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Your search keyword '"Papaefstathiou, G. S."' showing total 19 results
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19 results on '"Papaefstathiou, G. S."'

2. A 1-D coordination polymer based on a Mn-40 octagonal super-structure

Author

Manoli, M., Inglis, R., Manos, M. J., Papaefstathiou, G. S., Brechin, E. K., and Tasiopoulos, A. J.

Subjects
complexes, wheels, aggregate, family, layered networks, clusters, single-molecule magnets, dy, ln
Abstract

A 1-D coordination polymer, constructed using a combination of diols and phenolic oximes, contains a novel [Mn-9] sub-unit, a nanosized [Mn-40] octagonal super-structure and a [Mn-21] repeating unit. Chemical Communications

Published
2013

3. New Zn2+ Metal Organic Frameworks with Unique Network Topologies from the Combination of Trimesic Acid and Amino-Alcohols

Author

Manos, M. J., Moushi, E. E., Papaefstathiou, G. S., and Tasiopoulos, A. J.

Subjects
coordination polymers, complexes, secondary building units, carboxylate frameworks, zinc, ionothermal synthesis, single-molecule magnets, crystal-structures, imidazolate frameworks, gas-storage
Abstract

A series of new Zn2+-trimesate (btc(3-)) metal organic frameworks (MOFs) has been isolated in the presence of various amino-alcohols under solvothermal conditions. Thus, the reaction of ZnCl2 with trimesic acid (H(3)btc) and the amino alcohols triethanolamine (teoa), 2(hydroxymethyl)piperidine (hmpip), N-tert-butyldiethanolamine (tbdeoa), 1,4-bis(2-hydroxyethyl)piperazine (bhep), N-methyldiethanolamine (mdeoa), or 4-(2-hydroxyethyl)morpholine (hem) in a 1.6:1:5.6 molar ratio in DMF afforded compounds (teoaH)(2)[Zn(btc)(1.33)] (MOAAF-1) (MOAAF = metal organic amino-alcohol framework), (NH2Me2)(2)(hmpipH)[Zn-3(btc)(3)] (MOAAF-2), (NH2Me2)-(tbdmaH)(2)[Zn-3(btc)(3)] (MOAAF-3) (tbdma = N-tert-butyl-dimethylamine), (NH2Me2)(bhepH(2))[Zn-3(btc)(3)] (MOAAF-4), (NH2Me2) [Zn-4(btc)(3)(mdeoa)(2)] (MOAAF-5), and (NH2Me2)[Zn-4(btc)(3)(hem)(2)] (MOAAF-6), respectively. The compounds display 3D structures with relatively large cavities (4-10 angstrom) and high potential solvent-accessible areas (38-68% of the unit cell volumes). A number of novel structural features are revealed in the reported MOFs, such as unprecedented dinuclear [Zn-2(COO)(5)](-1) secondary building units (SBUs) and unique network topologies (e.g., in compounds MOAAF-2, MOAAF-3, MOAAF-5, and MOAAF-6). The amino-alcohols employed played a key role for the appearance of such novel structural features in MOAAF 1-6 since they were found to act as bases responsible for the deprotonation of H(3)btc, templates, and chelating ligands. Specifically, most of the compounds synthesized were shown to be templated by protonated amino alcohols that are involved in hydrogen bonding interactions with the frameworks, whereas in two cases (compounds MOAAF-5 and MOAAF-6) the amino alcohols acted as chelating ligands affecting significantly the underline topology of the MOFs. The thermal stability and photoluminescence properties of the MOFs are also discussed. This work represents the initial systematic investigation on the use of combination of amino alcohols and polycarboxylate ligands for the synthesis of new MOFs, demonstrating it as a powerful synthetic strategy for the isolation of novel MOFs. Crystal Growth & Design

Published
2012

4. A flexible Cd2+ metal organic framework with a unique (3,3,6)-connected topology, unprecedented secondary building units and single crystal to single crystal solvent exchange properties

Author

Kyprianidou, E. J., Papaefstathiou, G. S., Manos, M. J., and Tasiopoulos, A. J.

Subjects
storage, state, sorption properties, family, chemistry, ligand, imidazolate frameworks
Abstract

A new flexible Cd2+ metal organic framework (MOF), denoted as UCY-3, which is the second example of a MOF with the ligand H3CIP [H3CIP = 5-(4-carboxybenzylideneamino)isophthalic acid], is reported. It shows a unique (3,3,6)-connected topology and is based on a neutral non-oxo triangular [Cd-3(COO)(6)] secondary building unit that appears for the first time in MOFs chemistry. UCY-3 displays significant structural flexibility, capability for exchange of the guest solvents by various organic molecules in a single-crystal-to-single-crystal fashion as well as breathing capacity allowing the incorporation of relatively large amount of benzene into its pores. Overall this work indicates that MOFs based on semi-rigid polytopic ligands may adopt unprecedented structural types and exhibit unexpectedly high absorption capacities for relatively bulky organic molecules, as a result of their flexibility and breathing capability. Crystengcomm

Published
2012

5. A Highly Porous Interpenetrated Metal-Organic Framework from the Use of a Novel Nanosized Organic Linker

Author

Manos, M. J., Markoulides, M. S., Malliakas, C. D., Papaefstathiou, G. S., Chronakis, N., Kanatzidis, M. G., Trikalitis, P. N., and Tasiopoulos, A. J.

Subjects
porosity, catalysis, adsorption, design, crystals, surface-area, imidazolate frameworks, hydrogen storage, gas-storage, capacities
Abstract

The initial use of a novel elongated tricarboxylic acid H(3)hmpib in metal-organic framework (MOF) chemistry resulted in a [Zn(4)O(hmpib)(2)] MOF (UCY-1) with pyrite topology. The compound displays a remarkably high internal surface area despite its double-interpenetrated structure as well as high CO(2) uptake and selective adsorption for it over CH(4). Inorg Chem

Published
2011

10. Toward a Reactant Library in Template-Directed Solid-State Organic Synthesis:  Reactivity Involving a Monofunctional Reactant Based on a Stilbazole

Author

MacGillivray, L. R., Reid, J. L., Ripmeester, J. A., and Papaefstathiou, G. S.

Abstract

Cocrystallization of 4-chlorostilbazole (4-Cl-sbz) with either resorcinol (res) or 4-ethylresorcinol (4-Et-res) yields three-component molecular assemblies, (res)·2(4-Cl-sbz) and (4-Et-res)·2(4-Cl-sbz), held together by two O−H···N hydrogen bonds. The olefins of each assembly conform to the distance criterion of Schmidt for [2+2] photoreaction. In the former, the olefins lie antiparallel, whereas in the latter, the olefins lie parallel. Both solids are photoactive, leading to the regiocontrolled solid-state synthesis of rctt-1,2-bis(4-pyridyl)-3,4-bis(4-chlorophenyl)cyclobutane (4-Cl-dpcb) in near or quantitative yield. The photoactivity of (res)·2(4-Cl-sbz) is attributed to the reactant undergoing a pedal-like change in conformation prior to cyclobutane formation. The ability to change the diol to achieve olefin alignment is expected to provide additional synthetic flexibility to this template approach.

Published
2002

11. Discrete versus Infinite Molecular Self-Assembly:  Control in Crystalline Hydrogen-Bonded Assemblies Based on Resorcinol

Author

Papaefstathiou, G. S. and MacGillivray, L. R.

Abstract

Cocrystallization of 1,2-bis(4-pyridyl)ethane (4,4‘-bipyeth) with resorcinol (res), 4-chlororesorcinol (4-Cl-res), and 4,6-dichlororesorcinol (4,6-di-Cl-res) yields molecular solids (4,4‘-bipyeth)·(res) 1a, 2(4,4‘-bipyeth)·2(4-Cl-res) 1b, and 2(4,4‘-bipyeth)·2(4,6-di-Cl-res) 1c with components held together by O−H···N hydrogen bonds. In 1a the components form an infinite 1D polar array, whereas in 1b and 1c the components form 0D four-component complexes. Formation of the discrete assemblies is attributed to peripheral steric effects, which block the solid-state polymerization.

Published
2001

16. A Rod-Shaped Guest Leads to Architectural Isomerism in a Multicomponent Crystalline Framework Based on a Resorcin[4]arene

Author

MacGillivray, L. R., Papaefstathiou, G. S., Reid, J. L., and Ripmeester, J. A.

Abstract

Cocrystallization of C-methylcalix[4]resorcinarene 1 with 4,4‘-bipyridine 2 in the presence of 4-bromobiphenyl (4-brbp) yields a molecular solid, of composition 3d·(4-brbp), [where 3d = 1·2(2)], in which 1 assembles with 2 to form a one-dimensional hydrogen-bonded polymer 3d that includes two copies of the biphenyl, within elliptical cavities of dimensions ~ 11 × 7 × 6 Å, as guests. The framework 3d represents a third architectural isomer of three previously reported supramolecular isomers of the parent material 3.

Published
2001

18. Exploiting modularity in template-controlled synthesis: a new linear template to direct reactivity within discrete hydrogen-bonded molecular assemblies in the solid state.

Author

Papaefstathiou GS, Kipp AJ, and MacGillivray LR

Abstract

Co-crystallization of 1,8-naphthalenedicarboxylic acid (1,8-nap) with trans-1,2-bis(n-pyridyl)ethylene (n,n'-bpe) (n = 2 or 4) yields a discrete four-component molecular assembly, 2(n,n'-bpe).2(1,8-nap) 1, that is held together by four O-H...N hydrogen bonds where the dicarboxylic acid, serving as a linear template, directs alignment of olefins in the solid state for [2 + 2] photoreaction.

Published
2001
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19. Reactivity in polynuclear transition metal chemistry as a means to obtain high-spin molecules: substitution of mu 4-OH- by eta 1,mu 4-N3- increases nine times the ground-state S value of a nonanuclear nickel(II) cage.

Author

Papaefstathiou GS, Escuer A, Vicente R, Font-Bardia M, Solans X, and Perlepes SP

Abstract

The reaction of di-2-pyridyl ketone, (2-py)2CO, with Ni(O2CMe)(2).4H2O yields the cage [Ni9(OH)2(O2CMe)8((2-py)2CO2)4], which reacts further with N3- ions to give the structurally similar cluster [Ni9(N3)2(O2CMe)8((2-py)2CO2)4] containing extremely rare eta 1,mu 4-N3- groups; magnetic studies reveal that the spin ground state of the latter is nine times the ground state of the former.

Published
2001
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