NiII and ZnII complexes of the hexadentate macrocyclic ligand cis‐6,13‐di­methyl‐1,4,8,11‐tetra­aza­cyclo­tetra­decane‐6,13‐di­amine

The title pendent‐arm macrocyclic hexa­amine ligand binds stereospecifically in a hexadentate manner, and we report here its isomorphous Ni^II and Zn^II complexes (both as perchlorate salts), namely (cis‐6,13‐di­methyl‐1,4,8,11‐tetra­aza­cyclo­tetra­decane‐6,13‐di­amine‐κ⁶N)­nickel(II) di­per­chlorate, [Ni(C₁₂H₃₀N₆)]­­(ClO₄)₂, and (cis‐6,13‐di­methyl‐1,4,8,11‐tetraaza‐cyclo­tetra­decane‐6,13‐di­amine‐κ⁶N)­zinc(II) di­per­chlorate, [Zn(C₁₂H₃₀N₆)]­(ClO₄)₂. Distortion of the N—M—N valence angles from their ideal octahedral values becomes more pronounced with increasing metal‐ion size and the present results are compared with other structures of this ligand.     

catena‐Poly­[bis­[(2,2‐bi­pyridine‐κ2N,N′)­copper(II)]‐μ4‐1,2,4,5‐benzene­tetra­carboxyl­ato‐κ4O1:O2:O3:O4]

In the title complex, [Cu₂(C₁₀H₂O₈)(C₁₀H₈N₂)₂]_n, the Cu^II cation has a four‐coordinated environment, completed by two carboxyl O atoms belonging to two 1,2,4,5‐benzene­tetra­carboxyl­ate anions (TCB⁴⁻) and two N atoms from one 2,2′‐bi­pyridine (2,2′‐bipy) ligand, forming a distorted square‐planar geometry. The [Cu(2,2′‐bipy)]²⁺ moieties are bridged by TCB⁴⁻ anions, which lie about inversion centres, forming an infinite one‐dimensional coordination polymer with a double‐chain structure along the a axis. A two‐dimensional network structure is formed via a face‐to‐face π–π interaction between the 2,2′‐bipy rings belonging to two adjacent double chains, at a distance of approximately 3.56 Å.     

A 1,3,2‐ox­aza­borolidine dimer derived from (S)‐α,α‐di­phenyl­prolinol

The reaction of (S)‐α,α‐di­phenyl­prolinol with an excess of borane–tetra­hydro­furan complex yields a stable crystalline material with the composition C₃₄H₃₈B₂N₂O₂, which features a borane adduct of a spiro­cyclic structure with two ox­aza­borolidine rings joined by a central tetrahedral B atom. This dimeric ox­aza­borolidine complex, viz. 3,3,3′,3′‐tetra­phenyl‐1,1′‐spiro­bi(3a,4,5,6‐tetra­hydro‐3H‐pyrrolo­[1,2‐c][1,3,2]­ox­azaborole)–7‐borane, is the dominant product under various reaction conditions; its crystal structure is consistent with ¹¹B, ¹H and ¹³C NMR and IR analyses.     

Three oxo complexes with a tetra­nuclear [Cu4(μ2‐Cl)6(μ4‐O)] unit

The three title compounds, namely 4‐phenyl‐1H‐imidazolium hexa‐μ₂‐chloro‐chloro‐μ₄‐oxo‐tris­(4‐phenyl‐1H‐imidazole‐κN¹)­tetra­copper(II) monohydrate, (C₉H₉N₂)[Cu₄Cl₇O(C₉H₈N₂)₃]·H₂O, hexa‐μ₂‐chloro‐μ₄‐oxo‐tetra­kis­(pyridine N‐oxide‐κO)tetra­copper(II), [Cu₄Cl₆O(C₅H₅NO)₄], and hexa‐μ₂‐chloro‐tetra­kis(2‐methyl‐1H‐imidazole‐κN¹)‐μ₄‐oxo‐tetra­copper(II) methanol trisolvate, [Cu₄Cl₆O(C₄H₆N₂)₄]·3CH₄O, exhibit the same Cu₄OCl₆ framework, where the O atom at the centre of an almost regular tetra­hedron bridges four copper cations at the corners. This group is in turn surrounded by a Cl₆ octa­hedron, leading to a rather globular species. This special arrangement of the Cu^II cations results in a diversity of magnetic behaviours.     

[Ni(terpy)(H2O)]‐trans‐[Ni‐(μ‐CN)2‐(CN)2]n,a one‐dimensional linear tetra­cyano­nickelate chain

The one‐dimensional chain catena‐poly­[[aqua(2,2′:6′,2′′‐terpyridyl‐κ³N)­nickel(II)]‐μ‐cyano‐κ²N:C‐[bis­(cyano‐κC)nickelate(II)]‐μ‐cyano‐κ²C:N], [Ni(terpy)(H₂O)]‐trans‐[Ni‐μ‐(CN)₂‐(CN)₂]_n or [Ni₂­(CN)₄­(C₁₅H₁₁N₃)(H₂O)], consists of infinite linear chains along the crystallographic [10] direction. The chains are composed of two distinct types of nickel ions, paramagnetic octahedral [Ni(terpy)(H₂O)]²⁺ cations (with twofold crystallographic symmetry) and diamagnetic planar [Ni(CN)₄]^2? anions (with the Ni atom on an inversion center). The [Ni(CN)₄]^2? units act as bidentate ligands bridging through two trans cyano groups thus giving rise to a new example of a trans–trans chain among planar tetra­cyano­nickelate complexes. The coordination geometry of the planar nickel unit is typical of slightly distorted octahedral nickel(II) complexes, but for the [Ni(CN)₄]^2? units, the geometry deviates from a planar configuration due to steric interactions with the ter­pyridine ligands.     

A uniform and one‐dimensional stacking of 2,5‐di­chloro­tetra­cyano­quinodimethanide mol­ecules in the tetra­methyl­arsonium salt

In the tetra­methyl­arsonium salt of 2,5‐di­chloro‐7,7,8,8‐tetra­cyano­quinodimethanide [systematic name: tetra­methyl­arson­ium 2,2′‐(2,5‐dichlorocyclohexa‐2,5‐diene‐1,4‐diylidene)bis(propanedinitrile)], C₄H₁₂As⁺·C₁₂H₂Cl₂N₄^? or [As(CH₃)₄](C₁₂H₂Cl₂N₄), the cation lies disordered about a twofold axis and the radical ion lies about an inversion center forming a uniform [interplanar distance 3.35 (2) Å] and one‐dimensional stacking without any slip. The electrical conductivity of the single crystal at room temperature was less than 10^?9 S cm^?1, and the temperature dependence of para­magnetic susceptibility obeyed a one‐dimensional antiferromagnetic Heisenberg model with a spin‐exchange integral of 83 K in the temperature range 1.8–320.0 K.     

A chloro(2‐pyridinecarboxaldehyde)(2,2′:6′,2′′‐ter­pyridine)­ruthenium(II) complex

The aldehyde moiety in the title complex, chloro(2‐pyridinecarboxaldehyde‐N,O)(2,2′:6′,2′′‐terpyridine‐κ³N)ruthenium(II)–chloro­(2‐pyridine­carboxyl­ic acid‐N,O)(2,2′:6′,2′′‐ter­pyridine‐κ³N)­ruthenium(II)–perchlorate–chloro­form–water (1.8/0.2/2/1/1), [RuCl­(C₆H₅NO)­(C₁₅H₁₁N₃)]_1.8[RuCl­(C₆H₅­NO₂)(C₁₅H₁₁N₃)]_0.2­(ClO₄)₂·­CHCl₃·­H₂O, is a structural model of substrate coordination to a transfer hydrogenation catalyst. The title complex features two independent Ru^II complex cations that display very similar distorted octahedral coordination provided by the three N atoms of the 2,2′:6′,2′′‐ter­pyridine ligand, the N and O atoms of the 2‐pyridine­carbox­aldehyde (pyCHO) ligand and a chloride ligand. One of the cation sites is disordered such that the aldehyde group is replaced by a 20 (1)% contribution from a carboxyl­ic acid group (aldehyde H replaced by carboxyl O—H). Notable dimensions in the non‐disordered complex cation are Ru—N 2.034 (2) Å and Ru—O 2.079 (2) Å to the pyCHO ligand and O—C 1.239 (4) Å for the pyCHO carbonyl group.     

Two new dimeric cadmium(II) and zinc(II) sulfate complexes with 2,4,6‐tris(2‐pyridyl)‐1,3,5‐triazine and 2,2:6′,2′′‐ter­pyridine

The structures of two new sulfate complexes are reported, namely di‐μ‐sulfato‐κ³O,O′:O′′‐bis{aqua­[2,4,6‐tris(2‐pyridyl)‐1,3,5‐triazine‐κ³N¹,N²,N⁶]­cadmium(II)} tetra­hydrate, [Cd₂(SO₄)₂(C₁₆H₁₂N₆)₂(H₂O)₂]·4H₂O, and di‐μ‐sulfato‐κ²O:O′‐bis­[(2,2′:6′,2′′‐ter­pyridine‐κ³N¹,N^1′,N^1′′)­zinc(II)] dihydrate, [Cd₂(SO₄)₂(C₁₅H₁₁N₃)₂]·2H₂O, the former being the first report of a Cd(tpt) complex [tpt is 2,4,6‐tris(2‐pyridyl)‐1,3,5‐triazine]. Both compounds crystallize in the space group P and form centrosymmetric dimeric structures. In the cadmium complex, the metal center is heptacoordinated in the form of a pentagonal bipyramid, while in the zinc complex, the metal ion is in a fivefold environment, the coordination geometry being intermediate between square pyramidal and trigonal bipyramidal. Packing of the dimers leads to the formation of planar structures strongly linked by hydrogen bonding.     

A polymeric zinc thio­sulfate complex containing anionic and cationic chains based on tetra­hedral and octa­hedral zinc sites

catena‐Poly[[[tetra­aqua­zinc(II)]‐μ‐4,4′‐bipyridine‐κ²N:N′] [[μ‐thio­sulfato‐κ²O:S‐bis­[(thio­sulfato‐κS)zinc(II)]]‐di‐μ‐4,4′‐pyridine‐κ⁴N:N′] dihydrate], {[Zn(C₁₀H₈N₂)(H₂O)₄][Zn₂(S₂O₃)₃(C₁₀H₈N₂)₂]·2H₂O}_n, is a polymeric zinc complex built up from thio­sulfate‐containing anionic chains, where the Zn atom is tetra­hedrally coordinated, and aqua‐containing cationic chains incorporating octa­hedrally coordinated Zn. In each type of chain, the 4,4′‐bipyridine units act as spacers, and the chains run along three non‐inter­secting almost orthogonal directions in space. The profusion of hydrogen‐bond donors (all the H atoms of the water mol­ecules) and acceptors (the thio­sulfate O and S atoms) generates a very complex hydrogen‐bonding scheme.     

Dichloro­(4,4′‐dialkyl‐2,2′‐bipyridine‐κ2N,N′)platinum(II), where alkyl is pentyl and heptyl

Dichloro­(4,4′‐dipentyl‐2,2′‐bipyridine‐κ²N,N′)platinum(II), [PtCl₂(C₂₀H₂₈N₂)], adopts a discrete π–π stacking structure, where the alkyl chains are located in a random manner. In contrast, dichloro­(4,4′‐diheptyl‐2,2′‐bipyridine‐κ²N,N′)platinum(II), [PtCl₂(C₂₄H₃₆N₂)], forms a layer structure comprised of alkyl chain layers and paired coordination sites, as observed for analogous complexes with longer alkyl chains.     

(Borohydrido)(18‐crown‐6)potassium and (borohydrido)(dibenzo‐18‐crown‐6)(tetra­hydro­furan)potassium

In the two compounds (borohydrido)(1,4,7,10,13,16‐hexa­oxacyclo­octa­decane‐κ⁶O)potassium, [K(BH₄)(C₁₂H₂₄O₆)], (I), and (borohydrido)(1,4,7,10,13,16‐hexa­oxa‐2,3:11,12‐di­benzo­cyclo­octa­deca‐2,11‐diene‐κ⁶O)(tetra­hydro­furan)­potassium, [K(BH₄)(C₄H₈O)(C₂₀H₂₄O₆)], (II), the K atom is bound to the six O atoms of the crown ether and to a tridentate borohydride group, with further coordination to a tetra­hydro­furan mol­ecule in (II). The alkali metal ion environment is thus distorted hexa­gonal–pyramidal in (I) and bipyramidal in (II).     

Unusual O‐coordination of caffeine in tetra­kis(μ‐3,5‐dinitro­benzoato‐κ2O:O′)bis­[(caffeine‐κO)copper(II)]

The title compound {systematic name: tetra­kis(μ‐3,5‐dinitro­benzoato‐κ²O:O′)bis­[(3,7‐dihydro‐1,3,7‐trimethyl‐1H‐purine‐2,6‐dione‐κO²)copper(II)]}, [Cu₂(C₇H₃N₂O₆)₄(C₈H₁₀N₄O₂)₂], consists of paddle‐wheel dimeric tetra­kis(μ‐3,5‐dinitro­benzoato‐κ²O:O′)dicopper(II) units with O‐coordinated caffeine mol­ecules in both apical positions. The entire dimeric mol­ecule lies on a tetra­gonal inversion axis, and thus one nitro­benzoate anion with one Cu atom in a special position belong to the independent part of the mol­ecule. The caffeine ligand bonded to the Cu atom is disordered on a local twofold non‐crystallographic axis coincident with the axis. A π–π stacking inter­action is observed between the caffeine rings and adjacent symmetry‐related benzene rings of the 3,5‐dinitro­benzoate anions.     

A new photochromic tetra­hydro­indolizine

The title compound, di­methyl 10b′‐(4‐fluoro­styryl)‐8′,9′‐di­methoxy‐4‐nitro‐5′,6′‐di­hydrospiro­[9H‐fluorene‐9,1′(10b′H)‐pyrrolo­[2,1‐a]­iso­quinoline]‐2′,3′‐di­carboxyl­ate, C₃₈H₃₁FN₂O₈, is a new photochromic tetra­hydro­indolizine. One of the C—C bonds at the spiro C atom is very long [1.630 (2) Å], thus explaining the photochromic behaviour.     

(2,2′‐Biquinoline‐κ2N,N′)dichloropalladium(II), ‐copper(II) and ‐zinc(II)

In the three title complexes, namely (2,2′‐biquinoline‐κ²N,N′)dichloro­palladium(II), [PdCl₂(C₁₈H₁₂N₂)], (I), and the corresponding copper(II), [CuCl₂(C₁₈H₁₂N₂)], (II), and zinc(II) complexes, [ZnCl₂(C₁₈H₁₂N₂)], (III), each metal atom is four‐coordinate and bonded by two N atoms of a 2,2′‐biquinoline molecule and two Cl atoms. The Pd^II atom has a distorted cis‐square‐planar coordination geometry, whereas the Cu^II and Zn^II atoms both have a distorted tetra­hedral geometry. The dihedral angles between the N—M—N and Cl—M—Cl planes are 14.53 (13), 65.42 (15) and 85.19 (9)° for (I), (II) and (III), respectively. The structure of (II) has twofold imposed symmetry.     

[N,N′‐Bis­(salicyl­idene)‐2,2‐di­methyl‐1,3‐propane­diaminato]­nickel(II) and [N,N′‐bis­(salicyl­idene)‐2,2‐di­methyl‐1,3‐propane­diaminato]copper(II)

In the title compounds, {2,2′‐[2,2‐di­methyl‐1,3‐propane­diyl­bis­(nitrilo­methyl­idyne)]­diphenolato‐κ⁴N,N′,O,O′}nickel(II), [Ni(C₁₉H₂₀N₂O₂)], and {2,2′‐[2,2‐di­methyl‐1,3‐propane­diyl­bis­(nitrilo­methyl­idyne)]­diphenolato‐κ⁴N,N′,O,O′}copper(II), [Cu(C₁₉H₂₀N₂O₂)], the Ni^II and Cu^II atoms are coordinated by two iminic N and two phenolic O atoms of the N,N′‐bis­(salicyl­idene)‐2,2‐di­methyl‐1,3‐propane­diaminate (SALPD^2?, C₁₇H₁₆N₂O₂^2?) ligand. The geometry of the coordination sphere is planar in the case of the Ni^II complex and distorted towards tetrahedral for the Cu^II complex. Both complexes have a cis configuration imposed by the chelate ligand. The dihedral angles between the N/Ni/O and N/Cu/O coordination planes are 17.20 (6) and 35.13 (7)°, respectively.     

1,1′‐Di(hydrazinocarbonylmethyl)‐2,2′‐biimidazole monohydrate and 1,1′‐di[2‐(hydrazinocarbonyl)ethyl]‐2,2′‐bi­imidazole

The crystal structures of the title compounds, alternatively called 2,2′‐(2,2′‐bi­imid­azole‐1,1′‐diyl)­diaceto­hydra­zide monohydrate, C₁₀H₁₄N₈O₂·H₂O, (I), and 3,3′‐(2,2′‐bi­imid­azole‐1,1′‐diyl)­dipropion­o­hydra­zide, C₁₂H₁₈N₈O₂, (II), respectively, have been determined. The mol­ecules consist of half‐mol­ecule asymmetric units related by a twofold rotation in (I) and by a center of inversion in (II). The imidazole rings of both mol­ecules crystallize in a nearly coplanar fashion [dihedral angles of 5.91 (3) and 0.0 (1)° for (I) and (II), respectively]. Both planar hy­dra­zinocarbonylalkyl substituents are essentially planar and assume the E orientation.     

Di‐μ‐hydro­xo‐bis­(diiso­propyl­gallium)–1,4,8,11‐tetra­methyl‐1,4,8,11‐tetra­aza­cyclo­tetra­decane (1/1)

The hydro­lysis product [Ga₂(C₃H₇)₄(OH)₂]·C₁₄H₃₂N₄, derived from the tetrakis­(triiso­propyl­gallium)–1,4,8,11‐tetra­methyl‐1,4,8,11‐tetra­aza­cyclo­tetra­decane (1/1) adduct, consists of a centrosymmetric [ⁱPr₂Ga(μ‐OH)]₂ unit hydrogen bonded through the hydroxyl group to a nitro­gen on an adjacent centrosymmetric 1,4,8,11‐tetra­methyl‐1,4,8,11‐tetra­aza­cyclo­tetra­decane molecule, resulting in the generation of a molecular chain through the crystal.     

A novel cadmium(II) coordination polymer with biphenyl‐3,3′,4,4′‐tetra­carboxylic acid and 4,4′‐bipyridine

A novel cadmium(II) coordination polymer, poly[[[bis­(4,4′‐bipyridine)cadmium(II)]‐μ₃‐4,4′‐dicarboxy­biphenyl‐3,3′‐di­carboxyl­ato] 0.35‐hydrate], {[Cd(C₁₆H₈O₈)(C₁₀H₈N₂)₂]·0.35H₂O}_n, was obtained by reaction of Cd(CH₃COO)₂·3H₂O, 4,4′‐bipyridine (4,4′‐bpy) and biphenyl‐3,3′,4,4′‐tetra­car­boxylic acid (H₄L) under hydro­thermal conditions. Each Cd^II atom lies at the centre of a distorted octa­hedron, coordinated by four O atoms from three H₂L²⁻ ligands and N atoms from two monodentate 4,4′‐bpy ligands. Each H₂L²⁻ ligand coordinates to three Cd^II atoms through two carboxyl­ate groups, one acting as a bridging bidentate ligand and the other in a chelating bidentate fashion. Two Cd atoms, two H₂L²⁻ anions and four 4,4′‐bpy ligands form a ring dimer node, which links into an extended broad zonal one‐dimensional chain along the c axis.     

Mixed dicationic and monocationic benzidine species in the proton‐transfer compound of benzidine with 3,5‐dinitro­salicylic acid

The crystal structure of the proton‐transfer compound of 1,1′‐biphenyl‐4,4′‐diamine (benzidine) with 3,5‐dinitro­salicylic acid, viz. 1,1′‐biphenyl‐4,4′‐diaminium bis­(4′‐amino‐1,1′‐bi­phenyl‐4‐aminium) tetra­kis(2‐carb­oxy‐4,6‐dinitro­phenol­ate) ethanol disolvate, C₁₂H₁₄N₂²⁺·2C₁₂H₁₃N₂⁺·4C₇H₃N₂O₇⁻·2C₂H₆O, shows the presence of both diprotonated and monoprotonated benzidine cations. The diprotonated species lie across crystallographic inversion centres in the unit cell, while the monoprotonated species occupy general sites. All amine H atoms participate in hydrogen bonding with carboxyl, phenolate and nitro O‐atom acceptors of the salicylate anions, which also participate in hydrogen bonding with the disordered ethanol solvent mol­ecules. Significant inter‐ring anion–anion and anion–monocation π–π inter­actions are also present, giving a three‐dimensional framework structure.     

An ion pair formed by protonated Fe(cp*py)2 and the octanuclear cluster U8Cl24O4(cp*py)2 [cp*py is tetramethyl‐5‐(2‐pyridyl)cyclopentadiene]

In bis­[1,1′,2,2′,3,3′,4,4′‐octa­methyl‐5‐(2‐pyridinio)‐5′‐(2‐pyri­dyl)­ferrocene] di‐μ₃‐chloro‐hexadeca‐μ₂‐chloro‐hexa­chloro­di‐μ₄‐oxo‐di‐μ₃‐oxo‐bis­[(η⁵,κN)‐1,2,3,4‐tetra­methyl‐5‐(2‐pyridyl)­cyclo­penta­dienyl]octauranium(IV) di­chloro­methane tetrasolvate, [Fe(C₁₄H₁₇N)(C₁₄H₁₆N)]₂[U₈Cl₂₄O₄(C₁₄H₁₆N)₂]·4CH₂Cl₂, (I), two protonated Fe(cp*py)₂ units [cp*py is tetra­methyl‐5‐(2‐pyridyl)­cyclo­penta­diene] form an ion pair with the dianionic centrosymmetric cluster U₈Cl₂₄O₄(cp*py)₂. The latter is the highest nuclearity assemblage in the chemistry of uranium (non‐uranyl) compounds reported to date.