7-methoxy-4′-hydroxyisoflavone-3′-sulfonate, L2 = 7-ethoxy-4′-hydroxyisoflavone-3′-sulfonate, L3 = 7-ethoxy-4′,5-dihydroxyisoflavone-3′-sulfonate]. The crystal structures of 1–4 were determined by single-crystal X-ray diffraction. The influences of 4′-hydroxyisoflavone-3′-sulfonate ligands and Cs⁺, Rb⁺ on their structural features and self-assembly were investigated. The sulfonates of L1–L3 not only coordinate with Cs⁺ or Rb⁺ directly, but also bridge the organic region and the inorganic region in 1–4. Non-covalent interactions such as coordination interaction, π–π stacking interaction and hydrogen bonding assembled 1–4 into 3-D networks together with the electrostatic interactions between Cs⁺, Rb⁺ and the sulfonate anions.     

Synthesis of New Dioxacyclophanes Derived from 1,1′-Binaphthyl-2, 2′-diol

Abstract

The Williamson reaction between (R,S)-[1,1′-binaphthyl]-2, 2′-diol 1 and (R,S)-2,2′-bis (bromomethyl)-1,1′ binaphthyl 2 in acetone, gave the diastereoisomeric dioxacyclophanes (R?, S?)-3a and (R?, R?)-3b in high yield.     

5′-O-TBDMS-3′-O--(1H-Imidazole-1-Thiocarbonyl)thymidine: A Novel Intermediate for the Synthesis of 2,3′-Anhydrothymidine

Thermal or base-promoted conversion of 5′-O-TBDMS-3′-O-(1H-imidazole-1-thiocarbonyl)thymidine (1) afforded 5′-O-TBDMS-2,3′-anhydro-thymidine (2), a pivotal intermediate for the transformation of the 3′-hydroxy group of 2′-deoxyribonucleosides, in high yield.     

Chemical constituents from the flowering buds of Bauhinia tomentosa Linn (FBBT)

Isolation and characterisation of compounds, 1-(2′-hydroxy-4′-methoxyphenyl)-3-(4″-methoxyphenyl)-2-hydroxypropane-1,3-dione (1), 5-hydroxyflavone (2), 3,5,7,3′,4′-pentahydroxyflavone (3), 3,5,7,2′,4′-pentahydroxyflavone (4) and 5,7,3′,4′-tetrahydroxyflavone-3-O-rhamnoside (5) are reported from the air dried flowering buds of Bauhinia tomentosa Linn. Their structures are determined on the basis of extensive chemical and spectral evidences. Compound (1) is reported for the first time from the plant source. While compounds (2) and (4) are reported for the first time from this genus, compound (2) is reported for the second time from the natural source.     

Indium(III) complexes containing bithiazole derivatives,chloride, methanol,and dimethyl sulfoxide: X‐ray studies,spectroscopic characterization,and thermal analyses

[In(dm4bt)Cl₃(MeOH)]?·?0.5dm4bt (1) (dm4bt is 2,2′‐dimethyl‐4,4′‐bithiazole) and [In(4bt)Cl₃(MeOH)] (2) (4bt is 4,4′‐bithiazole) were prepared from the reaction of 4,4′‐bithiazole and 2,2′‐dimethyl‐4,4′‐bithiazole with InCl₃?·?4H₂O in methanol, respectively. [In(4bt)Cl₃(DMSO)] (3) was also prepared from recrystallization of 2 in DMSO. These complexes were characterized by IR, UV‐Vis, ¹H NMR, ¹³C{¹H} NMR, and luminescence spectroscopy and their structures were studied by single‐crystal X‐ray crystallography. The thermal stabilities of 1 and 3 were studied by thermogravimetric and differential thermal analyses.     

Synthesis and Photochemical Properties of Covalently-Linked Dimers of Ruthenium(II) Tris (Bipyridine) Complex: Comparison with Ru(II)(bpy)2 (Poly-4-Methyl-4′-Vinylbipyridine)

Covalently linked dimers of Ru(bpy)₃ ²⁺ (3 and 4) connected by two or three carbon atoms were synthesized as models for Ru(bpy)₃ ²⁺-containing vinyl polymer (1). The luminescence properties of 3 and 4 were compared with those of its component monomer, 4,4′-dimethyl-2,2′-bipyridine-bis(2,2′-bipyridine)ruthenium(II) complex (2). In excited 3 and 4, intramolecular interaction leading to enhanced quenching was not observed. Electron-transfer quenching of the excited dimer with methylviologen (MV²⁺) and the zwitterionic viologen, 1,1′-bis(3-sulfopropyl)4,4′-bipyridinium (SPV), was studied and compared with that of 1 and 2. The low quenching efficiency in 1, 3, and 4 systems can be ascribed to the steric hindrance of unexcited ruthenium complex. Energy migration between ruthenium complexes in the excited 1, 3, and 4 can be ruled out from the kinetic evidence.     

The construction of two lanthanide coordination polymers based on 5-hydroxyisophthalate and bipyridine

Two lanthanide coordination polymers, [Tm₂·(5-IPA)₄·(2,2′-Hbipy)₂]·3H₂O (1, 5-H₂IPA?=?5-hydroxyisophthalic acid, 2,2′-bipy?=?2,2′-bipyridine) and [Er·(5-HIPA)₃·(4,4′-bipy)₃·(H₂O)₂]·3H₂O (2, 4,4′-bipy?=?4,4′-bipyridine), have formed by hydrothermal synthesis. Complex 1 exhibits a 2-D coordination network containing parallelepiped-shaped voids occupied by guest 2′2-bipy molecules. Complex 2 possesses a 1-D linear chain structure. The 1-D chains are linked by 4,4′-bipy molecules to form a 3-D supramolecular framework. IR spectroscopy, elemental analysis, and thermogravimetric analysis were also investigated.     

A series of multidimensional MOFs incorporating a new N-heterocyclic building block: 5,5′-Di(pyridin-3-yl)-3,3′-bi(1,2,4-triazole)

Using the N-heterocyclic building block 5,5′-di(pyridin-3-yl)-3,3′-bi(1,2,4-triazole) (3,3′-H₂dbpt), four 3-D coordination polymers with diverse connectivity, [M(3,3′-dbpt)]_n, M=Co (1), M=Ni (2), M=Zn (3), and [Cd₂(3,3′-dbpt)Cl₂]_n (4), were constructed. By changing the central metal ions, 3,3′-H₂dbpt had three different coordination modes. Consequently, 1–3, which are isostructural, have a 3-D 4-connected topology with (4².8⁴) Schläfli symbol. 4 has a 3-D (4, 6)-topology, with (4³.6³)₂(4⁶.6⁶.8³) Schläfli symbol. Both 1 and 2 reveal weak antiferromagnetic behavior. In addition, 3 and 4 exhibit purple and blue emission bands, respectively. These results indicate that 3,3′-H₂dbpt is an excellent multi-connection linker to construct MOFs with interesting structures and properties.     

Pyridazine Derivatives and Related Compounds Part 19: 1 The Synthesis of Different Heterocycles from Ethyl 5-Amino-3,4-diphenylthieno[2, 3-c]pyridazine-6-carboxylate

7-substituted pyrido[2′, 3′: 4, 5]thieno[2, 3-c]pyridazines and 6-substituted pyrimido- [4′, 5′: 4, 5]thieno[2′, 3′: 4, 5]pyridazines were synthesized starting from ethyl 5-aminothieno[2′, 3′: 4, 5]pyridazino-6-carboxylate 1. The reaction of amino ester 1 with benzoyl isothiocyanate affords thiourea derivative 8, which undergoes further transformation to the related fused heterocyclic systems.     

Preparation and Structure of (E)-1-(3′-Hydroxy-2-Furanyl)-3-(3″-Hydroxy-4″-Methoxyphenyl)-2-Propen-1-One

Abstract

A facile procedure is presented for the synthesis of (E)-1-(3′-hydroxy-2′-furanyl)-3-(3″-hydroxy-4″-methoxyphenyl)-2- propen-1-one (6). Galactosylisomaltol (1) was condensed with isovanillin (2) under strong alkaline conditions at 25 [ddot]C to form (E)-1-(3′-O-β-D-galactopyranosyloxy-2′-furanyl)-3-(3″- hydroxy-4″-methoxyphenyl)-2-propen-1-one (4). (E)-1-(3′-hydroxy-2′-furanyl)-3-(3″-hydroxy-4″-methoxyphenyl)-2-propen-1-one (6) was obtained by acid hydrolysis of 4 in a 53.9% yield. This hetero-cyclic 2-propen-1-one was characterized on the basis of spectral data (IR and ¹H NMR), physicochemical properties, and conversion to a mono-O-acetyl derivative.     

Dinucleoside (5′ → 3′)-O,S-Phosphorodithioates - New Class of Dinucleotide Analogues

Abstract

Nucleoside 3′-0- and 5′-O-phosphorodithioates have been recently described by Caruthers et al.¹ as a new type of nucleotide analogues. These compounds have also been obtained in our Laboratory by one-pot dithiaphospholane approach.² We now report on the transformation of some of these derivatives into new class of dinucleotide analogues. We have found that nucleoside 3′-O-phosphorodithioates (1) react in DMF solution with 5′-bromo-5′-deoxythymidine to give in high yield corresponding dinucleoside (5′→3′)-O,S-phosphorodithioates (2) - first examples of a new class of dinucleotide analogues possessing the internucleotide phosphorothioate linkage with one of the sulfur atoms in a 3′-bridging position.     

DNA-binding and cleavage activity of polypyridyl ruthenium(II) complexes

Polypyridyl ruthenium(II) complexes [Ru^II(3-bptpy)(dmphen)Cl]ClO₄ (1), [Ru^II(3-cptpy)(dmphen)Cl]ClO₄ (2), [Ru^II(2-tptpy)(dmphen)Cl]ClO₄ (3), and [Ru^II(9-atpy)(dmphen)Cl]ClO₄ (4) {where 3-bptpy?=?4′-(3-bromophenyl)-2,2′:6′,2″-terpyridine, 3-cptpy?=?4′-(3-chlorophenyl)-2,2′:6′,2″-terpyridine, 2-tptpy?=?4′-(2-thiophenyl)-2,2′:6′,2″-terpyridine, 9-atpy?=?4′-(9-anthryl)-2,2′:6′,2″-terpyridine, dmphen?=?2,9-dimethyl-1,10-phenanthroline} have been synthesized and characterized. The DNA-binding properties of the complexes with Herring Sperm DNA have been investigated by absorption titration and viscosity measurements. The ability of complexes to break the pUC19 DNA has been checked by gel electrophoresis. The experimental results suggest that all the complexes bind DNA via partial intercalation. The results also show that the order of DNA-binding affinities of the complexes is 4?<?3?<?2?<?1, confirming that planarity of the ligand in a complex is very important for DNA-binding.     

Stereoselective Preparation of 1-[5-O-(tert-Butyldimethylsilyl)-2,3-dideoxy-3-iodo-β-D-threo-pentofuranosyl]thymine from Thymidine: An Efficient Entry to 3′,4′-Unsaturated Nucleoside

The title compound (13) has been synthesized from 5′-O-TBS-thymidine (8) through a highly stereoselective iodination of the 3′-hydroxyl group utilizing I₂/PPh₃/imidazole. This method provides an efficient entry to the 3′,4′-unsaturated derivative (7).     

Syntheses of Novel 3-Substituted-2′-deoxy-3-deazauridine Nucleosides

Syntheses of novel 3-ethynyl (8), 3-vinyl (10) and 3-acetoxy (13)-2′-deoxy-3-deazauridine analogs starting from the protected 2′-deoxy-3-deazauridine derivative 4 are described.     

Studies on Organophosphorus Compounds VII1,2: Transformation of Steroidal Ketones with Lawesson's Reagent into Thioxo and Heterofused Steroids. Results of Antimicrobial and Antifungal Activity

The reactivity of Lawesson's reagent (LR) toward some steroidal hormones was studied, 4-androsten-3,17-dione 2 reacted with LR to produce the corresponding thioxosteroids 3 and 4. Epi-androsterone 5 showed a great activity to LR and produced 3β-mercaptospiro-(androstan-17,4′dithiaphosphetan)thione 8 and the sulfide derivative 9. Also progesterone 10 reacted with LR to yield the thiaphospholo[3′, 4′:16,17]androsten-3-one 13 and the sulfide product 16. The new modified steroidal derivatives thieno[2′,3′:2,3]cholestan 18 and thieno[2′,3′:2,3]-androstan 20 were synthesized and examined against LR, the corresponding thiazaphosphorinothieno steroidal derivatives 23 and 24 were isolated respectively. The in vitro biological activity of some newly synthesized compounds against bacteria, yeast, and fungi was studied.