Distorted Octahedron Coordination Research Articles

Structure and spectral performance of Co(II) and Co(III) complexes for DNA-binding: Synthesis, characterization and comparison

There have been many literatures reporting the binding performance of transition metal complexes towards DNA, aiming at anti-cancer and anti-tumor drugs. However, most of these references focused on divalent transition metal cations, such as Co(II), Ni(II), Cu(II) and Zn(II). Only a few efforts have been devoted to high-valent transition metal cations. In this paper, we synthesized two Co(II) and Co(III) complexes, tris{2-(pyridin-2-yl)benzo[d]imidazole-1-ide}-cobalt(III) [denoted as Co(L)3] and bis{2-(pyridin-2-yl)benzo[d]imidazole-1-ide}-{2-(pyridin-2-yl)-1H-benzo[d]imidazole}-cobalt(II) [denoted as Co(HL)(L)2], using a diamine ligand 2-(pyridin-2-yl)-1H-benzo[d]imidazole (denoted as HL). Their molecular structure was identified with their single crystals, MS and NMR spectra. Co(L)3 and Co(HL)(L)2 share the same crystal system (monoclinic) and space group (P21/c). Their crystal cell parameters were found rather similar to each other owing to their rather similar ligands, showing a slightly distorted octahedron coordination geometry. No intramolecular interaction, superamolecular interactions and π-π staking between neighboring Co(L)3 molecules or neighboring Co(HL)(L)2 molecules were found, forming a clean coordination environment. Density functional theory calculation on their single crystals suggested that they had similar onset electronic transitions. Their thermal stability, absorption and emission were compared. Owing to their rather similar molecular structures, most of their features were similar. Their binding performance for calf thymus DNA (CT-DNA) was then analyzed and compared. The binding mode between two Co complexes and CT-DNA was analyzed and confirmed by means of viscosity monitoring, circular dichroism analysis, SEM and XRD comparison. Their binding constants were determined as 974.89 M-1 for Co(L)3 and 829.25 M-1 for Co(HL)(L)2, respectively. We found a hydrogen bond between Co(L)3 and CH3OH. No hydrogen bonds were found in Co(HL)(L)2. This result suggested that the Co(L)3 interact with Ct-DNA via the combination of hydrogen bond and weak intermolecular interaction with DNA, while Co(HL)(L)2 interacts with Ct-DNA via only weak intermolecular interaction with DNA. These values were two fold higher than those of literature values (<450 M−1), indicating their potential for DNA treatment.

A novel iron(III) complex: synthesis, spectra, X-ray structure photoluminescence study, and antibacterial properties

The binuclear iron(III) complex of the formula {[Fe(5,5′-dmbpy)2(OH2)]2(µ-O)}(NO3)4 was prepared from the reaction of Fe(NO3)3·9H2O with 5,5′-dimethyl-2,2′-bipyridine. The complex was characterized by FT-IR, UV–Vis, TGA, 1HNMR spectroscopy, elemental analysis, and luminescence measurements. Its structure was investigated using the single-crystal diffraction method. Crystal structure analysis showed that two crystallographically distinct oxygen-bridged Fe(III) cations are each coordinated by two bidentate ligands and one water molecule, resulting in a distorted coordination octahedron formed by four nitrogen atoms and two oxygen atoms. Several types of hydrogen bonds stabilize the crystal packing. In vitro biological screening of the free ligand, the complex and its metal salt against diverse microorganisms was done using the micro-dilution (tube) broth method. The antibacterial effects were also examined in vitro against standard bacterial strains, the Gram-positive Staphylococcus aureus, S. aureus ATCC 25923, and the Gram-negative Escherichia coli; E. coli ATCC 25922. Using these strains, the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and inhibition zones (IZ) were obtained for the complex, its ligand (5,5′-dmbipy) and its metal salt with Fe(NO3)3.9H2O.

Screening and Design of Novel 2D Ferromagnetic Materials with High Curie Temperature above Room Temperature.

Two-dimensional (2D) intrinsic ferromagnets with high Curie temperature ( TC) are desirable for spintronic applications. Using systematic first-principles calculations, we investigate the electronic and magnetic properties of 22 monolayer 2D materials with layered bulk phases. From these candidates, we screen out five ferromagnetic monolayer materials belonging to three types of structures: type i (ScCl, YCl, LaCl), type ii (LaBr2), and type iii (CrSBr). Type i is a kind of metallic ferromagnetic material, whereas LaBr2 and CrSBr of type ii and iii are small-bandgap ferromagnetic semiconductors with TC near room temperature. Moreover, the ferromagnetic CrSBr monolayer possesses a large magnetic moment of ∼3 μB per Cr atom, originating from its distorted octahedron coordination. The robust ferromagnetism of the CrSBr monolayer is ascribed to the halogen-mediated (Cr-Br-Cr) and chalcogen-mediated (Cr-S-Cr) superexchange interactions; then, an isoelectronic substitution strategy is proposed to tailor the magnetic coupling strength. Hence, monolayer structures of CrSI, CrSCl, and CrSeBr with notably enhanced Curie temperature up to 500 K as well as favorable formation energy are designed. The moderate interlayer binding energy and high TC make these monolayer ferromagnetic materials feasible for experimental synthesis and attractive as 2D spintronic devices.

Antioxidative vs cytotoxic activities of organotin complexes bearing 2,6‐di‐tert‐butylphenol moieties

Two series of organotin(IV) complexes with Sn–S bonds on the base of 2,6‐di‐tert‐butyl‐4‐mercaptophenol (L1SH) of formulae Me2Sn(L1S)2 (1); Et2Sn(L1S)2 (2); Bu2Sn(L1S)2 (3); Ph2Sn(L1S)2 (4); (L1)2Sn(L1S)2 (5); Me3Sn(L1S) (6); Ph3Sn(L1S) (7) (L1 = 3,5‐di‐tert‐butyl‐4‐hydroxyphenyl), together with the new ones [Me3SnCl(L2)] (8), [Me2SnCl2(L2)2] (9) (L2 = 2‐(N‐3′,5′‐di‐tert‐butyl‐4′‐hydroxyphenyl)‐iminomethylphenol) were used to study their antioxidant and cytotoxic activity. Novel complexes 8, 9 of MenSnCl4 − n (n = 3, 2) with Schiff base were synthesized and characterized by 1H, 13C NMR, IR and elemental analysis. The crystal structures of compounds 8 and 9 were determined by X‐ray diffraction analysis. The distorted tetrahedral geometry around the Sn center in the monocrystals of 8 was revealed, the Schiff base is coordinated to the tin(IV) atom by electrostatic interaction and formation of short contact Sn–O 2.805 Å. In the case of complex 9 the distorted octahedron coordination of Sn atom is formed. The antioxidant activity of compounds as radical scavengers and reducing agents was proved spectrophotometrically in tests with stable radical DPPH, reduction of Cu2+ (CUPRAC method) and interaction with superoxide radical‐anion. Moreover, compounds have been screened for in vitro cytotoxicity on eight human cancer cell lines. A high activity against all cell lines with IC50 values 60–160 nM was determined for the triphenyltin complex 7, while the introduction of Schiff base decreased the cytotoxicity of the complexes. The influence on mitochondrial potential and mitochondrial permeability for the compounds 8 and 9 has been studied. It is shown that studied complexes depolarize the mitochondria but don't influence the calcium‐induced mitochondrial permeability transition.

Synthesis, Crystal Structure, and Properties of a New Coordination Polymer From 4-(4-Hydroxypyridinium-1-yl) Phthalic Acid

A copper supramolecular coordination polymer, {[CuL(H2O)2]2}n (1), has been hydrothermally synthesized and structurally characterized by IR, UV spectroscopy, and elemental analyses, and also by single-crystal X-ray diffraction (H2L = 4-(4-hydroxypyridinium-1-yl) phthalic acid). The coordination around Cu center is distorted octahedron coordination geometry involving six O atoms, and each L2– ligand links three center atoms in the μ3-η1: η1: η1 mode; Adjacent Cu(II) atoms are united by the monodentate carboxylate group and hydroxy group to form infinite 1D chains (···Cu1LCu2L···)n, which are further linked by coordinated bonds between Cu1 and chelating carboxylate groups to produce 2D layers. These 2D layers are extended by interlayer hydrogen-bonded interactions to form 3D supramolecular framework.

Synthesis, Crystal Structure, and Photophysical Properties of Nickel Complex From Triphenylamine Schiff Base Ligand

A novel Schiff base ligand L and its mononuclear nickel complex Ni(L)2(SCN)2 were designed, synthesized and characterized by elemental analysis, IR spectra, MS, 1H-NMR spectroscopy, and single-crystal X-ray diffraction analysis. The crystals of L and Ni(L)2(SCN)2 belong to orthorhombic crystal system with the space group of P212121 for L and Pbcn for Ni(L)2(SCN)2, respectively. The center atom Ni(II) is coordinated with six nitrogen atoms in a distorted octahedron coordination environment. The four N atoms of them are from the two independent ligands and the other two nitrogen atoms from two SCN−. Their photophysical properties of the ligand and its Ni(II) complex were investigated and interpreted on the basis of theoretical calculations (TD-DFT).

Low-dimensional compounds containing cyanido groups. XXVII. Two forms of nitrosodicyanomethanide in Fe(II) complexes

Abstract Two new ionic [Fe(bpy)3](ONC(CN)2)2·2HONC(CN)2 (1) and [Fe(phen)3](ONC(CN)2)2 (2) complexes have been synthesized (bpy is 2,2′-bipyridine, phen is 1,10-phenanthroline). X-ray structural analysis ((1): P21/n, a=11.7294(5), b=22.0774(11), c=16.2415(8) Å, β=98.910(5)°; (2): P21/c, a=9.4951(3), b=21.6640(9), c=17.3365(6) Å, β=92.483(3)°) revealed that their structures consist of one [Fe(bpy)3]2+ or [Fe(phen)3]2+ complex cation and two uncoordinated nitrosodicyanomethanide, ONC(CN)2 - counteranions; two molecules of unique nitrosodicyanomethanide acid HONC(CN)2 were found in (1), too. In the cations, the Fe(II) atom is coordinated by six nitrogen atoms of chelate coordinated neutral ligands forming a distorted octahedron coordination geometry. Both structures are stabilized by π-π interactions and hydrogen bonds, which are very strong in (1).

Synthesis, Crystal Structure, and DNA-Binding Properties of a Cadmium(II) Complex With the Bis(2-benzimidazolymethyl)amine Ligand

A V-shaped ligand Bis(2-benzimidazolymethyl)amine (bba) and its cadmium(II) picrate (pic) complex, with composition [Cd(bba)2](pic)2·4DMF, have been synthesized and characterized on the basis of elemental analyses, molar conductivities, IR spectra and UV-vis measurements. In the complex, the Cd(II) ion is six-coordinated with a N6 ligand set, resulting in a distorted octahedron coordination geometry. In addition, the DNA-binding properties of the Cd(II) complex have been investigated by electronic absorption, fluorescence and viscosity measurements. The experimental results suggest that the Cd(II) complex binds to DNA by partial intercalation binding mode.

Low-dimensional compounds containing cyanido groups. XXIII. Synthesis and crystal structures of three ionic iron(II) complexes

Abstract Three new ionic [Fe(phen)3](N(CN)2)2 · 4.5 H2O (1), [Fe(dmeophen)3](N(CN)2)2 · 1.5 H2O (2) and [Fe(dmeophen)3](C(CN)3)2 (3) complexes have been synthesized (phen is 1,10-phenanthroline, dmeophen is 4,7-dimethoxy-1,10-phenanthroline). X-ray structural analysis ((1): C2/c, a = 18.1041(3), b = 16.8244(3), c = 24.6691(5) Å, β = 92.138(2)°; (2): C2/c, a = 22.0291(10), b = 18.8654(5), c = 11.6914(5) Å, β = 114.872(5)°; (3): Pbca, a = 12.0841(5), b = 22.0624(13), c = 34.2729 (16) Å) revealed that the structures of all discussed complexes consist of one [Fe(phen)3]2+ or [Fe(dmeophen)3]2+ complex cation and two uncoordinated tcm or dca counteranions (tcm is tricyanomethanide, dca is dicyanamide); water molecules were found in (1) and (2), too. In the cations, the Fe(II) atom is coordinated by six nitrogen atoms of chelate coordinated neutral ligands forming a distorted octahedron coordination geometry. One of the anions in each structure is disordered. Weak π–π interactions between planar dca anions and pyridine rings of phen in (1) and O—H … O and O—H … N hydrogen bonds in (1) and (2) stabilize their structures.

Synthesis, Crystal Structure and Luminescent Property of a 1D Chain Hg(II) Coordination Polymer Based on 4-Cyanopyridine

A novel 1D chain Hg(II) coordination polymer catena-(bis(μ2-chloro)-bis(4-cyanopyridyl))-mercury(II) [Hg(μ2-Cl)2(4-CNpy)2]n (1) (where 4-CNpy is 4-cyanopyridine) has been synthesized in DMF solution with 4-CNpy and HgCl2. The polymer was characterized by single-crystal X-ray diffraction analysis, FTIR and X-ray powder diffraction. The crystal belongs to orthorhombic system, space group Fdd 2. The cell parameters are: a = 23.729(8) A, b = 59.83(2) A, c = 3.913(1) A, V = 5556(3) A3, Z = 16, μ (Mo Kα) = 11.455 mm−1, F(000) = 3552, R 1 = 0.0370, wR 2 = 0.1051 [I > 2σ(I)]. The Hg(II) atoms locate in distorted coordination octahedron and are bridged by four chloride ions to form a 1D chain, and the remaining two coordination sites are occupied by two pyridine N atoms of 4-CNpy molecules. The 1D chain extends in the c direction. The experimental results show that 1 has good luminescence property and could be used as potential optical materials. A 1D Hg(II) coordination chain polymer of 4-cyanopyridine was synthesized and characterized. The solid-state complex exhibits strong fluorescence emission at room temperature.

Synthesis, Crystal Structure and Luminescent Property of Mg(II) Complex with N-Benzenesulphonyl-L-Leucine and 1,10-Phenanthroline.

A new complex [Mg(L)2(phen)(H2O)2](phen)(H2O)2 [L= N-benzenesulphonyl-L-leucine] was synthesized by the reaction of magnesium chloride hexahydrate with N-benzenesulphonyl-L-leucine and 1,10-phenanthroline in the CH3CH2OH/H2O (v:v = 5:1). It was characterized by elemental analysis, IR and X-ray single crystal diffraction analysis. The crystal of the title complex [Mg(L)2(phen)(H2O)2](phen)(H2O)2 belongs to triclinic, space group P-1 with a = 0.72772(15) nm, b = 1.4279(3) nm, c = 1.4418(3) nm, α = 63.53(3)°, β = 79.75(3)°, γ = 81.83(3)°, V = 1.3163(5) nm3, Z =1, Dc= 1.258 μg·m−3, μ = 0.177 mm−1, F(000) = 526, and final R1 = 0.0506, ωR2 = 0.1328. The complex comprises a six-coordinated magnesium(II) center, with a N2O4 distorted octahedron coordination environment. The molecules are connected by hydrogen bonds and π-π stacking to form one dimensional chain structure. The luminescent property of the Mg(II) complex has been investigated in solid.

Synthesis, Crystal Structure, and DNA-Binding Studies of a Nickel(II) Complex with the Bis(2-benzimidazolymethyl)amine Ligand.

A V-shaped ligand Bis(2-benzimidazolymethyl)amine (bba) and its nickel(II) picrate (pic) complex, with composition [Ni(bba)2](pic)2·3MeOH, have been synthesized and characterized on the basis of elemental analyses, molar conductivities, IR spectra, and UV/vis measurements. In the complex, the Ni(II) ion is six-coordinated with a N2O4 ligand set, resulting in a distorted octahedron coordination geometry. In addition, the DNA-binding properties of the Ni(II) complex have been investigated by electronic absorption, fluorescence, and viscosity measurements. The experimental results suggest that the nickel(II) complex binds to DNA by partial intercalation binding mode.

Trinuclear-based coordination compounds of Mn(II) and Co(II) with 4-amino-3,5-dimethyl-1,2,4-triazole and azide and thiocyanate anions: Synthesis, structure and magnetic properties

A 2D layer complex 1 and a linear trinuclear complex 2 with mixed ligands have been synthesized and characterized by elemental analyses, IR and single-crystal X-ray diffraction. In 1, the Mn(II) ions are six-coordinated and lie in distorted octahedron coordination environments. Complex 1 is connected into a 2D layer structure based on a linear trinuclear Mn 3(admtrz) 4(N 3) 6 (admtrz = 4-amino-3,5-dimethyl-1,2,4-triazole) building unit with either (6,3) topology when Mn1 cations as three-connected nodes or (4,4) network when the coordination trinuclear units being regarded as four connected nodes. In 2, the Co(II) ions are in slightly distorted octahedron coordination geometries. The magnetic behaviors are investigated in the temperature range 1.8–300 K. The magnetic susceptibility measurements show that the Mn(II) ions of complex 1 are weakly antiferromagnetically coupled with g = 1.98(1), J1 = −6.31(5) cm −1 and J2 = −1.88(1) cm −1. There is dominant zero field splitting (ZFS) effects with g values, g // = 2.38(2) and g ⊥ = 4.96(4), indicated a significant presence of the spin–orbit coupling and magnetization experiment reveals large, uniaxial zero-field splitting parameters of D = −29.55 cm −1 for 2.

Bond Activation in Iron(II)‐Coordinated Polypodal Phosphane Ligands

AbstractA mononuclear iron(II) complex is readily formed when combining equimolar amounts of iron(II) tetrafluoroborate hexahydrate, the pyridine‐derived triphosphane C5H3N{2‐[CMe(CH2PMe2)2]}{6‐[CMe2(CH2PMe2)]} (2) and diethylphosphane (Et2PH) in methanol at room temperature. The chelate ligand is in fact pentadentate, as one of the methyl groups of the neopentyl‐like sidearm engages in a C–H‐bonded contact (agostic interaction) with the metal centre, in addition to the expected NP3 coordination. The remaining site of what is a distorted coordination octahedron is occupied by monodentate Et2PH. The autoclave reaction of this purple complex with CO (10 bar, ethanol solvent, 65 °C) yields a yellow microcrystalline precipitate, whose analysis reveals a mixture of two products, in an approximate ratio of 40:1. One of the products is the cis‐dicarbonyl complex[Fe(2)(CO)2](BF4)2 (4), in which the chelate ligand acts as an NP3 donor, and the other is the monocarbonyl complex of the tetrapodal pentadentate NP4 ligand 1. The latter ligand is formed from 2 by incorporation of an additional PMe2 donor, in what, in effect, is a metal‐mediated phosphenium group transfer. A mechanism is suggested for this reaction. Other species in the reaction mixture have been identified on the basis of mass spectra, and the full NMR spectroscopic assignment of complex 4 (1H, 31P, 13C) is reported.

Synthesis and Crystal Structure of a New Cobalt(II) Complex: Bis(pyridine)bis(4,4,4-trifluoro-1-(6-methoxynaphthalen-2-yl)butane-1,3-dione) Cobalt(II)

AbstractA new Co(II) complex 2 with ligand 4,4,4-trifluoro-1-(6-methoxynaphthalen-2-yl) butane-1,3-dione 1 and pyridine are prepared and crystallized from an acetone solution. The obtained red and transparent crystal conforms to the empirical formula of Co(C 15 H 10 O 3 F 3 ) 2 ·(C 5 H 5 N) 2 . It crystallizes in monoclinic, space group C2/c with a = 23.3152(14), b = 12.0225(7), c = 15.3950(10) A, β = 124.1360(10)°, V = 3571.8(4) A 3 , Z = 4, C 40 H 30 CoF 6 N 2 O 6 , Mr = 807.59, F(000) = 1652, Dc = 1.502 g/cm 3 , μ = 0.564 mm −1 , the final R = 0.0466 and wR = 0.1043 for 3901 observed reflections with I > 2σ(I). X-ray structural analysis revealed that the Co(II) atom is coordinated by two oxygen atoms of 1,3-dione ligands 1 and two nitrogen atoms of pyridines, forming a distorted octahedron coordination geometry.Graphical AbstractA new cobalt complex 2 bis(pyridine)bis(4,4,4-trifluoro-1-(6-methoxynaphthalen-2-yl)butane-1,3-dione) Cobalt(II), Co(C 15 H 10 O 3 F 3 ) 2 ·(C 5 H 5 N) 2 , has been synthesized and characterized by X-ray structure determination. In the complex, the Co(II) atom is coordinated by four oxygen atoms of the β-diketonate ligands and two nitrogen atoms of pyridines, forming a distorted octahedron coordination geometry.[IMAGE]

Synthesis, spectral, and thermal properties, and crystal structure of cobalt (III) complex derived from Imazameth

A novel metal–organic coordination compound [Co(Imazameth)3]·0.5DMF·4H2O (where Imazameth = (±)-2-(4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H- imidazol-2-yl)-5-methyl-3-pyridinecarboxylic acid; DMF = N,N-dimethylformamide) has been prepared and characterized by spectral method (IR), elemental analysis, thermal gravimetric analysis (TGA), fluorescence properties, and single crystal X-ray diffraction techniques. It crystallizes in the trigonal system, space group R-3 and the asymmetric unit contains four water molecules. The four lattice water molecules and their symmetric equivalent form a slight distorted cubical water cluster through hydrogen bonds. The O···O bonds of the water cluster are in the range of (2.80(7)–2.99(2) A), and O···O···O angles are in the range of (82.54°–101.38°). In the cubical water clusters, the six O(5) atoms of each cube are connected to six O(1) atoms of the six molecules (O(1)···O(5) = 2.77(1) A) by hydrogen bonding, respectively. The Co atom is six-coordinated by six N atoms in distorted octahedron coordination geometry. Intramolecular N–H···O and intermolecular O–H···O hydrogen bonds result in the formation of a supermolecular crystal, in which they seem to be effective in the stabilization of the structure. The complex displays strong fluorescence property and good thermal stability.

An electrochemical sensing platform based on a new copper complex for the determination of hydrogen peroxide and nitrite

A new copper(II) complex [Cu(C12H23N3)4Br2·2H2O] was synthesized and its structure was characterized by x-ray crystallography and elemental analysis. The copper atom had a distorted octahedron coordination involving two bromide anions and four nitrogen atoms from the 1-decyl-1H-[1,2,4]triazole ligands. Moreover, the electrochemical behavior and electrocatalysis of the carbon paste electrode (Cu-CPE) bulk-modified by the complex have been studied in detail. The Cu-CPE showed excellent electrocatalytic activities toward the reduction of hydrogen peroxide and nitrite, and the detection limit was much lower than that mentioned in earlier reports. This bulk-modified CPE has good reproducibility, long-term stability and surface renewability, which appear promising for constructing chemical sensors.

Synthesis, crystal structure, and catalytic properties of a one-dimensional nickel(II) polymer

The title complex [Ni2(C10H9N3)2(C14H8O5)2]n, which has an inversion center, midway between two Ni(II) atoms forms a one-dimensional polymer bridged by 4,4′-oxydibenzoate ligands with a Ni…Ni separation of 14.4705(11) A. The Ni(II) atom is six-coordinated by two N atoms of a bis(2-pyridyl)amine ligand and four O atoms from two 4,4′-oxydibenzoate ligands, to form a distorted octahedron coordination geometry and then are linked via N-H…O and C-H…O hydrogen bonding into a polymeric ribbon structure. The activity and selectivity profiles of the polymer indicate that the optimization temperature and time span are 175°C and 30–40 min for the dehydration of cyclohexanol, respectively.

Synthesis, characterization and X-ray crystal structure of [Re(L4)(CO) 3]Br · 2CH 3OH (L4 = N, N-bis[(2-diphenylphosphino)ethyl]methoxyethylamine): A model compound for novel cationic 99mTc(I)-tricarbonyl radiotracers useful for heart imaging

This report describes synthesis and evaluation of cationic complexes, [ 99mTc(CO) 3(L)] + (L = N-methoxyethyl- N, N-bis[2-(bis(3-ethoxypropyl)phosphino)ethyl]amine (L1), N-[(15-crown-5)-2-yl]- N, N-bis[2-(bis(3-ethoxypropyl)phosphino)ethyl]amine (L2) and N-[(18-crown-6)-2-yl]- N, N-bis[2-(bis(3-ethoxypropyl)phosphino)ethyl]amine (L3)) as potential radiotracers for heart imaging. Preliminary results from biodistribution studies in female adult BALB-c mice indicated that the cationic 99mTc(I)-tricarbonyl complex, [ 99mTc(CO) 3(L2)] +, has a significant localization in the heart at 60 min post-injection. To understand the coordination chemistry of these bisphosphine ligands with the 99mTc(I)-tricarbonyl core, we prepared [Re(CO) 3(L4)]Br (L4: N, N-bis[(2-diphenylphosphino)ethyl]methoxyethylamine) as a model compound. [Re(CO) 3(L4)]Br has been characterized by elemental analysis, IR, ESI-MS, NMR ( 1H, 13C, 1H– 1H COSY, and 1H– 13C HMQC) methods, and X-ray crystallography. In solid state, [Re(CO) 3(L4)] + has a distorted octahedron coordination geometry with PNP occupying one facial plane. The chelator backbone adopts a “chair” conformation with phosphine-P atoms at equatorial positions and the amine-N at the apical site. In solution, [Re(CO) 3(L4)] + is able to maintain its cationic nature with no dissociation of carbonyl ligands or any of the three PNP donors.

The first sodium ion-mediated one-dimensional single-strand helical coordination polymer bridged by tetrafluoroborate

A new sodium tetrafluoroborate bridged neutral helical coordination polymer, formulated as [Na(1,10-phenanthroline)BF 4] n , has been synthesized and characterized. X-ray single crystal determination reveals that the Na(I) center has hexa-coordinate distorted octahedron coordination geometry and BF 4 − anion serves as a multidentate bridging ligand coordinated to three adjacent sodium cations forming an infinite one-dimensional single-strand helix. To the best of our knowledge, the title complex is an unprecedented type of helical structure in which only coordinated alkali metal sodium(I) and bridging tetrafluoroborate are present.