Complexes of unsymmetric bis-hydrazide ligands: crystal structures and properties

Two unsymmetric bis-aroyl-hydrazines, N′-(2-hydroxybenzoyl)isonicotinohydrazide (L1) and N′-(2-hydroxybenzoyl)nicotinohydrazide (L2), were synthesized through reactions of salicyl hydrazide with isonicotinoyl chloride and nicotinoyl chloride, respectively. Reactions of metal salts with L1 or L2 gave three new complexes, [Cd(L1)₂(SCN)₂] _n (1), [Zn(L1)₂Cl₂]?·?H₂O (2), and [Zn(L2)₂Cl₂] (3). Complex 1 features a 1-D double-chain structure built by SCN^– bridging six-coordinate Cd^II centers while 2 and 3 are mononuclear Zn^II complexes. In 1–3, isomeric ligands L1 and L2 coordinate with metal ions in a terminal coordination mode. Ligands L1 and L2 through O–H···N and N–H···O hydrogen-bonding interactions in 1–3 are crucial for the structure extension into 3-D supramolecular structures of 1 and 2, or 2-D sheet of 3. Complexes 1–3 emit interesting blue-green luminescence. Thermal behaviors of 1–3 as well as the specific rotation of 2 were also investigated.     

U(VI) and Zn(II) coordination complexes with 5-[N-acetato(4-pyridyl)]tetrazolate anions

A U(VI) mononuclear coordination complex [UO₂(a4-ptz)₂·(H₂O)₃] (1) and a Zn(II) 1-D coordination polymer [Zn(a4-ptz)₂·(H₂O)₂]·2H₂O (2) have been synthesized with 5-[N-acetato(4-pyridyl)]tetrazolate (a4-ptz) as ligand. Complex 1 has a slightly distorted pentagonal bipyramid around each U center. Complex 2 is octahedral with four a4-ptz and two water ligands. Each Zn center is linked by carboxylate-O(1) and tetrazolate-N(2) of a4-ptz forming a 1-D polymeric chain. Complexes 1 and 2 are self-assembled to form 3-D supramolecular structures through hydrogen bonds. The luminescence properties of 1 and 2 were investigated at room temperature in the solid state. The results suggest that 1 and 2 may be useful as photoactive materials.     

Two manganese(II) coordination polymers driven by (iso)nicotinoyl-hydrazone blocks and pseudohalide ancillary ligands: syntheses,structural features,and magnetic properties

Two coordination polymers, [Mn₂(μ-L¹)₂(μ-N₃)₂]_n (1) and [Mn(μ-HL²)(SCN)₂]_n (2), were assembled in a single-pot from MnCl₂·4H₂O, HL¹ (2-acetylpyridine isonicotinoylhydrazone) or HL² (2-acetylpyridine nicotinoylhydrazone) and ancillary ligand sources (NaN₃ or NH₄NCS). The products were fully characterized, including by single-crystal X-ray diffraction, which revealed a 2-D metal–organic layer in 1 and a 1-D zigzag coordination chain in 2. Both 1 and 2 are constructed from six-coordinate Mn(II) nodes that adopt distorted octahedral (MnN₅O) environments; the adjacent nodes are driven by the μ-L¹ and μ-N₃ linkers in 1 or μ-HL² linkers in 2 to form different metal–organic networks. Their topological classification was performed, disclosing the hcb and 2C1 topology in 1 and 2, respectively. Different weak non-covalent interactions promote dimensionality extension. Variable-temperature magnetic susceptibility measurements were carried out, revealing weak ferromagnetic and antiferromagnetic interactions in 1 and 2, respectively.     

Zur Synthese kondensierter Heterocyclen aus Malonsäurederivaten

Zusammenfassung Die Reaktion der 2-alkylsubstit. Benzoxazole (1 a, 1 c), Benzothiazole (1 b, 1 d) und des Benzoselenazols (1 e) mit Malonsäuretrichlorphenylestern (2 a, b) führt in Abhängigkeit von der Art des Alkylrestes zu den kondensierten Hydroxypyridonen3 oder deren Hydroxypyronoderivaten4. In analoger Weise reagiert 2,5-Dimethyl-thiadiazol (5) mit2 a zu einem Pyrono-thiadiazolo-pyridon (7).

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Syntheses of heterocycles, CLIX: Syntheses of fused heterocycles from malonic acid derivatives

The reaction of 2-substituted benzoxazoles (1 a, 1 c), benzothiazoles (1 b, 1 d) and benzoselenazole (1 e) with 2,4,6-trichlorophenyl malonates (2 a, b) gives—depending on the nature of the alkyl substituent—the fused hydroxypyridones3 or their hydroxypyrono derivatives. 2,5-Dimethyl-thiadiazol5 reacts in the same way with2 a yielding the pyrono-thiadiazolopyridon7.

     

Bis(3-cyano-pentane-2,4-dionato) Co(II) as a linear building block for coordination polymers: combinations with two polypyridines

Two types of bis(β-diketonato) Co(II) complexes, [Co(CNacac)₂] (CNacac?=?3-cyano-pentane-2,4-dionato), and [Co(dbm)₂] (dbm?=?dibenzoylmethanato or 1,3-diphenyl-propane-1,3-dionato) were examined as linear building blocks for the construction of coordination polymers in combination with two oligopyridines, 1,4-bis(4,2’:6’,4”-terpyridin-4’-yl)benzene (L1) and 1,3-bis(3,2’:6’,3”-terpyridin-4’-yl)benzene) (L2). From combinations of [Co(CNacac)₂] with L1 and L2, 2-D coordination polymers, [Co(CNacac)₂]₂(L1)·(CHCl₃)·(CH₃OH) (CoCN-1) and [Co(CNacac)₂](L2)_1/2·(tetrachloroethane)_3/2 (CoCN-2), are obtained. Both CoCN-1 and CoCN-2 have 2D (4,4) net structures, in which L1 and L2 are tetradentate. In contrast, combination of [Co(dbm)₂] with L2 affords a 1-D coordination polymer, [Co(dbm)₂](L2)·4(CH₃OH) (Codbm-1), in which L2 is bidentate. L2 as a tetradentate ligand was inhibited by bulky phenyl rings in [Co(dbm)₂]. These results indicate that [Co(CNacac)₂] with a relatively simplified structure is useful as a linear building block in combinations with bulky oligopyridines.     

DIBUTADIENYL PIPERAZINE,DIBUTADIENYL HOMOPIPERAZINES AND BUTADIENYL-SUBSTITUTED PIPERIDINES FROM MONOSUBSTITUTED HALODIENES

Compounds 3a–k were obtained from the reactions of compounds 1a–k with homopiperazine (2) in CH ₂ Cl ₂ . Compounds 1a–b, 1d–f, and 1h–l gave compounds 5a–b, 5d–f, and 5h–l with 2-methylpiperazine (4) in dichloromethane. Compounds 7c and 9c were obtained from the reactions of compound 1c with 4-ethoxycarbonyl piperazine (6) and 4-piperidinol (8) in CH ₂ Cl ₂ . Compounds 1a and 1f gave compounds 11a and 11f with 4-methylpiperazine (10), and compound 13f was obtained from the reactions of compound 1f with 4-methylpiperidine (12) in CH ₂ Cl ₂ .     

Synthesis and Characterization of Novel Chiral (1R,2R)-1,2-Bis[5-(Aminomethylphospinic Acid)-1,3,4-Thiadiazol-2-YL]Ethane-1,2-Diols

Abstract

(1R,2R)-1,2-bis[5-(arylideneamino)-1,3,4-thiadiazol-2-yl]ethane-1,2-diol (2a–d) were synthesized by using appropriate aldehydes and (1R,2R)-1,2-bis(5-amino-1,3,4-thiadiazol-2-yl)ethane-1,2-diol (1) as a starting compound. Then, the phosphinic acid component (3a–d) were obtained from (2a–d) and hypophosporus acid. In addition, the structures of the novel chiral compounds (2a–d) and (3a–d) were confirmed by elemental analyses, IR, ¹H-NMR, ¹³C-NMR, and ³¹P-NMR spectra.

¹H NMR and ¹³C NMR spectra for 1, 2a, and 3a (Figures S1–S6) are available online in the Supplemental Materials.     

Syntheses and structures of three zinc coordination polymers with 1-D zigzag chain,double chain,and triple chain

Three new coordination polymers [Zn(btp)(NCS)₂] _n (1), {[Zn(btp)₂(dca)₂] _n (2), and {[Zn(btp)₃](BF₄)₂} _n (3) (btp = 1,3-bis(1,2,4-triazol-1-yl)propane, dca = dicyanamide) were synthesized and characterized. In 1, 2, and 3, one-, double-, triple-btp ligands link two Zn(II) atoms and extend to form a 1-D zigzag chain for 1, 1-D double chain for 2, and 1-D triple chain for 3. The conformations of the btp ligands in 1, 2, and 3 are analyzed. 1, 2, and 3 have emission maxima at approximately 405, 407, and 409 nm, respectively, in the solid state at room temperature.     

Coordination-driven synthesis of Ag(I) compounds based on a double emission ligand consisting of 1,3,4-oxadiazole and cyclotriphosphazene units

A new ligand (L) which consists of cyclotriphosphazene and 1,3,4-oxadiazole units is reported. Two new Ag(I) coordination compounds {[Ag(L)SO₃CF₃] _n (1) and Ag₂L₂(NO₃)₂ (2)} based on L and Ag(I) salts are obtained. Compound 1 features a 1-D chain, in which the ligand L adopts a divergent trans-conformation, whereas 2 is a discrete binuclear Ag(I) molecule in which L adopts convergent cis-conformation. Compounds 1 and 2 are fully characterized by ¹H-NMR, Infrared, elemental analysis, X-ray powder, and single-crystal diffraction. Luminescent properties of 1 and 2 are investigated.     

Synthesis,structures, catalytic,and anticancer activities of some coordination compounds involving two new triazole derivatives

Five N-heterocyclic carboxylate-based coordination complexes, [Co(L¹)₂(H₂O)₂]·2H₂O (1), [Cd(L¹)₂(H₂O)₂]·2H₂O (2), [Co(L²)(H₂O)₃] (3), [Ni(L²)(H₂O)₃] (4), and [Cu₂(L²)₂(H₂O)₂] (5), have been synthesized and characterized by elemental analysis, IR spectroscopy, Powder X-ray diffraction, thermogravimetric analyses, and single-crystal X-ray crystallography, where HL¹ is 2-((5-amino-1H-1,2,4-triazol-3-yl)thio)acetic acid and H₂L² is 2-((5-amino-1-(carboxymethyl)-1H-1,2,4-triazol-3-yl)thio)acetic acid. In these complexes, the hydrogen bonds (H-bonds) play an important role in their packing structures. Complex 1 has nine H-bonds showing a 3-D sqc38 topology. Complex 2 has 17 H-bonds exhibiting a 3-D hxl network. Complexes 3 and 4 are isomorphic, both of which possess ten H-bonds to present a 3-D btc topology. Complex 5 with eight H-bonds forms a 2-D sq1 structure. In addition, complex 3 catalyzes the decolorization of methyl orange. Meanwhile, 1, 3, and 5 show certain anticancer activities to inhibit the growth of HepG2 cells.     

Three cobalt coordination polymers based on bis(1,2,4-triazol-1-ylmethyl)benzene positional isomer ligands and thiocyanate

The reaction of three positional isomer ligands of bis(1,2,4-triazol-1-ylmethyl)benzene and Co(NCS)₂ gives three coordination polymers [Co(obtz)₂(NCS)₂] _n (1), [Co(mbtz)₂(NCS)₂] _n (2), and {[Co(bbtz)₂(NCS)₂]?·?2DMF} _n (3). Polymers 1 and 2 are comprised of similar 1-D double chains. In 1, each chain forms π–π stacking interactions with four adjacent chains (two above and two below) to extend to a 3-D supramolecular network. Polymer 3 is a neutral 2-D (4,4) network. The dangling NCS^? inserts into the window of adjacent layers in a mutual relationship and result in a 2-D?→?3-D polythreaded network in 3. The thermal stability and the diffuse reflectance UV-Vis spectroscopy of 1, 2, and 3 were measured.     

两种马来二腈基二硫烯镍(Ⅲ)近红外吸收配合物的结构、磁和电化学性质

合成并表征了两种新的离子对化合物(BMIB)[(Ni(mnt)2]2(1)和(BMIO)[(Ni(mnt)2)]2(2)(其中mnt2-=马来二氰基二硫烯,BMIB=1,4-bis(1-methylimidazolium)butane,BMIO=1,8-bis(1-methylimidazolium)octane)。在化合物1中,[Ni(mnt)2]-阴离子排列形成阴离子三聚体以及与阳离子交替排列形成阴、阳离子混合柱。化合物2的堆积结构与化合物1不同,阴、阳离子堆积成非等间距的阴、阳离子柱。化合物1和2分别在861和857 nm近红外波段处出现较强的近红外吸收。电化学性质研究结果表明,2个化合物均出现了两对不可逆的电化学氧化/还原过程,且平衡阳离子的烷基链长显著影响化合物的氧化、还原电极电势。变温磁化率测量表明,在2～400 K温度范围内,化合物1表现出弱的顺磁性质,变温摩尔磁化率遵循简单的Curie-Weiss定律。化合物2表现出低维反铁磁交换自旋体系磁化率特征。     

Two independent, 1-D metal–organic nanotubes based on rings or helical chain units

Three coordination polymers {[Mn(bte)(NO₂-1,3-bdc)(H₂O)]·H₂O}_n (1), {[Mn(btp)(NO₂-1,3-bdc)(H₂O)]·2H₂O}_n (2), and {[Mn(btb)(NO₂-1,3-bdc)(H₂O)]·H₂O}_n (3) (bte, 1,2-bis(1,2,4-triazol-1-yl)ethane; btp, 1,3-bis(1,2,4-triazol-1-yl)propane; btb, 1,4-bis(1,2,4-triazol-1-yl)butane, NO₂-1,3- H₂bdc, 5-nitroisophthalic acid) were synthesized by combination of bte, btp, and btb, conformationally flexible ligands with different spacer lengths, and the rigid [NO₂-1,3-bdc]^2?. In 1, two [NO₂-1,3-bdc]^2? anions link adjacent [Mn₂(bte)₂] rings to give an independent, 1-D metal–organic nanotube (MONT). The structure of 2 is an undulating 2-D (4,4) network. In 3, the combination of a [Mn(btb)]_n single helical chain and two [Mn(NO₂-1,3-bdc)]_n linear chains assemble an intriguing independent, 1-D MONT. An interesting structural feature of 1 and 3 is that the nitro groups of each 1-D MONT interpenetrate into two adjacent 1-D MONTs to form a 1-D → 2-D interdigitated array. 3-D architectures in 1 and 3 are assembled via hydrogen bond interactions. The luminescent properties and thermal stabilities of 1, 2, and 3 were investigated.     

Ruthenium(II) carbonyl complexes of P,P and P,O donor diphosphine ligands,Ph2P(CH2)nPPh2 and Ph2P(CH2)nP(O)Ph2, n = 2, 3 and their activities in catalytic transfer hydrogenation reactions

The polymeric precursor [RuCl₂(CO)₂]_n reacts with the ligands, P∩P (a, b) and P∩O (c, d), in 1:1 M ratio to generate six-coordinate complexes [RuCl₂(CO)₂(?²-P∩P)] (1a, 1b) and [RuCl₂(CO)₂(?²-P∩O)] (1c, 1d), where P∩P: Ph₂P(CH₂)_nPPh₂, n = 2(a), 3(b); P∩O: Ph₂P(CH₂)_nP(O)Ph₂, n = 2(c), 3(d). The complexes are characterized by elemental analyses, mass spectrometry, thermal studies, IR, and NMR spectroscopy. 1a–1d are active in catalyzed transfer hydrogenation of acetophenone and its derivatives to corresponding alcohols with turnover frequency (TOF) of 75–290 h^?1. The complexes exhibit higher yield of hydrogenation products than catalyzed by RuCl₃ itself. Among 1a–1d, the Ru(II) complexes of bidentate phosphine (1a, 1b) show higher efficiency than their monoxide analogs (1c, 1d). However, the recycling experiments with the catalysts for hydrogenation of 4-nitroacetophenone exhibit a different trend in which the catalytic activities of 1a, 1b, and 1d decrease considerably, while 1c shows similar activity during the second run.     

Three Cd(II) coordination polymers based on a pyridyldicarboxylate: effect of coordinated water

Abstract

By systematic change of the solvothermal synthesis, three new coordination polymers, [Cd(L)?(H₂O)]?2H₂O (1), [Cd(L)?(H₂O)]?H₂O (2), and [Cd(L)] (3), have been synthesized based on a tritopic ligand 4-(pyridin-3-yl)isophthalic acid (H₂L). Compounds 1 and 2 show very similar two-dimensional (2D) bilayers further linked by interlayer hydrogen bonds into three-dimensional (3D) supramolecular structures, while 3 displays a 3D structure constructed form one-dimensional (1D) Cd-carboxyl chains. Notably, 1 and 2 have a pair of unusual isomers with the opposite orientation of coordinated H₂O on the metal centers, leading to different hydrogen bonding interactions. Thermal stabilities and solid-state photoluminescences for 1–3 were also investigated.     

Hydrothermal syntheses and structures of transition metal 2-(4,5-diphenyl-1H-imidazol-2-yl)benzoic acid complexes

Two new transition metal complexes, [Zn(Hdiba)₂(H₂O)]?·?H₂O (1) and [Cu(Hdiba)₂] (2) (H₂diba?=?2-(4,5-diphenyl-1H-imidazol-2-yl)benzoic acid), were synthesized and characterized by IR, elemental analysis, and single-crystal X-ray diffraction. Complex 1 exhibits a monomeric structure, while 2 displays a dimeric structure. Both structures extend to 2-D supramolecular networks via hydrogen bonds. Thermal stabilities of 1 and 2 and photophysical properties of 1 are also discussed.     

Multidentate bis(pyrazolylmethyl)pyridine ligands: coordination chemistry and binding properties with zinc(II) and cadmium(II) cations

The coordination chemistry and cationic binding properties of 2,6-bis(pyrazol-1-ylmethyl)pyridine (L1), 2,6-bis(3,5-dimethylpyrazol-1-ylmethyl)pyridine (L2), and 2,6-bis(3,5-ditertbutylpyrazol-1-ylmethyl)pyridine (L3) with zinc(II) and cadmium(II) have been investigated. Reactions of L2 with zinc(II) and cadmium(II) nitrate or chloride salts produced monometallic complexes [Zn(NO₃)₂(L2)] (1), [ZnCl₂(L2)] (2), [Cd(NO₃)₂(L2)] (3), and [CdCl₂(L2)] (4). Solid state structures of 1 and 3 confirmed that L2 binds in a tridentate mode. While the nitrates in the zinc complex (1) adopt monodentate binding fashion, in cadmium complex (3), they exhibit bidentate mode. L1–L3 show binding efficiencies of 99% for zinc(II), 60% for lead(II), and 30% for cadmium(II) cations from aqueous solutions of the metal ions. Theoretical studies using Density Functional Theory were consistent with the observed extraction results.     

Synthesis and characterization of calcium(II) coordination polymers based on phenylacetic acid

The syntheses, crystal structures, and thermal properties of the coordination polymers [Ca(H₂O)₂(L₁)₂]?·?H₂O (1) (L₁?=?4-methoxyphenylacetate) and [Ca(H₂O)₂(L₂)₂]?·?2H₂O (2) (L₂?=?2-chlorophenylacetate) are described. 1 and 2 can be dehydrated to the anhydrous [Ca(L₁)₂] (1a) or [Ca(L₂)₂] (2a), respectively. Compounds 1 and 2 crystallize in the non-centrosymmetric monoclinic space group P2₁ and the structures consist of a central Ca(II), two terminal waters, and two crystallographically unique L₁ (or L₂) anions, one of which functions as a chelating bidentate ligand. The second independent L₁ (or L₂) is tetradentate, coordinated in a μ₃-bridging mode leading to the formation of a 1-D coordination polymer. In the infinite chain extending along the b-axis, each Ca(II) is eight-coordinate and bonded to two terminal waters and six oxygens from four different L₁ or L₂ ligands.     

Tuning the topological net of two new copper(II) coordination polymers based on a paddle-wheel secondary building unit via altering the auxiliary ligands

Two new coordination polymers, [Cu(BDC)(L₁)_0.5]_n (1) and [Cu(BDC)(L₂)_0.5]_n (2) [H₂BDC=5-methyl-1,3-benzenedicarboxylic acid, L₁=1,4-bis(2-methyl-imidazol-1-yl) butane and L₂=1,4-bis(1-imidazol-yl)-2,5-dimethylbenzene], were synthesized from Cu(II), H₂BDC, and L₁/L₂. The carboxylate groups in 1 and 2 are bis-monodentate. By changing the N-donor ligands, 1 and 2 exhibit different topologies from a rob topological net to a twofold interpenetrating pcu net; however, they possess the same paddle-wheel secondary building unit in which Cu(II) has square-pyramidal geometry. The thermal stabilities of 1 and 2 are investigated.     

Maximizing the Solar Energy Storage of the Norbornadiene-Quadricyclane System: Mono-Heteroatom Effect by DFT Calculations

An attempt was made to maximize the solar energy storage in a norbornadiene (1)/quadricyclane (2) system, through the angling of mono-heteroatoms at C₁, C₂, or C₇ atoms of 1 and 2 and calculating the corresponding energies at the B3LYP/6-311++G(3df,2p) level of theory. Free energy gaps between 1 _nX and 2 _nX, Δ G_{(1nx) ? (2nx)}, as well as solar energy storage was the most for 1 _1As (–24.20),1 _2N (–32.48), and 1 _7As (–29.77) in kcalmol^?1 from group V of the Periodic Table.