[CoIICuI2(Im)4];∞: A Layered Bimetallic Imidazolate Polymer,the First Hybridized Cobalt(II) Imidazolate

A 2D grid‐shaped bimetallic imidazolate polymer [Co^IICu^I₂(Im)₄]_;∞ ( 1 ) was solvothermally synthesized and characterized with single crystal X‐ray analysis: tetragonal space group P 2₁/c (No.114), a = b = 10.9513(15) Å, c = 6.3063(13) Å, V = 756.3(2) ų. This is the first cobalt(II) imidazolate polymer hybridized with other transition metals.     

Solvothermal Syntheses and Magnetic Properties of Two New Coordination Polymers with Mixed Ligands

Two new coordination polymers, [Ni(H₂O)(BDC)(bpp)]_n ( 1 ) and [Co(mBDC)(bpp)]_n ( 2 ) (BDC = 1,4‐benzene dicarboxylate anion; bpp = 4,4′‐trimethylene dipyridine; mBDC = 1,3‐benzene dicarboxylate anion), were synthesized by solvothermal reaction and structurally characterized. Single crystal X‐ray diffraction showed that 1 consists of an inclined interpenetration of 1D nets generating an overall 3D entanglement and compound 2 of 1D chains. The luminescent and magnetic properties of both compounds in the solid state were also investigated. Crystal data: 1 : orthorhombic, Pnna; a = 18.3648(6), b = 13.6854(4), c = 16.2307(5) Å, V = 4079.3(2) ų, and Z = 8. Crystal data: 2 : triclinic, ; a = 8.6966(4), b = 10.1093(4), c = 11.8334(4) Å, α = 68.263(1)°, β = 82.895(1)°, γ = 78.370(1)°, V = 945.16(7) ų, and Z = 2.     

A Novel Two‐dimensional Coordination Polymer based on Rhombic Tetrameric Subunit Zn4O4 as Building Block

Hydrothermal reaction of olsalazine sodium, phenanthroline and Zn(ClO₄)₂·6H₂O in the presence of water and ethanol affords a two‐dimensional coordination polymer [Zn₄(OSA)₃(Phen)₂(H₂O)₂]_n ( 1 ) (OSA = olsalazine) which is characterized by single X‐ray determination, IR and UV spectrum. The local coordination around all zinc ions can be best described as a slightly distorted triangle bipyramid. Complex 1 consists of a tetrameric subunit, which is made up of four Zn atoms bridged by four O atoms. Two types of osalazine ligands can be found in the complex according to their different coordination modes of carboxyl groups. Crystal data for 1 : , a = 10.087(7), b = 12.830(9), c = 14.545(11) Å, α =114.598(10)°, β = 92.552(10)°, γ = 108.515(10)°, V = 1588(2) ų, Z = 2, R1 = 0.0818, wR2 = 0.1855. In comparison with the free ligand, the UV spectrum of 1 in solution (H₂O: EtOH = 1:1) shows a small Einstein shift probably due to the formation of coordination polymer and supramoleculer hydrogen‐bonding interactions.     

Preparation,Crystal Structure,and Thermal Decomposition of the Energetic Compound [Co(IMI)4(PA)](PA) (IMI = Imidazole and PA = Picrate)

The novel multi‐ligand coordination compound [Co(IMI)₄(PA)](PA) ( 1 ) was synthesized by using imidazole (IMI) and picrate (PA) and characterized by elemental analysis and FT‐IR spectroscopy. The crystal structure was determined by X‐ray single crystal diffraction and the crystallographic data showed that the compound crystallizes in the triclinic space group P$\bar{1}$ (α = 8.839(2) Å, b = 13.550(3) Å, c = 13.840(3) Å, α = 68.386(6)°, β = 88.349(9)°, and γ = 87.494(9)°). Furthermore, the Co^II ion is six‐coordinated by four nitrogen atoms from four imidazole ligands and two oxygen atoms from a PA group. Its thermal decomposition mechanism was determined based on differential scanning calorimetry (DSC) and thermogravimetry‐derivative thermogravimetry (TG‐DTG) analysis. The kinetic parameters of the first exothermic process were studied by using Kissinger's and Ozawa's method, respectively. The energy of combustion and the enthalpy of formation were measured and calculated. They showed good combustion performance of the compound. Additionally, the sensitivity properties were determined with standard methods. The results of all these studies showed that [Co(IMI)₄(PA)](PA) has potential application as ignition composition.     

A New Transition Metal Tetracyanidoborate: Synthesis,Structure and Properties of Co[B(CN)4]2·2H2O

The reaction of tetracyanidoboronic acid, H[B(CN)₄], with CoCO₃ or Co(OH)₂ in aqueous solution leads after slow evaporation of water to single crystals of Co[B(CN)₄]₂ · 2H₂O. The compound has been characterized by single crystal X‐ray diffraction ( , a = 12.2922(9), c = 9.2235(7) Å, Z = 4). The Co²⁺ ion is octahedrally coordinated by four nitrogen atoms of four different tetracyanidoborate CN groups occupying the four equatorial positions and two molecules of water occupying the remaining corners of the octahedron. The single crystal X‐ray structure, the vibrational spectra, and the thermal properties are compared with other known tetracyanidoborates with divalent cations.     

Synthesis and Characterization of a Purely Inorganic Open‐framework Bimetallic Phosphite with Intersecting 12‐ and 16‐membered Ring Channels

A new three‐dimensional open‐framework cobalt‐zinc phosphite [Co(H₂O)₄Zn(HPO₃)₂]·H₂O ( 1 ), has been prepared under hydrothermal conditions and characterized by single‐crystal X‐ray diffraction, XRD, IR and SQUID magnetometer. The compound crystallizes in the triclinic space group with a = 7.552(5), b = 7.671(5), c = 9.443(5) Å, α = 88.538(5)°, β = 89.109(5)°, γ = 87.056(5)°, V = 546.1(6) ų, Z = 2. The structure of 1 consists of corner‐shared (cs) four‐membered‐ring chains formed by alternating ZnO₄ tetrahedra and HPO₃ pseudopyramids, which are further linked through CoO₂(H₂O)₄ octahedra giving rise to a three‐dimensional (3‐D) neutral open‐framework with intersecting 12‐ and 16‐MR channels. The synthesis of system required the presence of L‐histidine which is not incorporated into the structure of the product. It is noteworthy that compound 1 represents the only known example of purely inorganic open‐framework cobalt‐zinc phosphite.     

Base Hydrolysis of Pentaaminecobalt(III) Complexes: The [CoX(dien) (dapo)]n+ system. Part 1. Syntheses,structures, configuration,and spectroscopy

Oxygentation of aqueous solutions of Co^III in presence of stoichiometric amounts of N-(2-aminoethyl)ethane-1,2-diamine (dien) and 1,3-diaminopropan-2-ol (dapo) produces μ-peroxocobalt(III) dimers. Acid cleavage (HCI) yields mer-exo(H)-, mer-endo (H)-, unsym-fac-exo(OH)-, and unsym-fac-endo(OH)-[CoCl(dien)(dapo)]²⁺ ( A–D )(X = Cl), resp. and unsym-fac-[Co-(dien)(dapo-N,N′,O)]³⁺ ( G ). Isomer seperation was achieved by fractional crystallization as ZnCl and ClO salts and by ion-exchange chromatography. The corresponding bromo, azido, nitrito-O, nitro-N, thiocyanato, hydroxo, and aqua complexes were also synthesized. Optically resolved samples were prepared for chiral compounds, and the complexes were structurally characterized by X-ray analyses ($ \mathop {\it \Lambda} \limits^ \to $(?)_436(CD) -A (X = N₃)), ($ \mathop {\it \Delta} \limits^ \to $(?)₄₃₆(CD) -B ). (X = N₃), $ \mathop {\it \Delta} \limits^ \to $ (+)₄₃₆(CD) -B by their chiroptical properties, and by ¹³C-NMR spectroscopy supported by ¹H-NMR, IR, CD, and UV/VIS spectroscopy. $ \mathop {\it \Lambda} \limits^ \to $(?)_436(CD)-mer-exo(H)-[Co(N₃)(dien)(dapo)](hydrogen di-O-benzoyl-L-tartrate)₂.4 H₂O crystallizes in the orthorhombic space group P2₁2₁2₁, a = 7.676(1) Å, b = 19.457(1) Å, c = 34.702(2) Å. $ \mathop {\it \Lambda} \limits^ \to $(?)_436(CD)-mer-endo(H)-[Co(N₃)(dien)(dapo)] (hydrogen di-O-benzoyl-L-tartrate)₂.2.75 H₂O crystallizes in the triclinic space group P1, a = 8.062(3) Å b = 10.296(1) Å, c = 15.056(2) Å, alpha = 80.55(1)°, β = 85.18(2)°, γ = 89.10(2)°. $ \mathop {\it \Delta} \limits^ \to $(+)_436(CD)-mer-endo(H)-[Co(N₃)(dien)(dapo)](hydrogen di-O-benzoyl-L-tartrate)₂. 5.75 H₂O crystallizes in the triclinic space group P1, a = 7.742(1) Å, b = 10.014(1) Å, c = 18.045(2) Å, α = 99.57(1)°, β = 92.87(1)°, γ = 102.56(1)°. The absolute configurations of the three cations were determined unambiguously. Interconversions of the various isomers and derivatives and structural, configurational, and spectroscopic aspects are discussed in detail.     

An open-framework cobalt molybdate possessing {Mo2O7} building block: hydrothermal synthesis and structural characterization of [CoMo2O7(4,4′-bipy)1.5]

The hydrothermal reaction of Co(COO)₂?·?4H₂O, MoO₃, H₃PO₄ and 4,4′-bipyridine yields bipyridine-ligated cobalt dimolybdate [CoMo₂O₇(4,4′-bipy)_1.5] (1) (4,4′-bipy?=?4,4′-bipyridine) in the triclinic system with space group of P 1 and cell parameters of a?=?7.1951(8)?Å, b?=?11.1708(17)?Å, c?=?11.4514(11)?Å, α?=?98.545(7)°, β?=?90.315(2)°, γ?=?105.777(5)°, V?=?874.88(19)?ų, and Z?=?2. Its structure consists of Co/Mo/O bimetal oxide layers with {Mo₂O₇} building blocks, linked by the coordination of 4,4′-bipy ligand with Co and Mo atoms, into a 3D porous hybrid framework.     

Three Copper(II) Coordination Polymers Constructed by Both Rigid and Flexible Ligands

Three new Copper(II) polymers coordinated by both rigid and flexible ligands, [Cu(bpy)(C₅H₆O₄)]_n ( 1 ), [Cu(bpy)(C₆H₈O₄)]_n ( 2 ), and [Cu₂(bpy)₂(C₆H₈O₄)₂]_n ( 3 ) (bpy = 4,4′‐bipyridine), have been hydrothermally synthesized and structurally characterized. Complex 1 features a box‐like bilayer motif of (4, 4) net. It crystallizes in triclinic space group with cell parameters: a = 8.1395(6) Å, b = 9.43 12(8) Å, c = 10.5473(8) Å, α = 112.1830(1)°, β = 92.423(2)°, γ = 104.752(2)°, V = 716.31(1) ų, Z = 2. Complex 2 crystallizes in triclinic space group with a = 8.8652(4) Å, b = 8.9429(4) Å, c = 10.6390(4) Å, α = 89.520(2)°, β = 69.123(2)°, γ = 75.2440(1)°, V = 758.92(6) ų, Z = 2. Complex 3 crystallizes in monoclinic space group Cc with a = 11.1521(1) Å, b = 15.3961(1) Å, c = 17.7419(1) Å, β = 105.715(3)°, V = 2932.4(5) ų, Z = 4. Complexes 2 and 3 are isomeric with different coordination modes of adipato ligand. Both of them possess the two‐fold interpenetrated 3‐D pcu topological net.     

Synthesis,Crystal Structure,and Hydrogen Bonding of μ‐Hydroxo‐μ‐peroxo‐bis[bis(ethylenediamine)cobalt(III)] Squarate

Black‐brown needle‐shaped single crystals of [Co₂(en)₄(O₂)(OH)][C₄O₄]_1.5 · 4H₂O (en = ethylenediamine) were prepared in aqueous solution at room temperature [space group P$\bar{1}$ (no.2) with a = 800.20(8), b = 1225.48(7), c = 1403.84(9) pm, α = 100.282(5), β = 94.515(7), and γ = 95.596(6)°]. The Co³⁺ cations [Co(1), Co(2)] are coordinated in an octahedral manner by four nitrogen atoms stemming from the ethylenediamine molecules and two oxygen atoms each from a hydroxo group and a peroxo group, respectively. Both Co³⁺ coordination polyhedra are connected by a common corner and by the peroxo group leading to the dinuclear [(en)₂Co(O₂)(OH)Co(en)₂]³⁺ cation. The squarate dianions, not bonded to Co³⁺, and the [(en)₂Co(O₂)(OH)Co(en)₂]³⁺ cations are linked by hydrogen bonds forming a three‐dimensional supramolecular network containing water molecules. Magnetic measurements revealed a diamagnetic behavior indicating a low‐spin electron configuration of Co³⁺. The UV/Vis spectra show two LMCT bands [π*(O₂^2–) → d_σ*(Co³⁺)] at 274 and 368 nm and the d–d transition (¹A_1g → ¹T_1g) at 542 nm. Thermoanalytical investigations in air show that the compound is stable up to 120 °C. Subsequent decomposition processes to cobalt oxide are finished at 460 °C.     

Adipato‐Bridged Mixed Ligand catena Complexes: ${_{\infty}^1}${[M(phen)(H2O)]L2/2} with M = NiII,CuII, ZnII; H2L = Adipic Acid

Three adipato bridged mixed ligand catena complexes {[M(phen)(H₂O)]‐(C₆H₈O₄)_2/2} with M = Ni^II ( 1 ), Cu^II ( 2 ), Zn^II ( 3 ) were synthesized. Structure determination based on X‐ray diffraction shows that they crystallize isostructurally in the monoclinic space group C2/c (no. 15) with cell dimensions of: 1 a = 22.451(4)Å, b = 9.041(1)Å, c = 17.440(2)Å, β = 103.41(1)°, U = 3443.4(9)ų, Z = 8; 2 a = 22.479(2)Å, b = 9.067(1)Å, c = 17.494(3)Å, β = 103.67(1)°, U = 3464.6(8)ų, Z = 8; 3 a = 22.635(3)Å, b = 9.052(1)Å, c = 17.571(3)Å, β = 103.24(1)°, U = 3504.5(9)ų, Z = 8. The crystal structure consists of 1D {[M(phen)(H₂O)]‐(C₆H₈O₄)_2/2} zigzag chains, in which the metal atoms are all octahedrally coordinated by two N atoms of one phen ligands and four O atoms of one H₂O molecule and two adipato ligands. The zigzag chains are held together by interchain π‐π stacking interactions and interchain hydrogen bonds.     

Synthesis and Crystal Structure of SrFe[BP2O8(OH)2]

SrFe[BP₂O₈(OH)₂] was synthesised under mild hydrothermal conditions. The crystal structure was determined from single–crystal X–ray diffraction data: triclinic, space group P (No. 2), a = 6.6704(12) Å, b = 6.6927(13) Å, c = 9.3891(19) Å, α = 109.829(5)°, β = 102.068(6)°, γ = 103.151(3)°, V = 364.74(12) ų and Z = 2. The crystal structure of SrFe[BP₂O₈(OH)₂] contains isolated borophosphate oligomers, [BP₂O₈(OH)₂]^5–, which are interconnected by Fe^IIIO₄(OH)₂ coordination octahedra. The resulting three–dimensional framework is characterised by elliptical channels running along [011]. Strontium takes positions inside the channels.     

Crystal Structures and Magnetic Properties of Charge-Transfer Salts: Cobaltocenium Bis(cis 1,2-diphenylethene-1,2-dithiolato)metalates (Metal = Ni,Pd, Pt)

Charge-transfer salts [Co(C₅H₅)₂][M(dpt)₂] (M = Ni and Pt; dpt = cis-1,2-diphenylethene-1,2-dithiolate) were synthesized and crystallographically characterized. [Co(C₅H₅)₂][Ni(dpt)2] crystallizes in the monoclinic space group C2/c with a = 25, 607(3) Å, b = 9.4151(11) Å, c = 14.407(4) Å, β = 101.373(22)°, V = 3405.3(10) Å₃ and Z = 4. [Co(C₅H₅)₂][Pt(dpt)₂] belongs to the triclinic space group $ {\rm P}\bar 1 $ with a = 9.4666(11) Å, b = 13.9869(12) Å, c = 14.2652(9) Å, α = 99.983(6)°, β = 90.034(7)°, γ = 109.751(7)°, V = 1747.2(3) ų and Z = 2. Both structures consist of ··· D⁺A^?D⁺A^?D⁺A^? ··· linear chains with the local C₅ axis of the eclipsed [Co(C₅H₅)₂]⁺ cation parallel to the best MS₄ plane of the [M(dpt)₂]^? anion. Magnetic susceptibility measurements show that χ_M T values of the complexes [Co(C₅H₅)₂][M(dpt)₂] (M = Ni, Pd, and Pt) remain nearly constant in the temperature range 15–300 K, but decrease rapidly with further decreasing of temperature, indicating weak antiferromagnetic interactions at low temperatures.     

Two Glutarato Bridged Coordination Polymers: ${_{\infty}^1}${[Mn(phen)]2L4/2} and ${_{\infty}^1}${[Zn(phen)(H2O)]L2/2}·H2O with H2L = Glutaric Acid

Two new glutarato bridged coordination polymers {[Mn(phen)]₂(C₅H₆O₄)_4/2} ( 1 ) and {[Zn(phen)(H₂O)](C₅H₆O₄)_2/2}· H₂O ( 2 ) were structurally characterized on the basis of single crystal X‐ray diffraction data. Crystal data: ( 1 ) P2/c (no. 13), a = 10.340(2)Å, b = 10.525(2)Å, c = 13.891(2)Å, β = 98.31(1)°, U = 1495.9(5)ų, Z = 2; ( 2 ) P2₁/n (no. 14), a = 6.738(1)Å, b = 25.636(3)Å, c = 10.374(1)Å, β = 106.13(1)°, U = 1721.4(4)ų, Z = 4. Complex 1 consists of 1D ribbon‐like {[Mn(phen)]₂(C₅H₆O₄)_4/2} chains, in which the [Mn(phen)] units were interlinked by glutarato ligands to generate 8‐ and 16‐membered rings. The Mn atoms are octahedrally coordinated by two N atoms of one phen ligand and four O atoms of three glutarato ligands with d(Mn‐N) = 2.270, 2.276Å, d(Mn‐O) = 2.114—2.283Å. Through the interchain π‐π stacking interactions, the 1D chains are assembled into 2D puckered layers, which are further held together by interlayer π‐π stacking interactions into a 3D network. Complex 2 is built up by 1D {[Zn(phen)(H₂O)](C₅H₆O₄)_2/2} linear chains and hydrogen bonded H₂O molecules. The Zn atoms are coordinated by two N atoms of one phen ligand and three O atoms of one H₂O molecule and two glutarato ligands to form slightly elongated trigonal bipyramids with the water O atom and one phen N atom at the apical positions (d(Zn‐N) = 2.101, 2.168Å, d(Zn‐O) = 1.991—2.170Å). The 1D linear chains result from [Zn(phen)(H₂O)] units bridged by bis‐monodentate glutarato ligands. The resulting 1D chains are assembled by π‐π stacking interactions into 2D layers, between which the hydrogen bonded H₂O molecules are situated.     

A 3-D cobalt(II)-coordination polymer with mixed-connected network topology constructed from 4-pyridin-3-yl-benzoic acid

A new coordination polymer, [Co₂(μ-H₂O)(4,3-pybz)₄] _n (1), has been hydrothermally synthesized from Co(NO₃)₂ · 6H₂O and an unsymmetrical 4-pyridin-3-yl-benzoic acid (4,3-Hpybz), which is characterized by IR, elemental analysis, thermogravimetric analysis, and single crystal X-ray diffraction. This compound crystallizes in monoclinic, space group C2/c with a = 11.876(3) Å, b = 15.462(3) Å, c = 21.545(4) Å, β = 94.873(5)°, V = 3942.0(15) ų, Z = 4, Dc = 1.565 g cm^?3, F(000) = 1904, GOF = 1.025, μ = 0.910 mm^?1, R ₁ = 0.0456, wR ₂ = 0.0983. Compound 1 shows a 3-D (3,6)-connected coordination framework with (3.4.5)(3².4⁴.5⁵.6².7²) topology, in which cobalt is a six-connected node, and the 4,3-Hpybz ligands serve as two-connected spacers and three-connected nodes. In addition, the magnetic and thermal properties of 1 have also been investigated.     

MII(C4H12N2)[B2P3O12(OH)] (MII = Co,Zn): Synthesis and Crystal Structure of Novel Open Framework Borophosphates

Two novel borophosphates, M^II(C₄H₁₂N₂)[B₂P₃O₁₂(OH)] (M^II = Co, Zn), exhibiting open frameworks, have been synthesized by hydrothermal reactions (T = 165 °C). The crystal structures of the isotypic compounds have been determined both at 293 K (orthorhombic, Ima2 (no. 46), Z = 4; M^II = Co: a = 12.4635(4) Å, b = 9.4021(4) Å, c = 11.4513(5) Å, V = 1341.90 ų, R₁ = 0.0202, wR₂ = 0.0452, 2225 observed reflections with I > 2σ(I); M^II = Zn: a = 12.4110(9) Å, b = 9.4550(5) Å, c = 11.4592(4) Å, V = 1344.69 ų, R₁ = 0.0621, wR₂ = 0.0926, 1497 observed reflections with I > 2σ(I)). Distorted CoO₆‐octahedra and ZnO₅‐square‐pyramids, respectively, share common oxygen‐corners with BO₄‐, PO₄‐ and (HO)PO₃‐tetrahedra. The tetrahedral groups are linked via common corners to form infinite loop‐branched borophosphate chains [B₂P₃O₁₂(OH)^4–]. The open framework of M^II‐coordination polyhedra and tetrahedral borophosphate chains contains a three‐dimensional system of interconnected structural channels running along [100], [011] and [011], respectively, which are occupied by di‐protonated piperazinium ions.     

Rhenium(I) Tellurolate,Telluroether and Bidentate-Telluroether Complexes: Crystal Structures of Re(CO)3Br(PhTe(CH2)3TePh), PhTeRe(CO)5 Re2(μ-SePh)2(CO)8 and [(PhTeMe)Re(CO)5][BF4]

The monomeric rhenium(I) complex with bidentate telluroether ligand Re(CO)₃Br(PhTe(CH₂)₃TePh) (1) was accessible via reaction of the PhTe(CH₂)₃TePh with Re(CO)₅Br. This chelate complex crystallized in triclinic space group $ {\rm P}\bar 1 $ with a = 9.390(5) Å, b = 10.961(3) Å, c = 11.849(4) Å a = 63.30(3)°, β = 87.49(4)° γ = 69.31(4)°, V = 1009.5(7) ų Z = 2, R = 0.033, and R_w = 0.034. Reaction of Re(CO)₅Cl with NaTePh yielded the Re(I) specics PhTeRe(CO)₅ (2). This complex crystallized in triclinic space group $ {\rm P}\bar 1 $ with a = 7.085(1) Å, b = 9.203(1) Å, c = 11.341(1) Å, α = 107.24(1)°, β = 100.56(1)°, γ = 96.47(1)°, V = 683.2(2) ų, Z = 2, R = 0.027, R_w = 0.022. Reaction of PhTeRe(CO)₅ and (PhSe)₂ in THF at 65 °C yielded a product that was confirmed crystallographically to be the known species Re₂(μ-SePh)₂(CO)₈ (3), in which two phenylselenolate ligands bridge the two Re(I). Compound 3 crystallized in monoclinic space group P2₁/n with a = 7.210(2) Å, b = 18.862(6) Å, c = 9.083(3) Å, β = 107.48(3)° V = 1178.2(7) ų, Z = 2, R = 0.046, and R_w = 0.051. Methylation of PhTeRe(CO)₅ with [Me₃O][BF₄] afforded Re(I) product [(PhTeMe)Re(CO)₅][BF₄] (4). This monodentate telluroether species crystallized in monoclinic space group P2₁/n with a = 8.405(1) Å, b = 13.438(3) Å, c = 15.560(2) Å, β = 92.59(1)° V = 1755.5(5) ų, Z = 4, R = 0.035, and R_w = 0.035.     

Cobalt(II) Complexes with Dicyanamide — from Binuclear Entities to Chains

One binuclear complex [Co(bpm*)₂(dca)]₂(ClO₄)₂ ( 1 ) and two 1D chain Co^II complexes, {[Co(bpm)₂(dca)](ClO₄)}_n ( 2 ) and [Co(dmf)₂(dca)₂]_n ( 3 ), (bpm*: bis[(3, 5‐dimethyl)pyrazolyl]methane; bpm: bis(pyrazolyl)methane; dca: dicyanamide; dmf: N, N‐dimethyl formamide) have been prepared and structurally characterized. The cobalt atoms are hexa‐coordinated forming a slightly distorted octahedral coordination. Compound 1 crystallizes in the monoclinic system, space group P2₁/c, a = 9.849(3)Å, b = 21.944(7)Å, c = 13.814(5)Å, β = 94.824(6), Z = 4, R₁ = 0.0672, wR₂ = 0.1395. 1 is a binuclear complex linked by two dca ligands, and each Co^II ion is coordinated by two terminal bpm* ligands. Compound 2 crystallizes in the orthorhombic system, space group Cmcm, a = 10.377(4)Å, b = 13.594(5)Å, c = 15.999(6)Å, Z = 4, R₁ = 0.0609, wR₂ = 0.1328. The structure of 2 can be described as a one‐dimensional zigzag chain of Co^II ions bridged by one dca ligand. Each Co^II ion in the chain is coordinated by two bpm ligands. Compound 3 crystallizes in the monoclinic system, space group C₂, a = 13.559(15)Å, b = 7.393(8)Å, c = 8.110(9)Å, β = 112.228(15), Z = 2, R₁ = 0.0260, wR₂ = 0.0760. 3 has a one‐dimensional linear chain of Co^II ions bridged by two dca ligands, in which each Co^II ion is coordinated with two dmf molecules.     

Synthesis,crystal structure,and electrochemistry of [Co{(Me-sal)2dien}(N3)] and [Co{(Me-sal)2dpt}(N3)]

The structure, spectroscopic, and electrochemical properties of [Co{(Me-sal)₂dien}(N₃)] and [Co{(Me-sal)₂dpt}(N₃)], where (Me-sal)₂dien = 2,2′-[1,1′-(3-azapentane-1,5-diyldinitrilo)diethylidyne] diphenolate and (Me-sal)₂dpt = 2,2′-[1,1′-(4-azapentane-1,7-diyldinitrilo)diethylidyne] diphenolate, have been investigated. These complexes have been characterized by elemental analyses, IR, UV–Vis, and ¹H-NMR spectroscopy. The crystal structures of these complexes have been determined by X-ray diffraction. Complex 1 crystallizes in the triclinic space group P 1, with a = 7.8443(4) Å, b = 11.0660(5) Å, c = 11.6216(6) Å, α = 73.360(1)°, β = 76.965(1)°, γ = 84.436(1)° and Z = 2. Complex 2 crystallizes in the monoclinic space group P2₁/n, with a = 12.1985(13) Å, b = 10.9332(12) Å, c = 15.2808(16) Å, β = 76.965(1)° and Z = 4. The coordination geometry around cobalt(III) in both complexes is a distorted octahedron. The electrochemical reduction of these complexes at a glassy carbon electrode in acetonitrile indicates that the first reduction corresponding to Co^III–Co^II is electrochemically irreversible, accompanied by dissociation of the axial Co–N(N₃) bond. The second reduction step of Co(II/I) leads to decomposition of the complex. These observations are rationalized based on the structure-function relations.     

Copper(I) π‐Complexes with 2‐Butyne‐1,4‐diol. Synthesis and Crystal Structure of Na[CuCl2(HOCH2C≡CCH2OH)]·2H2O

Crystals of anionic Na[CuCl₂(HOCH₂C≡CCH₂OH)]·2H₂O π‐complex have been synthesized by interaction of 2‐butyne‐1,4‐diol with CuCl in a concentrated aqueous NaCl solution and characterized by X‐ray diffraction at 100 K. The crystals are triclinic: space group , a = 7.142(3), b = 7.703(3), c = 10.425(4) Å, α = 105.60(3), β = 99.49(3), γ = 110.43(3)°, V = 495.9(4) ų, Z = 2, R = 0.0203 for 3496 reflections. The structure is built of discrete [CuCl₂(HOCH₂C≡CCH₂OH)]^? anionic stacks and polymeric cations among the stacks. The Cu^I atom adopts trigonal planar coordination of two Cl^? anions and the C≡C bond of 2‐butyne‐1,4‐diol, Cu–(C≡C) distance is equal to 1.903(3) Å. Na⁺ cations environment is octahedral and consists of O and Cl atoms. The crystal packing is governed by strong hydrogen bonds of O–H···Cl and O–H···O types.