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Mume E.,Australian Nuclear Science and Technology Organisation | Mume E.,Australian National University | Lynch D.E.,Exilica Ltd | Uedono A.,University of Tsukuba | Smith S.V.,Australian Nuclear Science and Technology Organisation
Dalton Transactions | Year: 2011

Understanding how the size, charge and number of available pores in porous material influences the uptake and release properties is important for optimising their design and ultimately their application. Unfortunately there are no standard methods for screening porous materials in solution and therefore formulations must be developed for each encapsulated agent. This study investigates the potential of a library of radiotracers (nuclear sensors) for assessing the binding properties of hollow silica shell materials. Uptake and release of Cu2+ and Co2+ and their respective complexes with polyazacarboxylate macrocycles (dota and teta) and a series of hexa aza cages (diamsar, sarar and bis-(p-aminobenzyl)-diamsar) from the hollow silica shells was monitored using their radioisotopic analogues. Coordination chemistry of the metal (M) species, subtle alterations in the molecular architecture of ligands (Ligand) and their resultant complexes (M-Ligand) were found to significantly influence their uptake over pH 3 to 9 at room temperature. Positively charged species were selectively and rapidly (within 10 min) absorbed at pH 7 to 9. Negatively charged species were preferentially absorbed at low pH (3 to 5). Rates of release varied for each nuclear sensor, and time to establish equilibrium varied from minutes to days. The subtle changes in design of the nuclear sensors proved to be a valuable tool for determining the binding properties of porous materials. The data support the development of a library of nuclear sensors for screening porous materials for use in optimising the design of porous materials and the potential of nuclear sensors for high through-put screening of materials. © 2011 The Royal Society of Chemistry.


Smith G.,Queensland University of Technology | Lynch D.E.,Exilica Ltd.
Acta Crystallographica Section E: Crystallographic Communications | Year: 2015

The anhydrous salts of 2-(1H-indol-3-yl)ethanamine (tryptamine) with isomeric (2,4-dichlorophenoxy)acetic acid (2,4-D) and (3,5-dichlorophenoxy)acetic (3,5-D), both C10H13N2 +·C8H5Cl2O3 - [(I) and (II), respectively], have been determined and their one-dimensional hydrogen-bonded polymeric structures are described. In the crystal of (I), the aminium H atoms are involved in three separate inter-species N-H⋯O hydrogen-bonding interactions, two with carboxylate O-atom acceptors and the third in an asymmetric three-centre bidentate carboxylate O,O' chelate [graph set R1 2 (4)]. The indole H atom forms an N-H·Ocarboxylate hydrogen bond, extending the chain structure along the b-axis direction. In (II), two of the three aminium H atoms are also involved in N-HOcarboxylate hydrogen bonds similar to (I) but with the third, a threecentre asymmetric interaction with carboxylate and phenoxy O atoms is found [graph set R1 2 (5)]. The chain polymeric extension is also along b. There are no π - π ring interactions in either of the structures. The aminium side-chain conformations differ significantly between the two structures, reflecting the conformational ambivalence of the tryptaminium cation, as found also in the benzoate salts.


Santos P.F.,University of Trás os Montes e Alto Douro | Reis L.V.,University of Trás os Montes e Alto Douro | Almeida P.,University of Beira Interior | Lynch D.E.,Exilica Ltd
CrystEngComm | Year: 2011

The crystal structures of 4-[(3-hexylbenzoselenazol-3-ium-2-yl)methylidene] -2-[(3-hexyl-3H-benzoselenazol-2-ylidene)methyl]-3-oxocyclobut-1-en-1-olate and its analogues substituted at the squaric ring with O-methyl, NH-methyl and N,N-diethylamino groups have been determined using single crystal X-ray crystallography techniques. The unsubstituted squaraine dye is symmetrical and packs as a stepped ribbon array (via a C-H⋯O close interaction), which is in contrast to the slip-stacked arrangements observed in similar squaraine analogues. Each of the substituted analogues is asymmetric and pack in slightly differing slip-stacked charge-transfer columns. The NH-methyl analogue packs with a single water molecule per squaraine unit. © 2011 The Royal Society of Chemistry.


Smith G.,Queensland University of Technology | Lynch D.E.,Exilica Ltd
Acta Crystallographica Section C: Crystal Structure Communications | Year: 2013

The crystal structures of the anhydrous products from the interaction of 5-(4-bromophenyl)-1,3,4-thiadiazol-2-amine with 2-(naphthalen-2-yloxy)acetic acid, viz. the 1:1 adduct C8H6BrN3S· C12H10O3, (I), and with 3,5-dinitrobenzoic acid, viz. the salt 2-amino-5-(4-bromophenyl)-1,2,4-thiadiazol-3-ium 3,5-dinitrobenzoate, C8H7BrN3S +·C7H3N2O6 -, (II), have been determined. In adduct (I), a heterodimer is formed through a cyclic hydrogen-bonding motif [graph set R2 2(8)], involving carboxylic acid-heteroatom O - H⋯N and amine-carboxylic acid N - H⋯O interactions. The heterodimers are essentially planar, with a thiadiazole-to-naphthalene ring dihedral angle of 15.9 (2)° and an intramolecular thiadiazole-to-benzene ring angle of 4.7 (2)°. An amine-heteroatom N - H⋯N hydrogen bond between the heterodimers generates a one-dimensional chain structure extending down [001]. Also present are weak benzene-benzene and naphthalene-naphthalene π-π stacking interactions down the b axis [minimum ring-centroid separation = 3.936 (3) Å]. With salt (II), the cation-anion association is also through a cyclic R2 2(8) motif but involving duplex N - H⋯Ocarboxylate hydrogen bonds, giving a heterodimer that is close to planar [dihedral angles between the thiadiazole ring and the two benzene rings = 5.00 (16) (intra) and 7.23 (15)° (inter)]. A secondary centrosymmetric cyclic (8) N - H⋯Ocarboxylate hydrogen-bonding association involving the second amino H atom generates a heterotetramer. Also present in the crystal structure are weak π-π interactions between thiadiazolium rings [minimum ring-centroid separation = 3.9466 (18) Å], as well as a short Br⋯Onitro interaction [3.314 (4) Å]. The two structures reported here now provide a total of three crystallographically characterized examples of cocrystalline products from the interaction of 5-(4-bromophenyl)-1,3,4- thiadiazol-2-amine with carboxylic acids, of which only one involves proton transfer. © 2013 International Union of Crystallography.


Lynch D.E.,Exilica Ltd
Metals | Year: 2015

Pyrrolyl squaraines, both dyes and polymers, were first reported in 1965 and since then a fascinating body of work has been produced investigating the chemistry of these interesting molecules. A major aspect of these molecules that makes them so appealing to those researchers who have contributed to this field over the last 50 years is their chemical versatility. In this review, subjects, such as the synthetic history, an understanding of the molecular structure, an overview of the optical properties, a discussion of both the electrical conduction properties, and magnetic properties, plus use of the particles of pyrrolyl squaraines, are presented. Furthermore, previously published results are not just presented; they are in certain cases collated and used to both highlight and explain important aspects of pyrrolyl squaraine chemistry. © 2015, by the authors.


Smith G.,Queensland University of Technology | Lynch D.E.,Exilica Ltd.
Acta Crystallographica Section E: Crystallographic Communications | Year: 2015

The anhydrous salts morpholinium (tetrahydro-2-H-1,4-oxazin-4-ium) phenoxyacetate, C4H10NO+·C8H7O3 -, (I), morpholinium (4-fluorophenoxy)acetate, C4H10NO+·C8H6 FO3 -, (II), and isomeric morpholinium (3,5-dichlorophenoxy)acetate (3,5-D), (III), and morpholinium (2,4-dichlorophenoxy)acetic acid (2,4-D), C4H10NO+·C8H5Cl2O3 -, (IV), have been determined and their hydrogen-bonded structures are described. In the crystals of (I), (III) and (IV), one of the the aminium H atoms is involved in a three-centre asymmetric cation-anion N - H⋯O,O′ R1 2(4) hydrogen-bonding interaction with the two carboxyl O-atom acceptors of the anion. With the structure of (II), the primary N - H⋯O interaction is linear. In the structures of (I), (II) and (III), the second N - H⋯Ocarboxyl hydrogen bond generates one-dimensional chain structures extending in all cases along [100]. With (IV), the ion pairs are linked though inversion-related N - H⋯O hydrogen bonds [graph set R4 2(8)], giving a cyclic heterotetrameric structure.


Lynch D.E.,Exilica Ltd | Cox M.,Coventry University
Dyes and Pigments | Year: 2015

Eight metal complexes of dual-pendant sulfonate bis(indolenine)squaraines (four d-transition metals and four f-transition metals) have been prepared and examined as fluorescent probes for solution protein determination. Of the eight, the cobalt-squaraine complex exhibited the highest fluorescence response in the presence of protein (in aqueous solution) and the partial determination of its crystal structure meant that it could be examined further and compared against the previously determined bis-piperidinium and bis-morpholinium squaraine species. Comparative examination of these three variants in water, 10 mM phosphate buffer (pH = 7.0), and 10 mM Tris/HCl buffer (pH = 7.0) led to the conclusion that the use of Tris/HCl buffer resulted in less reduction of fluorescence intensity (over that of water alone) than the more widely used phosphate buffer. © 2015 Elsevier Ltd.All rights reserved.


Patent
Exilica Ltd | Date: 2013-02-27

The present invention provides the use of a hollow particulate glass as a support for an active agent, characterised in that said hollow particulate glass is produced by pyrolysis of glass-coated polymer particles which are produced by copolymerising an unsaturated heterocyclic monomer and squaric acid,wherein said polymer has the structure:


Smith G.,Queensland University of Technology | Lynch D.E.,Exilica Ltd
Acta Crystallographica Section C: Structural Chemistry | Year: 2014

The two-dimensional polymeric structures of the caesium complexes with the phenoxyacetic acid analogues (4-fluorophenoxy)acetic acid, (3-chloro-2- methylphenoxy)acetic acid and the herbicidally active (2,4-dichlorophenoxy) acetic acid (2,4-D), namely poly[[μ5-(4-fluorophenoxy)acetato][μ4-(4- fluorophenoxy)acetato]dicaesium], [Cs2(C8H 6FO3)2]n, (I), poly[aqua[μ 5-(3-chloro-2-methylphenoxy)acetato]caesium], [Cs(C9H 8ClO3)(H2O)]n , (II), and poly[[μ7-(2,4-dichlorophenoxy)acetato][(2,4-dichlorphenoxy)acetic acid]caesium], [Cs(C8H5Cl2O3)(C 8H6Cl2O3)]n, (III), are described. In (I), the Cs+ cations of the two individual irregular coordination polyhedra in the asymmetric unit (one CsO7 and the other CsO8) are linked by bridging carboxylate O-atom donors from the two ligand molecules, both of which are involved in bidentate chelate O carboxy, Ophenoxy interactions, while only one has a bidentate carboxylate O,O'-chelate interaction. Polymeric extension is achieved through a number of carboxylate O-atom bridges, with a minimum Cs⋯Cs separation of 4.3231(9)Å, giving layers which lie parallel to (001). In hydrated complex (II), the irregular nine-coordination about the Cs+ cation comprises a single monodentate water molecule, a bidentate O carboxy, Ophenoxy chelate interaction and six bridging carboxylate O-atom bonding interactions, giving a Cs⋯Cs separation of 4.2473(3)Å. The water molecule forms intralayer hydrogen bonds within the two-dimensional layers, which lie parallel to (100). In complex (III), the irregular centrosymmetric CsO6Cl2 coordination environment comprises two O-atom donors and two ring-substituted Cl-atom donors from two hydrogen bis[(2,4-dichlorophenoxy)acetate] ligand species in a bidentate chelate mode, and four O-atom donors from bridging carboxyl groups. The duplex ligand species lie across crystallographic inversion centres, linked through a short O-H⋯O hydrogen bond involving the single acid H atom. Structure extension gives layers which lie parallel to (001). The present set of structures of Cs salts of phenoxyacetic acids show previously demonstrated trends among the alkali metal salts of simple benzoic acids with no stereochemically favourable interactive substituent groups for formation of two-dimensional coordination polymers. © 2014 International Union of Crystallography.


Grant
Agency: GTR | Branch: Innovate UK | Program: | Phase: Feasibility Study | Award Amount: 74.44K | Year: 2013

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