Structural and Coordinative Variability in Zinc(II), Cadmium(II), and Mercury(II) Complexes of 2‐Pyridineformamide 3‐Hexamethyleneiminylthiosemicarbazone

Sodium in dry methanol reduces 2‐cyanopyridine in the presence of 3‐hexamethyleneiminylthiosemicarbazide and produces 2‐pyridineformamide 3‐hexamethyleneiminylthiosemicarbazone, HAmhexim ( 1 ). Complexes with zinc(II ), cadmium(II ) and mercury(II ) have been prepared and characterized by spectroscopic techniques. In addition, the crystal structures of HAmhexim ( 1 ), [Zn(Amhexim)(OAc)]₂μ·μDMSO ( 2 ), [Cd(HAmhexim)Cl₂]μ·μDMSO ( 7 ), [Cd(Amhexim)₂] ( 8 ), [Cd(HAmhexim)Br₂]μ·μDMSO ( 9 ), [Cd(HAmhexim)I₂]μ·μEtOH ( 10 ), [Hg(HAmhexim)Cl₂]μ·μDMSO ( 11 ), [Hg(Amhexim)Br]₂ ( 13 ), [Hg₃(HAmhexim)(Amhexim)Br₅]μ·μH₂O ( 14 ) and [Hg(Amhexim)I]₂ ( 15 ) have been determined. Coordination of the anionic and neutral thiosemicarbazone ligand occurs through the pyridine nitrogen atom, imine nitrogen atom, and thiolato or thione sulfur atom. In [Zn(Amhexim)(OAc)]₂ one of the bridging acetato ligands has monodentate coordination and the other bridges in a bidentate manner. [Cd(Amhexim)₂] is a 6‐coordinate species while the other cadmium complexes are 5‐coordinate. In [Hg(Amhexim)Br]₂ and [Hg(Amhexim)I]₂ the thiolato sulfur atoms act as bridges between the Hg atoms to form dimeric compounds and [Hg₃(HAmhexim)(Amhexim)Br₅]μ·μH₂O is a trinuclear complex with three different centers — two metallic centers have a 5‐coordination and the another one has 4‐coordination. In addition, [Hg(HAmhexim)Cl₂]μ·μDMSO and [Hg₃(HAmhexim)(Amhexim)Br₅]μ·μH₂O shown a supramolecular one‐dimensional hydrogen‐bonded self‐assembling.     

Coordination of ZnII,CdII, and HgII by 2‐Pyridineformamide‐3‐piperidyl‐thiosemicarbazone

Sodium in dry methanol reduces 2‐cyanopyridine in the presence of 3‐piperidylthiosemicarbazide and produces 2‐pyridine‐formamide‐3‐piperidylthiosemicarbazone, HAmpip. Complexes with zinc(II), cadmium(II), and mercury(II) have been prepared and characterized by elemental analyses and spectroscopic techniques. In addition, the crystal structures of [Zn(Ampip)₂], [Zn(Ampip)(Oac)]₂, [Cd(HAmpip)Cl₂]·(CH₃)₂SO, [Cd(HAm‐pip)Br₂] · (CH₃)₂SO, [Cd(HAmpip)I₂]·(CH₃)₂SO, [Cd(Ampip)₂] and [Hg(HAmpip)Br₂]·(CH₃)₂SO have been solved. Coordination of the anionic and neutral thiosemicarbazone ligand is via the pyridyl nitrogen, imine nitrogen and thiolato/thione sulfur atom, respectively. In [Zn(Ampip)(OAc)]₂ one of the bridging acetato ligands has monodentate coordination and the other bridges in a bidentate manner. ¹¹³Cd NMR studies were carried out on the [Cd(HAmpip)X₂](X = Cl, Br or I) and [Cd(Ampip)(OAc)]₂ complexes. The ¹¹³Cd chemical shifts are affected by the halogen and range from 411 to 301 ppm, and the spectrum of [Cd(Ampip)(OAc)]₂ shows two signals at 450 and 251 ppm. The ¹⁹⁹Hg NMR spectrum of [Hg(HAmpip)Cl₂] also is discussed.     

Crystal Structure of a New Triply‐Bridged Cobalt(III) Dimer with 2, 2′‐Dipyridylamine (dipyam), [Co2(μ‐OH)2(μ‐OAc)(OAc)2(dipyam)2]AcO·EtOH

The structure of [Co₂(μ‐OH)₂(μ‐OAc)(OAc)₂(dipyam)₂]AcO · EtOH ( 1 ) has been determined by single‐crystal X‐ray analysis. The cationic complex may be described as a “di(μ‐hydroxo)(μ‐acetato)dicobalt(III)” core with chelating 2, 2′‐dipyridylamine and monodentate acetate ligands. The coordination polyhedron around each cobalt atom is a distorted octahedral. The dimers are linked in the crystal by N‐H···O_{ionic AcO} and C‐H···O_{monodentate AcO} hydrogen bonds. Spectroscopic data are also presented.     

Two Succinato‐bridged Zinc(II) Phenanthroline Complexes: [Zn(phen)L2/2](H2L) and [(phen)2Zn(μ‐L)Zn(phen)2]L � 11H2O with H2L = Succinic Acid

Two mixed ligand Zn^II complexes [Zn(phen)L_2/2](H₂L) ( 1 ) and [(phen)₂Zn(μ‐L)Zn(phen)₂]L � 11H₂O ( 2 ) with H₂L = suc‐cinic acid were prepared and crystallographically characterized. Complex 1 crystallizes in the monoclinic space group C2/c (no. 15) with a = 13.618(1) Å, b = 9.585(1) Å, c = 15.165(1) Å, β = 96.780(6)°, V = 1965.6(3)ų, Z = 4 and complex 2 in the triclinic space group P 1¯ (no. 2) with a = 12.989(2)Å, b = 14.464(2)Å, c = 18.025(3)Å, α = 90.01(1)°, β = 109.69(1)°, γ = 112.32(1)°, V = 2917.4(8) ų, Z = 2. 1 consists of succinic acid molecules and 1D zigzag [Zn(phen)(C₄H₄O₄)_2/2] polymeric chains, in which the tetrahedrally coordinated Zn atoms are bridged by bis ‐ monodentate succinato ligands. Succinic acid molecules play an important role in supramolecular assemblies of the polymeric chains into 2D layers as well as in the stacking of 2D layers. 2 is composed of [(phen)₂Zn(μ‐L)Zn(phen)₂]²⁺ complex cations, succinate anions and hydrogen bonded water molecules. Within the divalent cations, Zn atoms are octahedrally coordinated by four N atoms of two phen ligands and two O atoms of one bis‐chelating succinato ligand. Through the intermolecular π—π stacking interactions, the complex cations form positively charged 2D layers, between which the noncoordinating succinate anions and water molecules are sandwiched.     

Two Heteroleptic Zinc(II) Complexes: [Zn(phen)(C9H15O6)2] and [Zn2(phen)2(H2O)2(C10H16O4)2] · 3H2O

Reactions of a freshly prepared Zn(OH)_2‐2x(CO₃)x · yH₂O precipitate, phenanthroline with azelaic and sebacic acid in CH₃OH/H₂O afforded [Zn(phen)(C₉H₁₅O₄)₂] ( 1 ) and [Zn₂(phen)₂(H₂O)₂(C₁₀H₁₆O₄)₂] · 3H₂O ( 2 ), respectively. They were structurally characterized by X‐ray diffraction methods. Compound 1 consists of complex molecules [Zn(phen)(C₉H₁₅O₄)₂] in which the Zn atoms are tetrahedrally coordinated by two N atoms of one phen ligand and two O atoms of different monodentate hydrogen azelaato groups. Intermolecular C(alkyl)‐H···π interactions and the intermolecular C(aryl)‐H···O and O‐H···O hydrogen bonds are responsible for the supramolecular assembly of the [Zn(phen)(C₉H₁₅O₄)₂] complexes. Compound 2 is built up from crystal H₂O molecules and the centrosymmetric binuclear [Zn₂(phen)₂(H₂O)₂(C₁₀H₁₆O₄)₂] complex, in which two [Zn(phen)(H₂O)]²⁺ moieties are bridged by two sebacato ligands. Through the intermolecular C(alkyl)‐H···O hydrogen bonds and π‐π stacking interactions, the binuclear complex molecules are assembled into layers, between which the lattice H₂O molecules are sandwiched. Crystal data: ( 1 ) C2/c (no. 15), a = 13.887(2), b = 9.790(2), c = 22.887(3)Å, β = 107.05(1)°, U = 2974.8(8)ų, Z = 4; ( 2 ) P1¯ (no. 2), a = 8.414(1), b = 10.679(1), c = 14.076(2)Å, α = 106.52(1)°, β = 91.56(1)°, γ = 99.09(1)°, U = 1193.9(2)ų, Z = 1.     

Spectral and Structural Studies of Transition Metal Complexes of 2‐Pyridineformamide N(4)‐ethylthiosemicarbazone

The reduction of 2‐cyanopyridine in the presence of N(4)‐ethylthiosemicarbazide produces 2‐pyridineformamide N(4)‐ethylthiosemicarbazone, HAm4E. Complexes with cobalt(III), nickel(II), copper(II), palladium(II) and platinum(II) have been prepared and characterized by molar conductivity, magnetic susceptibility and spectroscopic techniques. In addition, the crystal structures of HAm4E, [Co(Am4E)₂](ClO₄), [Ni(HAm4E)₂](ClO₄)₂, and [Ni(HAm4E)₂]Cl(OAc)·AcOH·H₂O have been obtained. Coordination occurs through the pyridyl nitrogen, imine nitrogen and either the thione or thiolato sulphur atom when coordinating as the neutral or anionic ligand, respectively. Extensive hydrogen bonding occurs in both HAm4E and its metal complexes, with the amide hydrogen atoms being significant contributors.     

Synthesis,Crystal Structure and Properties of [Cu(phen)3][Cu(pheida)2]·10H2O and [(phen)2Cu(μ‐BAAP)Cu(μ‐BAAP)Cu(phen)2][Cu(BAAP)2]·8.5H2O (H2pheida = N‐phenetyl‐iminodiacetic acid,H2BAAP = N‐benzylaminoacetic‐2‐propionic acid)

The salts [Cu(phen)₃][Cu(pheida)₂]·10H₂O ( 1 ) and [(phen)₂Cu(μ‐BAAP)Cu(μ‐BAAP)Cu(phen)₂][Cu(BAAP)₂]·8.5H₂O ( 2 ) (H₂pheida = N‐phenetyl‐iminodiacetic acid, H₂BAAP = N‐benzylaminoacetic‐2‐propionic acid, phen = 1, 10‐phenanthroline) have been prepared and studied by thermal, spectroscopic and X‐ray diffraction methods. 1 has the rather unusual [Cu(phen)₃]²⁺ cation and two non‐equivalent [Cu(pheida)₂]^2— anions with a coordination type 4+2 but quite different tetragonality (T = 0.848 and 0.703 for anions 1 and 2, respectively). The crystal consists of multi‐π, π‐stacked chains (…anion 2 — cation — cation — anion 2…) connected by hydrophobic interactions; these chains build channels which are partially filled by anions 1 and water molecules. In contrast, compound 2 has a mixed‐ligand trinuclear cation with a bridging central moiety close similar to the counter anion. The formation of such a trinuclear cation is discussed as a consequence of the most advantageous molecular recognition process between [Cu(phen)₂(H₂O)_{1 or 2}]²⁺ and [Cu(BAAP)₂]^2— in solution. In the crystal of 2, multi‐π, π‐stacked arrays of C₆‐rings from phen and (BAAP)^2— ligands of trinuclear cations generate channels where counter anions and water molecules are located.     

Synthesis,crystal structures and luminescence properties of seven mononuclear zinc(II), cadmium(II), cobalt(II) and nickel(II) complexes with 5‐(4‐methylphenyl)‐3‐(pyridin‐2‐yl)‐1H‐1,2,4‐triazole

Due to their versatile coordination modes and metal‐binding conformations, triazolyl ligands can provide a wide range of possibilities for the construction of supramolecular structures. Seven mononuclear transition metal complexes with different structural forms, namely aquabis[3‐(4‐methylphenyl)‐5‐(pyridin‐2‐yl)‐1H‐1,2,4‐triazolato‐κ²N ¹,N ⁵]zinc(II), [Zn(C₁₄H₁₁N₄)₂(H₂O)], (I), bis[5‐(4‐methylphenyl)‐3‐(pyridin‐2‐yl)‐1H‐1,2,4‐triazole‐κ²N ³,N ⁴]bis(nitrato‐κO )zinc(II), [Zn(NO₃)₂(C₁₄H₁₂N₄)₂], (II), bis(methanol‐κO )bis[3‐(4‐methylphenyl)‐5‐(pyridin‐2‐yl)‐1H‐1,2,4‐triazolato‐κ²N ¹,N ⁵]zinc(II), [Zn(C₁₄H₁₁N₄)₂(CH₄O)₂], (III), diiodidobis[5‐(4‐methylphenyl)‐3‐(pyridin‐2‐yl)‐1H‐1,2,4‐triazole‐κ²N ³,N ⁴]cadmium(II), [CdI₂(C₁₄H₁₂N₄)₂], (IV), bis[5‐(4‐methylphenyl)‐3‐(pyridin‐2‐yl)‐1H‐1,2,4‐triazole‐κ²N ³,N ⁴]bis(nitrato‐κO )cadmium(II), [Cd(NO₃)₂(C₁₄H₁₂N₄)₂], (V), aquabis[3‐(4‐methylphenyl)‐5‐(pyridin‐2‐yl)‐1H‐1,2,4‐triazolato‐κ²N ¹,N ⁵]cobalt(II), [Co(C₁₄H₁₁N₄)₂(H₂O)], (VI), and diaquabis[3‐(4‐methylphenyl)‐5‐(pyridin‐2‐yl)‐1H‐1,2,4‐triazolato‐κ²N ¹,N ⁵]nickel(II), [Ni(C₁₄H₁₁N₄)₂(H₂O)₂], (VII), have been prepared by the reaction of transition metal salts (Zn^II, Cd^II, Co^II and Ni^II) with 3‐(4‐methylphenyl)‐5‐(pyridin‐2‐yl)‐1H‐1,2,4‐triazole (pymphtzH) under either ambient or hydrothermal conditions. These compounds have been characterized by elemental analysis, IR spectroscopy and single‐crystal X‐ray diffraction. All the complexes form three‐dimensional supramolecular structures through hydrogen bonds or through π–π stacking interactions between the centroids of the pyridyl or arene rings. The pymphtzH and pymphtz⁻ entities act as bidentate coordinating ligands in each structure. Moreover, all the pyridyl N atoms are coordinated to metal atoms (Zn, Cd, Co or Ni). The N atom in the 4‐position of the triazole group is coordinated to the Zn and Cd atoms in the crystal structures of (II), (IV) and (V), while the N atom in the 1‐position of the triazolate group is coordinated to the Zn, Co and Ni atoms in (I), (III), (VI) and (VII).     

Synthesis,X‐ray characterization and density functional theory studies of N6‐benzyl‐N6‐methyladenine–M(II) complexes (M = Zn,Cd): The prominent role of π–π, C–H···π and anion–π interactions

We report the synthesis and X‐ray characterization of the N⁶‐benzyl‐N⁶‐methyladenine ligand (L) and three metal complexes, namely [Zn(HL)Cl₃]·H₂O ( 1 ), [Cd(HL)₂Cl₄] ( 2 ) and [H₂L]₂[Cd₃(μ‐L)₂(μ‐Cl)₄Cl₆]·3H₂O ( 3 ). Complex 1 consists of the 7H‐adenine tautomer protonated at N3 and coordinated to a tetrahedral Zn(II) metal centre through N9. The octahedral Cd(II) in complex 2 is N⁹‐coordinated to two N⁶‐benzyl‐N⁶‐methyladeninium ligands (7H‐tautomer protonated at N3) that occupy apical positions and four chlorido ligands form the basal plane. Compound 3 corresponds to a trinuclear Cd(II) complex, where the central Cd atom is six‐coordinated to two bridging μ‐L and four bridging μ‐Cl ligands. The other two Cd atoms are six‐coordinated to three terminal chlorido ligands, to two bridging μ‐Cl ligands and to the bridging μ‐L through N3. Essentially, the coordination patterns, degree of protonation and tautomeric forms of the nucleobase dominate the solid‐state architectures of 1 – 3 . Additionally, the hydrogen‐bonding interactions produced by the endocyclic N atoms and NH groups stabilize high‐dimensional‐order supramolecular assemblies. Moreover, energetically strong anion–π and lone pair (lp)–π interactions are important in constructing the final solid‐state architectures in 1 – 3 . We have studied the non‐covalent interactions energetically using density functional theory calculations and rationalized the interactions using molecular electrostatic potential surfaces and Bader's theory of atoms in molecules. We have particularly analysed cooperative lp–π and anion–π interactions in 1 and π⁺–π⁺ interactions in 3 .     

A threefold interpenetrated two‐dimensional zinc(II) supramolecular architecture based on 3‐nitrobenzoic acid and 4,4′‐bipyridine

With regard to crystal engineering, building block or modular assembly methodologies have shown great success in the design and construction of metal–organic coordination polymers. The critical factor for the construction of coordination polymers is the rational choice of the organic building blocks and the metal centre. The reaction of Zn(OAc)₂·2H₂O (OAc is acetate) with 3‐nitrobenzoic acid (HNBA) and 4,4′‐bipyridine (4,4′‐bipy) under hydrothermal conditions produced a two‐dimensional zinc(II) supramolecular architecture, catena‐poly[[bis(3‐nitrobenzoato‐κ²O,O′)zinc(II)]‐μ‐4,4′‐bipyridine‐κ²N:N′], [Zn(C₇H₄NO₄)₂(C₁₀H₈N₂)]_n or [Zn(NBA)₂(4,4′‐bipy)]_n, which was characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis and single‐crystal X‐ray diffraction analysis. The Zn^II ions are connected by the 4,4′‐bipy ligands to form a one‐dimensional zigzag chain and the chains are decorated with anionic NBA ligands which interact further through aromatic π–π stacking interactions, expanding the structure into a threefold interpenetrated two‐dimensional supramolecular architecture. The solid‐state fluorescence analysis indicates a slight blue shift compared with pure 4,4′‐bipyridine and HNBA.     

Assembly of Three 2D Metal‐Organic Frameworks (MOFs) Derived from Flexible Ligands, 1,4‐bis(3‐pyridyl)‐2,3‐diaza‐1,3‐butadiene (3‐bpd) and/or 1,2‐bis(4‐pyridyl)ethane (dpe)

Three coordination polymers, {[Cd(3‐bpd)₂(NCS)₂]×C₂H₅OH}_n ( 1 ), {[Cd(3‐bpd)(dpe)(NO₃)₂]×(3‐bpd)}₂ ( 2 ), {[Cd(dpe)₂(NCS)₂]×3‐bpd×2H₂O}_n ( 3 ) (3‐bpd = 1,4‐bis(3‐pyridyl)‐2,3‐diaza‐1,3‐butadiene; dpe = 1,2‐bis(4‐pyridyl)ethane), were prepared and structurally characterized by a single‐crystal X‐ray diffraction method. In compound 1 , each Cd(II) ion is six‐coordinate bonded to six nitrogen atoms from four 3‐bpd and two NCS^? ligands. The 3‐bpd acts as a bridging ligand connecting the Cd(II) ion to generate a 2D layered metal‐organic framework (MOF) by using a rhomboidal‐grid as the basic building units with the 4⁴ topology. In compound 2 , the Cd(II) ion is also six‐coordinate bonded to four nitrogen atoms of two 3‐bpd, two dpe and two oxygen atoms of two NO₃^? ligands. The 3‐bpd and dpe ligands both adopt bis‐monodentate coordination mode connecting the Cd(II) ions to generate a 2D layered MOF by using a rectangle‐grid as the basic building units with the 4⁴ topology. In compound 3 , two crystallographically independent Cd(II) ions are both coordinated by four nitrogen atoms of dpe ligands in the basal plane and two nitrogen atom of NCS^? in the axial sites. The dpe acts as a bridging ligand to connect the Cd(II) ions forming a 2D interpenetrating MOFs by using a square‐grid as the basic unit with the 4⁴ topology. All of their 2D layered MOFs in compounds 1 ‐ 3 are then arranged in a parallel non‐interpenetrating ABAB—packing manner in 1 and 2 , and mutually interpenetrating manner in 3 , respectively, to extend their 3D supramolecular architectures with their 1D pores intercalated with solvent (ethanol in 1 or H₂O in 3 ) or free 3‐bpd molecules in 2 and 3 , respectively. The photoluminescence measurements of 1 ‐ 3 reveal that the emission is tentatively assigned to originate from π‐π* transition for 1 and 2 and probably due to ligand‐center luminescence for compounds 3 , respectively.     

Structural and Solution Studies of two Mercury(II) Complexes with [1,3‐Bis(2‐ethoxy)benzene]triazene

The reaction of [1,3‐bis(2‐ethoxy)benzene]triazene, [ HL ], with Hg(SCN)₂ and Hg(CH₃COO)₂, resulted in the formation of the complexes [Hg L (SCN)] ( 1 ) and [Hg L ₂] · CH₃OH ( 2 ). They were characterized by means of X‐ray crystallography, CHN analysis, FT‐IR, ¹H NMR, and ¹³C NMR spectroscopy. The structure of compound 1 consists of two independent complexes in which the Hg^II atoms are stacked along the crystallographic a axis to form infinite chains. Each Hg^II atom is chelated by one L ligand and one SCN ligand, whereas in compound 2 , the Hg^II atom is surrounded by two L ligands. In addition, 1D chains formed by metal–π interactions are connected to each other by C–H ··· π stacking interactions in the structure of 1 , which results in a 2D architecture. An interesting feature of compound 2 is the presence of C–H ··· π edge‐to‐face interactions.     

A Hydrogen Adipato‐bridged Copper(II) Coordination Polymer: [Cu(bpy)(HL)]2L · 6H2O (bpy = 2, 2'‐Bipyridine,H2L = Adipic Acid)

Reaction of a fresh Cu(OH)_2x(CO₃)_1—x · yH₂O precipitate with adipic acid (H₂L) and 2, 2'—bipyridine (bpy) in ethanolic aqueous solution at room temperature afforded the hydrogen adipato bridged Cu^II coordination polymer [Cu(bpy)(HL)]₂L · 6H₂O consisting of double chains according to {[Cu(bpy)(HL)_2/2]₂L} and hydrogen bonded H₂O molecules. The chains result from [Cu(bpy)]²⁺ units bridged by bis—monodentate hydrogen adipato ligands and further crosslinked by bis—monodentate adipato ligands. Through the interchain π—π stacking interactions and interchain C(bpy)—H···O(adipato) hydrogen bonding interactions, the double chains are assembled into layers, between which the crystal H₂O molecules are located. The Cu atoms are square pyramidally coordinated by two N atoms of one bpy ligand and three O atoms of one adipato ligand and two hydrogen adipato ligands. The doubly bonded oxygen atom of the protonated carboxyl group occupies the apical position (Cu—N: 1.997, 2.005 Å; equatorial Cu—O: 1.925, 1.942 Å; apical Cu—O: 2.354 Å). Furthermore, the thermal behavior of the compound will be discussed. Crystal data: triclinic, P1¯ (no. 2), a = 9.618(1) Å, b = 9.933(1) Å, c = 12.782(2) Å, α = 70.88(1)°, β = 73.70(1)°, γ = 75.60(1)°, V = 1090.7(2) ų, Z = 1, R = 0.0453 and wR² = 0.1265 for 4643 observed reflections (F_o² > 2σ(F_o²)) out of 4985 unique reflections.     

Structural Study of Nickel(II), Copper(II), and Palladium(II) Complexes of 2‐Pyridineformamide 3‐Hexamethyleneiminylthiosemicarbazone

Reduction of 2‐cyanopyridine by sodium in the presence of 3‐hexamethyleneiminylthiosemicarbazide produces 2‐pyridineformamide 3‐hexamethyleneiminylthiosemicarbazone, HAmhexim. Complexes with nickel(II), copper(II) and palladium(II) have been prepared and the following complexes structurally characterized: [Ni(Amhexim)OAc], [{Cu(Amhexim)}₂C₄H₄O₄]·2DMSO·H₂O, [Cu(HAmhexim)Cl₂] and [Pd(Amhexim)Cl]. Coordination is via the pyridyl nitrogen, imine nitrogen and thiolato or thione sulfur atom when coordinating as the anionic or neutral ligand, respectively. [{Cu(Amhexim)}₂C₄H₄O₄] is a binuclear complex with the two copper(II) ions bridged by the succinato group in [Cu‐(HAmhexim)Cl₂] the Cu atom is 5‐coordinate and close to a square pyramid structure and in [Ni(Amhexim)OAc] and [Pd(Amhexim)Cl] the metal atoms are planar, 4‐coordinate.     

A New Succinato‐bridged Supramolecular Helix Chain: Crystal Structure of [Mn(H2O)2(bpy)(C4H4O4)] · H2O with bpy = 2,2′‐bipyridine

Yellow crystals of [Mn(H₂O)₂(bpy)(C₄H₄O₄)] · H₂O were obtained by the reaction of 2,2′‐bipyridine, succinic acid, MnSO₄ · H₂O and Na₂CO₃ in an aqueous methanol solution. The crystal structure (monoclinic, P2₁/c (no. 14), a = 8.294(1), b = 11.556(1), c = 17.064(1)Å, β = 95.181(6)°, Z = 4, R = 0.0349, wR² = 0.0887) consists of 1D supramolecular helix chains [Mn(H₂O)₂(bpy)(C₄H₄O₄)_2/2] and hydrogen bonded H₂O molecules. The Mn atoms are octahedrally coordinated by two N atoms of one bidentate chelating bpy ligand and four O atoms of two H₂O molecules and two bis‐monodentate bridging succinato ligands with d(Mn–O) = 2.139–2.237Å and d(Mn–N) = 2.268, 2.281 Å. The helix chains are held together by π‐π stacking interactions and hydrogen bonds.     

A Novel Trinuclear Nickel(II) Phenanthroline Suberato Complex: {Ni[Ni(phen)(H2O)4]2L4/2}L · 4H2O (H2L = suberic acid)

The Reaction of freshly precipitated NiCO₃ with phenanthroline and suberic acid in CH₃OH/H₂O at room temperature gave the title complex consisting of polymeric {Ni[Ni(phen)(H₂O)₄]₂L_4/2}²⁺ cationic chains, suberate anions and hydrogen bonded H₂O molecules. The cationic chains are generated from bis‐monodentate suberato ligands bridging the trinuclear {Ni[Ni(phen)(H₂O)₄]₂}⁶⁺ groups, in which the central Ni atom is, via two μ‐H₂O molecules, coordinated to two monodentate cationic [Ni(phen)(H₂O)₄]²⁺ complex ligands at trans positions. The NiO₆ octahedral coordination about the central Ni atom is elongated tetragonally distorted with d(Ni—O) = 2.033—2.166Å and the NiN₂O₄ octahedra about the side Ni atoms are significantly distorted with d(Ni—N) = 2.089, 2.099Å, d(Ni—O) = 2.046—2.117Å. The polymeric cationic chains are assembled via π—π stacking interactions into open 2D layers, between which the suberate anions and crystal H₂O molecules are sandwiched. Crystal data: triclinic, P1¯ (no. 2), a = 11.397(2)Å, b = 11.975(2)Å, c = 12.500(2)Å, α = 107.75(1)°, β = 104.50(1)°, γ = 109.68(1)°, Z = 1, R = 0.0521, wR² = 0.1249 for 3892 out of 6198 reflections with F_o² > 2σ(F_o²).     

An Azelaato‐bridged Dinuclear Copper(II) Complex, [Cu2(phen)2(C9H14O4)2] · 6 H2O (phen = 1,10‐phenanthroline)

The title compound [Cu₂(phen)₂(C₉H₁₄O₄)₂] · 6 H₂O was prepared by the reaction of CuCl₂ · 2 H₂O, 1,10‐phenanthroline (phen), azelaic acid and Na₂CO₃ in a CH₃OH/H₂O solution. The crystal structure (monoclinic, C2/c (no. 15), a = 22.346(3), b = 11.862(1), c = 17.989(3) Å, β = 91.71(1)°, Z = 4, R = 0.0473, wR² = 0.1344 for 4279 observed reflections) consists of centrosymmetric dinuclear [Cu₂(phen)₂(C₉H₁₄O₄)₂] complexes and hydrogen bonded H₂O molecules. The Cu atom is square‐planar coordinated by the two N atoms of the chelating phen ligand and two O atoms of different bidentate bridging azelaate groups with d(Cu–N) = 2.053, 2.122(2) Å and d(Cu–O) = 1.948(2), 2.031(2) Å. Two azelaate anions bridge two common Cu atoms via the terminal O atoms (d(C–O) = 1.29(2) Å; d(C–C) = 1.550(4)–1.583(4) Å). Phen ligands of adjacent complexes cover each other at distances of about 3.62 Å, indicating π‐π stacking interaction, by which the complexes are linked to 1 D bands.     

Zinc(II) and Cadmium(II) Complexes of the 3‐(2‐Pyridyl)‐5,6‐diphenyl‐1,2,4‐triazine (PDPT) Ligand,Structural Studies of [Zn(PDPT)2Cl(ClO4)] and [Cd(PDPT)2(NO3)(ClO4)]

Two new mixed‐anion zinc(II) and cadmium(II) complexes of 3‐(2‐pyridyl)‐5,6‐diphenyl‐1,2,4‐triazine (PDPT) ligand, [Zn(PDPT)₂Cl(ClO₄)] and [Cd(PDPT)₂(NO₃)(ClO₄)], have been synthesized and characterized by elemental analysis, IR‐ and ¹H NMR spectroscopy. The single crystal X‐ray analyses show that the coordination number in these complexes is six with four N‐donor atoms from two “PDPT” ligand and two of the anionic ligands, ZnN₄ClO_perchlorate, CdN₄O_nitrateO_perchlorate. Self‐assembly of these compounds in the solid state via π–π‐stacking interactions is discussed.     

Syntheses,Crystal Structures,and Thermal Behavior of Co(phen)(HL)2 and [Co2(phen)2(H2O)4L2]·H2O with H2L = Pimelic Acid

Two Co^II complexes, Co(phen)(HL)₂ ( 1 ) and [Co₂(phen)₂(H₂O)₄L₂]·H₂O ( 2 ) (H₂L = HOOC‐(CH₂)₅‐COOH), were synthesized and structurally characterized on the basis of single crystal X‐ray diffraction data. In complex 1 the Co atoms are tetrahedrally coordinated by two N atoms of one phen ligand and two O atoms of different hydrogenpimelato ligands. Through π—π stacking interactions between carboxyl group and phen ligand, the complex molecules are assembled into 1D columnar chains, which are connected by intermolecular hydrogen bonds. Complex 2 consists of the centrosymmetric dinuclear [Co₂(phen)₂(H₂O)₄L₂] molecules and hydrogen bonded H₂O molecules. The Co atoms are each octahedrally surrounded by two N atoms of one phen ligand and four O atoms from two bis‐monodentate pimelato ligands and two H₂O molecules at the trans positions. The results about thermal analyses, which were performed in flowing N₂ atmosphere, on both complexes were discussed. Crystal data: ( 1 ) C2/c (no. 15), a = 13.491(1)Å, b = 9.828(1)Å, c = 19.392(2)Å, β = 100.648(1)°, U = 2526.9(4)ų, Z = 4; ( 2 ) P1 (no. 2), a = 11.558(1)Å, b = 11.947(3)Å, c = 15.211(1)Å, α = 86.17(1)°, β = 75.55(1)°, γ = 69.95(1)°, U = 1910.3(3)ų, Z = 2.     

Crystal Structures of [Mn2(H2O)4(phen)2(C4H4O4)2] · 2 H2O and [Mn(phen)2(H2O)2][Mn(phen)2(C4H4O4)](C4H4O4) · 7 H2O

Reactions of 1,10‐phenanthroline monohydrate, Na₂C₄H₄O₄ · 6 H₂O and MnSO₄ · H₂O in CH₃OH/H₂O yielded a mixture of [Mn₂(H₂O)₄(phen)₂(C₄H₄O₄)₂] · 2 H₂O ( 1 ) and [Mn(phen)₂(H₂O)₂][Mn(phen)₂(C₄H₄O₄)](C₄H₄O₄) · 7 H₂O ( 2 ). The crystal structure of 1 (P1 (no. 2), a = 8.257(1) Å, b = 8.395(1) Å, c = 12.879(2) Å, α = 95.33(1)°, β = 104.56(1)°, γ = 106.76(1)°, V = 814.1(2) ų, Z = 1) consists of the dinuclear [Mn₂(H₂O)₄(phen)₂(C₄H₄O₄)₂] molecules and hydrogen bonded H₂O molecules. The centrosymmetric dinuclear molecules, in which the Mn atoms are octahedrally coordinated by two N atoms of one phen ligand and four O atoms from two H₂O molecules and two bis‐monodentate succinato ligands, are assembled via π‐π stacking interactions into 2 D supramolecular layers parallel to (101) (d(Mn–O) = 2.123–2.265 Å, d(Mn–N) = 2.307 Å). The crystal structure of 2 (P1 (no. 2), a = 14.289(2) Å, b = 15.182(2) Å, c = 15.913(2) Å, α = 67.108(7)°, β = 87.27(1)°, γ = 68.216(8)°, V = 2934.2(7) ų, Z = 2) is composed of the [Mn(phen)₂(H₂O)₂]²⁺ cations, [Mn(phen)₂(C₄H₄O₄)] complex molecules, (C₄H₄O₄)^2– anions, and H₂O molecules. The (C₄H₄O₄)^2– anions and H₂O molecules form 3 D hydrogen bonded network and the cations and complex molecules in the tunnels along [001] and [011], respectively, are assembled via the π‐π stacking interactions into 1 D supramolecular chains. The Mn atoms are octahedrally coordinated by four N atoms of two bidentate chelating phen ligands and two water O atoms or two carboxyl O atoms (d(Mn–O) = 2.088–2.129 Å, d(Mn–N) = 2.277–2.355 Å). Interestingly, the succinato ligands in the complex molecules assume gauche conformation bidentately to chelate the Mn atoms into seven‐membered rings.