Four isostructural lanthanide(III) coordination compounds based on a new N‐oxydic pyridyl naphthalenediimide ligand: synthesis and characterization

Naphthalenediimides, an attractive class of electron‐deficient organic dyes with rich redox and photoredox properties, have been investigated extensively as building blocks for coordination networks or metal–organic frameworks in recent decades. However, most of the available work has focused on d‐block metal cations rather than f‐block lanthanide ions, whose complexes exhibit a large variability in coordination numbers. In this article, four coordination polymers composed of naphthalenediimides and lanthanide cations, namely catena‐poly[[[tris(nitrato‐κ²O,O′)lanthanide]‐bis{μ‐N,N′‐bis[(1‐oxidopyridin‐1‐ium‐3‐yl)methyl]‐1,8:4,5‐naphthalenetetracarboxdiimide‐κ²O:O′}‐[tris(nitrato‐κ²O,O′)lanthanide]‐μ‐N,N′‐bis[(1‐oxidopyridin‐1‐ium‐3‐yl)methyl]‐1,8:4,5‐naphthalenetetracarboxdiimide‐κ²O:O′] methanol disolvate], {[Ln(C₂₆H₁₆N₄O₄)_1.5(NO₃)₃]·CH₃OH}_n, with Ln = Eu, 1 , Gd, 2 , Dy, 3 , and Er, 4 , have been successfully synthesized under hydrothermal conditions. Single‐crystal X‐ray diffraction analyses revealed that the four compounds are isomorphic and that each asymmetric unit contains one nine‐coordinated Ln centre, one and a half diimide ligands, three nitrate anions and one uncoordinated methanol molecule. In addition, each metal centre is surrounded by nine O atoms in a distorted tricapped trigonal–prismatic geometry. Two centres are bridged by two cis ligands to form a ring, which is further bridged by trans ligands to generate one‐dimensional chains. Neighbouring chains are stacked via π–π interactions between pyridine rings to give a two‐dimensional structure, which is stabilized by π–π interactions between naphthalene rings, forming the final three‐dimensional supermolecular network. Solid‐state optical diffuse‐reflectance spectral studies indicate that compound 4 is a potential wide band gap semiconductor.     

Synthesis of ReI tricarbonyl complexes with various sulfur‐ and oxygen‐donating ligands: crystal structures of two ReI dinuclear structures bridged by S atoms

The synthesis and characterization of two dinuclear complexes, namely fac‐hexacarbonyl‐1κ³C,2κ³C‐(pyridine‐1κN)[μ‐2,2′‐sulfanediyldi(ethanethiolato)‐1κ²S¹,S³:2κ³S¹,S²,S³]dirhenium(I), [Re₂(C₄H₈S₃)(C₅H₅N)(CO)₆], ( 1 ), and tetraethylammonium fac‐tris(μ‐2‐methoxybenzenethiolato‐κ²S:S)bis[tricarbonylrhenium(I)], (C₈H₂₀N)[Re₂(C₇H₇OS)₃(CO)₆], ( 2 ), together with two mononuclear complexes, namely (2,2′‐bithiophene‐5‐carboxylic acid‐κ²S,S′)bromidotricarbonylrhenium(I), ( 3 ), and bromidotricarbonyl(methyl benzo[b]thiophene‐2‐carboxylate‐κ²O,S)rhenium(I), ( 4 ), are reported. Crystals of ( 1 ) and ( 2 ) were characterized by X‐ray diffraction. The crystal structure of ( 1 ) revealed two Re—S—Re bridges. The thioether S atom only bonds to one of the Re^I metal centres, while the geometry of the second Re^I metal centre is completed by a pyridine ligand. The structure of ( 2 ) is characterized by three S‐atom bridges and an Re…Re nonbonding distance of 3.4879 (5) Å, which is shorter than the distance found for ( 1 ) [3.7996 (6)/3.7963 (6) Å], but still clearly a nonbonding distance. Complex ( 1 ) is stabilized by six intermolecular hydrogen‐bond interactions and an O…O interaction, while ( 2 ) is stabilized by two intermolecular hydrogen‐bond interactions and two O…π interactions.     

A new lanthanum coordination polymer built from a semi‐rigid tripodal carboxylic acid ligand: synthesis,crystal structure and properties

By employing the semi‐rigid multidentate carboxylic acid ligand 4,4′,4′′‐{[(2,4,6‐trimethylbenzene‐1,3,5‐triyl)tris(methylene)]tris(oxy)}tribenzoic acid (denoted H₃L), a new lanthanum coordination polymer, namely poly[[bis(dimethylformamide)(μ₆‐4,4′,4′′‐{[(2,4,6‐trimethylbenzene‐1,3,5‐triyl)tris(methylene)]tris(oxy)}tribenzoato)lanthanum(III)] dimethylformamide tetrasolvate 0.25‐hydrate], {[La(C₃₃H₂₇O₉)(C₃H₇NO)₂]·4C₃H₇NO·0.25H₂O}_n or {[La(L)(DMF)₂]·4(DMF)·0.25(H₂O)}_n (DMF is dimethylformamide) ( 1 ), was prepared and characterized by single‐crystal X‐ray diffraction, elemental analysis, thermogravimetric analysis, IR spectroscopy and photoluminescence studies. The asymmetric unit contains one La^III cation, one anionic L^3? ligand, two coordinated DMF molecules, four free DMF molecules and one‐quarter of a free water molecule. Compound 1 possesses (3,6)‐connected two‐dimensional kgd topology sheets consisting of secondary building units of La₂ clusters and L^3? ligands, which further stack into three‐dimensional supramolecular networks through π–π interactions. Compound 1 exhibits a photoluminescence emission at room temperature, with a peak at 410 nm, owing to a ligand‐centred excited state.     

Manganese(II), lead(II) and cadmium(II) coordination complexes containing a tetrazole‐based acylamide ligand: synthesis and the influence of the metal ions on the structures

Three new manganese(II), lead(II) and cadmium(II) coordination complexes have been prepared by reaction of N‐(1H‐tetrazol‐5‐yl)cinnamamide (HNTCA) with divalent metal salts (MnCl₂, PbCl₂ and CdCl₂) in a mixed‐solvent system, affording mononuclear to trinuclear structures namely, bis(methanol‐κO)bis[5‐(3‐phenylprop‐2‐enamido)‐1H‐1,2,3,4‐tetrazol‐1‐ido‐κ²N¹,O]manganese(II), [Mn(C₁₀H₈N₅O)₂(CH₃OH)₂], (1), bis[μ‐5‐(3‐phenylprop‐2‐enamido)‐1H‐1,2,3,4‐tetrazol‐1‐ido]‐κ³N¹,O:N²;κ³N²:N¹,O‐bis{aqua[5‐(3‐phenylprop‐2‐enamido)‐1H‐1,2,3,4‐tetrazol‐1‐ido‐κ²N¹,O]lead(II)}, [Pb₂(C₁₀H₈N₅O)₄(H₂O)₂], (2), and hexakis[μ₂‐5‐(3‐phenylprop‐2‐enamido)‐1H‐1,2,3,4‐tetrazol‐1‐ido‐κ³N¹,O:N²]tricadmium(II), [Cd₃(C₁₀H₈N₅O)₆], (3). The structures of these three compounds reveal that the nature of the metal ions and the side groups of the organic building blocks have a significant effect on the structures of the coordination compounds formed. Intermolecular hydrogen bonds link the molecules into two‐dimensional [complex (1)] and three‐dimensional hydrogen‐bonded networks. Complexes (2) and (3) show significant fluorescence, while complex (1) displays no fluorescence.     

The influence of alkane spacer of bis(diphenylphosphino)alkanes on the nuclearity of silver(I): Syntheses and structures of P,P′-bridged clusters and coordination polymers involving dithiophosphates

The effect of the length of alkane spacer in diphosphines on the nuclearity of Ag(I) complexes containing dialkyl dithiophosphates (dtp) ligands has been investigated. 1,1-Bis(diphenylphosphino)methane (dppm) yielded tetranuclear [Ag₄(dppm)₂{S₂P(OEt)₂}₄] (1), [Ag₄(dppm)₂{S₂P(OⁱPr)₂}₄] (3), trinuclear [Ag₃(dppm)₃{S₂P(OEt)₂}₂](PF₆) (2), and a dinuclear [Ag₂(dppm)₂{S₂P(OⁱPr)}](PF₆) (4). The increase in spacer length from one methylene in dppm to two in 1,2-bis(diphenylphosphino)ethane (dppe) resulted in the formation of polymeric, [Ag(dppe){S₂P(OR)₂}]_∞ (R = Et, 5a and 5a′; ⁱPr, 5b), and [Ag₄(μ₃-Cl)(dppe)_1.5{S₂P(OR)₂}₃]_∞ (R = Et, 6a; ⁱPr, 6b). Compounds 5a, 5b, 6a and 6b were reported earlier [C.W. Liu, B.-J. Liaw, L.-S. Liou, J.-C. Wang, Chem. Commun. (2005) 1983]. Further increase in the chain length to four methylene units in 1,4-bis(diphenylphosphino)butane (dppb) yielded dppb-bridged polymers, [Ag(dppb){S₂P(OEt)₂}]_∞ (7) and [Ag₂(dppb){S₂P(OEt)₂}₂]_∞ (8). In all the polynuclear compounds, diphosphines acted as P,P′-bridging ligands, while the dtp ligands (S,S′-donors) adopted varieties of coordination patterns: S,S′-chelating (5, 7), S,S′-bridging (4), bimetallic-triconnective, μ₂:η²,η¹ (1, 3, 8), bimetallic-diconnective, μ₂:η² (2, 3) and trimetallic-triconnective, μ₃:η²,η¹ (6). Some of the complexes exhibit argentophilicity with Ag?Ag distances in the range, 2.918-3.360 Å. Concomitant bridging of two silver atoms either by dppm and dtp ligands (1, 3 and 4) or two dtp ligands (8) lead to close silver-silver contacts. The diphosphines (dppe and dppb) with longer spacer appeared to favor 1D or 2D polymers due to the flexibility of the spacer within the diphosphine unit by adopting anti conformation as opposed to syn conformation of the dppm linker is revealed in complexes.     

Novel quasi‐scorpionate ligand structures based on a bis‐N‐heterocyclic carbene chelate core: synthesis,complexation and catalysis

A series of novel quasi‐scorpionate CNC donor ligands, MeC(2‐C₅H₄N){CH₂(imidazole‐R)} (R = methyl, n‐butyl, n‐propenyl), in which a chelating bis(NHC) core is supplemented by a hemi‐labile pyridyl donor, were prepared. The coordination chemistry of these ligands was investigated with silver, palladium, rhodium and iridium. The single crystal X‐ray structures of [Rh(NC₂^Me)(COD)]Cl 8a and [Ir(NC₂^Pr)(COD)]Br 9b were determined. The catalytic potential of the rhodium and iridium complexes was assessed in the transfer hydrogenation of ketones; the iridium complexes, which show superior performance, form very effective and stable catalysts. Copyright © 2011 John Wiley & Sons, Ltd.     

Dinuclear cobalt and nickel complexes of a mercaptoacetic acid substituted 1,2,4‐triazole ligand: syntheses,structures and urease inhibitory studies

Because of its versatile coordination modes and strong coordination ability, the mercaptoacetic acid substituted 1,2,4‐triazole 2‐{[5‐(pyridin‐2‐yl)‐4H‐1,2,4‐triazol‐3‐yl]sulfanyl}acetic acid ( H₂L ) was synthesized and characterized. Treatment of H₂L with cobalt and nickel acetate afforded the dinuclear complexes {μ‐3‐[(carboxylatomethyl)sulfanyl]‐5‐(pyridin‐2‐yl)‐4H‐1,2,4‐triazol‐4‐ido‐κ²N¹,N⁵:N²,O}bis[aqua(methanol‐κO)cobalt(II)] methanol disolvate, [Co₂(C₉H₆N₄O₂S)₂(CH₃OH)₂(H₂O)₂]·2CH₃OH ( 1 ), and {μ‐3‐[(carboxylatomethyl)sulfanyl]‐5‐(pyridin‐2‐yl)‐4H‐1,2,4‐triazol‐4‐ido‐κ²N¹,N⁵:N²,O}bis[diaquanickel(II)] methanol disolvate dihydrate, [Ni₂(C₉H₆N₄O₂S)₂(H₂O)₄]·2CH₃OH·2H₂O ( 2 ), respectively. Complex 1 crystallized in the monoclinic space group P2₁/c, while 2 crystallized in the tetragonal space group I4₁/a. Single‐crystal X‐ray diffraction studies revealed that H₂L is doubly deprotonated and acts as a tetradentate bridging ligand in complexes 1 and 2 . For both of the obtained complexes, extensive hydrogen‐bond interactions contribute to the formation of their three‐dimensional supermolecular structures. Hirshfeld surface analysis was used to illustrate the intermolecular interactions. Additionally, the urease inhibitory activities of 1 , 2 and H₂L were investigated against jack bean urease, where the two complexes revealed strong urease inhibition activities.     

A new copper(II) supramolecular coordination polymer and a dinuclear compound with multifunctional 2‐amino‐5‐sulfobenzoic acid and flexible N‐donor ligands: synthesis,structure and characterization

Multifunctional 2‐amino‐5‐sulfobenzoic acid (H₂afsb) can exhibit a variety of roles during the construction of supramolecular coordination polymers. The pendant carboxylic acid, sulfonic acid and amino groups could not only play a role in directing bonding but could also have the potential to act as hydrogen‐bond donors and acceptors, resulting in extended high‐dimensional supramolecular networks. Two new Cu^II coordination compounds, namely catena‐poly[[[diaquacopper(II)]‐μ‐1,6‐bis(1H‐1,2,4‐triazol‐1‐yl)hexane‐κ²N⁴:N^4′] bis(3‐amino‐4‐carboxybenzenesulfonate) dihydrate], {[Cu(C₁₀H₁₆N₆)₂(H₂O)₂](C₇H₆NO₅S)₂·2H₂O}_n or {[Cu(bth)₂(H₂O)₂](Hafsb)₂·2H₂O}_n, (1), and bis(μ‐2‐amino‐5‐sulfonatobenzoato‐κ²O¹:O^1′)bis{μ‐1,2‐bis[(1H‐imidazol‐1‐yl)methyl]benzene‐κ²N³:N^3′}bis[aquacopper(II)] trihydrate, [Cu₂(C₇H₅NO₅S)₂(C₁₄H₁₄N₄)₂(H₂O)₂]·3H₂O or [Cu₂(afsb)₂(obix)₂(H₂O)₂]·3H₂O, (2), have been obtained through the assembly between H₂afsb and the Cu^II ion in the presence of the flexible N‐donor ligands 1,6‐bis(1H‐1,2,4‐triazol‐1‐yl)hexane (bth) and 1,2‐bis[(1H‐1,2,4‐triazol‐1‐yl)methyl]benzene (obix), respectively. Compound (1) consists of a cationic coordination polymeric chain and 3‐amino‐4‐carboxybenzenesulfonate (Hafsb⁻) anions. Compound (2) exhibits an asymmetric dinuclear structure. There are hydrogen‐bonded networks within the lattices of (1) and (2). Interestingly, both (1) and (2) exhibit reversible dehydration–rehydration behaviour.     

Palladium(II) complexes of aminothiazole‐based phosphines: Synthesis,structural characterization,density functional theory calculations and catalytic application in heck reaction

Three Pd(II) complexes of some hemilabile ligands, aminothiazole‐based phosphines, were synthesized to investigate the catalytic activity of them in Heck cross‐coupling reactions. The crystal structures of complexes PdCl₂[(Ph₂P)HN(C₃H₂NS)] ( C ₁ ) and PdCl₂[(Ph₂P)HN(C₇H₄NS)] ( C ₃ ) were determined using X‐ray crystallography, which reveals that the ligand coordinates in a chelating mode through P and N (endocyclic) atoms in square planar geometry. Experimental and theoretical studies (atoms in molecules and natural bond orbital analyses) show that the Pd(II) interacts more strongly with the P atom than the N atom in the chelated ligand, N^P. This trait can promote catalytic activity of the complexes in comparison with our previous work in which chelated ligands with two phosphorus atoms, P^P, were used. The influence of non‐covalent intermolecular interactions on the assembly of the solid‐state structures is also discussed in terms of geometrical analysis. The prepared complexes turn out to be useful pre‐catalysts in Heck cross‐coupling reactions owing to the coordinative flexibility of the hemilabile ligands. The protocol affords the corresponding products in greater yield than the same reactions with bis(phosphino)amine Pd(II) complexes, as the catalysts in our previous work.     

Crystallographic report: A two‐dimensional homochiral coordination polymer: [cadmium(II) bis(S‐(−)‐lactate)]n

In the two‐dimensional (2D) homochiral structure of [cadmium(II) bis(S‐(?)‐lactate)]_n, the lactate ligand adopts a µ₃‐bridging mode to connect two cadmium atoms, leading to the formation of a 2D network. Copyright © 2004 John Wiley & Sons, Ltd.     

Chemistry of N,S‐Heterocyclic Carbene and Metallaboratrane Complexes: A New η3‐BCC‐Borataallyl Complex

A high‐yielding synthetic route for the preparation of group 9 metallaboratrane complexes [Cp*MBH(L)₂], 1 and 2 ( 1 , M=Rh, 2 , M=Ir; L=C₇H₄NS₂) has been developed using [{Cp*MCl₂}₂] as precursor. This method also permitted the synthesis of an Rh–N,S‐heterocyclic carbene complex, [(Cp*Rh)(L₂)(1‐benzothiazol‐2‐ylidene)] ( 3 ; L=C₇H₄NS₂) in good yield. The reaction of compound 3 with neutral borane reagents led to the isolation of a novel borataallyl complex [Cp*Rh(L)₂B{CH₂C(CO₂Me)}] ( 4 ; L=C₇H₄NS₂). Compound 4 features a rare η³‐interaction between rhodium and the B‐C‐C unit of a vinylborane moiety. Furthermore, with the objective of generating metallaboratranes of other early and late transition metals through a transmetallation approach, reactions of rhoda‐ and irida‐boratrane complexes with metal carbonyl compounds were carried out. Although the objective of isolating such complexes was not achieved, several interesting mixed‐metal complexes [{Cp*Rh}{Re(CO)₃}(C₇H₄NS₂)₃] ( 5 ), [Cp*Rh{Fe₂(CO)₆}(μ‐CO)S] ( 6 ), and [Cp*RhBH(L)₂W(CO)₅] ( 7 ; L=C₇H₄NS₂) have been isolated. All of the new compounds have been characterized in solution by mass spectrometry, IR spectroscopy, and ¹H, ¹¹B, and ¹³C NMR spectroscopies, and the structural types of 4 – 7 have been unequivocally established by crystallographic analysis.     

Two new two‐dimensional coordination polymers based on isophthalate and a flexible N‐donor ligand containing benzimidazole and pyridine rings: synthesis,crystal structures and a solid‐state UV–Vis study

In coordination chemistry and crystal engineering, many factors influence the construction of coordination polymers and the final frameworks depend greatly on the organic ligands used. N‐Donor ligands with diverse coordination modes and conformations have been employed to assemble metal–organic frameworks. Carboxylic acid ligands can deprotonate completely or partially when bonding to metal ions and can also act as donors or acceptors of hydrogen bonds and are thus good candidates for the construction of supramolecular architectures. Two new transition metal complexes, namely poly[diaqua(μ₄‐1,4‐bis{[1‐(pyridin‐3‐ylmethyl)‐1H‐benz[d]imidazol‐2‐yl]methoxy}benzene)bis(μ₂‐isophthalato)dicobalt(II)], [Co(C₈H₄O₄)(C₃₄H₂₈N₆O₂)_0.5(H₂O)]_n, (1), and poly[diaqua(μ₄‐1,4‐bis{[1‐(pyridin‐3‐ylmethyl)‐1H‐benz[d]imidazol‐2‐yl]methoxy}benzene)bis(μ₂‐isophthalato)dicadmium(II)], [Cd(C₈H₄O₄)(C₃₄H₂₈N₆O₂)_0.5(H₂O)]_n, have been constructed using a symmetric N‐donor ligand and a carboxylate ligand under hydrothermal conditions. X‐ray crystallographic studies reveal that complexes (1) and (2) are isostructural, both of them exhibiting three‐dimensional supramolecular architectures built by hydrogen bonds in which the coordinated water molecules serve as donors, while the O atoms of the carboxylate groups act as acceptors. Furthermore, (1) and (2) have been characterized by elemental, IR spectroscopic, powder X‐ray diffraction (PXRD) and thermogravimetric analyses. The UV–Vis absorption spectrum of complex (1) has also been investigated.     

A trinuclear palladium(II) complex containing N,S‐coordinating 2‐(benzylsulfanyl)anilinide and 1,3‐benzothiazole‐2‐thiolate ligands with a central square‐planar PdN4 motif

The reaction of dichlorido(cod)palladium(II) (cod = 1,5‐cyclooctadiene) with 2‐(benzylsulfanyl)aniline followed by heating in N,N‐dimethylformamide (DMF) produces the linear trinuclear Pd₃ complex bis(μ₂‐1,3‐benzothiazole‐2‐thiolato)bis[μ₂‐2‐(benzylsulfanyl)anilinido]dichloridotripalladium(II) N,N‐dimethylformamide disolvate, [Pd₃(C₇H₄NS₂)₂(C₁₃H₁₂NS)₂Cl₂]·2C₃H₇NO. The molecule has symmetry and a Pd...Pd separation of 3.2012 (4) Å. The outer Pd^II atoms have a square‐planar geometry formed by an N,S‐chelating 2‐(benzylsulfanyl)anilinide ligand, a chloride ligand and the thiolate S atom of a bridging 1,3‐benzothiazole‐2‐thiolate ligand, while the central Pd^II core shows an all N‐coordinated square‐planar geometry. The geometry is perfectly planar within the PdN₄ core and the N—Pd—N bond angles differ significantly [84.72 (15)° for the N atoms of ligands coordinated to the same outer Pd atom and 95.28 (15)° for the N atoms of ligands coordinated to different outer Pd atoms]. This trinuclear Pd₃ complex is the first example of one in which 1,3‐benzothiazole‐2‐thiolate ligands are only N‐coordinated to one Pd centre. The 1,3‐benzothiazole‐2‐thiolate ligands were formed in situ from 2‐(benzylsulfanyl)aniline.     

A new photoluminescent coordination polymer constructed with an N‐donor ligand having extended coordination capabilities derived from quinoline and pyridine

Employment of the organic 2‐(pyridin‐4‐yl)quinoline‐4‐carboxylic acid ligand with extended coordination capabilities leads to the formation of the one‐dimensional copper(II) coordination polymer catena‐poly[[diaquacopper(II)]‐bis[μ‐2‐(pyridin‐4‐yl)quinoline‐4‐carboxylato]‐κ²N²:O;κ²O:N], {[Cu(C₁₅H₉N₂O₂)₂(H₂O)₂]·2H₂O}_n, under hydrothermal conditions. The ligand, isolated as its hydrochloride salt, namely, 4‐(4‐carboxyquinolin‐2‐yl)pyridinium chloride monohydrate, C₁₅H₁₁N₂O₂⁺·Cl^?·H₂O, reveals a pseudosymmetry element (translation a/2) in its crystal structure. The additional pyridyl N atom, in comparison with the previously reported analogues with an arene ring instead of the pyridyl ring in the present ligand molecule, promotes the formation of a one‐dimensional coordination polymer, rather than discrete molecules. This polymer shows photoluminescent properties with bathochromic/hypsochromic shifts of the ligand absorption bands, leading to a single band at 479 nm. The Cu^II ions are involved in weak antiferromagnetic interactions within dimeric units, as evidenced by SQUID magnetometry.     

A new two‐dimensional ZnII coordination polymer constructed by a multidentate N‐heterocyclic ligand and 5‐carboxybenzene‐1,3‐dicarboxylate

In the coordination polymer, poly[[{μ‐1‐[(1H‐benzimidazol‐2‐yl)methyl]‐1H‐imidazole‐κ²N:N′}(μ‐5‐carboxybenzene‐1,3‐dicarboxylato‐κ²O¹:O³)zinc(II)] dimethylformamide monosolvate pentahydrate], {[Zn(C₉H₄O₆)(C₁₁H₁₀N₄)]·C₃H₇NO·5H₂O}_n, the Zn^II ion is coordinated by two N atoms from two symmetry‐related 1‐[(1H‐benzimidazol‐2‐yl)methyl]‐1H‐imidazole (bmi) ligands and two O atoms from two symmetry‐related 5‐carboxybenzene‐1,3‐dicarboxylate (Hbtc²⁻) ligands in a slightly distorted tetrahedral geometry. The Zn^II ions are bridged by Hbtc²⁻ and bmi ligands, leading to a 4‐connected two‐dimensional network with the topological notation (4⁴.6²). Adjacent layers are further connected by 12 kinds of hydrogen bonds and also by π–π interactions, resulting in a three‐dimensional supramolecular architecture in the solid state.     

A cadmium(II) coordination polymer with both polyrotaxane and polycatenane features constructed by a V‐shaped semi‐rigid ligand: synthesis and fluorescence properties

One of the most interesting phenomena in coordination polymers (CPs) is the co‐existence of different interlaced motifs. However, CPs having two different interlaced motifs at the same time are still rare. Colourless block‐shaped crystals of the two‐dimensional polymer poly[[aqua(μ₂‐naphthalene‐2,6‐dicarboxylato){μ₂‐4,4′‐[oxybis(4,1‐phenylene)]dipyridine}cadmium(II)] monohydrate], {[Cd(C₁₂H₆O₄)(C₂₂H₁₆N₂O)(H₂O)]·H₂O}_n , (I), was synthesized under hydrothermal conditions by the self‐assembly of 4,4′‐[oxybis(4,1‐phenylene)]dipyridine (OPY) with Cd^II in the presence of naphthalene‐2,6‐dicarboxylic acid (H₂ndc). Each Cd^II ion is six‐coordinated by two N atoms from the pyridine rings of two OPY ligands and by four O atoms, three of which are from two ndc²⁻ ligands and one of which is from a water molecule. In (I), every two identical two‐dimensional (2D) 6³ layers are interpenetrated in a parallel fashion, resulting in an interesting 2D→2D framework with both polyrotaxane and polycatenane characteristics. The extension of these sheets into a three‐dimensional supramolecular net is via O—H…O hydrogen bonds. The solid‐state photoluminescence properties of (I) are also discussed.     

Yttrium and lanthanide complexes with various P,N ligands in the coordination sphere: synthesis, structure, and polymerization studies

Yttrium and lanthanide complexes with different P,N ligands in the coordination sphere have been synthesized. First the chloride complexes [{CH(PPh2NSiMe3)2}Ln{(Ph2P)2N}Cl] (Ln = Y (1 a), La (1 b), Nd (1 c), Yb (1 d)) having the bulky [CH(PPh2NSiMe3)2]- and the flexible [(Ph2P)2N]- ligands in the same molecule were prepared by three different synthetic pathways. Compounds 1 a-d can be obtained by reaction of [{[CH(PPh2NSiMe3)2]LnCl2}2] with [K(thf)nN(PPh2)2] (n = 1.25, 1.5) or by treatment of [{(Ph2P)2N}LnCl2(thf)3] with K[CH(PPh2NSiMe3)2]. Furthermore, a one-pot reaction of K[CH(PPh2NSiMe3)2] with LnCl3 and [K(thf)nN(PPh2)2] leads to the same products. Single-crystal X-ray structures of 1 a-d show that the conformation of the six-membered metallacycle (N1-P1-C1-P2-N2-Ln) which is formed by chelation of the [CH(PPh2NSiMe3)2]- ligand to the lanthanide atom is influenced by the ionic radius of the central metal atom. In solution dynamic behavior of the [(Ph2P)2N]- ligand is observed, which is caused by rapid exchange of the two different phosphorus atoms. Further reaction of 1 b with KNPh2 resulted in [{(Me3SiNPPh2)2CH}La{N(PPh2)2}(NPh2)] (2). Compounds 1 a-d and 2 are active in the ring-opening polymerization of epsilon-caprolactone and the polymerization of methyl methacrylate. In some cases high molecular weight polymers with good conversions and narrow polydispersities were obtained. In both polymerizations the catalytic activity depends on the ionic radius of the metal center.     

Organometallic based biologically active compounds: synthesis of mono‐ and di‐ethanolamine derived ferrocenes with antibacterial,antifungal and cytotoxic properties

Condensation reactions of 1,1′‐diacetylferrocene with ethanolamine were studied. The obtained compounds were further investigated for their ligation and biological properties with Co(II), Cu(II), Ni(II) and Zn(II) metal ions. The synthesized compounds were characterized by their physical, spectral and analytical properties and screened for their antibacterial properties against pathogenic bacterial strains, e.g. Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Staphylococcus aureus and Salmonella typhi and for antifungal activity against Trichophyton longifusus, Candida albicans, Aspergillus flavus, Microsporum canis, Fusarium solani and Candida glaberata using the agar‐well diffusion method. All the compounds have shown good antibacterial and antifungal activity, which increased on coordination with the metal ions, thus introducing a potential class of organometallic‐based antibacterial and antifungal agents. Brine shrimp bioassay was also carried out for in vitro cytotoxic properties against Artemia salina. Copyright © 2007 John Wiley & Sons, Ltd.     

Recent research progress in the synthesis,properties and applications of ferrocene‐based derivatives and polymers with azobenzene

Aromatic azobenzene derivatives are outstanding organic photochromic compounds that possess unique photochemical properties. These compounds are widely used in research and development for various applications, especially in information storage, owing to their ability to isomerize between cis (Z) and trans (E) forms under the influence of light of different wavelengths. On account of these advantages, many efforts have been made to generalize the use of azobenzene derivatives. Furthermore, ferrocene‐based polymers and derivatives are promising candidates for functional materials due to their unique redox properties. By interlinking ferrocene with azobenzene, novel functional materials can be obtained that will integrate the excellent properties of both and will provide new applications in various fields including information storage, ion recognition, molecular devices, etc. This article provides an overview of the synthesis, properties and applications of novel ferrocene‐based polymers and derivatives containing azobenzene units. Copyright © 2015 John Wiley & Sons, Ltd.