Search

The crystal structure of the new double CuII complex salt, [Cu(L)(H2O)2][Cu(L)]Br4·2H2O (L = 3,14-diethyl-2,6,13,17-tetra­aza­tri­cyclo­[16.4.0.07,12]docosane, C22H44N4) has been determined using synchrotron radiation. The asymmetric unit contains one half of a [Cu(L)(H2O)2]2+ cation, one half of a [Cu(L)]2+ cation (both completed by crystallographic inversion symmetry), two bromide anions and one water solvent mol­ecule. The CuII atom in the first complex exists in a tetra­gonally distorted octa­hedral environment with the four N atoms of the macrocyclic ligand in equatorial and two aqua ligands in axial positions, whereas the CuII atom in the second complex exists in a square-planar environment defined by the four nitro­gen atoms of the macrocyclic ligand. The two macrocyclic rings adopt the most stable trans-III configuration with normal Cu—N bond lengths from 2.016 (3) to 2.055 (3) Å and an axial Cu—O bond length of 2.658 (4) Å. The crystal structure is stabilized by inter­molecular hydrogen bonds involving the macrocycle N—H or C—H groups and the O—H groups of water mol­ecules as donor groups, and the O atoms of water mol­ecules and bromide anions as acceptor groups, giving rise to a one-dimensional network extending parallel to [100]. [ABSTRACT FROM AUTHOR]

The crystal structure of the novel hydrated CuII salt, [Cu(L)(H2O)2]Cl2·4H2O (L = 3,14-diethyl-2,6,13,17-tetra­aza­tri­cyclo­[16.4.0.07,12]docosane, C22H44N4) has been determined using synchrotron radiation. The asymmetric unit contains one half of the [Cu(L)(H2O)2]2+ cation (completed by crystallographic inversion symmetry), one chloride anion and two lattice water mol­ecules. The copper(II) atom exists in a tetra­gonally distorted octa­hedral environment with the four N atoms of the macrocyclic ligand in equatorial and two O atoms from water mol­ecules in axial positions. The latter exhibit a long axial Cu—O bond length of 2.7866 (16) Å due to the Jahn–Teller distortion. The macrocyclic ring adopts a stable trans-III conformation with typical Cu—N bond lengths of 2.0240 (11) and 2.0441 (3) Å. The complex is stabilized by hydrogen bonds formed between the O atoms of coordinated water mol­ecules and the NH groups as donors, and chloride anions as acceptors. The chloride anions are further connected to the lattice water solvent molecules through O—H⋯Cl hydrogen bonds, giving rise to a three-dimensional network structure. [ABSTRACT FROM AUTHOR]

The crystal structure of the title salt, C20H42N42+·2ClO4−, has been determined using synchrotron radiation at 220 (2) K. The structure determination reveals that protonation has occurred at diagonally opposite amine N atoms. The asymmetric unit comprises one half of the organic dication, which lies about a center of inversion, and one perchlorate anion. The macrocyclic dication adopts the most stable endodentate trans-III conformation. The crystal structure is stabilized by intra­molecular N—H...N, and inter­molecular N—H...O and C–H...O hydrogen bonds involving the macrocycle N—H and C—H groups as donors and the O atoms of perchlorate anions as acceptors, giving rise to a three-dimensional network. [ABSTRACT FROM AUTHOR]

The crystal structure of the title complex, cis-[Cr(NCS)2(cyclam)]Br (cyclam = 1,4,8,11-tetraazacyclotetradecane, C10H24N4), has been determined from synchrotron X-ray data. The asymmetric unit contains one [Cr(NCS)2(cyclam)]+ cation and one bromide anion. The CrIII ion of the complex cation is coordinated by the four N atoms of the cyclam ligand and by two N-coordinating NCS groups in a cis arrangement, displaying a distorted octahedral coordination sphere. The Cr--N(cyclam) bond lengths are in the range 2.075 (3) to 2.081 (3) Å while the average Cr--N(NCS) bond length is 1.996 (16) Å. The macrocyclic cyclam moiety adopts the most stable cis-V conformation. The crystal structure is stabilized by intermolecular hydrogen bonds involving the cyclam N--H groups as donor groups, and the bromide anion and the S atom of one of the NCS ligands as acceptor groups. [ABSTRACT FROM AUTHOR]

The crystal structure of the hydrated title salt, C22H48N44+4Cl-4H2O(C22H48N4 =H4L = 3,14-diethyl-2,6,13,17-tetraazoniatricyclo[16.4.0.07,12]docosane), has been determined using synchrotron radiation at 220 K. The structure determination reveals that protonation has occurred at all four amine N atoms. The asymmetric unit comprises one half of the macrocyclic cation (completed by crystallographic inversion symmetry), two chloride anions and two water molecules. The macrocyclic ring of the tetracation adopts an exodentate (3,4,3,4)-D conformation. The crystal structure is stabilized by intermolecular hydrogen bonds involving the macrocycle N-H groups and water O-H groups as donors, and the O atoms of the water molecules and chloride anions as acceptors, giving rise to a three-dimensional network. [ABSTRACT FROM AUTHOR]

The crystal structure of title compound, (C14H36N4)[CrO3Cl]2Cl2, has been determined by synchrotron radiation X-ray crystallography at 220 K. The macrocyclic cation lies across a crystallographic inversion center and hence the asymmetric unit contains one half of the organic cation, one chlorochromate anion and one chloride anion. Both the Cl- anion and chlorochromate Cl atom are involved in hydrogen bonding. In the crystal, hydrogen bonds involving the 1,4,8,11-tetramethyl-1,4,8,11-tetraazoniacyclotetradecane (TMC) N--H groups and C--H groups as donor groups and three O atoms of the chlorochromate and the chloride anion as acceptor groups link the components, giving rise to a threedimensional network. [ABSTRACT FROM AUTHOR]

The crystal structure of title salt, C14H36N44+·2ClO4-·2Cl-, has been determined using synchrotron radiation at 220-K. The structure determination reveals that protonation has occurred at all four amine N atoms. The asymmetric unit contains one half-cation (completed by crystallographic inversion symmetry), one perchlorate anion and one chloride anion. A distortion of the perchlorate anion is due to its involvement in hydrogen-bonding interactions with the cations. The crystal structure is consolidated by intermolecular hydrogen bonds involving the 1,4,8,11-tetramethyl-1,4,8,11-tetraazoniacyclotetradecane N-H and C-H groups as donor groups, and the O atoms of the perchlorate and chloride anion as acceptor groups, giving rise to a three-dimensional network. [ABSTRACT FROM AUTHOR]

The crystal structure of title salt, C22H46N42+·2NO3−·2H2O, has been determined using synchrotron radiation at 220 K. The structure determination reveals that protonation has occurred at diagonally opposite amine N atoms. The asymmetric unit contains half a centrosymmetric dication, one nitrate anion and one water mol­ecule. The mol­ecular dication, C22H46N42+, together with the nitrate anion and hydrate water mol­ecule are involved in an extensive range of hydrogen bonds. The mol­ecule is stabilized, as is the conformation of the dication, by forming inter­molecular N—H⋯O, O—H⋯O, together with intra­molecular N—H⋯N hydrogen bonds. [ABSTRACT FROM AUTHOR]

The structure of the title compound, [Cr(tacn)2]2[ZnCl4]3·H2O (tacn is 1,4,7-tri­aza­cyclo­nonane; C6H15N3), has been determined from synchrotron X-ray data. Each CrIII cation is coordinated by the six N atoms from the two tacn ligands, displaying a distorted octa­hedral geometry. Three distorted tetra­hedral [ZnCl4]2− anions and one lattice water mol­ecule lie outside this coordination sphere. The Cr—N bond lengths are in the range 2.0621 (11) to 2.0851 (12) Å, while the mean inner N—Cr—N bond angle is 82.51 (5)°. The crystal packing is stabilized by hydrogen-bonding inter­actions with the N—H groups of the tacn ligands and the water O—H groups acting as donors, and the O atoms of the water mol­ecules and Cl atoms of the [ZnCl4]2− anions as acceptors. Overall these contacts lead to the formation of a three-dimensional network. [ABSTRACT FROM AUTHOR]

The crystal structure of the title salt, C20H44N4 4+4Cr-4H2O, has been determined using synchrotron radiation at 220 K. The structure determination reveals that protonation has occurred at all four amine N atoms. The asymmetric unit contains one half-cation (completed by crystallographic inversion symmetry), two chloride anions and two water molecules. There are two molecules in the unit cell. The Cl- anions and hydrate molecules are involved in hydrogen bonding. The crystal structure is stabilized by intermolecular hydrogen bonds involving the macrocycle N--H groups and water O--H groups as donors and the O atoms of the water molecules and the Cl- anions as acceptors, giving rise to a three-dimensional network. [ABSTRACT FROM AUTHOR]

The asymmetric unit of the title compound, [Ag(C24H46N6O2)](NO3)2 [C24H46N6O2 is (5,16-dimethyl-2,6,13,17-tetra­aza­tri­cyclo­[16.4.0.07,12]docosane-2,13-di­yl)diacetamide, L], consists of one independent half of the [Ag(C24H46N6O2)]2+ cation and one nitrate anion. The Ag atom, lying on an inversion centre, has a square-planar geometry and the complex adopts a stable trans-III conformation. Inter­estingly, the two O atoms of the pendant acetamide groups are not coordinated to the AgII ion. The longer distance of 2.227 (2) Å for Ag—N(tertiary) compared to 2.134 (2) Å for Ag—N(secondary) may be due to the effects of the attached acetamide group on the tertiary N atom. Two nitrate anions are very weakly bound to the AgII ion in the axial sites and are further connected to the ligand of the cation by N—H⋯O hydrogen bonds. The crystal packing is stabilized by hydrogen-bonding inter­actions among the N—H donor groups of the macrocycle and its actetamide substituents, and the O atoms of the nitrate anions and of an acetamide group as the acceptor atoms. [ABSTRACT FROM AUTHOR]

The asymmetric unit of the title compound, Ag[Cr(C11H14N2O8)]·3H2O, contains one [Cr(1,3-pdta)]- anion [1,3-pdta is (propane-1,3-diyldinitrilo)tetraacetate], one Ag+ cation and three water molecules. The Cr3+ ion is coordinated to the four O and two N atoms of the 1,3-pdta ligand, displaying a distorted octahedral geometry. The mean Cr--N and Cr--O bond lengths are 2.0727 (17) and 1.9608 (15) Å, respectively. The conformations of the chelate rings were found to be envelope for the glycinates and twist-boat for the six-membered diamine (T) ring. The Ag+ cation is surrounded by six O atoms from three noncoordinated carbonyl O atoms of neighbouring 1,3-pdta groups and three water molecules. The crystal structure is stabilized by intermolecular hydrogen bonding involving the water O--H group as donor and the carboxyl O atom as acceptor. [ABSTRACT FROM AUTHOR]

The asymmetric unit of the hydrated title salt, (C10H28N4)[Cr2O7]2⋅H2O [C10H28N4 = H4(cyclam) = 1,4,8,11-tetraazoniacyclotetradecane], contains two half-cations (both completed by crystallographic inversion symmetry), two dichromate anions and one water molecule. The two [CrO7]2- anions exhibit a nearly staggered conformation, with bridging angles of 133.37 (11) and 136.28 (12)°. The distortions of the dichromate anions are due to their participation in hydrogen-bonding interactions with the water molecule and the cations. Intermolecular hydrogen bonds involving the cyclam N--H groups and water O--H groups as donor groups, and the O atoms of the dichromate anions as acceptor groups give rise to a three-dimensional network. [ABSTRACT FROM AUTHOR]

The reactions of group 4 metals (Ti, Zr, and Hf) and 2,5-dihydroxyterephthalic acid (H4dobdc) under solvothermal conditions have been systematically explored, and their major crystalline phases have been investigated by single-crystal diffractions. Ti(IV) forms a layered framework [Ti2(Hdobdc)3] where honeycomb-type sheets are interconnected through strong hydrogen bonding. Various gases are reversibly adsorbed within the straight one-dimensional channels decorated with polar O atoms, and H2 and CO2 show relatively high isosteric heats of adsorption at 6.6 and 29.4 kJ/mol, respectively. Zr(IV)- and Hf(IV)-based MOFs have also been synthesized using the same ligand and are isostructural with the formula (H3O) x [M(dobdc)(bz) x ] (M = Zr or Hf). They have a unique, nonoxo-trinuclear building block that forms a polyhedral network of 6-connected topology. Unlike the two-dimensional net of Ti, the Zr and Hf metal-organic frameworks are hydrothermally stable as unambiguously shown by variable-temperature X-ray diffraction. [ABSTRACT FROM AUTHOR]

The asymmetric unit of the title compound, [Cr(C2O4)(C10H24N4)]2[Cr2O7]·-8H2O (C10H24N4 = 1,4,8,11-tetraazacyclotetradecane, cyclam; C2O4 = oxalate, ox) contains one [Cr(ox)(cyclam)]+ cation, one half of a dichromate anion that lies about an inversion centre so that the bridging O atom is equally disordered over two positions, and four water molecules. The terminal O atoms of the dichromate anion are also disordered over two positions with a refined occupancy ratio 0.586 (6):0.414 (6). The CrIII ion is coordinated by the four N atoms of the cyclam ligand and one bidentate oxalato ligand in a cis arrangement, resulting in a distorted octahedral geometry. The Cr--N(cyclam) bond lengths are in the range 2.069 (2)-2.086 (2) Å, while the average Cr--O(ox) bond length is 1.936 Å. The macrocyclic cyclam moiety adopts the cis-V conformation. The dichromate anion has a staggered conformation. The crystal structure is stabilized by intermolecular hydrogen bonds involving the cyclam N--H groups and water O--H groups as donors, and the O atoms of oxalate ligand, water molecules and the Cr2O72- anion as acceptors, giving rise to a three-dimensional network. [ABSTRACT FROM AUTHOR]

The structure of the title compound, C21H40N4·2H2O, has been determined from synchrotron X-ray radiation data. The asymmetric unit comprises one 12-membered macropolycycle and two lattice water molecules. The macropolycycle contains two cyclohexane rings and one 1,3-diazacyclohexane ring, all in chair conformations. The C--N and C--C bond lengths are in the ranges 1.4526 (16)-1.4786 (17) and 1.517 (2)-1.5414 (17) Å, respectively. One intramolecular N--H⋯N hydrogen bond helps to stabilize the molecular conformation while medium-strength intermolecular N--H⋯O, O--H⋯N and O--H⋯O hydrogen bonds involving the lattice water molecules connect the components into a three-dimensional network. [ABSTRACT FROM AUTHOR]

The structure of the complex salt, cis-[Cr(NCS)2(cyclam)]2[Cr2O7]·H2O (cyclam = 1,4,8,11-tetraazacyclotetradecane, C10H24N4), has been determined from synchrotron data. The asymmetric unit comprises of one [Cr(NCS)2(cyclam)]+ cation, one half of a Cr2O72- anion (completed by inversion symmetry) and one half of a water molecule (completed by twofold rotation symmetry). The CrIII ion is coordinated by the four cyclam N atoms and by two N atoms of cis-arranged thiocyanate anions, displaying a distorted octahedral coordination sphere. The Cr-N(cyclam) bond lengths are in the range 2.080 (2) to 2.097 (2) Å while the average Cr-N(NCS) bond length is 1.985 (4) Å . The macrocyclic cyclam moiety adopts the cis-V conformation. The bridging O atom of the dichromate anion is disordered around an inversion centre, leading to a bending of the Cr-O-Cr bridging angle [157.7 (3)°]; the anion has a staggered conformation. The crystal structure is stabilized by intermolecular hydrogen bonds involving the cyclam N-H groups and water O-H groups as donor groups, and the O atoms of the Cr2O72- anion and water molecules as acceptor groups, giving rise to a three-dimensional network. [ABSTRACT FROM AUTHOR]

The structure of the title hybrid compound, (C6H16N2)[CrO4], has been determined from synchrotron data. The organic cation adopts a chair conformation. The inorganic CrO42- anion is slightly distorted owing to its involvement in N--H⋯O hydrogen-bonding interactions with neighbouring trans-cyclohexane-1,2-diammonium cations, whereby the two Cr--O bonds to the O atoms acting as acceptor atoms for two hydrogen bonds are slightly longer than the other two Cr--O bonds for which only one acceptor interaction per O atom is observed. In the crystal, cations and anions are packed into layers parallel to (001), held together through the aforementioned N--H⋯O hydrogen bonds. [ABSTRACT FROM AUTHOR]

In the asymmetric unit of the title compound, [CrCl2(C10H24N4)][Cr(C2O4)- (C10H24N4)](ClO4)2 (C10H24N4 = 1,4,8,11-tetraazacyclotetradecane, cyclam; C2O4 = oxalate, ox), there are two independent halves of the [CrCl2(cyclam)]+ and [Cr(ox)(cyclam)]+ cations, and one perchlorate anion. In the complex cations, which are completed by application of twofold rotation symmetry, the CrIII ions are coordinated by the four N atoms of a cyclam ligand, and by two chloride ions or one oxalate bidentate ligand in a cis arrangement, displaying an overall distorted octahedral coordination environment. The Cr--N(cyclam) bond lengths are in the range of 2.075 (5) to 2.096 (4) Å while the Cr--Cl and Cr--O(ox) bond lengths are 2.3358 (14) and 1.956 (4) Å, respectively. Both cyclam moieties adopt the cis-V conformation. The slightly distorted tetrahedral ClO4- anion remains outside the coordination sphere. The supramolecular architecture includes N--H...O and N--H...Cl hydrogen bonding between cyclam NH donor groups, O atoms of the oxalate ligand or ClO4- anions and one Cl ligand as acceptors, leading to a three-dimensional network structure. [ABSTRACT FROM AUTHOR]

The structure of the title compound, [CrCl2(tn)2]2[Cr2O7] (tn = propane-1,3-diamine; C3H10N2), has been determined from synchrotron data. The asymmetric unit contains one CrIII complex cation and half a [Cr2O7]2- anion. In the complex cation, the CrIII ion is coordinated by the four N atoms of two propane-1,3-diamine (tn) ligands in the equatorial plane and by two Cl atoms in a trans configuration, displaying a distorted octahedral coordination sphere. The two six-membered rings in the complex cation have an anti chair-chair conformation with respect to each other. The mean Cr-N(tn) and Cr-Cl bond lengths are 2.09 (1) and 2.320 (2) Å, respectively. The slightly bent dichromate anion is disordered over two sets of sites (occupancy ratio = 0.7:0.3) and has a staggered conformation. The crystal structure is stabilized by intermolecular hydrogen bonds involving the NH2 groups of the tn ligands as donors and the O atoms of the [Cr2O7]2- anion and chlorido ligands as acceptors. [ABSTRACT FROM AUTHOR]

The structure of the title compound, [(NH4)0.8K0.2][Cr(C5H7NO4)2] (C5H7NO4 is methyliminodiacetate; mida), has been determined from synchrotron data. The CrIII atom is located on a centre of symmetry and is coordinated by two N atoms and four O atoms of two facially arranged tridentate mida ligands, displaying a slightly distorted octahedral coordination environment. The Cr-N and mean Cr-O bond lengths are 2.0792 (14) and 1.958 (14) Å, respectively. The cation site is located on a twofold rotation axis and shows occupational disorder, being occupied by ammonium and potassium cations in a 0.8:0.2 ratio. In the crystal, intermolecular hydrogen bonds involving the N-H groups of the ammonium cation as donor and the two non-coordinating O atoms of the carboxylate group as acceptor groups consolidate the three-dimensional packing. [ABSTRACT FROM AUTHOR]

The asymmetric unit of the title complex salt, [Cr(C10H24N4)(NH3)2][ZnCl4]Cl•H2O, is comprised of four halves of the CrIII complex cations (the counterparts being generated by application of inversion symmetry), two tetrachloridozincate anions, two chloride anions and two water molecules. Each CrIII ion is coordinated by the four N atoms of the cyclam (1,4,8,11-tetraazacyclotetradecane) ligand in the equatorial plane and by two N atoms of ammine ligands in axial positions, displaying an overall distorted octahedral coordination environment. The Cr--N(cyclam) bond lengths range from 2.0501 (15) to 2.0615 (15) Å, while the Cr--(NH3) bond lengths range from 2.0976 (13) to 2.1062 (13) Å. The macrocyclic cyclam moieties adopt the trans-III conformation with six- and five-membered chelate rings in chair and gauche conformations. The [ZnCl4]2- anions have a slightly distorted tetrahedral shape. In the crystal, the Cl- anions link the complex cations, as well as the solvent water molecules, through N--H⋯Cl and O--H⋯Cl hydrogen-bonding inter-actions. The supramolecular set-up also includes N--H⋯Cl, C--H⋯Cl, N--H⋯O and O--H⋯Cl hydrogen bonding between N--H or C--H groups of cyclam, ammine N--H and water O--H donor groups, and O atoms of the water molecules, Cl- anions or Cl atoms of the [ZnCl4]2- anions as acceptors, leading to a three-dimensional network structure. [ABSTRACT FROM AUTHOR]

The structure of the title complex, [CrCl2(2,3,2-tet)]ClO4 (2,3,2-tet is 1,4,8,11-tetraazaundecane, C7H20N4), has been determined from synchrotron data. The CrIII ion is coordinated by the four N atoms of the 1,4,8,11-tetraazaundecane ligand in the equatorial plane and two chloride ions in an axial arrangement, displaying a slightly distorted octahedral coordination environment. The two H atoms of the secondary amines are grouped on the same side of the equatorial N4 plane (meso-RS conformation). The Cr-N bond lengths range from 2.069 (2) to 2.084 (2) Å, while the mean Cr-Cl bond length is 2.325 (2) Å. The crystal structure is stabilized by intermolecular hydrogen-bonding interactions between the primary and secondary amine groups of the 2,3,2-tet ligands, the Cl ligands and the O atoms of the perchlorate counter-anion, forming corrugated layers parallel to (010). [ABSTRACT FROM AUTHOR]

The structure of the title salt, [CrCl(C10H8N2)2(H2O)][ZnCl4], has been determined from synchrotron data. The CrIII ion is coordinated by four N atoms from two 2,2'-bipyridine (bipy) ligands, one O atom from a water molecule and a chloride anion in a cis arrangement, displaying a distorted octahedral geometry. The tetrahedral [ZnCl4]2- anion is slightly distorted owing to its involvement in O-H···Cl hydrogen bonding with the coordinating water molecule. The Cr-N(bipy) bond lengths are in the range 2.0485 (13)-2.0632 (12) Å , while the Cr-Cl and Cr-OH2) bond lengths are 2.2732 (6) and 1.9876 (12) Å, respectively. In the crystal, molecules are stacked along the a axis. [ABSTRACT FROM AUTHOR]

Crystallographic observation of adsorbed gas molecules is a highly difficult task due to their rapid motion. Here, we report the in situ single-crystal and synchrotron powder X-ray observations of reversible CO2sorption processes in an apparently nonporous organic crystal under varying pressures at high temperatures. The host material is formed by hydrogen bond network between 1,3,5-tris-(4-carboxyphenyl)benzene (H3BTB) and N,N-dimethylformamide (DMF) and by π-π stacking between the H3BTB moieties. The material can be viewed as a well-ordered array of cages, which are tight packed with each other so that the cages are inaccessible from outside. Thus, the host is practically nonporous. Despite the absence of permanent pathways connecting the empty cages, they are permeable to CO2 at high temperatures due to thermally activated molecular gating, and the weakly confined CO2 molecules in the cages allow direct detection by in situ single-crystal X-ray diffraction at 323 K. Variable-temperature in situ synchrotron powder X-ray diffraction studies also show that the CO2 sorption is reversible and driven by temperature increase. Solid-state magic angle spinning NMR defines the interactions of CO2 with the organic framework and dynamic motion of CO2 in cages. The reversible sorption is attributed to the dynamic motion of the DMF molecules combined with the axial motions/angular fluctuations of CO2 (a series of transient opening/closing of compartments enabling CO2 molecule passage), as revealed from NMR and simulations. This temperature-driven transient molecular gating can store gaseous molecules in ordered arrays toward unique collective properties and release them for ready use. [ABSTRACT FROM AUTHOR]

The article reports the synthesis, crystal structure and spectroscopic properties of the trans-anti [CR(Me,2tn)2(OH)(H2O)]-CIO4)2 to elucidate the influence of O-donor ligands occupying the axial positions and counter anion. It shows that chromium atom is in a distorted octahedral environment coordinated by 2 biidetate, 2,2-dimethyl-1,3-propanediamine ligands and 2 O atoms of hydroxy group and water molecule in trans position.

Two different 2D layered metal–organic frameworks (MOFs) have been prepared using a hexanuclear manganese metallamacrocycle and an octanuclear manganese metallamacrocycle as supramolecular building blocks viaa simple change of the solvent used and/or addition of a templating agent. While the sheets in the 2D MOF [Mn6(pshz)6(bpea)2(dma)2]n, 2(where, pshz3−is N-propionylsalicylhydrazidate, bpea is 1,2-bis(pyridyl)ethane, and dma is N,N-dimethylacetamide), built based on a hexanuclear metalladiazamacrocycle are in a staggered orientation, the sheets in the 2D MOF [Mn8(pshz)8(bpea)2(dma)4]n, 3, built based on an octanuclear metalladiazamacrocycle are in an eclipsed orientation. However, both MOFs have the same 3-connected 4.82network topology. [ABSTRACT FROM AUTHOR]

We have demonstrated a triangular assembly driven by 12 charged hydrogen bonds and π-π interactions. This assembly is stable even in polar solvents because of its charged hydrogen-bond nature. Helical arrangement of the complex is confirmed by its crystal structure. A solution structure is assigned to the D3 isomer corresponding to the solid-state structure by temperature-dependent ¹H NMR experiments. [ABSTRACT FROM AUTHOR]

By modulating the secondary building units derived from the primary building units, N-acylsalicylhydrazides (H3xshz), we have been able to construct isostructural but tunable host networks, [Mn6(xshz)6(dmf)2(bpea)2], with different cavity sizes and shapes where the secondary building units, [Mn6(xshz)6], were linked through exo-bidentate bridging ligand, 1,2-bis(pyridyl)ethane (bpea) to form 3-D networks. With a short length linear N-acyl side chain at the primary building unit, the host networks have a 3-D network with three-dimensional cavities. With an appropriate length linear N-acyl side chain at the primary building unit, the host network keeps the isostructural 3-D network but with two types of one-dimensional channels of reduced cavity volume. The tuned host networks showed not only size selectivity for the guest molecules but also shape selectivity. While the three-dimensional channeled host showed selectivity depending on the length of the podal guests, the one-dimensional channeled host showed selectivity depending on both the length and/or the podality of the guest molecules. [ABSTRACT FROM AUTHOR]

By using the tripodal tetradentate ligand tris(2-benzimidazolylmethyl)amine (H[sub 3]ntb), which can have several charge states depending on the number of secondary amine protons, mononuclear octahedral and dinuclear trigonal bipyramidal Fe(lll) complexes were prepared. The reaction of mononuclear octahedral [Fe[sup III](H[sub 3]ntb)Cl[sub 2]]ClO[sub 4], 1, with 3 equiv of sec-butylamine in methanol led to the formation of mononuclear cis-dimethoxo octahedral Fe[sup III](H[sub 2]ntb)(OMe)[sub 2], 2. One equivalent of the sec-butylamine was used to generate the monoanionic H[sub 2]ntb[sup -] ligand where one of the three amines in the benzimidazolyl groups was deprotonated. The remaining 2 equiv were used to generate two methoxides that were coordinated to the octahedral Fe(lll) ion in a cis fashion as demonstrated by the chlorides in 1. Reaction of 1 with excess (7 equiv) sec-butylamine generated the doubly deprotonated dianionic Hntb[sup 2-] that stabilized the dinudear μ-oxo Fe[sup III][sub 2]O(Hntb)[sub 2], 3, adopting a five-coordinate trigonal bipyramidal geometry. The magnetic data for 3 are consistent with the antiferromagnetically coupled Fe[sup III] (S = 5/2) sites with the coupling constant J = -127 cm[sup -1]. [ABSTRACT FROM AUTHOR]

A 3D chiral microporous metal–organic framework containing a nonanuclear cluster as a secondary building unit was prepared using a bent and rigid dicarboxylic ligand, 2,7-naphthalene dicarboxylic acid, and the zinc ion, where a nonanuclear cluster with potential exposed metal sites is in the form of a corner-sharing cyclic trimer of a tetrahedral Zn4O motif. [ABSTRACT FROM AUTHOR]

A novel S4-symmetric icosanuclear manganese metalladiazamacrocycle was synthesized using a pentadentate ligand, N-3-phenyl- trans-2-propenoylsalicylhydrazide (H3L), that has a rigid and bulky terminal N-acyl group. A 20 cyclic repeat of an -(Mn-N-N)- linkage resulted in a highly puckered diaza-bridged 60-membered icosanuclear metallamacrocycle. The steric interaction between the ligands in the cyclic system leads to five consecutive MnIII centers in a chemically different -(MnAMnBMnCMnDMnE)- environment, with the chiralities of the metal centers being in a rather complicated -(ΛΛΔΛΛ)(ΔΔΛΔΔ)- sequence. [ABSTRACT FROM AUTHOR]

We report on helical coordination networks that were prepared using a hexanuclear manganese metallamacrocycle as a helical tecton. We were able to prepare the three-dimensional helical coordination networks using a hexanuclear manganese metallamacrocycle, [Mn6(Ishz)6], as a helical tecton, where N-lauroyl salicylhydrazide (H3lshz) was used as the primary building unit to generate the helical tecton as a secondary building unit. While the 41/43 screw symmetry-linked helical coordination network was obtained when the primary building units had an N-acetyl group, both the 31/32 screw symmetry-linked and the 41/43 screw symmetry-linked helical coordination networks were obtained simultaneously in the same batch when the primary building unit had a long alkyl N-lauroyl group at the N-acetyl site. [ABSTRACT FROM AUTHOR]

The article examines the utilization of the C3-symmetric facial ligands and C4-symmetric metal ions for the preparation of truncated octahedral nanocages. The curvature needed for truncation at the octahedral vertices was accomplished using ligands with a tilted pyridyl group and a nitrogen donor atom. The nanocages have 12 ports at the edges of the truncated octahedron.

The title compound, [Ni(C6H4NO2)2(C16H38N6)], was prepared through selfassembly of a nickel(II) azamacrocyclic complex with isonicotinic acid. The Nill atom is located on an inversion center and exhibits a distorted octahedral N4O2 coordination environment, with the four secondary N atoms of the azamacrocyclic ligand in the equatorial plane [average Ni--Neq = 2.064 (11) Å] and two O atoms of monodentate isonicotinate anions in axial positions [Ni--Oax = 2.137 (1) Å]. Intramolecular N--H···O hydrogen bonds between one of the secondary amine N atoms of the azamacrocyclic ligand and the noncoordinating carboxylate O atom of the anion stabilize the molecular structure. Intermolecular N--H···N hydrogen bonds, as well as π - π interactions between neighbouring pyridine rings, give rise to the formations of supramolecular ribbons extending parallel to [001]. [ABSTRACT FROM AUTHOR]

Discrete metal-organic polyhedra (MOP) with nanosized cavities and/or clusters of MOP could be prepared when C3-symmetric facial ligands and a potential hexatopic Cu(II) ion are combined in the presence of perchlorate as a weak linker, while similar reaction conditions in the presence of a nitrate linker led to extended metal-organic frameworks made of MOP as supramolecular building blocks. [ABSTRACT FROM AUTHOR]

Two topologically different metallamacrocycles—S8 symmetric octanuclear gallium(iii) metalladiazamacrocycle and pseudo-D4 symmetric octanuclear gallium(iii) metalladiazamacrocycle—could be prepared using two similar heteroditopic bridging ligands having asymmetrical tridentate–bidentate binding residues. [ABSTRACT FROM AUTHOR]

In this article, we report Mn(II), Fe(II) and Cu(I) complexes (BIP-Mn, BIP-Fe and BIP-Cu) bearing a non-innocent, NNN pincer ligand, 4-aminoantipyrine tethered 2,6-bis(iminoantipyrine)pyridine (BIP) and structural diversity. The complexes were characterized by different spectroscopic and single-crystal X-ray analysis. Superoxide dismutase (SOD) activity has been evaluated for BIP and complexes BIP-Mn, BIP-Fe and BIP-Cu. It was observed that the sevencoordinate BIP-Mn complex showed preeminent SOD activity on comparing to BIP-Fe and BIP-Cu complexes. Besides, preliminary in vitro anticancer properties of BIP-Mn, BIP-Fe and BIP-Cu have been studied. Again, BIP-Mn complex showed stronger anticancer activity compared to ligand, BIP-Fe and BIP-Cu complexes. [ABSTRACT FROM AUTHOR]

Two distinct hydrogen-bonding modes, end-on and end-to-end coordination, have been observed in the complexation between macrocycles and polyatomic anions such as azide and oxoanions. [ABSTRACT FROM AUTHOR]

An unprecedented twofold interpenetrating (3,4)-connected topology of the Cu3L4-type metal–organic framework was prepared using N,N′,N″-tris(4-pyridinyl)-1,3,5-benzenetricarboxamide (L) as a trigonal three-connection node and the copper(ii) ion as a square planar four-connection node, where the framework contains remarkably large 1-D solvent channels. [ABSTRACT FROM AUTHOR]

Large-scale carbon fixation requires high-volume chemicals production from carbon dioxide. Dry reforming of methane could provide an economically feasible route if coke- and sintering-resistant catalysts were developed. Here, we report a molybdenum-doped nickel nanocatalyst that is stabilized at the edges of a single-crystalline magnesium oxide (MgO) support and show quantitative production of synthesis gas from dry reforming of methane. The catalyst runs more than 850 hours of continuous operation under 60 liters per unit mass of catalyst per hour reactive gas flow with no detectable coking. Synchrotron studies also show no sintering and reveal that during activation, 2.9 nanometers as synthesized crystallites move to combine into stable 17-nanometer grains at the edges of MgO crystals above the Tammann temperature. Our findings enable an industrially and economically viable path for carbon reclamation, and the “Nanocatalysts On Single Crystal Edges” technique could lead to stable catalyst designs for many challenging reactions. [ABSTRACT FROM AUTHOR]

The title compound, [Cu(NO3)2(C10H16N2O)], has been synthesized and characterized by synchrotron single-crystal diffraction at 100 K. The CuII ion has a distorted square-pyramidal coordination geometry with two N and one O atoms of the C10H16N2O ligand and one nitrate anion in the equatorial plane and another nitrate anion at the axial position. The equatorial Cu--N and Cu--O bond lengths are in the range 1.9608 (14)-2.0861 (15) Å, which are shorter than the axial Cu--Onitrate bond length [2.1259 (16) Å]. In the crystal, molecules are linked via intermolecular N--H...O and O--H...O hydrogen bonds, forming a sheet structure parallel to the bc plane. The sheets are further linked through a face-to-face π-π interaction [centroid-centroid distance = 3.994 (1) Å]. Weak intermolecular C--H...O interactions are also observed in the sheet and between adjacent sheets. [ABSTRACT FROM AUTHOR]

Hu and Ruckenstein state that our findings were overclaimed and not new, despite our presentation of evidence for the Nanocatalysts on Single Crystal Edges (NOSCE) mechanism. Their arguments do not take into account fundamental differences between our Ni-Mo/MgO catalyst and their NiO/MgO preparations. [ABSTRACT FROM AUTHOR]

A three-dimensional Mn(II) framework, [Mn2(H2L)(L)0.5(MeOH)(DEF)]·0.1MeOH·0.1DEF·1.4H2O (1; H4L = 2,3-dioxido-1,4-benzenedicarboxylic acid), was synthesized under solvothermal conditions in diethylformamide/methanol (DEF/MeOH), where the Mn centers adopt octahedral and unusual pentagonal bipyramidal geometries. The ligand H4L was subject to deprotonation to create μ4-H2L2– and μ6-L4– anionic bridges, leading to the construction of a coordination network. The MeOH exchange process of crystalline 1 allowed for another crystalline phase (1a), which reversibly returned to the original crystalline state upon resolvation in DEF/MeOH. After evacuation of 1a, the amorphous phase 1b was irreversibly formed, followed by the restoration of the original phase 1 upon resolvation in DEF/MeOH. Consequently, this framework underwent cyclic structural transformations from the crystalline (1) to crystalline (1a) to amorphous (1b) and back to crystalline (1) phase, which are unique transformations for soft coordination networks. Magnetic measurements demonstrated that antiferromagnetic interactions were operative between the Mn(II) ions and were effectively mediated by the oxygen moieties of the μ6-L4– bridge. [ABSTRACT FROM AUTHOR]

A new palladium-catalyzed asymmetric addition reaction of indoles to alkoxyallenes is reported. Remarkably, the reaction showed complete regioselectivity toward the nitrogen. A new mechanism distinct from that of conventional π-allyl chemistry is proposed to explain this unique selectivity. The utility of the reaction is demonstrated by highly efficient and flexible synthesis of N-glycosylindoles. [ABSTRACT FROM AUTHOR]

Calix[n]triazoles are developed as new derivatives in the calixarene family. Calixtriazole compounds 2-4 are synthesized using an iterative convergent strategy including an inter-/intramolecular copper(I)-catalyzed azide-alkyne cycloaddition reaction. Solid-state structures are clearly refined to give 1,2-alternate and partial cone conformations for calix[4]triazole and calix[5]triazole, respectively. Theoretical studies based on density functional theory (DFT) calculations indicated that intermolecular interactions are crucial in determining the conformers of the crystals, and the most stable conformers of calix[4]triazole, calix[5]triazole, and calix[6]triazole in the monomeric forms are 1,3-alternate, 1,3-alternate, and 1,3,5-alternate, respectively. [ABSTRACT FROM AUTHOR]

Non-interpenetrated three-dimensional (3D) metal-organic frameworks (MOFs) with both an interpenetration-favorable (3,5)-c hms topology and an interpenetration-unfavorable (3,5)-c gra topology are converted to doubly interpenetrated analogues with hms-c topology by thermal treatment, even in the absence of solvent. Depending on the conversion temperature and the properties of the pillaring ligand in the non-interpenetrated 3D MOF, which is based on two-dimensional sheets with 3-c hcb topology pillared by neutral ditopic linkers, the pillaring ligands in the interpenetrated MOFs produced are partially removed during the thermal conversions, leading to interpenetrated MOFs that simultaneously contain both micro- and mesopores. [ABSTRACT FROM AUTHOR]

Triphenylamine (TPA), a propeller-shaped optoelectronic molecule, has been used to generate stimuli-responsive smart fluorescent organic materials and correlate the effect of subtle structural changes on the molecular packing and mechanochromic fluorescence (MCF). The substituent (OCH3) position in the TPA phenyl ring and acceptors (malononitrile, cyanoacetamide, cyanoacetic acid, ethyl cyanoacetate, and diethylmalonate) strongly influenced the solid state and mechanochromic fluorescence as well as the molecular packing. The structure-property studies revealed that (i) TPA derivatives without the OCH3 substituent exhibit strong fluorescence (ϕf = 85% (TCAAD-1, 55% (TDEM)), (ii) higher dihedral angle (τ) between donor (aminophenyl) and acceptor lead to weak/non fluorescent material, (iii) substituent at the ortho position to acceptor increased the dihedral angle (τ = 26.49 (TCAAD-2), τ = 27.14 (TDMM)), and (iv) the increase of alkyl groups produced self-reversible high contrast off-on fluorescence switching materials (TDEM). Powder X-ray diffraction studies indicate that stimuli induced reversible phase transformation from crystalline to amorphous and vice versa was responsible for fluorescence switching. The computational studies also supported that OCH3 substitution at ortho to acceptor increased the dihedral angle and optical band gap. Thus, the present studies provide a structural insight for designing TPA based organic molecules for developing new smart organic materials. Stimuli responsive smart fluorescent triphenylamine derivatives have been synthesized that exhibited reversible and self-reversible mechanochromism, and nonfluorescence solids depend on the position of substitution and acceptor structure. [ABSTRACT FROM AUTHOR]

The title compound, [CuCl2(C10H16N2O)], has been synthesized and characterized by synchrotron single-crystal X-ray diffraction and FT-IR spectroscopy. The 2-methyl-2-[(pyridin-2-ylmethyl)amino]propan-1-ol (mpmapOH) ligand, including pyridine, amine and hydroxy groups, was synthesized by the reaction of 2-amino-2-methylpropan-1-ol with pyridine-2-carbaldehyde and was characterized by NMR spectroscopy. In its CuII complex, the metal ion has a distorted square-pyramidal coordination geometry with two N and one O atom of the mpmapOH ligand and one chloride anion in the equatorial plane, and the second chloride in an axial position. The bond lengths involving the CuII ion range from 1.9881 (10) to 2.0409 (9) for the Cu--N and Cu--O bonds, and from 2.2448 (5) to 2.5014 (6) Å for the equatorial and axial Cu--Cl bonds, respectively. Intermolecular hydrogen bonds (N--H...Cl and O--H...Cl) and face-to-face π-π interactions stabilize the molecular structure and give rise to a two-dimensional supramolecular structure extending parallel to (101). [ABSTRACT FROM AUTHOR]

The article provide information on the study concerning the construction of cyclic molecules in the U.S. The author infers that the construction of cyclic molecules has obtained much attention because of both scientific curiosity and their potential use in applications such as magnetic materials, sensors for small molecules, and new classes of catalysts.