Reaction of (η5‐C5H5)Fe(CO)2I with Anionic Bidentate Phosphine Ligands PPh2(o‐C6H4NHLi) or PPh2(o‐C6H4OLi)

The o‐substituted hybrid phenylphosphines, PPh₂(o‐C₆H₄NH₂) and PPh₂(o‐C₆H₄OH), could be deprotonated with LDA or n‐BuLi to yield PPh₂(o‐C₆H₄NHLi) and PPh₂(o‐C₆H₄OLi), respectively. When added to a solution of (η⁵‐C₅H₅)Fe(CO)₂I at room temperature, these two lithiated reagents produce a chelated neutral complex 1 (η⁵‐C₅H₅)Fe(CO)[C(O)NH(o‐C₆H₄)PPh₂‐C,P‐η²] for the former and mainly a zwitterionic complex 2 , (η⁵‐C₅H₅)Fe⁺(CO)₂[PPh₂(o‐C₆H₄O^?)] for the latter. Complex 1 could easily be protonated and then decarbonylated to give 4 [(η⁵‐C₅H₅)Fe(CO){NH₂(o‐C₆H₄)PPh₂‐N,P‐η²}⁺]. Complexes 1 and 4‐I have been crystallographically characterized with X‐ray diffraction.     

Pd(II) complexes of Schiff bases and their application as catalysts in Mizoroki–Heck and Suzuki–Miyaura cross‐coupling reactions

Schiff bases of 2‐(phenylthio)aniline, (C₆H₅)SC₆H₄N?CR (R = (o‐CH₃)(C₆H₅), (o‐OCH₃)(C₆H₅) or (o‐CF₃)(C₆H₅)), and their palladium complexes (PdLCl₂) were synthesized. The compounds were characterized using ¹H NMR and ¹³C NMR spectroscopy and micro analysis. Also, electrochemical properties of the ligands and Pd(II) complexes were investigated in dimethylformamide–LiClO₄ solution with cyclic and square wave voltammetry techniques. The Pd(II) complexes showed both reversible and quasi‐reversible processes in the ?1.5 to 0.3 V potential range. The synthesized Pd(II) complexes were evaluated as catalysts in Mizoroki–Heck and Suzuki–Miyaura cross‐coupling reactions. Copyright © 2015 John Wiley & Sons, Ltd.     

First‐row transition metal–pyridine (py)–sulfate [(py)xM](SO4) complexes (M = Ni,Cu and Zn): crystal field theory in action

The crystal structures of three first‐row transition metal–pyridine–sulfate complexes, namely catena‐poly[[tetrakis(pyridine‐κN)nickel(II)]‐μ‐sulfato‐κ²O:O′], [Ni(SO₄)(C₅H₅N)₄]_n, (1), di‐μ‐sulfato‐κ⁴O:O‐bis[tris(pyridine‐κN)copper(II)], [Cu₂(SO₄)₂(C₅H₅N)₆], (2), and catena‐poly[[tetrakis(pyridine‐κN)zinc(II)]‐μ‐sulfato‐κ²O:O′‐[bis(pyridine‐κN)zinc(II)]‐μ‐sulfato‐κ²O:O′], [Zn₂(SO₄)₂(C₅H₅N)₆]_n, (3), are reported. Ni compound (1) displays a polymeric crystal structure, with infinite chains of Ni^II atoms adopting an octahedral N₄O₂ coordination environment that involves four pyridine ligands and two bridging sulfate ligands. Cu compound (2) features a dimeric molecular structure, with the Cu^II atoms possessing square‐pyramidal N₃O₂ coordination environments that contain three pyridine ligands and two bridging sulfate ligands. Zn compound (3) exhibits a polymeric crystal structure of infinite chains, with two alternating zinc coordination environments, i.e. octahedral N₄O₂ coordination involving four pyridine ligands and two bridging sulfate ligands, and tetrahedral N₂O₂ coordination containing two pyridine ligands and two bridging sulfate ligands. The observed coordination environments are consistent with those predicted by crystal field theory.     

A three‐dimensional CdII coordination polymer constructed from 1,1′‐biphenyl‐2,2′,5,5′‐tetracarboxylate and 1,4‐bis(1H‐imidazol‐1‐yl)benzene ligands

The title coordination polymer, poly[[aqua(μ₅‐1,1′‐biphenyl‐2,2′,5,5′‐tetracarboxylato)bis[μ₂‐1,4‐bis(1H‐imidazol‐1‐yl)benzene]dicadmium(II)] dihydrate], {[Cd₂(C₁₆H₆O₈)(C₁₂H₁₀N₄)₂(H₂O)]·2H₂O}_n, was crystallized from a mixture of 1,1′‐biphenyl‐2,2′,5,5′‐tetracarboxylic acid (H₄bpta), 1,4‐bis(1H‐imidazol‐1‐yl)benzene (1,4‐bib) and cadmium nitrate in water–dimethylformamide. The crystal structure consists of two crystallographically independent Cd^II cations, with one of the Cd^II cations possessing a slightly distorted pentagonal bipyramidal geometry. The second Cd^II centre is coordinated by carboxylate O atoms and imidazole N atoms from two separate 1,4‐bib ligands, displaying a distorted octahedral CdN₂O₄ geometry. The completely deprotonated bpta⁴⁻ ligand, exhibiting a new coordination mode, bridges five Cd^II cations to form one‐dimensional chains viaμ₃‐η¹:η²:η¹:η² and μ₂‐η¹:η¹:η⁰:η⁰ modes, and these are further linked by 1,4‐bib ligands to form a three‐dimensional framework with a (4².6⁴)(4.6²)(4³.6⁵.7²) topology. The structure of the coordination polymer is reinforced by intermolecular hydrogen bonding between carboxylate O atoms, aqua ligands and crystallization water molecules. The solid‐state photoluminescence properties were investigated and the complex might be a candidate for a thermally stable and solvent‐resistant blue fluorescent material.     

Structural Variations and Molecular Dynamics of Rare‐Earth Metal Complexes with the N,N‐Bis(2‐{pyrid‐2‐yl}ethyl)hydroxylaminato Ligand

The reaction of the donor‐functionalised N,N‐bis(2‐{pyrid‐2‐yl}ethyl)hydroxylamine and [LnCp₃] (Cp=cyclopentadiene) resulted in the formation of bis(cyclopentadienyl) hydroxylaminato rare‐earth metal complexes of the general constitution [Ln(C₅H₅)₂{ON(C₂H₄‐o‐Py)₂}] (Py= pyridyl) with Ln=Lu ( 1 ), Y ( 2 ), Ho ( 3 ), Sm ( 4 ), Nd ( 5 ), Pr ( 6 ), La ( 7 ). These compounds were characterised by elemental analysis, mass spectrometry, NMR spectroscopy (for compounds 1 , 2 , 4 and 7 ) and single‐crystal X‐ray diffraction experiments. The complexes exhibit three different aggregation modes and binding motifs in the solid state. The late rare‐earth metal atoms (Lu, Y, Ho and Sm) form monomeric complexes of the formula [Ln(C₅H₅)₂{η²‐ON(C₂H₄‐η¹‐o‐Py)(C₂H₄‐o‐Py)}] ( 1 – 4 , respectively), in which one of the pyridyl nitrogen donor atoms is bonded to the metal atom in addition to the side‐on coordinating hydroxylaminato unit. The larger Nd³⁺ and Pr³⁺ ions in 5 and 6 make the hydroxylaminato unit capable of dimerising through the oxygen atoms. This leads to the dimeric complexes [(Ln(C₅H₅)₂{μ‐η¹:η²‐ON(C₂H₄‐o‐Py)₂})₂] without metal–pyridine bonds. Compound 7 exhibits a dimeric coordination mode similar to the complexes 5 and 6 , but, in addition, two pyridyl functions coordinate to the lanthanum atoms leading to the [(La(C₅H₅)₂{ON(C₂H₄‐o‐Py)}{μ‐η¹:η²‐ON(C₂H₄‐η¹‐o‐Py)})₂] complex. The aggregation trend is directly related to the size of the metal ions. The complexes with coordinative pyridine–metal bonds show highly dynamic behaviour in solution. The two pyridine nitrogen atoms rapidly change their coordination to the metal atom at ambient temperature. Variable‐temperature (VT) NMR experiments showed that this dynamic exchange can be frozen on the NMR timescale.     

Lead(II) coordination frameworks with 3-fluorophthalic acid: hydrothermal synthesis,crystal structure,and luminescence

Hydrothermal reactions of Pb(NO₃)₂ and 3-fluorophthalic acid (H₂Fpht) in the absence or presence of 2,2′-bipyridine (bpy) gave two coordination polymers: Pb₅(Fpht)₄(Fba)₂ (1) and [Pb₂(Fpht)₂(bpy)(H₂O)]·3H₂O (2). The 3-fluorobenzoic acid (HFba) results from an in situ decarboxylation of H₂Fpht. Solid 1 displays a 2-D structure, comprising center-related hexanuclear [Pb₃(COO)₆]₂ units. There are three crystallographically different Pb(II) ions and two different ligands, Fpht and Fba. The Fpht ligands adopt μ_6?:?η⁵η³ and μ_6?:?η³η⁴ unusual bridging coordination modes. A 3-D supramolecular architecture is formed via C–H?F hydrogen bonds. Solid 2 possesses a 1-D chain structure, comprising center-related tetranuclear [Pb₂(COO)₄]₂ units. There are two crystallographically different Pb(II) ions. The Fpht ligands adopt μ_3?:?η²η³ and μ_4?:?η³η³ bridging coordination. The free water molecules form (H₂O)₃ clusters to link the 1-D chain by hydrogen bonds. A 3-D supramolecular assembly is constructed via hydrogen bonds between the free water and the F of Fpht ligands. Fluorescence of the complexes originates from π*–π transitions of the ligands.     

Construction of Zn(II)-ferrocenyl carboxylate coordination complexes via changing adjuvant ligands

Five Zn(II)-ferrocenyl carboxylate complexes, {[Zn(OOCClH₃C₆Fc)(η ²OOCClH₃C₆Fc)(dpa)]?·?(H₂O)} (1), [Zn(η ²-OOCClH₃C₆Fc)₂(2,2′-dip)]?·?(H₂O)_0.25} (2), {[Zn(η-OOCClH₃C₆Fc)₂(bix)]₂?·?(THF)} (3), [Zn(η-OOCClH₃C₆Fc)₂?·?(Hfcz)] _n (4) and {[Zn(η-OOCClH₃C₆Fc)₂(H₂L₁)]?·?(DMF)₂} _n (5) [dpa?=?2,2′-dipyridylamine, 2,2′-dip?=?2,2′-bipyridine, bix?=?1,4-bis(imidazol-1-ylmethyl)benzene, Hfcz?=?α-(2,4-difluorophenyl)-α-(1H-1,2,4-triazol-l-ylmethyl)-1H-1,2,4-triazole-l-ethanol, H₂L₁?=?N,N′-bis(pyridin-4-yl)pyridine-2,6-dicarboxamide, Fc?=?ferrocene, FcC₆H₃ClCOONa?=?sodium 2-chloro-4-ferrocenylbenzoic], have been synthesized and characterized. Single-crystal X-ray analysis reveals that 1 and 2 are mononuclear structures, 3 is a dimer, and 4 and 5 are 1-D structures. The five complexes exhibit some differences in their conformations, which can be attributed to the influence of adjuvant ligands. Notably, various π–π interactions as well as CH/π interactions are discovered in 1–5, and they have significant contributions to self-assembly. The electrochemical properties of 1–5 indicate that half-wave potentials shift to positive potential compared with that of 2-chloro-4-ferrocenylbenzoic acid.     

Ferrocene-carboxylate coordination complexes bridged by different N-containing ligands

Six new coordination complexes, [Cd(η ²-OOCCH=(CH₃)CFc)₂(bix)]₂·(CH₃OH)_0.5 (1), [Zn(η ²-OOCCH=(CH₃)CFc)(η ¹-OOCCH=(CH₃)CFc)(bix)]₂·(H₂O)_0.5 (2), [Zn(η ²-OOCCH=(CH₃)CFc)₂(pbbm)]₂·(CH₃OH)₂ (3), {[Mn(η ¹-OOCCH=(CH₃)CFc)₂(bbbm)(H₂O)₂]·(CH₃OH)₃}_n (4), {[Cd(η ¹-OOCCH=(CH₃)CFc)₂(bbbm)]·(CH₃OH)₂}_n (5), and [Cd(η ²-OOCCH=(CH₃)CFc)₂(pmbbm)]_n (6) {Fc?=?(η ⁵-C₅H₄)Fe(η ⁵-C₅H₄), bix?=?1,4[bis(imidazol-1-ylmethyl)benzene], pbbm?=?1,1′-[(1,4-propanediyl)bis-1H-benzimidazole], bbbm?=?1,1′-[(1,4-butanediyl)bis-1H-benzimidazole)], pmbbm?=?1,1′-[(1,4-pentanediyl)bis-1H-benzimidazole]}, were prepared and characterized. X-ray crystallographic analysis reveals that 1–3 are dimers bridged by bix and pbbm. Complexes 4–6 are one-dimensional (1-D) structures bridged by bbbm and pmbbm, respectively. Various π–π interactions were discovered in 1–6 that make significant contributions to molecular self-assembly. Solution differential pulse voltammetry of 1–6 indicates that the half-wave potentials of the ferrocenyl moieties in these complexes shift to positive potential compared with that of 3-ferrocenyl-2-crotonic acid.     

Syntheses and structures of three coordination polymers based on 4-methylbenzenethiolates of Zn(II) and Cd(II) and bipyridine

Using 4-methylbenzenethiolates of Zn or Cd as precursors and 4,4′-bipyridine (4,4′-bpy) as bridges, we have synthesized three new Zn(II)/Cd(II) coordination polymers, {[Cd(4,4′-bpy)₂(NCS)₂] · 2(SC₆H₄CH₃-4)₂} _n (1), {[Zn(4,4′-bpy)(SC₆H₄CH₃-4)₂] · DMF} _n (2) and {[Zn(4,4′-bpy)(SC₆H₄CH₃-4)₂] · H₂O · 0.5CH₃OH} _n (3). Compound 1 is a 2-D sheet-like square polymer in which four 4,4′-bpy ligands and two isothiocyanate ligands complete the octahedral Cd(II) coordination sphere. Compounds 2 and 3 have similar coordination around Zn(II), but have different polymer structures. In 2, Zn(II) centers are linked via a bidentate 4,4′-bipyridine to form 1-D twisted arched chains, which is a new structural type for Zn(II). Compound 3 has 1-D zigzag chains. The 2-D sheets in 1 and 1-D chains in 2 and 3 are assembled via intermolecular C–H ··· π and C–H ··· S interactions into 3-D supramolecular networks. C–H ··· S interactions are a vital factor in constructing the sulfur-containing coordination polymers. Different coordination modes and packing schemes in 1–3 show that the guest molecule has a critical influence on formation of polymers.     

Syntheses of phenoxo-bridged Zn(II) and metallamacrocyclic Hg(II) complexes of organochalcogen (Se,Te) substituted Schiff-bases: structure and DNA-binding studies of Zn(II) complexes

The coordination of organochalcogen (especially Se and Te) substituted Schiff-bases L¹H, L²H, L³H, and L⁴H toward Zn(II) and Hg(II) has been studied. Reactions of these ligands with ZnCl₂ in 1?:?1 molar ratio gave binuclear complexes [{2-[PhX(CH₂) _n N?=?C(Ph)]-6-[PhCO]-4-MeC₆H₂O}₂Zn₂Cl₂] (where X?=?Se, n?=?2 (1); X?=?Se, n?=?3 (2); X?=?Te, n?=?2 (3); and X?=?Te, n?=?3 (4)) with partial hydrolytic cleavage of proligands. In these complexes, two partially hydrolyzed ligand fragments coordinate tridentate (NOO) with two Zn's. Reaction of HgBr₂ with L¹H and L²H in 1?:?1 molar ratio gave monometallic complexes [C₆H₂(4-Me)(OH)[2,6-{C(Ph)?=?N(CH₂) _n Se(Ph)}₂HgBr₂]] (n?=?2 (5) or 3 (6)) and under similar conditions with L³H and L⁴H gave bimetallic complexes [C₆H₂(4-Me)(OH)[2,6-{C(Ph)?=?N(CH₂) _n Te(Ph)}₂Hg₂Br₄]] (n?=?2?(7) or 3 (8)) in which the ligands coordinate with metal through selenium or tellurium, leaving the imino nitrogen and phenolic oxygen uncoordinated. The proligands L¹H, L²H give 14- or 16-membered metallamacrocycles through Se–Hg–Se linkages and L³H, L⁴H give 16- or 18-membered metallamacrocycles through Te–Hg–Br–Hg–Te linkages. All the complexes were characterized by elemental analyses, ESIMS, FTIR, multinuclear NMR, UV-Vis, and conductance measurements. The redox properties of the complexes were investigated by cyclic voltammetry (CV). Complexes 1–4 exhibited ligand-centered irreversible oxidation processes. Complexes 5 and 6 showed metal-centered quasi-reversible single electron transfer, whereas dinuclear complexes 7 and 8 displayed two quasi-reversible, one-electron transfer steps. A single-crystal X-ray structure determination of 1 showed that the coordination unit is centrosymmetric with Zn(II) in square-pyramidal coordination geometry and the two square pyramids sharing an edge. The Zn?···?Zn separation is 3.232?Å. The DNA-binding properties of 1 and 3 with calf thymus DNA were explored by a spectrophotometric method and CV.     

Scandium complexes with the tetraphenylethylene and anthracene dianions

The structural study of Sc complexes containing dianions of anthracene and tetraphenylethylene should shed some light on the nature of rare‐earth metal–carbon bonding. The crystal structures of (18‐crown‐6)bis(tetrahydrofuran‐κO)sodium bis(η⁶‐1,1,2,2‐tetraphenylethenediyl)scandium(III) tetrahydrofuran disolvate, [Na(C₄H₈O)₂(C₁₂H₂₄O₆)][Sc(C₂₆H₂₀)₂]·2C₄H₈O or [Na(18‐crown‐6)(THF)₂][Sc(η⁶‐C₂Ph₄)₂]·2(THF), ( 1b ), (η⁵‐1,3‐diphenylcyclopentadienyl)(tetrahydrofuran‐κO)(η⁶‐1,1,2,2‐tetraphenylethenediyl)scandium(III) toluene hemisolvate, [Sc(C₁₇H₁₃)(C₂₆H₂₀)(C₄H₈O)]·0.5C₇H₈ or [(η⁵‐1,3‐Ph₂C₅H₃)Sc(η⁶‐C₂Ph₄)(THF)]·0.5(toluene), ( 5b ), poly[[(μ₂‐η³:η³‐anthracenediyl)bis(η⁶‐anthracenediyl)bis(η⁵‐1,3‐diphenylcyclopentadienyl)tetrakis(tetrahydrofuran)dipotassiumdiscandium(III)] tetrahydrofuran monosolvate], {[K₂Sc₂(C₁₄H₁₀)₃(C₁₇H₁₃)₂(C₄H₈O)₄]·C₄H₈O}_n or [K(THF)₂]₂[(1,3‐Ph₂C₅H₃)₂Sc₂(C₁₄H₁₀)₃]·THF, ( 6 ), and 1,4‐diphenylcyclopenta‐1,3‐diene, C₁₇H₁₄, ( 3a ), have been established. The [Sc(η⁶‐C₂Ph₄)₂]⁻ complex anion in ( 1b ) contains the tetraphenylethylene dianion in a symmetrical bis‐η³‐allyl coordination mode. The complex homoleptic [Sc(η⁶‐C₂Ph₄)₂]⁻ anion retains its structure in THF solution, displaying hindered rotation of the coordinated phenyl rings. The 1D ¹H and ¹³C{¹H}, and 2D COSY ¹H–¹H and ¹³C–¹H NMR data are presented for M[Sc(Ph₄C₂)₂]·xTHF [M = Na and x = 4 for ( 1a ); M = K and x = 3.5 for ( 2a )] in THF‐d₈ media. Complex ( 5b ) exhibits an unsymmetrical bis‐η³‐allyl coordination mode of the dianion, but this changes to a η⁴ coordination mode for (1,3‐Ph₂C₅H₃)Sc(Ph₄C₂)(THF)₂, ( 5a ), in THF‐d₈ solution. A ⁴⁵Sc NMR study of ( 2a ) and UV–Vis studies of ( 1a ), ( 2a ) and ( 5a ) indicate a significant covalent contribution to the Sc—Ph₄C₂ bond character. The unique Sc ate complex, ( 6 ), contains three anthracenide dianions demonstrating both a η⁶‐coordination mode for two bent ligands and a μ₂‐η³:η³‐bridging mode of a flat ligand. Each [(1,3‐Ph₂C₅H₃)₂Sc₂(C₁₄H₁₀)₃]²⁻ dianionic unit is connected to four neighbouring units via short contacts with [K(THF)₂]⁺ cations, forming a two‐dimensional coordination polymer framework parallel to (001).     

A new two‐dimensional extended adenine and thiophenecarboxylate mixed‐ligand zinc(II) complex: synthesis,structure, thermostability and luminescent properties

The design and preparation of crystalline polymeric materials has attracted increasing attention due to their diverse applications as functional materials in gas storage, separation, catalysis, sensing and photoluminescence. The judicious selection of organic linkers is critical for varying the coordination behaviour of the metal ions and determining the overall characteristics of the networks. A new adenine‐based Zn^II coordination polymer, [Zn(C₆H₂O₄S)(C₅H₅N₅)]_n or [Zn(tdc)(9H‐ade)] (H₂tdc is thiophene‐2,5‐dicarboxylic acid and ade is adenine), has been prepared hydrothermally and the crystal structure exhibits in its packing two‐dimensional (4,4) grid sheets parallel to the ab plane, featuring two distinct square cavities delimited by the two types of ligands and the Zn^II ions with the dimensions 6.6 × 6.6 and 10.2 × 10.2 Å (based on the Zn...Zn distance). The title complex shows enhanced photoluminescence at 378 nm compared to the free ligands, suggesting that the coordination of H₂tdc or adenine to the metal centre effectively increases the rigidity of the ligands and reduces the energy loss by radiative decay of intraligand excited states.     

Synthesis and structural characterization of 2D Zn(II), Cd(II), and Co(II) coordination polymers containing 3-chloro-1,2-benzenedicarboxylate and positional isomers of triazole-bipyridine

Three compounds, [Zn₂L₂(4,4′-bpt)₂] _n (1), [Cd₂L₂(3,4′-bpt)(H₂O)₂] _n (2) and {[CoL(3,3′-bpt)(H₂O)]?H₂O} _n (3) (L?=?3-Cl-1,2-benzenedicarboxylate dianion, 4,4′-bpt?=?1H-3,5-bs(4-pyridyl)-1,2,4-itriazole, 3,4′-bpt?=?1H-3-(3-pyridyl)-5-(4-pyridyl)-1,2,4-triazole and 3,3′-bpt?=?1H-3,5-bis(3-pyridyl)-1,2,4-triazole), based on three positionally isomeric triazole-bipyridine ligands, were synthesized. Structural analyses of 1–3 reveal diverse 2-D network structures, which are based on different [ML] _n (M?=?Zn, Cd, Co) chains. In the [ZnL] _n chains of 1, the carboxylic groups of L connect the adjacent Zn(II) centers with a monodentate bridging coordination mode (μ₂-η^{1 ?}/^? η¹ ). In 2, [CdL] _n is a double chain connected by the carboxylic groups of L with μ₃-η^{1 ?}/^? η²/η² and μ₃-η^{1 ?}/^? η^{1 ?}/^? η² bridges. The [CoL] _n chains of 3 are formed by the carboxylic groups of L with the μ₂-η^{1 ?}/^? η² coordination mode. The powder X-ray diffraction and the thermal stability of 1–3, the luminescent properties of 1 and 2, and the magnetic behavior of 3 have been briefly investigated.     

Esterification and isolation of the carboxylic acid with salicyl-bis-hydrazide via coordination of iron(III) 18-metallacrown-6 complex

The trianionic heptadentate ligand, (Z)-3-(5′-bromosalicylhydrazinocarbonyl) propenoic acid ((Z)-H₄bshcpa), has been synthesized in good yield and reacted with FeCl₃?·?6H₂O to produce [Fe^III ₆(C₁₂H₈N₂O₅Br)₆(H₂O)₂(CH₃OH)₄]?·?8H₂O?·?8CH₃OH. The complex has been characterized by single-crystal X-ray diffraction. In the self-assembly process the ligand was esterified and transferred into (Z)-methyl 3-(5′-bromosalicylhydrazinocarbonyl) propenoate ((Z)-H₃mbshcp). In the crystal structure, the neutral Fe(III) complex contains an 18-membered metallacrown ring consisting of six Fe(III) and six trianionic ligands. The 18-membered metallacrown ring is formed by six structural moieties of the type [Fe(III)–N–N]. Due to the meridional coordination of the ligands to Fe³⁺, the ligands enforce stereochemistry of the Fe³⁺ ions as a propeller configuration with alternating Λ/Δ forms. The metallacrown can be treated with SnCl₂ to obtain purified ester. In addition, we have also obtained reduced esterified ligand, methyl 3-(5′-bromosalicylhydrazinocarbonyl) propanoate (H₃mbshcp), with Zn powder as reductant.     

Zinc(II) and lead(II) coordination polymers built by 3-(4-carboxyphenylhydrazono)pentane-2,4-dione

Two coordination polymers [Zn(L)₂(4,4′-bipy)₂] _n (4,4′-bipy = 4,4′-bipyridine) (1) and [Pb(η ²-L)(µ₃-η ²-CH₃COO)(H₂O)] _n (2) have been prepared by the reaction of 3-(4-carboxyphenylhydrazono)pentane-2,4-diketone (HL) with zinc(II) or lead(II) in solution. Polymer 1 shows an infinite zigzag chain, in which Zn(II) are linked by 4,4′-bipy bridges with carboxylate of L^? monodentate to Zn(II). In 2, Pb(II) are bridged by tetradentate µ₃-η ²-CH₃COO^? to form a linear 1-D chain, and each Pb(II) is chelated by carboxylate of L^?. Their molecular structures have been characterized by elemental analysis, infrared, and single-crystal X-ray diffraction. Thermal and fluorescent properties of the two complexes have been investigated.     

Ansa‐Complexes of [Mn(η5‐C5H5)(η6‐C6H6)]: Preparation,Characterization, and Reactivity of [n]Manganoarenophanes (n=1, 2, 3)

We report the synthesis of [n]manganoarenophanes (n=1, 2) featuring boron, silicon, germanium, and tin as ansa‐bridging elements. Their preparation was achieved by salt‐elimination reactions of the dilithiated precursor [Mn(η⁵‐C₅H₄Li)(η⁶‐C₆H₅Li)]?pmdta (pmdta=N,N,N′,N′,N′′‐pentamethyldiethylenetriamine) with corresponding element dichlorides. Besides characterization by multinuclear NMR spectroscopy and elemental analysis, the identity of two single‐atom‐bridged derivatives, [Mn(η⁵‐C₅H₄)(η⁶‐C₆H₅)SntBu₂] and [Mn(η⁵‐C₅H₄)(η⁶‐C₆H₅)SiPh₂], could also be determined by X‐ray structural analysis. We investigated for the first time the reactivity of these ansa‐cyclopentadienyl–benzene manganese compounds. The reaction of the distannyl‐bridged complex [Mn(η⁵‐C₅H₄)(η⁶‐C₆H₅)Sn₂tBu₄] with elemental sulfur was shown to proceed through the expected oxidative addition of the Sn?Sn bond to give a triatomic ansa‐bridge. The investigation of the ring‐opening polymerization (ROP) capability of [Mn(η⁵‐C₅H₄)(η⁶‐C₆H₅)SntBu₂] with [Pt(PEt₃)₃] showed that an unexpected, unselective insertion into the C_ipso?Sn bonds of [Mn(η⁵‐C₅H₄)(η⁶‐C₆H₅)SntBu₂] had occurred.     

A one‐dimensional zinc(II) coordination polymer with a three‐dimensional supramolecular architecture incorporating 1‐[(1H‐benzimidazol‐2‐yl)methyl]‐1H‐tetrazole and adipate

The synthesis of coordination polymers or metal–organic frameworks (MOFs) has attracted considerable interest owing to the interesting structures and potential applications of these compounds. It is still a challenge to predict the exact structures and compositions of the final products. A new one‐dimensional coordination polymer, catena‐poly[[[bis{1‐[(1H‐benzimidazol‐2‐yl)methyl]‐1H‐tetrazole‐κN³}zinc(II)]‐μ‐hexane‐1,6‐dicarboxylato‐κ⁴O¹,O^1′:O⁶,O^6′] monohydrate], {[Zn(C₆H₈O₄)(C₉H₈N₆)₂]·H₂O}_n, has been synthesized by the reaction of Zn(Ac)₂ (Ac is acetate) with 1‐[(1H‐benzimidazol‐2‐yl)methyl]‐1H‐tetrazole (bimt) and adipic acid (H₂adi) at room temperature. In the polymer, each Zn^II ion exhibits an irregular octahedral ZnN₂O₄ coordination geometry and is coordinated by two N atoms from two symmetry‐related bimt ligands and four O atoms from two symmetry‐related dianionic adipate ligands. Zn^II ions are connected by adipate ligands into a one‐dimensional chain which runs parallel to the c axis. The bimt ligands coordinate to the Zn^II ions in a monodentate mode on both sides of the main chain. In the crystal, the one‐dimensional chains are further connected through N—H…O hydrogen bonds, leading to a three‐dimensional supramolecular architecture. In addition, the title polymer exhibits fluorescence, with emissions at 334 and 350 nm in the solid state at room temperature.     

Four Zn(II)/Cd(II) coordination polymers derived from isomeric benzenedicarboxylates and 1,6-bis(triazol)hexane ligand: synthesis,crystal structure,and luminescent properties

Four coordination polymers, [Zn(o-bdc)(bth)_0.5(H₂O)] _n (1), [Cd(o-bdc)(bth)_0.5(H₂O)] _n (2), [Zn(m-bdc)(bth)] _n (3), and [Cd(p-bdc)(bth)?·?(H₂O)₂] _n (4) (where o-bdc?=?1,2-benzenedicarboxylate, m-bdc?=?1,3-benzenedicarboxylate, p-bdc?=?1,4-benzenedicarboxylate, and bth?=?1,6-bis(triazol)hexane), have been hydrothermally synthesized and structurally characterized. Both 1 and 2 are isostructural, featuring two binodal architectures: (6³)(6⁵·8) topology in terms of o-bdc and Zn^II/Cd^II as three- and four-connected nodes. Complex 3 shows a 2-D (4,4) network with the Zn?···?Zn?···?Zn angle of 57.84°, whereas 4 exhibits planar 2-D (4,4) network. These 2-D networks of 3 and 4 are extended by supramolecular interactions, such as CH?···?π/π–π stacking and hydrogen-bonding into 3-D architecture. A structural comparison of these complexes demonstrates that the dicarboxylate building blocks with different dispositions of the carboxyl site play a key role in governing the coordination motifs as well as 3-D supramolecular lattices. Solid-state properties such as photoluminescence and thermal stabilities of 1–4 have also been studied.     

A novel cadmium(II) coordination polymer with a four‐connected (4,4)‐net based on a trinuclear cadmium(II) node

In the title cadmium(II) coordination polymer, poly[tri‐μ₄‐adipato‐bis(2‐phenyl‐1H‐1,3,7,8‐tetraazacyclopenta[l]phenanthrene‐κ²N⁷,N⁸)tricadmium(II)], [Cd₃(C₆H₈O₄)₃(C₁₉H₁₂N₄)₂]_n, one of the Cd atoms is in a distorted pentagonal bipyramidal coordination environment, surrounded by five O atoms from three adipate (adip) ligands and two N atoms from one 2‐phenyl‐1H‐1,3,7,8‐tetraazacyclopenta[l]phenanthrene (L) ligand. A second Cd atom occupies an inversion center and is coordinated by six O atoms from six adip ligands in a distorted octahedral geometry. The carboxylate ends of the adip ligands link Cd^II atoms to form unique trinuclear Cd^II clusters, which are further bridged by the adip linkers to produce a two‐dimensional layer structure. Topologically, each trinuclear Cd^II cluster is connected to four others through six adip ligands, thus resulting in a unique two‐dimensional four‐connected framework of (4,4)‐topology. This work may help the development of the coordination chemistry of 1,10‐phenanthroline derivatives.     

Novel cyclohexyl‐based aminophosphine ligands and use of their Ru(II) complexes in transfer hydrogenation of ketones

Two new aminophosphines – furfuryl‐(N‐dicyclohexylphosphino)amine, [Cy₂PNHCH₂–C₄H₃O] ( 1 ) and thiophene‐(N‐dicyclohexylphosphino)amine, [Cy₂PNHCH₂–C₄H₃S] ( 2 ) – were prepared by the reaction of chlorodicyclohexylphosphine with furfurylamine and thiophene‐2‐methylamine. Reaction of the aminophosphines with [Ru(η⁶‐p‐cymene)(μ‐Cl)Cl]₂ or [Ru(η⁶‐benzene)(μ‐Cl)Cl]₂ gave corresponding complexes [Ru(Cy₂PNHCH₂–C₄H₃O)(η⁶‐p‐cymene)Cl₂] ( 1a ), [Ru(Cy₂PNHCH₂–C₄H₃O)(η⁶‐benzene)Cl₂] ( 1b ), [Ru(Cy₂PNHCH₂–C₄H₃S)(η⁶‐p‐cymene)Cl₂] ( 2a ) and [Ru(Cy₂PNHCH₂–C₄H₃S)(η⁶‐benzene)Cl₂] ( 2b ), respectively, which are suitable catalyst precursors for the transfer hydrogenation of ketones. In particular, [Ru(Cy₂PNHCH₂–C₄H₃S)(η⁶‐benzene)Cl₂] acts as a good catalyst, giving the corresponding alcohols in 98–99% yield in 30 min at 82 °C (up to time of flight ≤ 588 h^?1). Copyright © 2014 John Wiley & Sons, Ltd.