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

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

Synthesis and Characterization of Iron(III) Complexes of 5‐(8‐Carboxy‐1‐naphthyl)‐10, 15, 20‐tritolyl Porphyrin

5‐(8‐Carboxy‐1‐naphthyl)‐10, 5, 20‐tritolyl porphyrin (H₃CNTTP) and its iron(III) complexes, [Fe(CNTTP)]₂ and [Fe(CNTTP)(N‐MeIm)₂], were synthesized and characterized. X‐ray crystallography revealed that the carboxylate group is “hanging” over the porphyrin plane. The rigid framework makes the distance between the carboxylate oxygen and iron in the same porphyrin too long to form a coordination bond. On the other hand, the carboxylate group is not bulky enough to block the axial binding site. In the presence of OH^–, the carboxylate oxygen is coordinated to iron in the symmetry‐related unit, which led to the dimeric structure, [Fe(CNTTP)]₂. In the presence of excess N‐methylimidazole, a six‐coordinate species, [Fe(CNTTP)(N‐MeIm)₂], was obtained. In such a structure, CH ··· O interactions between the carboxylate group and imidazole probably play an important role to determine the orientation of imidazole plane. Two imidazole planes have relative parallel orientation. For [Fe(CNTTP)(N‐MeIm)₂], ¹H NMR shows pyrrole protons at the region –10 to –25 ppm. EPR shows rhombic spectrum. Those suggest [Fe(CNTTP)(N‐MeIm)₂] is a type II low‐spin iron(III) porphyrinate.     

Octahedral and Cyclic [Ag6] Cluster Cores Stabilized by {Ag3(Spz)3(N‐triphos)3} Motifs [HSpz = Pyrazine‐2‐thiolate,N‐triphos = Tris((diphenylphosphanyl)methyl)amine]: Ag···Ag Interactions

The complexes [Ag₁₂(Spz)₁₂(N‐triphos)₂][Ag₃(Spz)₃(N‐triphos)]₂ · (DMF)₆ ( 1 ) and [Ag₁₈(Spz)₁₂(N‐triphos)₄(CF₃CO₂)₆] ( 2 ) were synthesized and structurally characterized by X‐ray diffraction [HSpz = pyrazine‐2‐thiolate, N‐triphos = tris((diphenylphosphanyl)methyl)amine]. The central [Ag₆] ring with chair‐conformation in 1 and the ideally octahedral [Ag₆] cluster core in 2 are both stabilized by the tripodal building units of neutral [Ag₃(Spz)₃(N‐triphos)] compound. The Ag ··· Ag distances of the [Ag₆] moieties in 1 and 2 are 3.07 and 2.81 Å, respectively, exhibiting intermetallic interactions, which can enhance the stability of [Ag₆] conformations. In addition, the π ··· π interactions between parallel pyrazine rings could impose on the building and the Ag ··· Ag interactions of these Ag–S clusters.     

Synthesis and Crystal Structure of [(1‐(Phenyltriazenido)‐2‐(phenyltriazeno)benzene)(nitrato)mercury(II)], {Hg[PhN3C6H4N3(H)Ph](NO3)}, a Complex with Weak Metal‐Arene π‐Interactions

The reaction of PhN₃(H)C₆H₄N₃(H)Ph with Hg(NO₃)₂ in THF in the presence of triethylamine yields {Hg[PhN₃C₆H₄N₃(H)Ph](NO₃)} as a yellow powder that can be recrystallized from THF/acetone. The crystals belong to the monoclinic system, space group P2₁ with the cell dimensions a = 9.639(2), b = 5.412(1), c = 19.675(4) Å, β= 97.47(3)°, V = 1017.7 (4) ų, Z = 2. The crystal structure determination (2668 unique reflections with [I>2σ(I)], 262 parameters, R₁ = 0.0393) shows that the structure consists of mononuclear complexes. Hg atoms are linearly coordinated by one N_α atom of the triazenide unit of the planar ligand [Hg‐N(1) = 2.101(8) Å] and an O atom of the NO₃^— ion [Hg‐O(1) = 2.11(1) Å]. Additional weak Hg‐N contacts [Hg‐N(4) = 2.662(9) and Hg‐N(3) = 2.851(9) Å] and an intramolecular hydrogen bond between the triazenide hydrogen and an O atom of the nitrate group are observed [N(6)‐H(6)···O(2) = 2.92(2) Å]. The complexes are stacked to infinite chains by metal‐arene π‐interactions. Each Hg atom is coordinated by the terminal phenyl rings of two neighboring complexes [Hg‐C from 3.40(1) to 4.10(1) Å] in a η² fashion.     

Cadmium(II) Complexes with Mixed cis‐Epoxysuccinate and 2,2′‐Bipyridyl‐Like Ligands: Syntheses,Crystal Structures,and Luminescent Properties

Two new Cd^II complexes, [Cd( ces )(phen)]_∞ ( 1 ) and {[Cd( ces )(bpy)(H₂O)](H₂O)}₂ ( 2 ), were prepared by slow solvent evaporation methods from mixtures of cis‐epoxysuccinic acid and Cd(ClO₄)₂ · 6H₂O in the presence of phen or bpy co‐ligand ( ces = cis‐epoxysuccinate, phen = 1,10‐phenanthroline, and bpy = 2,2′‐bipyridine). Single‐crystal X‐ray diffraction analyses show that complex 1 has a one‐dimensional (1D) helical chain that is further assembled into a two‐dimensional (2D) sheet, and then an overall three‐dimensional (3D) network by the interchain C–H ··· O hydrogen bonds. Complex 2 features a dinuclear structure, which is further interlinked into a 3D supramolecular network by the co‐effects of intermolecular C–H ··· O and C–H ··· π hydrogen bonds as well as π ··· π stacking interactions. The structural differences between 1 and 2 are attributable to the intervention of different 2,2′‐bipyridyl‐like co‐ligands. Moreover, 1 and 2 exhibit intense solid‐state luminescence at room temperature, which mainly originates from the intraligand π→π* transitions of aromatic co‐ligands.     

Synthesis,Structures, Fluorescence Properties,and Natural Bond Orbital (NBO) Analysis of Two Metal [EuIII,CoII] Coordination Polymers Containing 1, 3‐Benzenedicarboxylate and 2‐(4‐methoxyphenyl)‐1H‐imidazo[4, 5‐f][1, 10]phenanthroline Ligands

Two new metal‐organic coordination polymers[Eu(m‐BDC)_1.5(MOPIP) · 1/2H₂O]_n ( 1 ) and [Co(m‐BDC)(MOPIP)₂ · 2H₂O]_n ( 2 ) [m‐H₂BDC = benzene‐1, 3‐dicarboxylic acid, MOPIP = 2‐(4‐methoxyphenyl)‐1H‐imidazo[4, 5‐f] 1 , 10 phenanthroline] were hydrothermally synthesized and structurally characterized by elemental analysis, IR spectroscopy, and single‐crystal X‐ray diffraction. The coordination polymers crystallize in monoclinic space group P2₁/m for 1 ( 2 : P2₁/n), with a = 9.779(2), b = 18.242(4), c = 17.146(3) Å, β = 106.41(3)° for 1 , and with a = 8.2153(16), b = 27.974(6), c = 17.974(4) Å, β = 100.40(3)° for 2 . The crystal structure of complex 1 is a zipper‐like chain of octacoordinate Eu³⁺ ions, in which Eu³⁺ ions are bridged in two coordination modes by m‐BDC²⁺ ligands and decorated by MOPIP ligands. The molecular structure of complex 2 consists of a hexacoordinte Co²⁺ atom, which generates a slightly distorted octahedral arrangement, and assembles into three‐dimensional supramolecular nets by π ··· π stacking interactions. Additionally, these two compounds show strong fluorescence in the solid state at room temperature. Natural bond orbital (NBO) analysis is performed by using the NBO method built in Gaussian 03 Program. The calculation results show a weak covalent interaction between the coordinated atoms and metal ions.     

Synthesis and Characterization of (–)‐Menthyl Containing N‐Alkyl Cycloimmonium Salts

The reaction of 4‐phenyl‐2‐aminothiazole or 2‐amino pyridine with α‐bromo acetic (–)‐menthyl ester ( 2c ) yields new N‐alkyl cycloimmonium bromides ( 1c , 3 ) with the chiral (–)‐menthyl substituent, which were isolated and fully characterized by ¹H and ¹³C NMR spectroscopy for the first time. In addition, starting from 4‐phenyl‐2‐aminothiazole, two further N‐alkyl cycloimmonium bromides ( 1a , 1b ) were prepared. The molecular and crystal structures of all three thiazole derived N‐alkyl cycloimmonium bromides ( 1a – c ) were determined by single‐crystal X‐ray diffraction. In all cases the crystal structures are dominated by N–H ··· Br hydrogen bonds, which results in the formation of an extensive hydrogen bonded network in the crystal. Interestingly, in all structures S ··· Br^– distances shorter than the sum of the van der Waals radii are observed.     

C—H···X (X = N,O, S) intramolecular interaction in 1‐vinyl‐2‐(2′‐heteroaryl)pyrroles as monitored by 1H and 13C NMR spectroscopy

¹H and ¹³C NMR spectroscopy of a series of 1‐vinyl‐2‐(2′‐heteroaryl)‐pyrroles were employed for the analysis of their electronic and spatial structure. The C—H···N intramolecular interaction between the α‐hydrogen of the vinyl group and the pyridine nitrogen, a kind of hydrogen bonding, was detected in 1‐vinyl‐2‐(2′‐pyridyl)pyrrole, which disappeared in its iodide methyl derivative. It was shown that this interaction is stronger than the C—H···O and C—H···S interactions in 1‐vinyl‐2‐(2′‐furyl)‐ and ‐2‐(2′‐thienyl)‐pyrroles. Copyright © 2001 John Wiley & Sons, Ltd.     

Syntheses,Structures, and Luminescent Properties of d10 Coordination Polymers with 2‐(4‐Carboxyphenyl)‐imidazo[4, 5‐f]‐1, 10‐phenanthroline and 1, 3‐Benzenedicarboxylate Derivatives

Four Zn^II/Cd^II coordination polymers (CPs) based on 2‐(4‐carboxy‐phenyl)imidazo[4, 5‐f]‐1, 10‐phenanthroline (HNCP) and different derivatives of 5‐R‐1, 3‐benzenedicarboxylate (5‐R‐1, 3‐BDC) (R = NO₂, H, OH), [Zn(HNCP)(5‐NO₂‐1, 3‐BDC)]_n ( 1 ), [Cd(HNCP)(5‐NO₂‐1, 3‐BDC)]_n ( 2 ), [Zn(HNCP)(1, 3‐BDC)(H₂O)₂]_n ( 3 ), and {[Zn(HNCP)(5‐OH‐1, 3‐BDC)(H₂O) · H₂O}_n ( 4 ) were synthesized under hydrothermal conditions. Compounds 1 – 4 were determined by elemental analyses, IR spectroscopy, and single‐crystal and powder X‐ray diffraction. Compounds 1 and 2 are isomorphous, presenting a 4‐connected uninodal (4, 4)‐sql 2D framework with threefold interpenetration, which are further extended into the three‐dimensional (3D) supramolecular architecture through π ··· π stacking interactions between the aryl rings of 5‐NO₂‐1, 3‐BDC. Compared to compound 1 , 3 is obtained by using different reaction temperatures and metal‐ligand ratios, generating a 3D framework with –ABAB– fashion via π ··· π stacking interactions. Compound 4 is a 1D chain, which is further extended into a 3D supramolecular net by hydrogen bonds and π ··· π stacking interactions. The thermogravimetric and fluorescence properties of 1 – 4 were also explored.     

Pentafluorobenzoato‐dimolybdenum(II) Solvate and Co‐crystal Complexes with Benzene and Naphthalin

The quadruply bonded Mo₂⁴⁺ complex Mo₂(DAniF)₃(OOCC₆F₅) ( 1 ) [DAniF = N,N′‐bis(4‐methoxyphenyl)formamidinate] was synthesized. The solvate Mo₂(DAniF)₃(OOCC₆F₅) · (C₆H₆) ( 2 ) and co‐crystal Mo₂(DAniF)₃(OOCC₆F₅) · (C₁₀H₈) ( 3 ) complexes were obtained by self‐assembly of crystals of 1 with benzene and naphthalin, respectively. Compounds 1 , 2 , and 3 were structurally characterized by single‐crystal X‐ray diffraction. In monomer 1 , the Mo–Mo bond length of 2.0874(6) Å is typical for dimolybdenum quadruple bonds. The solvate complex 2 was stabilized by weak π–π stacking interactions between the benzene molecule and the pentafluorophenyl ring (as indicated by a center‐to‐center distance of 3.838(10) Å and a center‐to‐plane distance of 3.712(4) Å between phenyl and pentafluorophenyl ring) and intermolecular C–H ··· F–C interactions (the shortest F ··· H distance is 2.560(2) Å). In complex 3 , a one‐dimensional chain was formed by C–H ··· F–C interactions between the hydrogen atoms in naphthalin and the fluorine atoms in the monomer (H ··· F distances of 2.582(2) Å). Information on the structures in solution of the three crystals was obtained by ¹H NMR spectroscopy.     

Preparation,Structure, Spectral,and Magnetic Properties of Copper(II) Halogenonicotinates: Crystal and Molecular Structure of Tetrakis(μ‐2‐chloronicotinato‐O,O′)‐diaquadicopper(II)

The characterization of the complexes [Cu₂(2‐Clnic)₄(H₂O)₂] ( 1 ), [Cu(2,6‐Cl₂nic)₂(H₂O)₂] ( 2 ) and [Cu(5‐Brnic)₂(H₂O)₂]_n ( 3 ) (where 2‐Clnic = 2‐chloronicotinate, 2,6‐Cl₂nic = 2,6‐dichloronicotinate or 5‐Brnic = 5‐bromonicotinate) was based on elemental analysis, IR, electronic and EPR spectra, and magnetic susceptibility. Complex 1 was also studied by X‐ray analysis at 298 1a and 80 K 1b . The complex 1 contains a dinuclear Cu‐acetate molecular structure in which the carboxyl groups of the 2‐chloronicotinate ligands act as bridges and water molecules are at apical positions. The stereochemistry about Cu atom at both temperatures is typical for square pyramidal geometry with CuO₄O chromophore. The Cu‐Cu distance is 2.6513(8) and 2.6382(6) Å for 1a and 1b , respectively. The Cu atoms are displaced by 0.2069(9) and 0.1973(7) Å, respectively, from the plane containing four oxygen atoms bonded to the Cu atom toward the apical water molecules. Strong and weak hydrogen bonds as well as C–Cl···π interactions in the crystal structure are discussed as well. Both complexes, monomeric [Cu(2,6‐Cl₂nic)₂(H₂O)₂] ( 2 ) and polymeric [Cu(5‐Brnic)₂(H₂O)₂]_n ( 3 ), possess octahedral copper(II) stereochemistry with differing tetragonal distortions.     

Synthesis,Characterization, and Crystal Structure of Three Coordination Polymers from 5‐(Pyridin‐2‐ylmethyl)aminoisophthalic Acid

Three new complexes: [M(L)(H₂O)] [M = Zn ( 1 ), Co ( 2 ), Ni ( 3 ); H₂L = 5‐(pyridin‐2‐ylmethyl)aminoisophthalic acid] were synthesized under hydrothermal conditions at 180 °C and were characterized by elemental analysis, FT‐IR spectroscopy, single‐crystal X‐ray diffraction, and thermogravimetric analysis (TGA). The results of X‐ray diffraction analysis reveal that complexes 1 – 3 are isostructural and crystallize in the monoclinic system with space group P2₁/c. Each of the complexes displays a (3,3′)‐connected two‐dimensional (2D) wave‐like network with (4,8²) topology, within which five‐membered uncoplanar N,N‐chelated metallacycles are shaped. Delicate N–H ··· O and O–H ··· O hydrogen bonding interactions exist in complexes 1 – 3 . Adjacent 2D layers are linked by intermolecular interactions, resulting in the construction of extended metal‐organic frameworks (MOFs) in complexes 1 and 2 .     

Synthesis,Structures, and Properties of Two Novel Supramolecular Architectures Constructed from [2,3‐f]Pyrazino[1,10]phenanthroline‐2,3‐dicarboxylic Acid

Two new compounds, [Ag(Hppdb)]_n ( 1 ) and {[Ag₂(Hppdb)₂(bpe)] · 5.5H₂O}_n( 2 ) [H₂ppdb = [2,3‐f]pyrazino[1,10]phenanthroline‐2,3‐dicarboxylic acid, bpe = trans‐1,2‐bis(4‐pyridyl)ethylene], were synthesized and characterized. In 1 , Hppdb^– ions link Ag^I cations to form an infinite 1D [–Ag–(Hppdb)–Ag–]_n chain, furthermore, the dimensionality is extended to 2D layers through synergistic π–π stacking, hydrogen‐bonding and weak Ag ··· O interactions. Correspondingly, the dimeric [(Ag)(Hppdb)]₂ subunits in 2 are connected by bpe ligands to generate a loop‐link‐shaped 1D chain motif, which is further joined through a R₂²(18)C–H ··· O hydrogen‐bonding ring to afford interesting diagonal/diagonal inclined catenation 2D + 2D → 3D supramolecular architectures. In addition, solid‐state properties such as photoluminescence and thermal stability of the two compounds were studied.     

3‐[5‐(4‐Chlorophenyl)‐1‐(4‐methoxyphenyl)‐1H‐pyrazol‐3‐yl]propionic acid and the corresponding methyl ester

The synthesis of 3‐[5‐(4‐chlorophenyl)‐1‐(4‐methoxyphenyl)‐1H‐pyrazol‐3‐yl]propionic acid, C₁₉H₁₇ClN₂O₃, (I), and its corresponding methyl ester, methyl 3‐[5‐(4‐chlorophenyl)‐1‐(4‐methoxyphenyl)‐1H‐pyrazol‐3‐yl]propionate, C₂₀H₁₉ClN₂O₃, (II), is regiospecific. However, correct identification of the regioisomer formed by spectroscopic techniques is not trivial and single‐crystal X‐ray analysis provided the only means of unambiguous structure determination. Compound (I) crystallizes with Z′ = 2. The propionic acid groups of the two crystallographically unique molecules form a hydrogen‐bonded dimer, as is typical of carboxylic acid groups in the solid state. Conformational differences between the methoxybenzene and pyrazole rings give rise to two unique molecules. The structure of (II) features just one molecule in the asymmetric unit and the crystal packing makes greater use than (I) of weak C—H...A interactions, despite the lack of any functional groups for classical hydrogen bonding.     

Synthesis,Crystal Structure and Properties of [Mn(hdpa)2(N(CN)2)2] and [Co(hdpa)2(N(CN)2)2] (hdpa = 2, 2'‐Dipyridylamine)

Two new transition metal(II) complexes [M(hdpa)₂(N(CN)₂)₂] (M = Mn ( 1 ), Co ( 2 ); hdpa = 2, 2'‐dipyridylamine) have been prepared and characterized structurally and magnetically. Both compounds crystallize in the monoclinic space group C2/c. 1 and 2 are isotypic with the unit cell parameters a = 8.634(9), b = 13.541(14), c = 21.99(2) Å, β = 94.806(18)°, and V = 2562(5) ų for 1 , a = 8.617(3) Å, b = 13.629(5)Å, c = 21.598(8)Å, β = 94.593(6)°, and V = 2528.4(15)ų for 2 , and Z = 4 for both. According to X‐ray crystallographic studies, each metal(II) ion was six‐coordinated with four nitrogen atoms from two bidentate hdpa ligand and two nitrogen atoms from two N(CN)^— anions to form slightly distorted octahedrons. Adjacent complex molecules are connected by hydrogen bonds or π···π interactions to form three‐dimensional network. The IR and UV spectroscopy were measured and the magnetic behaviors were investigated.     

Crystal Structure and Spectroscopic Characterization of Zinc(II) and Mercury(II) Complexes of N‐(Pyridin‐2‐ylmethylene)benzene‐1,4‐diamine

The behavior of N,N′‐bis(pyridin‐2‐ylmethylene)benzene‐1,4‐diamine (L) towards zinc(II), cadmium(II), and mercury(II) chlorides was studied in methanol solutions. In the presence of metal ions, the organic molecule was decomposed to N‐(pyridin‐2‐ylmethylene)benzene‐1,4‐diamine (L′), and complexes of general formula M(L′)Cl₂ were isolated from the mixture. The complexes were identified by elemental analysis, IR, ¹H NMR, and ¹³C NMR spectra, and their structures were further confirmed by single‐crystal X‐ray diffraction analysis of Zn(L′)Cl₂ and Hg(L′)Cl₂. In the solid state of both complexes, the molecules are stabilized by N–H ··· Cl hydrogen bonds and aromatic π–π stacking interactions.     

Van Der Waals heterogeneous layer‐layer carbon nanostructures involving π···H‐C‐C‐H···π···H‐C‐C‐H stacking based on graphene and graphane sheets

Noncovalent interactions involving aromatic rings, such as π···π stacking, CH···π are very essential for supramolecular carbon nanostructures. Graphite is a typical homogenous carbon matter based on π···π stacking of graphene sheets. Even in systems not involving aromatic groups, the stability of diamondoid dimer and layer‐layer graphane dimer originates from C − H···H − C noncovalent interaction. In this article, the structures and properties of novel heterogeneous layer‐layer carbon‐nanostructures involving π···H‐C‐C‐H···π···H‐C‐C‐H stacking based on [n ]‐graphane and [n ]‐graphene and their derivatives are theoretically investigated for n = 16–54 using dispersion corrected density functional theory B3LYP‐D3 method. Energy decomposition analysis shows that dispersion interaction is the most important for the stabilization of both double‐ and multi‐layer‐layer [n ]‐graphane@graphene. Binding energy between graphane and graphene sheets shows that there is a distinct additive nature of CH···π interaction. For comparison and simplicity, the concept of H‐H bond energy equivalent number of carbon atoms (noted as NHEQ), is used to describe the strength of these noncovalent interactions. The NHEQ of the graphene dimers, graphane dimers, and double‐layered graphane@graphene are 103, 143, and 110, indicating that the strength of C‐H···π interaction is close to that of π···π and much stronger than that of C‐H···H‐C in large size systems. Additionally, frontier molecular orbital, electron density difference and visualized noncovalent interaction regions are discussed for deeply understanding the nature of the C‐H···π stacking interaction in construction of heterogeneous layer‐layer graphane@graphene structures. We hope that the present study would be helpful for creations of new functional supramolecular materials based on graphane and graphene carbon nano‐structures. © 2017 Wiley Periodicals, Inc.     

Syntheses,Crystal Structures,and Properties of Lead(II), ­Zinc(II), and Manganese(II) Complexes Constructed from 2, 3, 5, 6‐Tetraiodo‐1, 4‐benzenedicarboxylic Acid

Three new coordination compounds, [Pb(HBDC‐I₄)₂(DMF)₄]( 1 ) and [M(BDC‐I₄)(MeOH)₂(DMF)₂]_n (M = Zn^II for 2 and Mn^II for ( 3 ) (H₂BDC‐I₄ = 2, 3, 5, 6‐tetraiodo‐1, 4‐benzenedicarboxylic acid), were synthesized and characterized by elemental analysis, IR spectroscopy, thermogravimetric (TG) analysis, and X‐ray single crystal structure analysis. Single‐crystal X‐ray diffraction reveals that 1 crystallizes in the monoclinic space group C2/c and has a discrete mononuclear structure, which is further assembled to form a two‐dimensional (2D) layer through intermolecular O–H ··· O and C–H ··· O hydrogen bonding interactions. The isostructural compounds 2 and 3 crystallize in the space group P2₁/c and have similar one‐dimensional (1D) chain structures that are extended into three‐dimensional (3D) supramolecular networks by interchain C–H ··· π interactions. The Pb^II and Zn^II complexes 1 and 2 display similar emissions at 472 nm in the solid state, which essentially are intraligand transitions.     

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.     

Metal Derivatives of 1,3‐Imidazolidine‐2‐thione with Divalent d10 Metal Ions (Zn–Hg) : Synthesis and Structures

Reactions of divalent Zn‐Hg metal ions with 1,3‐imidazolidine‐2‐thione (imdtH₂) in 1 : 2 molar ratio have formed monomeric complexes, [Zn(η¹‐S‐imdtH₂)₂(OAc)₂] ( 1 ), [Cd((η¹‐SimdtH₂)₂I₂] ( 2 ), [Cd(η¹‐S‐imdtH₂)₂Br₂] ( 3 ), and [Hg(η¹‐S‐imdtH₂)₂I₂] ( 4 ). Complexes 1 – 4 , have been characterized by elemental analysis (C, H, N), spectroscopy (IR, ¹H, NMR) and x‐ray crystallography ( 1 ‐ 4 ). Hydrogen bonding between oxygen of acetate and imino hydrogen of ligand, {N(2)–H(2C)···O(2)^#} in 1 , ring CH and imino hydrogen, {C(2A)–H(2A)···Br(2)^#} in 3 have formed H‐bonded dimers. Similarly, the interactions between molecular units of complexes 2 and 4 have yielded 2D polymers. The polymerization occurs via intermolecular interactions between thione sulfur and imino hydrogen, {N(2)–H(2)···S(1)^#}, imino hydrogen and the iodine atom, {NH(1)···I(2)^#} in 2 and imino hydrogen – iodine atom {N(2A)–H(2A)···I(2)} and I···I interaction in 4 . Crystal data: [Zn(η¹‐S‐imdtH₂)₂(OAc)₂] ( 1 ), C₁₀H₁₈N₄O₄S₂Zn, orthorhombic, Pbcn, a = 9.3854(7) Å, b = 12.4647(10) Å, c = 13.2263(11) Å; V = 1547.3(2) ų, Z = 4, R = 0.0280 [Cd((η¹‐S‐imdtH₂)₂I₂] ( 2 ), C₆H₁₂CdI₂N₄S₂, orthorhombic, Pnma, a = 13.8487(10) Å, b = 14.4232(11) Å, c = 7.0659(5) Å; Z = 4, V = 1411.36(18) ų, R = 0.0186.