Five-coordinate Zn Research Articles

Synthesis and crystal structures of five-coordinated β-pyrrole tetra(phenyl/cyano) substituted zinc(II)-tetraphenylporphyrins

Crystal structures of a series of 2,3,5,10,12,13,15,20-octaphenylporphinato zinc(II) complexes with varying axial ligands have been examined to elucidate the role of fifth ligand on the stereochemistry of the porphyrin macrocycle. The nonplanarity of the macrocycle varies in the order, ZnOPP < ZnOPP(pyridine) < ZnOPP(H 2O). The electron deficient porphyrin complex of five-coordinated Zn(II), ZnTPP(CN) 4(CH 3OH) showed enhanced nonplanarity of the macrocycle and it is less than that of ZnOPP(H 2O)·TCE complex. Normal coordinate structure decomposition analysis of the out-of-plane displacement of the porphyrin ring in these structures revealed negligible wave distortion in planar four-coordinated ZnOPP and saddle, ruffled and domed distortions in other five-coordinated Zn(II)-porphyrins. The pronounced distortion of the macrocyclic ring in these structures is possibly due to the axial ligand, solvate and/or intermolecular interactions compared to steric crowding of the peripheral substituents.

(μ-Ethane-1,2-diamine-κN:N')bis-[bis-(ethane-1,2-diamine-κN,N')zinc(II)] tetra-kis-(perchlorate).

In the title salt, [Zn2(C2H8N2)5](ClO4)4, an ethyl­enediamine mol­ecule bridges two bis­(ethyl­enediamine)­zinc units; the five-coordinate Zn atoms show a trigonal–bipyramidal coordination geometry that is distorted towards square-pyramidal (that of one Zn atom is distorted by 12% and that of the other by 34%). The perchlorate ions are all disordered over two positions in a 1:1 ratio. The cation inter­acts weakly with the anion by N—H⋯O hydrogen bonds, generating a three-dimensional network.

(μ-1,2-Di-4-pyridylethylene-κ2N:N′)bis[bis(N,N-dimethyldithiocarbamato-κ2S,S′)zinc(II)

The dinuclear title compound, [Zn2(C3H6NS2)4(C12H10N2)], features two five-coordinate Zn atoms, one with an NS4 coordination geometry distorted towards a trigonal-bipyramidal arrangement, and the other distorted towards a square pyramid. In the crystal, mol­ecules are connected into supra­molecular zigzag chains via C—H⋯S contacts. Chains are connected via C—H⋯π interactions, consolidating the crystal packing.

(μ-trans-1,2-Di-4-pyridylethylene-κ2N:N′)bis[bis(N,N-diisopropyldithiocarbamato-κ2S,S′)zinc(II)

The dinuclear title compound, [Zn2(C7H14NS2)4(C12H10N2)], is centrosymmetric about the central C=C bond. The five-coordinate Zn atom is bonded to two asymmetrically chelating dithio­carbamate ligands and a pyridine N atom to define an NS4 coordination geometry tending towards a square pyramid, with the N atom in the apical site. In the crystal structure, C—H⋯S contacts lead to supra­molecular chains.

(μ-trans-1,2-Di-4-pyridylethylene-κ2N:N′)bis[bis(N,N-diethyldithiocarbamato-κ2S,S′)zinc(II)] chloroform solvate

The dinuclear title solvate, [Zn2(C5H10NS2)4(C12H10N2)]·CHCl3, features two five-coordinate Zn atoms; both coordination polyhedra are distorted, but one has an NS4 donor set approximating to a square pyramid (with the N atom in the apical site), while the other is closer to a ZnNS4 trigonal-bipyramidal arrangement (with the N atom in an equatorial site). In both cases, the ZnII atom is chelated by two S,S′-bidentate dithiol­ate ligands. In the crystal, the chloro­form solvent mol­ecules reside in cavities defined by the dinuclear species and are held in place via C—H⋯S contacts.

Development of Five-Coordinate Zinc Mono- and Dithiolates as S-Donor Metalloligands: Formation of a Zn−W Coordination Polymer

The synthesis and isolation of mono- and dithiolate-bridged Zn(mu-SR)(n)W(CO)(m) (where n = 1, m = 5; n = 2, m = 4) species from the dimeric N,N'-bis(2-mercaptoethyl)-1,4-diazacycloheptanezinc(II), [Zn-1'](2), and the monomeric [N-(3-thiabutyl)-N'-(3-thiapentaneoate)-1,5-diazacycloheptane]zinc(II), Zn-1'-Ac, are described. Upon cleavage of the dimeric [Zn-1'](2) with Na(+)[ICH(2)CO(2)](-), the resulting Zn-1'-Ac product is isolated as a monomeric, five-coordinate Zn(N(2)SS'O) complex equipped with one available Zn-bound thiolate for further reactivity. Cleavage of [Zn-1'](2) with [Et(4)N](+)Cl(-) afforded a monomeric intermediate, [Zn-1'-Cl](-), containing two Zn-bound thiolates. The zinc mono- and dithiolato complexes demonstrated reactivity toward labile-ligand tungsten carbonyl species, (THF)W(CO)(5) and (pip)(2)W(CO)(4), to yield respectively [(Zn-1'-Ac)W(CO)(5)](x) and [(Zn-1'-Cl)W(CO)(4)](-) complexes that were isolated and characterized spectroscopically and via X-ray diffraction. Upon binding to W(CO)(5), the five-coordinate Zn(N(2)SS'O) complex becomes six-coordinate within the coordination polymer [(Zn-1'-Ac)W(CO)(5)](x), in which the acetate tether of each molecule provides an O donor to occupy the octahedral axial position of a neighboring moiety. The [(Zn-1'-Cl)W(CO)(4)](-) dithiolate-bridged complex maintains a five-coordinate, square-pyramidal [Zn(N(2)S(2)Cl)](-) center, utilizing a chloride as the apical donor and resulting in an overall anionic complex. The addition of CO(g) to the [(Zn-1'-Cl)W(CO)(4)](-) complex was monitored by IR spectroscopy, which showed the emergence of [(Zn-1'-Cl)W(CO)(5)](-).

Di-μ-chlorido-bis[chlorido(1,10-phenanthroline-κ2N,N′)zinc(II)

In the crystal structure of the title complex, [Zn2Cl4(C12H8N2)2], each of the two five-coordinated ZnII atoms displays a strongly distorted trigonal-bipyramidal geometry defined by two N atoms from the chelate ligand and by one terminal and two bridging chloride anions. The crystal structure is stabilized by C—H⋯Cl inter­actions. There is inter­molecular π–π stacking between adjacent phenanthroline ligands, with a centroid–centroid distance of 3.151 (3) Å.

Lithium zincopyrophosphate, Li2Zn3(P2O7)2

The title compound, dilithium(I) trizinc(II) bis[diphosphate(4-)], is the first quaternary lithium zincopyrophosphate in the Li-Zn-P-O system. It features zigzag chains running along c, which are built up from edge-sharing [ZnO(5)] trigonal bipyramids. One of the two independent Zn sites is fully occupied, whereas the other is statistically disordered by Zn(2+) and Li(+) cations, although the two Zn sites have similar coordination environments. Li(+) cations occupy a four-coordinated independent site with an occupancy factor of 0.5, as well as being disordered on the partially occupied five-coordinated Zn site with a Zn(2+)/Li(+) ratio of 1:1.

Synthesis and Crystal Structure of a Novel Five-Coordinate Complex from Zinc(II) and 1,3-Bis[2-(2-Hydroxybenzylideneamino)phenoxy]propan-2-ol Ligand

A novel five-coordinate Zn(II) complex of 1,3-bis[2-(2-hydroxybenzylideneamino)phenoxy]propan-2-ol (BHBAPP), namely [Zn2(BHBAPP)2](Pic)2 · C2H5OH (Pic = picrate) has been synthesized and characterized by elemental analyses, IR spectra and X-ray single-crystal diffraction. The complex crystallizes in the triclinic space group P−1 with cell constants a = 9.8145(9), b = 13.2398(12), c = 14.5058(13) A; α = 86.4560(10), β = 82.7260(10), γ = 73.0570(10)°, Mr = 1596.08, V = 1,788.0(3) A3, Z = 1, Dc = 1.482 g/cm3, F(000) = 822, μ = 0.760 mm−1. The structure was solved by direct methods and refined to R = 0.0390 (wR 2 = 0.0996). Examination of the structure shows the Zn atoms are coordinated to four oxygen atoms and one nitrogen atom from BHBAPP ligand to form a distorted trigonal bipyramidal geometry. Further, in the crystal structure [Zn(BHBAPP)]+1 cations and picrate anions are linked together via hydrogen bonding interactions tightly forming a three-dimensional supramolecular. It must be pointed out that the picrate anions play a special role in increasing the dimensionality of the supramolecular architecture. The novel five-coordinate Zn(II) complex of formula [Zn2(BHBAPP)2](Pic)2·C2H5OH (BHBAPP = 1,3-bis[2-(2-hydroxybenzylideneamino)phenoxy]propan-2-ol; Pic = picrate) was synthesized and its crystal structure determined. Single crystal X-ray diffraction analysis reveals that the Zn atom shows penta-coordination in a distorted trigonal bipyramidal geometry, and, the flexible BHBAPP ligand acts as a pentadentate ligand and adopts a fold configuration to wrap around the Zn(II) ion.

Novel Single‐Crystal‐to‐Single‐Crystal Anion Exchange and Self‐Assembly of Luminescent d10 Metal (CdII, ZnII, and CuI) Complexes Containing C3‐Symmetrical Ligands

Ligands L1 and L2' (L1=N,N',N''-tris(4-pyridyl)trimesic amide, L2'=N,N',N''-tris(3-pyridinyl)-1,3,5-benzenetricarboxamide) belonging to an interesting family of tripyridyltriamides with C(3)-symmetry have been utilized to construct 3D porous or hydrogen-bonded frameworks. Through a novel single-crystal-to-single-crystal anion-exchange process, [Cd(L1)(2)(ClO(4))(2)](n) (1c) can be obtained from [Cd(L1)(2)Cl(2)](n) (1b) in the presence of ClO(4)(-) anions. This anion-exchange process is highly selective and only the substitution of Cl(-) by ClO(4)(-) or PF(6)(-) could be realized; Cl(-) was found not to be substituted by BPh(4)(-). This demonstrates that the exchange process depends on the size of the anions in relation to the size of the cavities in the host material (ca. 7.5 A). In addition, the anion-exchange properties of 1 b have also been investigated by means of powder X-ray diffraction (PXRD), elemental analysis (EA), and infrared absorption spectroscopy (IR). Structurally, [Zn(L1)(NO(3))(2)](n)(2) consists of a 2D coordination network with five-coordinate Zn(II) ions. Surprisingly, different trigonal-bipyramidal Zn(II) ions propagate to form distinct respective sheet structures, A and B, which are packed in an A-B-A-B manner in the crystal lattice, and these are hydrogen-bonded to give a 3D extended framework. The molecular structure of [CuI(L2')](n)(3) shows that the Cu(I) ion adopts a distorted tetrahedral geometry, and 3 also forms a 2D coordination network. Significantly, this 2D coordination network is further assembled into a remarkable 3D homochiral framework through triple hydrogen bonding and pi...pi interactions. All of these 3D coordination polymers and/or hydrogen-bonded frameworks are luminescent in the solid state, and their solid-state luminescent properties have been investigated at room temperature and/or at 77 K.

{μ-6,6′-Dimethoxy-2,2′-[ethane-1,2-diylbis(nitrilomethylidyne)]diphenolato}-μ-nitrato-dinitratoholmium(III)zinc(II)

In the title heteronuclear ZnII–HoIII complex (systematic name: {μ-6,6′-dimeth­oxy-2,2′-[ethane-1,2-diylbis(nitrilo­methyl­idyne)]diphenolato-1κ4 O 1,O 1′,O 6,O 6′:2κ4 O 1,N,N′,O 1′)-μ-nitrato-1:2κ2 O:O′-dinitrato-1κ4 O,O′-holmium(III)zinc(II)), [HoZn(C18H18N2O4)(NO3)3], with the hexa­dentate Schiff base compartmental ligand N,N′-bis­(3-methoxy­salicyl­idene)ethyl­enediamine (H2 L), the Ho and Zn atoms are triply bridged by two phenolate O atoms of the Schiff base ligand and one nitrate ion. The five-coordinate Zn atom is in a square-pyramidal geometry with the donor centers of two imine N atoms, two phenolate O atoms and one of the bridging nitrate O atoms. The HoIII center has a ninefold coordination environment of O atoms, involving the phenolate O atoms, two meth­oxy O atoms, two O atoms from two nitrate ions and one from the bridging nitrate ion. Weak inter­molecular C—H⋯O inter­actions generate a two-dimensional double-layer structure.

{μ-6,6′-Dimethoxy-2,2′-[ethane-1,2-diylbis(nitrilomethylidyne)]diphenolato}-μ-nitrato-dinitratoterbium(III)zinc(II)

In the title heteronuclear ZnII—TbIII complex (systematic name: {6,6′-dimeth­oxy-2,2′-[ethane-1,2-diylbis(nitrilo­methyl­id­yne)]diphenolato-1κ4 O 6,O 1,O 1′,O 6′}:2κ4 O 1,N,N′,O 1′-μ-nitrato-1:2κ2 O:O′-dinitrato-1κ4 O,O′-terbium(III)zinc(II)), [TbZn(C18H18N2O4)(NO3)3], with the hexa­dentate Schiff base compartmental ligand N,N′-bis­(3-methoxy­salicyl­idene)ethyl­enediamine (H2 L), the Tb and Zn atoms are triply bridged by two phenolate O atoms of the Schiff base ligand and one nitrate ion. The five-coordinate Zn atom is in a square-pyramidal geometry with the donor centers of two imine N atoms, two phenolate O atoms and one of the bridging nitrate O atoms. The TbIII center has a ninefold coordination environment of O atoms, involving the phenolate O atoms, two meth­oxy O atoms, two O atoms from two nitrate ions and one from the bridging nitrate ion. Weak inter­molecular C—H⋯O inter­actions generate a two-dimensional layer structure.

{μ-6,6′-Dimethoxy-2,2′-[ethane-1,2-diylbis(nitrilomethylidyne)]diphenolato}-μ-nitrato-dinitratoeuropium(III)zinc(II)

In the title heteronuclear ZnII–EuIII complex [systematic name: {6,6′-dimeth­oxy-2,2′-[ethane-1,2-diylbis(nitrilo­methyl­idyne)]diphenolato-κ4 O 1,O 1′,O 6,O 6′:2κ4 O 1,N,N′,O 1′}-μ-nitrato-1:2κ2 O:O′-dini­trato-1κ4 O,O′-europium(III)zinc(II)], [EuZn(C18H18N2O4)(NO3)3], with the hexa­dentate Schiff base compartmental ligand N,N′-bis­(3-methoxy­salicyl­idene)ethyl­enediamine (H2 L), the Eu and Zn atoms are triply bridged by two phenolate O atoms of the Schiff base ligand and one nitrate ion. The five-coordinate Zn atom is in a square-pyramidal geometry with the donor centers of two imine N atoms, two phenolate O atoms and one of the bridging nitrate O atoms. The EuIII center has a ninefold coordination environment of O atoms, involving the phenol­ate O atoms, two meth­oxy O atoms, two O atoms from two nitrate ions and one from the bridging nitrate ion. Weak inter­molecular C—H⋯O inter­actions generate a two-dimensional double-layer structure.

Synthesis, spectral and structural characterization of three zinc(II) azide complexes with aminopyrazine

The reaction between zinc(II) azide, Zn(N 3) 2 and aminopyrazine (ampyz) afforded the complexes: [Zn(N 3) 2(ampyz) 2] ( 1), [Zn(N 3) 2(ampyz)] n ( 2) and [Zn 3(N 3) 6(ampyz) 2] n ( 3). These complexes are characterized by spectroscopic and crystallographic methods. The IR spectra of these compounds are measured and discussed. The structure of 1 consists of isolated tetrahedral zinc atom surrounded by two mono-dentate N-ampyz and two terminal azido ligands. Complex 2 features a zigzag chain of zinc centers in which each zinc is surrounded by alternate di-EO (end-on) and di-EE (end-to-end) azide bridges, the chain thus contains alternate four-membered Zn 2N 2 and eight-membered Zn 2(NNN) 2 rings. The two ampyz ligands are located in cis-arrangement and each of them further binds another zinc atom giving rise to a 3D network. Complex 3 contains two structurally different zinc atoms; the six-coordinate Zn(1) center links two di-EO azido bridges and two trans ampyz, thus having ZnN 6 chromophore. The five-coordinate Zn(2) center binds two di-EO bridging azido groups and the fifth position is occupied by an N atom from a bridging ampyz molecule. Both zinc centers, therefore participate in the formation of a 1D chain of cyclic Zn 2N 2 units. Each ampyz ligand binds another zinc atom via the second pyrazinic N atom giving another cross-chain and thus the structure consists of 2D sheets. In these three complexes the azido ligands of all types are asymmetric and linear within the experimental error.

{6,6′-Dimethoxy-2,2′-[ethane-1,2-diylbis(nitrilomethylidyne)]diphenolato}methanol-μ-nitrato-dinitratolutetium(III)zinc(II)

In the title heteronuclear ZnII–LuIII complex (systematic name: {6,6′-dimeth­oxy-2,2′-[ethane-1,2-diylbis(nitrilo­methyl­idyne)]diphenolato-1κ4O1,O1′,O6,O6′:2κ4O1,N,N′,O1′}(methanol-1κO)-μ-nitrato-1:2κ2O:O′-dinitrato-1κ4O,O′-lutetium(III)­zinc(II)), [LuZn(C18H18N2O4)(NO3)3(CH4O)], with the hexa­dentate Schiff base compartmental ligand N,N′-bis­(3-methoxy­salicyl­idene)ethyl­enediamine, the Lu and Zn atoms are triply bridged by two phenolate O atoms provided by the Schiff base ligand and one nitrate ion. The five-coordinated Zn is in a square-pyramidal geometry with the donor centers of two imine N atoms, two phenolate O atoms and one of the bridging nitrate O atoms. The LuIII center has a tenfold coordination environment of O atoms, involving the phenolate O atoms, two meth­oxy O atoms, one methanol O atom, and two O atoms from two nitrate ions and one from the bridging nitrate ion. Weak inter­molecular C—H⋯O inter­actions generate a two-dimensional layer structure.

{6,6′-Dimethoxy-2,2′-[ethane-1,2-diylbis(nitrilomethylidyne)]diphenolato}methanol-μ-nitrato-dinitratopraseodymium(III)zinc(II)

In the title heteronuclear ZnII–PrIII complex (systematic name: {6,6′-dimeth­oxy-2,2′-[ethane-1,2-diylbis(nitrilo­methylidyne)]diphenolato-1κ4O1,O1′,O6,O6′:2κ4O1,N,N′,O1′}(methanol-1κO)-μ-nitrato-1:2κ2O:O′-dinitrato-1κ4O,O′-praseodymium(III)zinc(II)), [PrZn(C18H18N2O4)(NO3)3(CH4O)], with the hexa­dentate Schiff base compartmental ligand N,N′-bis­(3-methoxy­salicyl­idene)ethyl­enediamine (H2L), the Pr and Zn atoms are triply bridged by two phenolate O atoms provided by the Schiff base ligand and one nitrate. The five-coordinate Zn atom is in a square-pyramidal geometry, with the donor centers of two imine N atoms, two phenolate O atoms and one of the bridging nitrate O atoms. The PrIII center has a tenfold coordination environment of O atoms, involving the phenolate O atoms, two meth­oxy O atoms, one methanol O atom, and two O atoms from two nitrates and one from the bridging nitrate. Strong inter­molecular O—H⋯O and some weak C—H⋯O inter­actions generate a two-dimensional layer structure.

{6,6′-Dimethoxy-2,2′-[ethane-1,2-diylbis(nitrilomethylidyne)]diphenolato}methanol-μ-nitrato-dinitratosamarium(III)nickel(II)

In the title heteronuclear ZnII–PrIII complex (systematic name: {6,6′-dimeth­oxy-2,2′-[ethane-1,2-diylbis(nitrilo­methylidyne)]diphenolato-1κ4O1,O1′,O6,O6′:2κ4O1,N,N′,O1′}(methanol-1κO)-μ-nitrato-1:2κ2O:O′-dinitrato-1κ4O,O′-praseodymium(III)zinc(II)), [PrZn(C18H18N2O4)(NO3)3(CH4O)], with the hexa­dentate Schiff base compartmental ligand N,N′-bis­(3-methoxy­salicyl­idene)ethyl­enediamine (H2L), the Pr and Zn atoms are triply bridged by two phenolate O atoms provided by the Schiff base ligand and one nitrate. The five-coordinate Zn atom is in a square-pyramidal geometry, with the donor centers of two imine N atoms, two phenolate O atoms and one of the bridging nitrate O atoms. The PrIII center has a tenfold coordination environment of O atoms, involving the phenolate O atoms, two meth­oxy O atoms, one methanol O atom, and two O atoms from two nitrates and one from the bridging nitrate. Strong inter­molecular O—H⋯O and some weak C—H⋯O inter­actions generate a two-dimensional layer structure.

Syntheses and structures of two Zn(II) complexes with the pentadentate Schiff-base ligands

Two structurally divergent zinc complexes [Zn · H 2L 1 · Cl 2] · 0.5CH 3OH ( 1) and [Zn 2 · L 2 · Cl 2 · (CH 3OH) 2] of the newly designed pentadentate H 2N 3O 2 Schiff bases H 2L 1 and H 2L 2 have been synthesized and structurally characterized. 1 has one five-coordinated Zn(II) ion in a distorted square-pyramid while 2 contains one novel seven-coordinate ZnN 3O 4 core in a pentagonal bipyramid polyhedron and one ZnO 2Cl 2 core in a trigonal pyramidal geometry. The coordinated units in 1 and 2 are both linked by hydrogen bonds forming infinite one-dimensional zigzag chains.

Catena-Poly[[(2,2′-diquinolyl)zinc(II)]-μ-terephthalato

The title complex, [Zn(C18H12N2)(C8H4O4)] n , consists of a one-dimensional zigzag [Zn(tpa)(quin)] n chain (tpa = terephthalate and quin = 2,2′-diquinolyl) with a pitch of 17.907 (2) Å. The tpa ligands bridge two Zn atoms in alternately bis(bidentate) and bis(monodentate) coordination modes. Each Zn atom is coordinated by two N atoms from a chelating quin, two O atoms from one bis(bidentate) tpa and one O atom from one bis(monodentate) tpa. The five-coordinate Zn geometry can be best described as distorted trigonal–bipyramidal.

Synthesis, crystal structures and properties of five-coordinate Schiff-base Zn(II) complexes

Five-coordinate Schiff-base Zn complexes (1,2-cyclohexanediamino-N,N′-bis(salicylidene)) zinc-pyridine 1 and (1,2-cyclohexanediamino-N,N′-bis(3,5-di-tert-butylsalicylidene)) zinc-pyridine 2 were synthesized and the structures of 1 and 2 have been determined by single-crystal X-ray analysis. All Zn atoms are five-coordinate in both structures. Both complexes exhibit interesting structures based on intermolecular π–π stacking and hydrogen bond interactions. Complex 1 has a one-dimensional molecular chain structure via π–π stacking interaction, while complex 2 has an interesting lattice structure (with cavities with dimensions 10.9 × 6.9 Å) formed through intermolecular π–π stacking and hydrogen bond interactions. 1 and 2 are compared and characterized by MS, elemental analysis, IR, UV-Vis and Photoluminescence (PL). Fluorescence spectra show that the maximal emission wavelength of 1 and 2 are 454 nm, and 480 nm, respectively, upon radiation by UV light. Cyclic voltammetry performed on 1 and 2 indicate a dependence of the cathodic potentials upon conformational and electronic effects. Electronic spectral properties of 1 and 2 were studied by TD-DFT methods. The fluorescent emission of these complexes originates from ligand-centred π–π* transitions. The Zn (II) centres play a key role in enhancing the fluorescent emission of the ligands.