Supramolecular architectures in metal(II) (Cd/Zn) halide/nitrate complexes of cytosine/5‐fluorocytosine

Three new metal(II)–cytosine (Cy)/5‐fluorocytosine (5FC) complexes, namely bis(4‐amino‐1,2‐dihydropyrimidin‐2‐one‐κN³)diiodidocadmium(II) or bis(cytosine)diiodidocadmium(II), [CdI₂(C₄H₅N₃O)₂], ( I ), bis(4‐amino‐1,2‐dihydropyrimidin‐2‐one‐κN³)bis(nitrato‐κ²O,O′)cadmium(II) or bis(cytosine)bis(nitrato)cadmium(II), [Cd(NO₃)₂(C₄H₅N₃O)₂], ( II ), and (6‐amino‐5‐fluoro‐1,2‐dihydropyrimidin‐2‐one‐κN³)aquadibromidozinc(II)–6‐amino‐5‐fluoro‐1,2‐dihydropyrimidin‐2‐one (1/1) or (6‐amino‐5‐fluorocytosine)aquadibromidozinc(II)–4‐amino‐5‐fluorocytosine (1/1), [ZnBr₂(C₄H₅FN₃O)(H₂O)]·C₄H₅FN₃O, ( III ), have been synthesized and characterized by single‐crystal X‐ray diffraction. In complex ( I ), the Cd^II ion is coordinated to two iodide ions and the endocyclic N atoms of the two cytosine molecules, leading to a distorted tetrahedral geometry. The structure is isotypic with [CdBr₂(C₄H₅N₃O)₂] [Muthiah et al. (2001). Acta Cryst. E 57 , m558–m560]. In compound ( II ), each of the two cytosine molecules coordinates to the Cd^II ion in a bidentate chelating mode via the endocyclic N atom and the O atom. Each of the two nitrate ions also coordinates in a bidentate chelating mode, forming a bicapped distorted octahedral geometry around cadmium. The typical interligand N—H…O hydrogen bond involving two cytosine molecules is also present. In compound ( III ), one zinc‐coordinated 5FC ligand is cocrystallized with another uncoordinated 5FC molecule. The Zn^II atom coordinates to the N(1) atom (systematic numbering) of 5FC, displacing the proton to the N(3) position. This N(3)—H tautomer of 5FC mimics N(3)‐protonated cytosine in forming a base pair (via three hydrogen bonds) with 5FC in the lattice, generating two fused R₂²(8) motifs. The distorted tetrahedral geometry around zinc is completed by two bromide ions and a water molecule. The coordinated and nonccordinated 5FCs are stacked over one another along the a‐axis direction, forming the rungs of a ladder motif, whereas Zn—Br bonds and N—H…Br hydrogen bonds form the rails of the ladder. The coordinated water molecules bridge the two types of 5FC molecules via O—H…O hydrogen bonds. The cytosine molecules are coordinated directly to the metal ion in each of the complexes and are hydrogen bonded to the bromide, iodide or nitrate ions. In compound ( III ), the uncoordinated 5FC molecule pairs with the coordinated 5FC ligand through three hydrogen bonds. The crystal structures are further stabilized by N—H…O, N—H…N, O—H…O, N—H…I and N—H…Br hydrogen bonds, and stacking interactions.     

Two cadmium(II) fluorous coordination compounds tuned by different bipyridines

Fluorine is the most electronegative element and can be used as an excellent hydrogen‐bond acceptor. Fluorous coordination compounds exhibit several advantageous properties, such as enhanced high thermal and oxidative stability, low polarity, weak intermolecular interactions and a small surface tension compared to hydrocarbons. C—H…F—C interactions, although weak, play a significant role in regulating the arrangement of the organic molecules in the crystalline state and stabilizing the secondary structure. Two cadmium(II) fluorous coordination compounds formed from 2,2′‐bipyridine, 4,4′‐bipyridine and pentafluorobenzoate ligands, namely catena‐poly[[aqua(2,2′‐bipyridine‐κ²N ,N ′)(2,3,4,5,6‐pentafluorobenzoato‐κO )cadmium(II)]‐μ‐2,3,4,5,6‐pentafluorobenzoato‐κ²O :O ′], [Cd(C₇F₅O₂)₂(C₁₀H₈N₂)(H₂O)]_n , (1), and catena‐poly[[diaquabis(2,3,4,5,6‐pentafluorobenzoato‐κO )cadmium(II)]‐μ‐4,4′‐bipyridine‐κ²N :N ′], [Cd(C₇F₅O₂)₂(C₁₀H₈N₂)(H₂O)₂]_n , (2), have been synthesized solvothermally and structurally characterized. Compound (1) shows a one‐dimensional chain structure composed of Cd—O coordination bonds and is stabilized by π–π stacking and O—H…O hydrogen‐bond interactions. Compound (2) displays a one‐dimensional linear chain structure formed by Cd—N coordination interactions involving the 4,4′‐bipyridine ligand. Adjacent one‐dimensional chains are extended into two‐dimensional sheets by O—H…O hydrogen bonds between the coordinated water molecules and adjacent carboxylate groups. Moreover, the chains are further linked by C—H…F—C interactions to afford a three‐dimensional network. In both structures, hydrogen bonding involving the coordinated water molecules is a primary driving force in the formation of the supramolecular structures.     

Supramolecular architectures in cytosinium 6‐chloronicotinate monohydrate and 5‐bromo‐6‐methylisocytosinium hydrogen sulfate

Aminopyrimidine derivatives are biologically important as they are components of nucleic acids and drugs. The crystals of two new salts, namely cytosinium 6‐chloronicotinate monohydrate, C₄H₆N₃O⁺·C₆H₃ClNO₂⁻·H₂O, ( I ), and 5‐bromo‐6‐methylisocytosinium hydrogen sulfate (or 2‐amino‐5‐bromo‐4‐oxo‐6‐methylpyrimidinium hydrogen sulfate), C₅H₇BrN₃O⁺·HSO₄⁻, ( II ), have been prepared and characterized by single‐crystal X‐ray diffraction. The pyrimidine ring of both compounds is protonated at the imine N atom. In hydrated salt ( I ), the primary R₂²(8) ring motif (supramolecular heterosynthon) is formed via a pair of N—H…O(carboxylate) hydrogen bonds. The cations, anions and water molecule are hydrogen bonded through N—H…O, N—H…N, O—H…O and C—H…O hydrogen bonds, forming R₂²(8), R₃²(7) and R₅⁵(21) motifs, leading to a hydrogen‐bonded supramolecular sheet structure. The supramolecular double sheet structure is formed via water–carboxylate O—H…O hydrogen bonds and π–π interactions between the anions and the cations. In salt ( II ), the hydrogen sulfate ions are linked via O—H…O hydrogen bonds to generate zigzag chains. The aminopyrimidinium cations are embedded between these zigzag chains. Each hydrogen sulfate ion bridges two cations via pairs of N—H…O hydrogen bonds and vice versa, generating two R₂²(8) ring motifs (supramolecular heterosynthon). The cations also interact with one another via halogen–halogen (Br…Br) and halogen–oxygen (Br…O) interactions.     

Two Fe3(μ3‐S)2(CO)8 clusters with terminal N‐heterocyclic carbenes

The title compounds with terminal N‐heterocyclic carbenes, namely octacarbonyl(imidazolidinylidene‐κC²)di‐μ₃‐sulfido‐triiron(II)(2 Fe—Fe), [Fe₃(C₃H₆N₂)(μ₃‐S)₂(CO)₈], (I), and octacarbonyl(1‐methylimidazo[1,5‐a]pyridin‐3‐ylidene‐κC³)di‐μ₃‐sulfido‐triiron(II)(2 Fe—Fe), [Fe₃(C₈H₈N₂)(μ₃‐S)₂(CO)₈], (II), have been synthesized. Each compound contains two Fe—Fe bonds and two S atoms above and below a triiron triangle. One of the eight carbonyl ligands deviates significantly from linearity. In (I), dimers generated by an N—H...S hydrogen bond are linked into [001] double chains by a second N—H...S hydrogen bond. These chains are packed by a C—H...O hydrogen bond to yield [101] sheets. In (II), dimers generated by an N—H...S hydrogen bond are linked by C—H...O hydrogen bonds to form [111] double chains.     

Synthesis and characterization of two novel bimetallic macrocyclic complexes generated from 1,2,4‐triazole‐containing semi‐rigid ligands and M(NO3)2 units (M = Ni and Zn)

Bimetallic macrocyclic complexes have attracted the attention of chemists and various organic ligands have been used as molecular building blocks, but supramolecular complexes based on semi‐rigid organic ligands containing 1,2,4‐triazole have remained rare until recently. It is easier to obtain novel topologies by making use of asymmetric semi‐rigid ligands in the self‐assembly process than by making use of rigid ligands. A new semi‐rigid ligand, 3‐[(pyridin‐4‐ylmethyl)sulfanyl]‐5‐(quinolin‐2‐yl)‐4H‐1,2,4‐triazol‐4‐amine (L), has been synthesized and used to generate two novel bimetallic macrocycle complexes, namely bis{μ‐3‐[(pyridin‐4‐ylmethyl)sulfanyl]‐5‐(quinolin‐2‐yl)‐4H‐1,2,4‐triazol‐4‐amine}bis[(methanol‐κO)(nitrato‐κ²O,O′)nickel(II)] dinitrate, [Ni₂(NO₃)₂(C₁₇H₁₄N₆S)₂(CH₃OH)₂](NO₃)₂, (I), and bis{μ‐3‐[(pyridin‐4‐ylmethyl)sulfanyl]‐5‐(quinolin‐2‐yl)‐4H‐1,2,4‐triazol‐4‐amine}bis[(methanol‐κO)(nitrato‐κ²O,O′)zinc(II)] dinitrate, [Zn₂(NO₃)₂(C₁₇H₁₄N₆S)₂(CH₃OH)₂](NO₃)₂, (II), by solution reactions with the inorganic salts M(NO₃)₂ (M = Ni and Zn, respectively) in mixed solvents. In (I), two Ni^II cations with the same coordination environment are linked by L ligands through Ni—N bonds to form a bimetallic ring. Compound (I) is extended into a two‐dimensional network in the crystallographic ac plane via N—H…O, O—H…N and O—H…O hydrogen bonds, and neighbouring two‐dimensional planes are parallel and form a three‐dimensional structure via π–π stacking. Compound (II) contains two bimetallic rings with the same coordination environment of the Zn^II cations. The Zn^II cations are bridged by L ligands through Zn—N bonds to form the bimetallic rings. One type of bimetallic ring constructs a one‐dimensional nanotube via O—H…O and N—H…O hydrogen bonds along the crystallographic a direction, and the other constructs zero‐dimensional molecular cages via O—H…O and N—H…O hydrogen bonds. They are interlinked into a two‐dimensional network in the ac plane through extensive N—H…O hydrogen bonds, and a three‐dimensional supramolecular architecture is formed via π–π interactions between the centroids of the benzene rings of the quinoline ring systems.     

Complexes of nickel(II) and copper(II) with 1,2,4‐triazole‐3‐carboxylic acid and of cobalt(III) with 3‐amino‐1,2,4‐triazole‐5‐carboxylic acid

Because of their versatile coordination modes and strong coordination ability for metals, triazole ligands can provide a wide range of possibilities for the construction of metal–organic frameworks. Three transition‐metal complexes, namely bis(μ‐1,2,4‐triazol‐4‐ide‐3‐carboxylato)‐κ³N ²,O :N ¹;κ³N ¹:N ²,O‐bis[triamminenickel(II)] tetrahydrate, [Ni₂(C₃HN₃O₂)₂(NH₃)₆]·4H₂O, (I), catena‐poly[[[diamminediaquacopper(II)]‐μ‐1,2,4‐triazol‐4‐ide‐3‐carboxylato‐κ³N ¹:N ⁴,O‐[diamminecopper(II)]‐μ‐1,2,4‐triazol‐4‐ide‐3‐carboxylato‐κ³N ⁴,O :N ¹] dihydrate], {[Cu₂(C₃HN₃O₂)₂(NH₃)₄(H₂O)₂]·2H₂O}_n , (II), (μ‐5‐amino‐1,2,4‐triazol‐1‐ide‐3‐carboxylato‐κ²N ¹:N ²)di‐μ‐hydroxido‐κ⁴O :O‐bis[triamminecobalt(III)] nitrate hydroxide trihydrate, [Co₂(C₃H₂N₄O₂)(OH)₂(NH₃)₆](NO₃)(OH)·3H₂O, (III), with different structural forms have been prepared by the reaction of transition metal salts, i.e. NiCl₂, CuCl₂ and Co(NO₃)₂, with 1,2,4‐triazole‐3‐carboxylic acid or 3‐amino‐1,2,4‐triazole‐5‐carboxylic acid hemihydrate in aqueous ammonia at room temperature. Compound (I) is a dinuclear complex. Extensive O—H…O, O—H…N and N—H…O hydrogen bonds and π–π stacking interactions between the centroids of the triazole rings contribute to the formation of the three‐dimensional supramolecular structure. Compound (II) exhibits a one‐dimensional chain structure, with O—H…O hydrogen bonds and weak O—H…N, N—H…O and C—H…O hydrogen bonds linking anions and lattice water molecules into the three‐dimensional supramolecular structure. Compared with compound (I), compound (III) is a structurally different dinuclear complex. Extensive N—H…O, N—H…N, O—H…N and O—H…O hydrogen bonding occurs in the structure, leading to the formation of the three‐dimensional supramolecular structure.     

Three‐dimensional hydrogen‐bonded framework structures in flunarizinium nicotinate and flunarizinediium bis(4‐toluenesulfonate) dihydrate

The structures of two salts of flunarizine, namely 1‐bis[(4‐fluorophenyl)methyl]‐4‐[(2E)‐3‐phenylprop‐2‐en‐1‐yl]piperazine, C₂₆H₂₆F₂N₂, are reported. In flunarizinium nicotinate {systematic name: 4‐bis[(4‐fluorophenyl)methyl]‐1‐[(2E)‐3‐phenylprop‐2‐en‐1‐yl]piperazin‐1‐ium pyridine‐3‐carboxylate}, C₂₆H₂₇F₂N₂⁺·C₆H₄NO₂⁻, (I), the two ionic components are linked by a short charge‐assisted N—H...O hydrogen bond. The ion pairs are linked into a three‐dimensional framework structure by three independent C—H...O hydrogen bonds, augmented by C—H...π(arene) hydrogen bonds and an aromatic π–π stacking interaction. In flunarizinediium bis(4‐toluenesulfonate) dihydrate {systematic name: 1‐[bis(4‐fluorophenyl)methyl]‐4‐[(2E)‐3‐phenylprop‐2‐en‐1‐yl]piperazine‐1,4‐diium bis(4‐methylbenzenesulfonate) dihydrate}, C₂₆H₂₈F₂N₂²⁺·2C₇H₇O₃S⁻·2H₂O, (II), one of the anions is disordered over two sites with occupancies of 0.832 (6) and 0.168 (6). The five independent components are linked into ribbons by two independent N—H...O hydrogen bonds and four independent O—H...O hydrogen bonds, and these ribbons are linked to form a three‐dimensional framework by two independent C—H...O hydrogen bonds, but C—H...π(arene) hydrogen bonds and aromatic π–π stacking interactions are absent from the structure of (II). Comparisons are made with some related structures.     

Mono‐ and dinuclear CuII complexes of the benzyldipicolylamine (BDPA) ligand: crystal structure,synthesis and characterization

The crystal structures of mono‐ and dinuclear Cu^II trifluoromethanesulfonate (triflate) complexes with benzyldipicolylamine (BDPA) are described. From equimolar amounts of Cu(triflate)₂ and BDPA, a water‐bound Cu^II mononuclear complex, aqua(benzyldipicolylamine‐κ³N ,N′ ,N ′′)bis(trifluoromethanesulfonato‐κO )copper(II) tetrahydrofuran monosolvate, [Cu(CF₃SO₃)₂(C₁₉H₁₉N₃)(H₂O)]·C₄H₈O, (I), and a triflate‐bridged Cu^II dinuclear complex, bis(μ‐trifluoromethanesulfonato‐κ²O :O ′)bis[(benzyldipicolylamine‐κ³N ,N′ ,N ′′)(trifluoromethanesulfonato‐κO )copper(II)], [Cu₂(CF₃SO₃)₄(C₁₉H₁₉N₃)₂], were synthesized. The presence of residual moisture in the reaction medium afforded water‐bound complex (I), whereas dinuclear complex (II) was synthesized from an anhydrous reaction medium. Single‐crystal X‐ray structure analysis reveals that the Cu^II centres adopt slightly distorted octahedral geometries in both complexes. The metal‐bound water molecule in (I) is involved in intermolecular O—H…O hydrogen bonds with triflate ligands and tetrahydrofuran solvent molecules. In (II), weak intermolecular C—H…F(triflate) and C—H…O(triflate) hydrogen bonds stabilize the crystal lattice. Complexes (I) and (II) were also characterized fully using FT–IR and UV–Vis spectroscopy, cyclic voltammetry and elemental analysis.     

Supramolecular interactions in salts/cocrystals involving pyrimidine derivatives of sulfonate/carboxylic acid

The crystal structures of three compounds involving aminopyrimidine derivatives are reported, namely, 5-fluorocytosinium sulfanilate–5-fluorocytosine–4-azaniumylbenzene-1-sulfonate (1/1/1), C₄H₅FN₃O⁺·C₆H₆NO₃S⁻·C₄H₄FN₃O·C₆H₇NO₃S, I , 5-fluorocytosine–indole-3-propionic acid (1/1), C₄H₄FN₃O·C₁₁H₁₁NO₂, II , and 2,4,6-triaminopyrimidinium 3-nitrobenzoate, C₄H₈N₅⁺·C₇H₄NO₄⁻, III , which have been synthesized and characterized by single-crystal X-ray diffraction. In I , there are two 5-fluorocytosine (5FC) molecules (5FC-A and 5FC-B) in the asymmetric unit, with one of the protons disordered between them. 5FC-A and 5FC-B are linked by triple hydrogen bonds, generating two fused rings [two R₂²(8) ring motifs]. The 5FC-A molecules form a self-complementary base pair [R₂²(8) ring motif] via a pair of N—H…O hydrogen bonds and the 5FC-B molecules form a similar complementary base pair [R₂²(8) ring motif]. The combination of these two types of pairing generates a supramolecular ribbon. The 5FC molecules are further hydrogen bonded to the sulfanilate anions and sulfanilic acid molecules via N—H…O hydrogen bonds, generating R₄⁴(22) and R⁶₆(36) ring motifs. In cocrystal II , two types of base pairs (homosynthons) are observed via a pair of N—H…O/N—H…N hydrogen bonds, generating R₂²(8) ring motifs. The first type of base pair is formed by the interaction of an N—H group and the carbonyl O atom of 5FC molecules through a couple of N—H…O hydrogen bonds. Another type of base pair is formed via the amino group and a pyrimidine ring N atom of the 5FC molecules through a pair of N—H…N hydrogen bonds. The base pairs (via N—H…N hydrogen bonds) are further bridged by the carboxyl OH group of indole-3-propionic acid and the O atom of 5FC through O—H…O hydrogen bonds on either side of the R₂²(8) motif. This leads to a DDAA array. In salt III , one of the N atoms of the pyrimidine ring is protonated and interacts with the carboxylate group of the anion through N—H…O hydrogen bonds, leading to the primary ring motif R₂²(8). Furthermore, the 2,4,6-triaminopyrimidinium (TAP) cations form base pairs [R₂²(8) homosynthon] via N—H…N hydrogen bonds. A carboxylate O atom of the 3-nitrobenzoate anion bridges two of the amino groups on either side of the paired TAP cations to form another ring [R₃²(8)]. This leads to the generation of a quadruple DADA array. The crystal structures are further stabilized by π–π stacking ( I and III ), C—H…π ( I and II ), C—F…π ( I ) and C—O…π ( II ) interactions.     

Supramolecular architectures in CoII and CuII complexes with thiophene‐2‐carboxylate and 2‐amino‐4,6‐dimethoxypyrimidine ligands

The coordination chemistry of mixed‐ligand complexes continues to be an active area of research since these compounds have a wide range of applications. Many coordination polymers and metal–organic framworks are emerging as novel functional materials. Aminopyrimidine and its derivatives are flexible ligands with versatile binding and coordination modes which have been proven to be useful in the construction of organic–inorganic hybrid materials and coordination polymers. Thiophenecarboxylic acid, its derivatives and their complexes exhibit pharmacological properties. Cobalt(II) and copper(II) complexes of thiophenecarboxylate have many biological applications, for example, as antifungal and antitumor agents. Two new cobalt(II) and copper(II) complexes incorporating thiophene‐2‐carboxylate (2‐TPC) and 2‐amino‐4,6‐dimethoxypyrimidine (OMP) ligands have been synthesized and characterized by X‐ray diffraction studies, namely (2‐amino‐4,6‐dimethoxypyrimidine‐κN)aquachlorido(thiophene‐2‐carboxylato‐κO)cobalt(II) monohydrate, [Co(C₅H₃O₂S)Cl(C₆H₉N₃O₂)(H₂O)]·H₂O, (I), and catena‐poly[copper(II)‐tetrakis(μ‐thiophene‐2‐carboxylato‐κ²O:O′)‐copper(II)‐(μ‐2‐amino‐4,6‐dimethoxypyrimidine‐κ²N¹:N³)], [Cu₂(C₅H₃O₂S)₄(C₆H₉N₃O₂)]_n, (II). In (I), the Co^II ion has a distorted tetrahedral coordination environment involving one O atom from a monodentate 2‐TPC ligand, one N atom from an OMP ligand, one chloride ligand and one O atom of a water molecule. An additional water molecule is present in the asymmetric unit. The amino group of the coordinated OMP molecule and the coordinated carboxylate O atom of the 2‐TPC ligand form an interligand N—H…O hydrogen bond, generating an S(6) ring motif. The pyrimidine molecules also form a base pair [R₂²(8) motif] via a pair of N—H…N hydrogen bonds. These interactions, together with O—H…O and O—H…Cl hydrogen bonds and π–π stacking interactions, generate a three‐dimensional supramolecular architecture. The one‐dimensional coordination polymer (II) contains the classical paddle‐wheel [Cu₂(CH₃COO)₄(H₂O)₂] unit, where each carboxylate group of four 2‐TPC ligands bridges two square‐pyramidally coordinated Cu^II ions and the apically coordinated OMP ligands bridge the dinuclear copper units. Each dinuclear copper unit has a crystallographic inversion centre, whereas the bridging OMP ligand has crystallographic twofold symmetry. The one‐dimensional polymeric chains self‐assemble via N—H…O, π–π and C—H…π interactions, generating a three‐dimensional supramolecular architecture.     

Hydrogen‐bonded chains in three cis‐dichloridoplatinum(II) complexes bearing piperidine and amine ligands

The crystal structures of cis‐dichlorido(ethylamine‐κN)(piperidine‐κN)platinum(II), [PtCl₂(C₂H₇N)(C₅H₁₁N)], (I), cis‐dichlorido(3‐methoxyaniline‐κN)(piperidine‐κN)platinum(II), [PtCl₂(C₅H₁₁N)(C₇H₉NO)], (II), and cis‐dichlorido(piperidine‐κN)(quinoline‐κN)platinum(II), [PtCl₂(C₅H₁₁N)(C₉H₇N)], (III), have been determined at 100 K in order to verify the influence of the nonpiperidine ligand on the geometry and crystal packing. The crystal packing is characterized by N—H...Cl hydrogen bonding, resulting in the formation of chains of molecules connected in a head‐to‐tail fashion. Hydrogen‐bonding interactions play a major role in the packing of (I), where the chains further aggregate into planes, but less so in the case of (II) and (III), where π–π stacking interactions are of greater importance.     

The synergistic co‐operation of N—H…O=P hydrogen bonds and C—H…OX weak intermolecular interactions (X is =P or —C) in the (CH3O)2P(O)(NH–NHC6F5) amidophosphoester: a combined X‐ray crystallographic and theoretical study

The asymmetric unit of O,O′‐dimethyl [(2,3,4,5,6‐pentafluorophenyl)hydrazinyl]phosphonate, C₈H₈F₅N₂O₃P, is composed of two symmetry‐independent molecules with significant differences in the orientations of the C₆F₅ and OMe groups. In the crystal structure, a one‐dimensional assembly is mediated from classical N—H…O hydrogen bonds, which includes R₂²(8), D(2) and some higher‐order graph‐set motifs. By also considering weak C—H…O=P and C—H…O—C intermolecular interactions, a two‐dimensional network extends along the ab plane. The strengths of the hydrogen bonds were evaluated using quantum chemical calculations with the GAUSSIAN09 software package at the B3LYP/6‐311G(d,p) level of theory. The LP(O) to σ*(NH) and σ*(CH) charge‐transfer interactions were examined according to second‐order perturbation theory in natural bond orbital (NBO) methodology. The hydrogen‐bonded clusters of molecules, including N—H…O and C—H…O interactions, were constructed as input files for the calculations and the strengths of the hydrogen bonds are as follows: N—H…O [R₂²(8)] > N—H…O [D(2)] > C—H…O. The decomposed fingerprint plots show that the contribution portions of the F…H/H…F contacts in both molecules are the largest.     

New rac‐XP(O)(OC6H5)(NHC6H4‐p‐CH3) [X = N(CH3)(cyclo‐C6H11) and NH(C3H5)] and rac‐(C6H5CH2NH)P(O)(OC6H5)(NH‐cyclo‐C6H11) mixed‐amide phosphinates

The mixed‐amide phosphinates, rac‐phenyl (N‐methylcyclohexylamido)(p‐tolylamido)phosphinate, C₂₀H₂₇N₂O₂P, (I), and rac‐phenyl (allylamido)(p‐tolylamido)phosphinate, C₁₆H₁₉N₂O₂P, (II), were synthesized from the racemic phosphorus–chlorine compound (R,S)‐(Cl)P(O)(OC₆H₅)(NHC₆H₄‐p‐CH₃). Furthermore, the phosphorus–chlorine compound ClP(O)(OC₆H₅)(NH‐cyclo‐C₆H₁₁) was synthesized for the first time and used for the synthesis of rac‐phenyl (benzylamido)(cyclohexylamido)phosphinate, C₁₉H₂₅N₂O₂P, (III). The strategies for the synthesis of racemic mixed‐amide phosphinates are discussed. The P atom in each compound is in a distorted tetrahedral (N¹)P(=O)(O)(N²) environment. In (I) and (II), the p‐tolylamido substituent makes a longer P—N bond than those involving the N‐methylcyclohexylamido and allylamido substituents. In (III), the differences between the P—N bond lengths involving the cyclohexylamido and benzylamido substituents are not significant. In all three structures, the phosphoryl O atom takes part with the N—H unit in hydrogen‐bonding interactions, viz. an N—H...O=P hydrogen bond for (I) and (N—H)(N—H)...O=P hydrogen bonds for (II) and (III), building linear arrangements along [001] for (I) and along [010] for (III), and a ladder arrangement along [100] for (II).     

The synthesis,crystal structure and magnetic properties of a one‐dimensional terbium(III)–octacyanidomolybdate(V) assembly

A one‐dimensional cyanide‐bridged coordination polymer, poly[[aquadi‐μ‐cyanido‐κ⁴C:N‐hexacyanido‐κ⁶C‐(dimethylformamide‐κO)bis(3,4,7,8‐tetramethyl‐1,10‐phenanthroline‐κ²N,N′)terbium(III)molybdate(V)] 4.5‐hydrate], [MoTb(CN)₈(C₁₆H₁₆N₂)₂(C₃H₇NO)(H₂O)]·4.5H₂O}_n, has been prepared and characterized through IR spectroscopy, elemental analysis and single‐crystal X‐ray diffraction. The compound consists of one‐dimensional chains in which cationic [Tb(tmphen)₂(DMF)(H₂O)]³⁺ (tmphen is 3,4,7,8‐tetramethyl‐1,10‐phenanthroline) and anionic [Mo^V(CN)₈]³⁻ units are linked in an alternating fashion through bridging cyanide ligands. Neighbouring chains are connected by three types of hydrogen bonds (O—H...O, O—H...N and C—H...O) and by π–π interactions to form a three‐dimensional supramolecular structure. In addition, magnetic investigations show that ferromagnetic interactions exist in the compound.     

Copper(II) bromide,nitrate and perchlorate complexes with sterically demanding N‐(6‐methylpyridin‐2‐yl)acetamide ligands

Functionalized acid amides are widely used in biology, medicine, environmental chemistry and many other areas. Among them, pyridine‐substituted amides, in particular N‐(pyridin‐2‐yl)acetamide and its derivatives, play an important role due to their excellent chelating properties. The donor properties of these ligands can be effectively modified by introducing electron‐donating substituents (e.g. alkyl groups) into the heterocycle. On the other hand, substituents in the α‐position of the pyridine ring can create steric hindrance, which significantly influences the coordination number and geometry. To achieve a better understanding of these effects, copper(II) complexes with sterically demanding N‐(6‐methylpyridin‐2‐yl)acetamide ligands (L ) and monoanions of different size, shape and coordination ability have been chosen as model compounds. The crystal structures of three new compounds, bromidobis[N‐(6‐methylpyridin‐2‐yl‐κN )acetamide‐κO ]copper(II) bromide, [CuBr(C₈H₁₀N₂O)]Br, (I), aquabis[N‐(6‐methylpyridin‐2‐yl‐κN )acetamide‐κO ]copper(II) dinitrate, [Cu(C₈H₁₀N₂O)(H₂O)](NO₃)₂, (II), and aquabis[N‐(6‐methylpyridin‐2‐yl‐κN )acetamide‐κO ]copper(II) bis(perchlorate), [Cu(C₈H₁₀N₂O)(H₂O)](ClO₄)₂, (III), have been determined by single‐crystal X‐ray diffraction analysis. It has been shown that the presence of the 6‐methyl group results in either a distorted square‐pyramidal or a distorted trigonal–bipyramidal coordination geometry around the Cu^II centres instead of the typical octahedral geometry observed when the methyl substituent is absent or occupies any other position on the pyridine ring. Moreover, due to the steric hindrance provided by the L ligands, only the bromide ligand, the smallest of the series, enters into the first coordination sphere of the Cu^II ion in (I). In (II) and (III), the vacant coordination site of the Cu^II ion is occupied by a water molecule, while the nitrate and perchlorate anions are not involved in coordination to the metal centre. The structures of (I)–(III) are characterized by the presence of one‐dimensional infinite chains formed by hydrogen bonds of the types N—H…Br [in (I)], N—H…O and O—H…O [in (II) and (III)] between the amide groups of the L ligands, the coordinated water molecules and the uncoordinated anions. The hydrogen‐bonded chains are further interconnected through π–π stacking interactions between the pyridine rings of the L ligands, with approximate interplanar separations of 3.5–3.6 Å.     

Three zinc(II) and cadmium(II) complexes containing 4‐amino‐3,5‐bis(pyridin‐2‐yl)‐1,2,4‐triazole and polynitrile ligands: synthesis,molecular and supramolecular structures,and photoluminescence properties

Three photoluminescent complexes containing either Zn^II or Cd^II have been synthesized and their structures determined. Bis[4‐amino‐3,5‐bis(pyridin‐2‐yl)‐1,2,4‐triazole‐κ²N ¹,N ⁵]bis(dicyanamido‐κN ¹)zinc(II), [Zn(C₁₂H₁₀N₆)₂(C₂N₃)₂], (I), bis[4‐amino‐3,5‐bis(pyridin‐2‐yl)‐1,2,4‐triazole‐κ²N ¹,N ⁵]bis(dicyanamido‐κN ¹)cadmium(II), [Cd(C₁₂H₁₀N₆)₂(C₂N₃)₂], (II), and bis[4‐amino‐3,5‐bis(pyridin‐2‐yl)‐1,2,4‐triazole‐κ²N ¹,N ⁵]bis(tricyanomethanido‐κN ¹)cadmium(II), [Cd(C₁₂H₁₀N₆)₂(C₄N₃)₂], (III), all crystallize in the space group P , with the metal centres lying on centres of inversion, but neither analogues (I) and (II) nor Cd^II complexes (II) and (III) are isomorphous. A combination of N—H…N and C—H…N hydrogen bonds and π–π stacking interactions generates three‐dimensional framework structures in (I) and (II), and a sheet structure in (III). The photoluminescence spectra of (I)–(III) indicate that the energies of the π–π* transitions in the coordinated triazole ligand are modified by minor changes of the ligand geometry associated with coordination to the metal centres.     

Two isomorphous ZnII/CoII complexes with tri‐tert‐butoxysilanethiol and histamine,and (4‐hydroxymethyl‐1H‐imidazole‐κN)bis(tri‐tert‐butoxysilanethiolato‐κ2O,S)zinc(II)

The complexes [2‐(1H‐imidazol‐4‐yl‐κN³)ethylamine‐κN]bis(tri‐tert‐butoxysilanethiolato‐κS)cobalt(II), [Co(C₁₂H₂₇O₃SSi)₂(C₅H₉N₃)], and [2‐(1H‐imidazol‐4‐yl‐κN³)ethylamine‐κN]bis(tri‐tert‐butoxysilanethiolato‐κS)zinc(II), [Zn(C₁₂H₂₇O₃SSi)₂(C₅H₉N₃)], are isomorphous. The central Zn^II/Co^II ions are surrounded by two S atoms from the tri‐tert‐butoxysilanethiolate ligand and by two N atoms from the chelating histamine ligand in a distorted tetrahedral geometry, with two intramolecular N—H...O hydrogen‐bonding interactions between the histamine NH₂ groups and tert‐butoxy O atoms. Molecules of the complexes are joined into dimers via two intermolecular bifurcated N—H...(S,O) hydrogen bonds. The Zn^II atom in [(1H‐imidazol‐4‐yl‐κN³)methanol]bis(tri‐tert‐butoxysilanethiolato‐κ²O,S)zinc(II), [Zn(C₁₂H₂₇O₃SSi)₂(C₄H₆N₂O)], is five‐coordinated by two O and two S atoms from the O,S‐chelating silanethiolate ligand and by one N atom from (1H‐imidazol‐4‐yl)methanol; the hydroxy group forms an intramolecular hydrogen bond with sulfur. Molecules of this complex pack as zigzag chains linked by N—H...O hydrogen bonds. These structures provide reference details for cysteine‐ and histidine‐ligated metal centers in proteins.     

Three new quinuclidine‐based structures: second harmonic generation response for 1,2‐bis(1‐azoniabicyclo[2.2.2]octan‐3‐ylidene)hydrazine dichloride

The crystal structures of three quinuclidine‐based compounds, namely (1‐azabicyclo[2.2.2]octan‐3‐ylidene)hydrazine monohydrate, C₇H₁₃N₃·H₂O ( 1 ), 1,2‐bis(1‐azabicyclo[2.2.2]octan‐3‐ylidene)hydrazine, C₁₄H₂₂N₄ ( 2 ), and 1,2‐bis(1‐azoniabicyclo[2.2.2]octan‐3‐ylidene)hydrazine dichloride, C₁₄H₂₄N₄²⁺·2Cl^? ( 3 ), are reported. In the crystal structure of 1 , the quinuclidine‐substituted hydrazine and water molecules are linked through N—H…O and O—H…N hydrogen bonds, forming a two‐dimensional array. The compound crystallizes in the centrosymmetric space group P2₁/c. Compound 2 was refined in the space group Pccn and exhibits no hydrogen bonding. However, its hydrochloride form 3 crystallizes in the noncentrosymmetric space group Pc. It shows a three‐dimensional network structure via intermolecular hydrogen bonding (N—H…C and N/C—H…Cl). Compound 3 , with its acentric structure, shows strong second harmonic activity.     

Structural comparison of group 7 tricarbonyl complexes of 2‐{[2‐(1H‐imidazol‐4‐yl)ethyl]iminomethyl}‐5‐methylphenolate

Two tricarbonyl complexes of rhenium(I) and manganese(I) coordinated by the ligand 2‐{[2‐(1H‐imidazol‐4‐yl)ethyl]iminomethyl}‐5‐methylphenolate are reported, viz. fac‐tricarbonyl(2‐{[2‐(1H‐imidazol‐4‐yl‐κN³)ethyl]iminomethyl‐κN}‐5‐methylphenolato‐κO)rhenium(I) methanol monosolvate, [Re(C₁₆H₁₄N₃O₄)(CO)₃]·CH₃OH, (I), and fac‐tricarbonyl(2‐{[2‐(1H‐imidazol‐4‐yl‐κN³)ethyl]iminomethyl‐κN}‐5‐methylphenolato‐κO)manganese(I), fac‐[Mn(C₁₆H₁₄N₃O₄)(CO)₃], (II), display facial coordination in a distorted octahedral environment. The crystal structure of (I) is stabilized by O—H...O, N—H...O and C—H...O hydrogen‐bond interactions, while that of (II) is stabilized by N—H...O hydrogen‐bond interactions only. These interactions result in two‐dimensional networks and π–π stacking for both structures.     

Tolterodinium (+)‐(2R,3R)‐hydrogen tartrate

In the crystal structure of (R)‐N,N‐diisopropyl‐3‐(2‐hydroxy‐5‐methyl­phenyl)‐3‐phenyl­propyl­aminium (2R,3R)‐hydrogen tartrate, C₂₂H₃₂NO⁺·C₄H₅O₆⁻, the hydrogen tartrate anions are linked by O—H⋯O hydrogen bonds to form helical chains built from (9) rings. These chains are linked by the tolterodine molecules via N—H⋯O and O—H⋯O hydrogen bonds to form separate sheets parallel to the (101) plane.