X-ray diffraction study of bisphosphonate metal complexes: Mg,Sr and Ba complexes of (dichloromethylene)bisphosphonic acid P,P′-dibenzoyl anhydride

The first alkaline earth metal complexes of a dibenzoyl derivative of clodronic acid were prepared and characterised by X-ray crystallography, elemental analysis and infrared spectroscopy. The complexes were [Mg{[Cl₂C(PO₂O(C(O)C₆H₅))₂](H₂O)₅} · H₂O] (1), [Sr₂{[Cl₂C(PO₂O(C(O)C₆H₅))₂]₂(H₂O)₉} · H₂O]_n (2) and [Ba{Cl₂C(PO₂O(C(O)C₆H₅))₂}(H₂O)₂]_n (3). The monomeric units of 1 and the polymeric chains of 2 and 3 form 2D layer-like structures through intermolecular hydrogen bonds. The Cl₂C(PO₂O(C(O)C₆H₅))₂²⁻ ligand acts as a bridging and chelating ligand, forming six- and eight-membered chelate rings with metal atoms. In addition, the previously determined polymeric calcium complex of clodronate, [Ca₂{Cl₂C(PO₃)₂}(H₂O)₆ · 4.5H₂O]_n(4), was synthesised by hydrolysis method from the dibenzoyl derivative of clodronic acid.     

Conformations and resulting hydrogen‐bonded networks of hydrogen {phosphono[(pyridin‐1‐ium‐3‐yl)amino]methyl}phosphonate and related 2‐chloro and 6‐chloro derivatives

In the crystal structures of the conformational isomers hydrogen {phosphono[(pyridin‐1‐ium‐3‐yl)amino]methyl}phosphonate monohydrate (pro‐E), C₆H₁₀N₂O₆P₂·H₂O, (Ia), and hydrogen {phosphono[(pyridin‐1‐ium‐3‐yl)amino]methyl}phosphonate (pro‐Z), C₆H₁₀N₂O₆P₂, (Ib), the related hydrogen {[(2‐chloropyridin‐1‐ium‐3‐yl)amino](phosphono)methyl}phosphonate (pro‐E), C₆H₉ClN₂O₆P₂, (II), and the salt bis(6‐chloropyridin‐3‐aminium) [hydrogen bis({[2‐chloropyridin‐1‐ium‐3‐yl(0.5+)]amino}methylenediphosphonate)] (pro‐Z), 2C₅H₆ClN₂⁺·C₁₂H₁₆Cl₂N₄O₁₂P₄²⁻, (III), chain–chain interactions involving phosphono (–PO₃H₂) and phosphonate (–PO₃H⁻) groups are dominant in determining the crystal packing. The crystals of (Ia) and (III) comprise similar ribbons, which are held together by N—H...O interactions, by water‐ or cation‐mediated contacts, and by π–π interactions between the aromatic rings of adjacent zwitterions in (Ia), and those of the cations and anions in (III). The crystals of (Ib) and (II) have a layered architecture: the former exhibits highly corrugated monolayers perpendicular to the [100] direction, while in the latter, flat bilayers parallel to the (001) plane are formed. In both (Ib) and (II), the interlayer contacts are realised through N—H...O hydrogen bonds and weak C—H...O interactions involving aromatic C atoms.     

Molecular and Supramolecular Structures of 1‐Phenyl‐4‐phenylacetyl‐2‐thiosemicarbazide (H2L) and its Complexes with Diphenyllead(IV) Chloride and Acetate

Reaction of 1‐phenyl‐4‐phenylacetyl‐2‐thiosemicarbazide (H₂L) with diphenyllead(IV) dichloride and acetate afforded the complexes [PbPh₂Cl₂(H₂L)₂] and [PbPh₂L]. The ligand and the complexes were characterized by elemental analyses, ¹H and ¹³C NMR spectroscopy and X‐ray crystallography. In the asymmetric unit of crystals of the ligand there are four independent molecules of H₂L and four molecules of water, which associate in the lattice as two independent sheets. The complex [PbPh₂Cl₂(H₂L)₂]·4MeOH has slightly distorted all‐trans octahedral geometry around the lead atom, and the fact that the ligand is S‐bound rather than O‐bound suggests that PbPh₂Cl₂ behaves as a “soft” Lewis acid. Hydrogen bonds involving NH groups, Cl atoms and MeOH molecules form a three‐dimensional supramolecular structure. In [PbPh₂L]·Me₂CO, the L^2? anion bridges between two metal centres, binding to one strongly via the N and S atoms and weakly via the O atom, and to the other via the O atom, thus creating polymeric chains along the b axis. The double deprotonation and metallation of H₂L induce significant changes in its configuration and lengthen the C‐S and C‐O bonds, suggesting an evolution of the dianion towards a thiol‐enol form.     

Supramolecular Hydrogen‐Bonded Frameworks from a New Bisphosphonic Acid and Transition Metal Ions

The reaction of 2‐morpholinoethylimino‐bis(methylenephosphonic acid) (H₄L) with cobalt(II), nickel(II) acetate, and cadmium(II) chloride in ethanol/water mixed solvents afforded three new crystal‐engineered supramolecular metal phosphonates, Co(H₃L)₂ · 2H₂O ( 1 ), Ni(H₃L)₂ · 2H₂O ( 2 ), and [Cd₂Cl₄(H₂O)₆]_0.5[H₄L] ( 3 ) by using a layering technique. The cobalt(II) ions in complex 1 are hexacoordinated by four phosphonate oxygen atoms and two imino nitrogen atoms. The mononuclear units of complex 1 are connected through hydrogen bonds to form a three dimensional supramolecular network. The structure of compound 2 is analogous to that of 1 except that the cobalt(II) ion in compound 1 is replaced by nickel(II) in compound 2 . In the molecular structure of compound 3 , cadmium is coordinated to three chloride ions and three aqua oxygen atoms to form a novel neutral dinuclear complex. Several hydrogen bonds connect the dinuclear complex and the neutral form of the ligand to build a supramolecular three dimensional structure.     

Hydrogen‐bonded structures of the 1:1 and 1:2 compounds of chloranilic acid with pyrrolidin‐2‐one and piperidin‐2‐one

In the four compounds of chloranilic acid (2,5‐dichloro‐3,6‐dihydroxycyclohexa‐2,5‐diene‐1,4‐dione) with pyrrolidin‐2‐one and piperidin‐2‐one, namely, chloranilic acid–pyrrolidin‐2‐one (1/1), C₆H₂Cl₂O₄·C₄H₇NO, (I), chloranilic acid–pyrrolidin‐2‐one (1/2), C₆H₂Cl₂O₄·2C₄H₇NO, (II), chloranilic acid–piperidin‐2‐one (1/1), C₆H₂Cl₂O₄·C₅H₉NO, (III), and chloranilic acid–piperidin‐2‐one (1/2), C₆H₂Cl₂O₄·2C₅H₉NO, (IV), the shortest interactions between the two components are O—H...O hydrogen bonds, which act as the primary intermolecular interaction in the crystal structures. In (II), (III) and (IV), the chloranilic acid molecules lie about inversion centres. For (III), this necessitates the presence of two independent acid molecules. In (I), there are two formula units in the asymmetric unit. The O...O distances are 2.4728 (11) and 2.4978 (11) Å in (I), 2.5845 (11) Å in (II), 2.6223 (11) and 2.5909 (10) Å in (III), and 2.4484 (10) Å in (IV). In the hydrogen bond of (IV), the H atom is disordered over two positions with site occupancies of 0.44 (3) and 0.56 (3). This indicates that proton transfer between the acid and base has partly taken place to form ion pairs. In (I) and (II), N—H...O hydrogen bonds, the secondary intermolecular interactions, connect the pyrrolidin‐2‐one molecules into a dimer, while in (III) and (IV) these hydrogen bonds link the acid and base to afford three‐ and two‐dimensional hydrogen‐bonded networks, respectively.     

Hydrogen‐bonding patterns in three substituted N‐benzyl‐N‐(3‐tert‐butyl‐1‐phenyl‐1H‐pyrazol‐5‐yl)acetamides

The molecules of N‐(3‐tert‐butyl‐1‐phenyl‐1H‐pyrazol‐5‐yl)‐2‐chloro‐N‐(4‐methoxybenzyl)acetamide, C₂₃H₂₆ClN₃O₂, are linked into a chain of edge‐fused centrosymmetric rings by a combination of one C—H...O hydrogen bond and one C—H...π(arene) hydrogen bond. In N‐(3‐tert‐butyl‐1‐phenyl‐1H‐pyrazol‐5‐yl)‐2‐chloro‐N‐(4‐chlorobenzyl)acetamide, C₂₂H₂₃Cl₂N₃O, a combination of one C—H...O hydrogen bond and two C—H...π(arene) hydrogen bonds, which utilize different aryl rings as the acceptors, link the molecules into sheets. The molecules of S‐[N‐(3‐tert‐butyl‐1‐phenyl‐1H‐pyrazol‐5‐yl)‐N‐(4‐methylbenzyl)carbamoyl]methyl O‐ethyl carbonodithioate, C₂₆H₃₁N₃O₂S₂, are also linked into sheets, now by a combination of two C—H...O hydrogen bonds, both of which utilize the amide O atom as the acceptor, and two C—H...π(arene) hydrogen bonds, which utilize different aryl groups as the acceptors.     

Binary salt of a palladium(II) complex with (phosphonomethyl)phosphonic (medronic) acid comprising `handbell‐like' [Pd{μ‐CH2(PO3)2}]3 units

The asymmetric unit of the title compound, dipotassium bis[hexaaquanickel(II)] tris(μ₂‐methylenediphosphonato)tripalladium(II) hexahydrate, K₂[Ni(H₂O)₆]₂[Pd₃{CH₂(PO₃)₂}₃]·6H₂O, consists of half a {[Pd{CH₂(PO₃)₂}]₃}⁶⁻ anion [one Pd atom (4e) and a methylene C atom (4e) occupy positions on a twofold axis] in a rare `handbell‐like' arrangement, with K⁺ and [Ni(H₂O)₆]²⁺ cations to form the neutral complex, completed by three solvent water molecules. The {[Pd{CH₂(PO₃)₂}]₃}⁶⁻ units exhibit close Pd...Pd separations of 3.0469 (4) Å and are packed via intermolecular C—H...Pd hydrogen bonds. The [KO₉] and [NiO₆] units are assembled into sheets coplanar with (011) and stacked along the [100] direction. Within these sheets there are [K₄Ni₄O₈] and [K₂Ni₂O₄] loops. Successive alternation of the sheets and [Pd{CH₂(PO₃)₂}]₃ units parallel to [001] produces the three‐dimensional packing, which is also supported by a dense network of hydrogen bonds involving the solvent water molecules.     

Two closely related,and unexpected,quinolinone derivatives: a three‐dimensional hydrogen‐bonded framework structure and a hydrogen‐bonded molecular ribbon of R22(18) and R44(24) rings

1,5‐Bis(4‐chlorophenyl)‐3‐(2‐oxo‐1,2‐dihydroquinolin‐3‐yl)pentane‐1,5‐dione, (Ia), and 1,5‐bis(2‐chlorophenyl)‐3‐(2‐oxo‐1,2‐dihydroquinolin‐3‐yl)pentane‐1,5‐dione, (Ib), crystallize as an 84:16 mixture, 0.84C₂₆H₁₉Cl₂NO₃·0.16C₂₆H₁₉Cl₂NO₃, in the space group I4₁/a, where the molecules of the two isomers occupy very similar sites in the unit cell. A combination of one N—H...O hydrogen bond and one C—H...O hydrogen bond links the molecules, regardless of isomeric form, into a single three‐dimensional framework structure. The molecules of (9RS,10RS)‐8,9‐bis(4‐chlorobenzyl)‐10‐(2‐oxo‐1,2‐dihydroquinolin‐3‐yl)‐5,6,9,10‐tetrahydrophenanthridine, C₃₆H₂₂Cl₂N₂O₄, (II), are linked by two hydrogen bonds, one each of the N—H...O and C—H...O types, into a molecular ribbon in which centrosymmetric rings of R₂²(18) and R₄⁴(24) types alternate. The hydrogen‐bonded ribbons enclose channels, which contain highly disordered solvent molecules.     

Hydrogen‐bonded chains in 2,2,2‐trichloro‐N,N′‐bis(4‐methoxyphenyl)ethane‐1,1‐diamine and a three‐dimensional hydrogen‐bonded framework in 2,2,2‐trichloro‐N,N′‐bis(4‐chlorophenyl)ethane‐1,1‐diamine

In 2,2,2‐trichloro‐N,N′‐bis(4‐methoxyphenyl)ethane‐1,1‐diamine, C₁₆H₁₇Cl₃N₂O₂, molecules are linked into helical chains by N—H...O hydrogen bonds. Molecules of 2,2,2‐trichloro‐N,N′‐bis(4‐chlorophenyl)ethane‐1,1‐diamine, C₁₄H₁₁Cl₅N₂, are connected into a three‐dimensional framework by two independent Cl...Cl interactions and one C—H...Cl hydrogen bond.     

The bimolecular structure of aquahexa‐μ‐chlorido‐μ4‐oxido‐tris(tetrahydrofuran‐κO)tetracopper(II)–hexa‐μ‐chlorido‐μ4‐oxido‐tetrakis(tetrahydrofuran‐κO)tetracopper(II)–tetrahydrofuran (2/1/4)

The title bimolecular structure, [Cu₄Cl₆O(C₄H₈O)₃(H₂O)]₂[Cu₄Cl₆O(C₄H₈O)₄]·4C₄H₈O, at 100 K has monoclinic (P2₁/c) symmetry. The structure contains nine symmetry‐independent molecules expressed in simplest molecular form as 6[Cu₄Cl₆O(C₄H₈O)₃(H₂O)·2(C₄H₈O)]:3Cu₄Cl₆O(C₄H₈O)₄. The compound exhibits a supercell (smaller than the unit cell based on weak reflections) structure due to pseudotranslational symmetry. The structure displays O—H...O hydrogen bonding between bound water ligands and tetrahydrofuran (THF) solvent molecules. The structure exhibits disorder for 12 of the THF molecules, of which seven are ligated to Cu and five are hydrogen bonded to H₂O ligands.     

Aqua(oxydiacetato‐κ3O,O′,O′′)(pyridine‐3‐carboxamide‐κN1)copper(II) sesquihydrate

In the monomeric title compound, [Cu(C₄H₄O₅)(C₆H₆N₂O)(H₂O)]·1.5H₂O, the Cu^II cation is bound in a square‐pyramidal coordination to a tridentate oxydiacetate (ODA) ligand, a monodentate pyridine‐3‐carboxamide (p3ca) ligand and one aqua ligand, where the two organic ligands form the basal plane and the water O atom occupies the unique apical site. The ODA ligand presents a slight out‐of‐plane puckering in its central ether O atom, while the p3ca ligand is essentially planar. The availability of efficient donors and acceptors for hydrogen bonding results in the formation of strongly linked hydrogen‐bonded bilayers parallel to (101), with an interplanar distance of 3.18 (1) Å and a stacking separation between the bilayers of 3.10 (1) Å, both of them governed by extended π–π interactions. The disordered nature of the solvent water molecules around inversion centres is discussed. The monoaqua compound is compared with the octahedral diaqua analogue, [Cu(C₄H₄O₅)(C₆H₆N₂O)(H₂O)₂], reported recently [Perec & Baggio (2009). Acta Cryst. C 65 , m296–m298].     

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 .     

基于2,4′-二羧基二苯甲酮构筑的具有一维梯状链和一维隧道的三维超分子体系

采用水热法设计合成了两个新型三维超分子化合物H₂L·H₂O (1)和[Ag(bpy)₂]·HL·H₂O (2) (其中bpy=2,2'-联吡啶, H₂L=2,4′-二羧基二苯甲酮),晶体结构分析表明,它们均是通过氢键采用不同的连接方式拓展而成。其中,化合物1 是2,4′-二羧基二苯甲酮和水分子通过O–H···O氢键形成的一维梯状链扩展构筑的三维超分子体系;化合物2 则是2,4′-二羧基二苯甲酮和水分子通过两种氢键形成含有一维隧道的三维超分子体系。有趣的是,[Ag(bpy)₂]⁺ 阳离子通过π–π 堆积和弱的Ag···Ag相互作用连在一起,进而以客体形式填充其中。荧光性质研究表明,由于存在bpy的螯合与堆积效应,化合物2相比配体和化合物1,其荧光发射峰发生红移。     

Coordination Polymers Derived from Non‐Steroidal Anti‐Inflammatory Drugs for Cell Imaging and Drug Delivery

A new series of Mn^II coordination polymers, namely, [{Mn(L)(H₂O)₂} ? 2 Nap]_∞ ( CP1 ), [{Mn(L)(Ibu)₂(H₂O)₂}]_∞ ( CP2 ), [{Mn(L)(Flr)₂(H₂O)₂}]_∞ ( CP3 ), [{Mn(L)(Ind)₂(H₂O)₂} ? H₂O]_∞ ( CP4 ), [{Mn₂(L)₂(μ‐Flu)₄(H₂O)} ? L]_∞ ( CP5 ), [{Mn₂(L)₂(μ‐Tol)₄(H₂O)₂}]_∞ ( CP6) and [{Mn₂(L)₂(μ‐Mef)₄(H₂O)₂}]_∞ ( CP7 ) (Nap=naproxen, Ibu=ibuprofen, Flr=flurbiprofen, Ind=indometacin, Flu=flufenamic acid, Tol=tolfenamic acid and Mef=mefenamic acid) derived from various non‐steroidal anti‐inflammatory drugs (NSAIDs) and the organic linker 1,2‐bis(4‐pyridyl)ethylene (L) have been synthesized with the aim of being used for cell imaging and drug delivery. Single‐crystal X‐ray diffraction (SXRD) studies revealed that the NSAID molecules were part of the coordination polymeric network either through coordination to the metal center (in the majority of the cases) or through hydrogen bonding. Remarkably, all the Mn^II coordination polymers were found to be soluble in DMSO, thereby making them particularly suitable for the desired biological applications. Two of the coordination polymers (namely, CP1 and CP3 ) reported herein, were found to be photoluminescent both in the solid as well as in the solution state. Subsequent experiments (namely, MTT (3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide), and PGE₂ (prostaglandin E₂) assays) established their biocompatibility and anti‐inflammatory response. In vitro studies by using a macrophage cell line (i.e., RAW 264.7) revealed that both CP1 and CP3 were excellent cell imaging agents. Finally, biodegradability studies under simulated physiological conditions in phosphate‐buffered saline (PBS) at pH 7.6 showed that slow and sustained release of the corresponding NSAID was indeed possible from both CP1 and CP3 .     

Two N,N′‐diaryl‐2,2,2‐trichloroethane‐1,1‐diamines: hydrogen‐bonded supramolecular structures in one and two dimensions

The molecules of 2,2,2‐trichloro‐N,N′‐diphenylethane‐1,1‐diamine, C₁₄H₁₃Cl₃N₂, are linked into (040) sheets by a combination of C—H...Cl and C—H...π(arene) hydrogen bonds. In 2,2,2‐trichloro‐N,N′‐bis(4‐methylphenyl)ethane‐1,1‐diamine, C₁₆H₁₇Cl₃N₂, the molecules are linked into C(7) chains by two independent C—H...Cl hydrogen bonds and one Cl...Cl contact.     

Palladium(II) and Platinum(II) Complexes with Bisphosphanes, [S2C=C(CN)2]2– and [Se2C=C(CN)2]2– as Chelating Ligands

The palladium(II) and platin(II) 1, 1‐dicyanoethylene‐2, 2‐dithiolates [(L–L)M{S₂C=C(CN)₂}] (M = Pd: L–L = dppm, dppe, dcpe, dpmb; M = Pt: dppe, dcpe, dpmb) were prepared either from[(L–L)MCl₂] and K₂[S₂C=C(CN)₂] or from [(PPh₃)₂M{S₂C=C(CN)₂}] and the bisphosphane. Moreover, [(dppe)Pt{S₂C=C(CN)₂}]was obtained from [(1, 5‐C₈H₁₂)Pt{S₂C=C(CN)₂}] and dppeby ligand exchange. The 1, 1‐dicyanoethylene‐2, 2‐diselenolates[(dppe)M{Se₂C=C(CN)₂}] (M = Pd, Pt) were prepared from[(dppe)MCl₂] and K₂[Se₂C=C(CN)₂]. The oxidation potentials of the square‐planar palladium and platinum complexes were determined by cyclic voltammetry. The reaction of [(dcpe)Pd(S₂C=O)] with TCNE led to a ligand fragment exchange and gave the 1, 1‐dicyanoethylene‐2, 2‐dithiolate [(dcpe)Pd{S₂C=C(CN)₂}] in good yield.     

Four related diethyl [(arylamino)(4‐ethynylphenyl)methyl]phosphonates

Crystal structures are reported for four related diethyl [(arylamino)(4‐ethynylphenyl)lmethyl]phosphonate derivatives, namely diethyl [(4‐bromoanilino)(4‐ethynylphenyl)methyl]phosphonate, C₁₉H₂₁BrNO₃P, (I), diethyl ((4‐chloro‐2‐methylanilino){4‐[2‐(trimethylsilyl)ethynyl]phenyl}methyl)phosphonate, C₂₃H₃₁ClNO₃PSi, (II), diethyl ((4‐fluoroanilino){4‐[2‐(trimethylsilyl)ethynyl]phenyl}methyl)phosphonate, C₂₂H₂₉FNO₃PSi, (III), and diethyl [(4‐ethynylphenyl)(naphthalen‐2‐ylamino)methyl]phosphonate, C₂₃H₂₄NO₃P, (IV). The conformation of the anilinobenzyl group is very similar in all four compounds. The P—C bond has an approximately staggered conformation, with the aniline and ethynylphenyl groups in gauche positions with respect to the P=O double bond. The two six‐membered rings are almost perpendicular. The sums of the valence angles about the N atoms vary from 344 (2) to 351 (2)°. In the crystal structures, molecules of (I), (III) and (IV) are arranged as centrosymmetric or pseudocentrosymmetric dimers connected by two N—H...O=P hydrogen bonds. The molecules of (II) are arranged as centrosymmetric dimers connected by C_methyl—H...O=P hydrogen bonds. The N—H bond of (II) is not involved in hydrogen bonding.     

Hydrogen‐bonded assembly in six closely related pyrazolo[3,4‐b]pyridine derivatives; a simple chain,three types of chains of rings and a complex sheet structure

Six closely related pyrazolo[3,4‐b]pyridine derivatives, namely 6‐chloro‐3‐methyl‐1,4‐diphenylpyrazolo[3,4‐b]pyridine‐5‐carbaldehyde, C₂₀H₁₄ClN₃O, (I), 6‐chloro‐3‐methyl‐4‐(4‐methylphenyl)‐1‐phenylpyrazolo[3,4‐b]pyridine‐5‐carbaldehyde, C₂₁H₁₆ClN₃O, (II), 6‐chloro‐4‐(4‐chlorophenyl)‐3‐methyl‐1‐phenylpyrazolo[3,4‐b]pyridine‐5‐carbaldehyde, C₂₀H₁₃Cl₂N₃O, (III), 4‐(4‐bromophenyl)‐6‐chloro‐3‐methyl‐1‐phenylpyrazolo[3,4‐b]pyridine‐5‐carbaldehyde, C₂₀H₁₃BrClN₃O, (IV), 6‐chloro‐4‐(4‐methoxyphenyl)‐3‐methyl‐1‐phenylpyrazolo[3,4‐b]pyridine‐5‐carbaldehyde, C₂₁H₁₆ClN₃O₂, (V), and 6‐chloro‐3‐methyl‐4‐(4‐nitrophenyl)‐1‐phenylpyrazolo[3,4‐b]pyridine‐5‐carbaldehyde, C₂₀H₁₃ClN₄O₃, (VI), which differ only in the identity of a single small substituent on one of the aryl rings, crystallize in four different space groups spanning three crystal systems. The molecules of (I) are linked into a chain of rings by a combination of C—H...N and C—H...π(arene) hydrogen bonds; those of (II), (IV) and (V), which all crystallize in the space group P, are each linked by two independent C—H...O hydrogen bonds to form chains of edge‐fused rings running in different directions through the three unit cells; the molecules of (III) are linked into complex sheets by a combination of two C—H...O hydrogen bonds and one C—H...π(arene) hydrogen bond; finally, the molecules of (VI) are linked by a single C—H...O hydrogen bond to form a simple chain.     

Synthesis,Structure and Photoluminescent Properties of Zn(II)/Cd(II)‐Complexes Containing 2,4,6‐Tris‐(benzimidazolyl‐2‐yl)pyridine Ligand

Hydrothermal reactions of tridentate rigid 2,4,6‐tris‐(benzimidazolyl‐2‐yl)pyridine (pytbzim) ligand and Zn(II)/Cd(II) salts generate binuclear complexes {[Cd₂Cl₂(pytbzim)₂(H₂O)₂]·2NO₃}_n ( 1 ) and two isomorphs {[M₂Cl₂(pytbzim)₂(H₂O)₂]Cl₂·2H₂O}_n [M=Cd ( 2 ), Zn ( 3 )]. All complexes include [M₂Cl₂(pytbzim)₂(H₂O)₂] dimers, which are further connected into a three‐dimensional supramolecular networks through ?‐? stacking interaction and hydrogen bonds. The solid state photoluminescent studies reveal good fluorescent properties of the pytbzim ligand and complexes 1 – 2 at room temperature.     

A novel two‐dimensional coordination polymer: poly[diaquatetra‐μ2‐chlorido‐[μ2‐2,2′‐(piperazine‐1,4‐diium‐1,4‐diyl)diacetate]dicadmium(II)]

In the crystal structure of the title two‐dimensional metal–organic polymeric complex, [Cd₂Cl₄(C₈H₁₄N₂O₄)(H₂O)₂]_n, the asymmetric unit contains a crystallographically independent Cd^II cation, two chloride ligands, an aqua ligand and half a 2,2′‐(piperazine‐1,4‐diium‐1,4‐diyl)diacetate (H₂PDA) ligand, the piperazine ring centroid of which is located on a crystallographic inversion centre. Each Cd^II centre is six‐coordinated in an octahedral environment by an O atom from an H₂PDA ligand and an O atom from an aqua ligand in a trans disposition, and by four chloride ligands arranged in the plane perpendicular to the O—Cd—O axis. The complex forms a two‐dimensional layer polymer containing [CdCl₂]_n chains, which are interconnected into an extensive three‐dimensional hydrogen‐bonded network by C—H...O, C—H...Cl and O—H...O hydrogen bonds.