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G Ferguson

Publications and source records attributed to G Ferguson.

At least 19 recordsLinked to original sources
PubMed2001

Hydrogen-bonded bilayers in piperazinium(2+) bis(mandelate) bis(methanol) solvate.

In the title compound, C(4)H(12)N(2)(2+).2C(8)H(7)O(3)(-).2CH(4)O, the cations lie across centres of inversion and are disordered over two orientations with equal occupancy; there are equal numbers of (R)- and (S)-mandelate anions present (mandelate is alpha-hydroxybenzeneacetate). The anions and the neutral water molecules are linked by O-H...O hydrogen bonds [O...O 2.658 (3) and 2.682 (3) A, and O-H...O 176 and 166 degrees] into deeply folded zigzag chains. Each orientation of the cation forms two symmetry-related two-centre N-H...O hydrogen bonds [N...O 2.588 (4) and 2.678 (4) A, and N-H...O 177 and 171 degrees] and two asymmetric, but planar, three-centre N-H...(O)(2) hydrogen bonds [N...O 2.686 (4)-3.137 (4) A and N-H...O 137-147 degrees], and by means of these the cations link the anion/water chains into bilayers.

Crystallography, X-Ray↗
PubMed2001

N,N'-Dimethylpiperazinium(2+) phosphonoacetate: hydrogen-bonded anion sheets containing cation-templated R(6)(6)(28) rings.

In the title compound, C(6)H(16)N(2)(2+).2C(2)H(4)O(5)P(-), the cations lie across centres of inversion; in the anions, two of the H-atom sites have 0.50 occupancy. The anions are linked by short O-H...O hydrogen bonds [O...O 2.465 (3)-2.612 (3) A and O-H...O 165-171 degrees ] into sheets of alternating R(2)(2)(12) and R(6)(6)(28) rings, both of which are centrosymmetric; the cations lie at the centres of the larger rings linked to the anion sheet by N-H...O hydrogen bonds [N...O 2.642 (2) A and N-H...O 176 degrees ].

Journal Article↗
PubMed2001

Sodium 2-nitroethanaloximate forms a layered-framework structure.

In the title compound, [Na(C(2)H(3)N(2)O(3))], the Na(+) cation lies on a centre of inversion in space group P2(1)/m and all the atoms of the anion lie on a mirror plane. Na is octahedrally coordinated by four O and two N atoms from six different anions and each anion is coordinated to six different Na(+) cations, forming chains of confacial octahedra which link the anion layers. Within these layers, the individual anions are linked by both O-H...O and C-H...O hydrogen bonds.

Journal Article↗
PubMed2001

Hydrogen-bonded adducts of ferrocene-1,1'-diylbis(diphenylmethanol): monomeric and dimeric 1:1 adducts with 1,2-bis(4-pyridyl)ethane and 1,2-diaminoethane.

In ferrocene-1,1'-diylbis(diphenylmethanol)-4,4'-ethylenedipyridine (1/1), [Fe(C(18)H(15)O)(2)].C(12)H(12)N(2), there is an intramolecular O-H...O hydrogen bond in the ferrocenediol component and a single O-H...N hydrogen bond linking the two components into a finite monomeric adduct. Ferrocene-1,1'-diylbis(diphenylmethanol)-ethylenediamine (1/1), [Fe(C(18)H(15)O)(2)].C(2)H(8)N(2), crystallizes with Z' = 2 in space group P1, and there are two independent four-component aggregates in the structure, both of which are centrosymmetric. In the first type of aggregate, the molecular components are linked by O-H...N and N-H...O hydrogen bonds, in which both diamine N atoms participate; in the second type of aggregate, the diamine component is disordered over two sets of sites, but only one N atom is involved in the hydrogen bonding.

Journal Article↗
PubMed2001

Mu-1,4-benzenedicarboxylato-bis[trans-aqua(1,4,8,11-tetraazacyclotetradecane)nickel(II)] diperchlorate forms a three-dimensional hydrogen-bonded framework.

The title compound, [Ni2(C8H4O4)(C10H24N4)2(H2O)2](ClO4)2, contains two independent octahedral Ni(II) centres with trans-NiN4O2 chromophores. The bridging benzenedicarboxylate ligand is bonded to the two Ni atoms, each via one O atom of each carboxylate, while the other O atom participates in an intramolecular N-H...O hydrogen bond, forming an S(6) motif. The cations are linked to the perchlorate anions via O-H...O and N-H...O hydrogen bonds [O...O 2.904 (6) and 2.898 (6) A; O-H...O 158 (6) and 165 (6) degrees; N...O 3.175 (7) and 3.116 (7) A; N-H...O 168 and 166 degrees ] to form molecular ladders. These ladders are linked by further O-H...O and N-H...O hydrogen bonds [O...O 2.717 (6) and 2.730 (5) A; O-H...O 170 (4) and 163 (6) degrees; N...O 3.373 (7) and 3.253 (7) A; N-H...O 163 and 167 degrees ] to form a continuous three-dimensional framework. The perchlorate anions both participate in three hydrogen bonds, and both are thus fully ordered.

Journal Article↗
PubMed2001

Ferrocenecarboxylic acid-1,4-diazabicyclo[2.2.2]octane (2/1): sheets built from O--H...N and C--H...O hydrogen bonds.

In the title compound, 2[Fe(C5H5)(C6H5O2)].C6H12N2, the molecular components are linked into finite three-component aggregates by strong O-H...N hydrogen bonds [O.N 2.578 (4) and 2.604 (5) A; O-H...N 170 (5) and 174 (6) degrees ]; these aggregates are further linked by C-H...O hydrogen bonds [C...O 3.327 (5)-3.401 (5) A; C-H...O 149-157 degrees ] into continuous sheets in the form of (6,3) nets.

Journal Article↗
PubMed2001

Hydrated salts of 3,5-dihydroxybenzoic acid with organic diamines: hydrogen-bonded supramolecular structures in two and three dimensions.

The trigonally trisubstituted acid 3,5-dihydroxybenzoic acid forms hydrated salt-type adducts with organic diamines. In 1,4-diazabicyclo[2.2.2]octane-3,5-dihydroxybenzoic acid-water (1/1/1) (1), where Z' = 2 in P2(1)/c, the constitution is [HN(CH(2)CH(2))(3)N](+).[(HO)(2)C(6)H(3)COO](-).H(2)O: the anions and the water molecules are linked by six O-H.O hydrogen bonds to form two-dimensional sheets and each cation is linked to a single sheet by one O-H.N and one N-H.O hydrogen bond. Piperazine-3,5-dihydroxybenzoic acid-water (1/2/4) (2) and 1,2-diaminoethane-3,5-dihydroxybenzoic acid-water (1/2/2) (3) are also both salts with constitutions [H(2)N(CH(2)CH(2))(2)NH(2)](2+).2[(HO)(2)C(6)H(3)COO](-).4H(2)O and [H(3)NCH(2)CH(2)NH(3)](2+).2[(HO)(2)C(6)H(3)COO](-).2H(2)O, respectively. Both (2) and (3) have supramolecular structures which are three-dimensional: in (2) the anions and the water molecules are linked by six O-H.O hydrogen bonds to form a three-dimensional framework enclosing large centrosymmetric voids, which contain the cations that are linked to the framework by two N-H.O hydrogen bonds; in (3) the construction of the three-dimensional framework requires the participation of cations, anions and water molecules, which are linked together by four O-H.O and three N-H.O hydrogen bonds.

Journal Article↗
PubMed2001

A hydrogen-bonded adduct containing seven-component supramolecular aggregates.

The title compound is a salt, 3,6,9,16,19,22-hexaazatricyclo[22.2.2.2(11,14)]triaconta-1(26),11(29),12,14(30),24,27-hexaene-3,5-dinitrobenzoic acid-methanol (1/4/2), C24H42N6(4+).4C7H3N2(O6)(-).2CH4O, in which the cation lies across a centre of inversion and one of the two independent anions is positionally disordered over two sets of atom sites having equal occupancy. The components are linked by four types of N-H...O hydrogen bond [N...O 2.674 (2)-2.815 (2) A; N-H.O 149-163 degrees] and one type of O-H...O hydrogen bond in which the acceptor is disordered over two closely adjacent sites [O...O 2.67 (4) and 2.75 (4) A; O-H...O 172 and 173 degrees], forming centrosymmetric seven-component aggregates.

Journal Article↗
PubMed2001

A three-dimensional hydrogen-bonded framework in 4,4'-trimethylenedipiperidinium-2,5-dicarboxybenzene-1,4-dicarboxylate-water (1/1/1).

The title compound is a salt, C13H28(N2)(2+).C10H4(O8)(2-).H2O. In the anion, there are two short intramolecular hydrogen bonds [O.O 2.395 (2) and 2.383 (2) A; O.H.O 175 and 172 degrees]. Pairs of anions and pairs of water molecules are linked by further O-H.O hydrogen bonds [O.O 2.756 (2) and 2.980 (2) A; O-H.O 171 and 175 degrees] into cyclic centrosymmetric R(6)(6)(16) aggregates; these aggregates are linked via the cations into a three-dimensional framework by means of four distinct N-H...O hydrogen bonds [N...O 2.787 (2)-3.204 (2) A; N-H...O 148-173 degrees].

Journal Article↗
PubMed2001

Hydrogen-bonded sheets in the 1:1 salt of tet-b and trimesic acid.

Tet-b (racemic 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane, C(16)H(36)N(4)) and trimesic acid (1,3,5-benzenetricarboxylic acid, C(9)H(6)O(6)) form a salt partially solvated by both water and methanol, i.e. 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane-1,3,5-benzenetricarboxylic acid--methanol--water (1/1/0.78/1.12), C(16)H(38)N(4)(2+) x C(9)H(4)O(6)(2-) x 0.78CH(4)O x 1.12H(2)O. The anions are linked by O--H...O hydrogen bonds [O...O 2.442 (4) and 2.458 (4) A; O--H...O 170 and 171 degrees ] into zigzag chains; orientationally disordered cations are linked to the anion chains by means of N--H...O hydrogen bonds [major orientation: N...O 2.695 (3)--3.071 (4) A, N--H...O 148--179 degrees; minor orientation: N...O 2.75 (2)--3.34 (2) A, N--H...O 147--170 degrees ] and link the chains into sheets. The solvent molecules are all disordered, but appear to play no significant structural role apart from space filling.

Journal Article↗
PubMed2001

N-Propionylhydroxylamine forms a three-dimensional hydrogen-bonded framework structure.

The title compound, N-hydroxypropanamide, C(3)H(7)NO(2), crystallizes with Z' = 3 in P2(1)/c. The molecules are linked by three N-H.O hydrogen bonds [N.O 2.8012 (16) to 2.8958 (15) A; N-H.O 163 to 168 degrees ] and by three O-H.O hydrogen bonds [O.O 2.6589 (15) to 2.6775 (17) A; O-H.O 165 to 177 degrees ] into a single three-dimensional framework.

Journal Article↗
PubMed2001

Ethane-1,2-diphosphonic acid as a building block in supramolecular chemistry; a pillared-layer framework and framework-encapsulated cations.

The 1:1 adduct of piperazine and ethane-1,2-diphosphonic acid is a salt [C(4)H(12)N(2)](2+).[C(2)H(6)O(6)P(2)](2-), in which both ions lie across centres of inversion in space group P2(1)/c. The anions are linked by a single type of O-H...O hydrogen bond [O...O, 2.562 (3) A; H...O, 1.73 A, O-H...O, 169 degrees ] into (6, 3) nets built from a single type of R(4)(4)(22) ring. The cations lie between these nets, linked to them by two types of N-H...O hydrogen bond [N...O, 2.635 (3) and 2.735 (3) A; H...O 1.72 and 1.82 A, N-H...O, 175 and 177 degrees ] such that the cations link adjacent sheets, thus forming a pillared-layer framework. The aquated adduct formed between trimethylenedipiperidine and ethane-1,2-diphosphonic acid is also a salt [C(13)H(28)N(2)](2+).[C(2)H(6)O(6)P(2)](2-).2.8[H(2)O], in which there are 12 different types of hydrogen bond, eight O-H...O and four N-H...O. The anions are linked into chains by pairs of O-H...O hydrogen bonds and these chains are linked by the water molecules into a continuous three-dimensional framework. Within the anion/water framework are large voids which contain pairs of cations, linked to the framework by N-H...O hydrogen bonds.

Journal Article↗
PubMed2001

Salts of 3,5-dinitrobenzoic acid with organic diamines: hydrogen-bonded supramolecular structures in one, two and three dimensions.

The trigonally trisubstituted carboxylic acid 3,5-dinitrobenzoic acid, (O(2)N)(2)C(6)H(3)COOH, forms 2:1 salts with a range of organic diamines L, with the general composition [LH(2)](2+) x [[(O(2)N)(2)C(6)H(3)COO](-)](2). When L is a bis-tertiary amine the hard N-H...O hydrogen bonds generate finite three-component aggregates, anion...cation...anion, and these aggregates are further linked by soft C-H...O hydrogen bonds to form one-dimensional molecular ladders when L is N,N,N',N"-tetramethyl-1,2-diaminoethane and chains of rings when L is 4,4'-dipyridylethane or 4,4'-dipyridylethene; two-dimensional sheets are formed when L is 1,4-diazabicyclo[2.2.2]octane and a three-dimensional framework is formed when L is N,N'-dimethylpiperazine. When L is the bis-secondary amine piperazine, the hard N-H...O and soft C-H...O hydrogen bonds each generate continuous motifs in the form of distinct chains of rings, the combination of which generates sheets, while when L is the bis-primary amine 1,2-diaminoethane the hard N-H...O hydrogen bonds alone generate a three-dimensional framework.

Journal Article↗
PubMed2001

Live-attenuated strains of improved genetic stability.

The current live-attenuated vaccine strains of poliovirus are genetically unstable and capable of rapid evolution in human hosts, resulting in reversion to neurovirulence and, occasionally, disease. They can also be shed by recipients for a considerable time after vaccination. This raises questions about how and when to stop vaccination after wild-type viruses have been eliminated. Persistence of vaccine revertant viruses in the population would present a risk to new cohorts of unvaccinated children and threaten the success of the eradication programme. A number of Sabin vaccine strain derivatives have been described that are, in theory, genetically more stable than the present vaccines and therefore less likely to revert to virulence. The approaches used in their derivation are outlined here and data presented for two strains showing a significant improvement in genetic stability. These strains were designed according to our understanding of the molecular basis of attenuation and incorporate changes in the sequence of an RNA structural domain that plays a key role in attenuation. They may also be less transmissible than the current type 3 vaccine strain and are potentially useful in the strategically difficult final stages of poliomyelitis eradication.

5' Untranslated Regions↗
PubMed2000

N-(6-Amino-3,4-dihydro-3-methyl-5-nitroso-4-oxopyrimidin-2-yl) derivatives of glycine, valine, serine, threonine and methionine: interplay of molecular, molecular-electronic and supramolecular structures.

In each of N-(6-amino-3, 4-dihydro-3-methyl-5-nitroso-4-oxopyrimidin-2-yl)valine, C(10)H(15)N(5)O(4) (3) (orthorhombic, P2(1)2(1)2(1)), N-(6-amino-3, 4-dihydro-3-methyl-5-nitroso-4-oxopyrimidin-2-yl)serine monohydrate, C(8)H(11)N(5)O(5).H(2)O (4) (orthorhombic, P2(1)2(1)2(1)), and N-(6-amino-3, 4-dihydro-3-methyl-5-nitroso-4-oxopyrimidin-2-yl)threonine, C(9)H(13)N(5)O(5)(5) (monoclinic, P2(1)), the C-nitroso fragments exhibit almost equal C-N and N-O bond lengths: the C-N range is 1. 315 (3)-1.329 (3) A and the N-O range is 1.293 (3)-1.326 (3) A. In each compound there are also very short intermolecular O-H.O hydrogen bonds, in which carboxyl groups act as hydrogen-bond donors to the nitrosyl O atoms: the O.O distances range from 2.440 (2) to 2. 504 (4) A and the O-H.O angles lie between 161 and 163 degrees. An interpretation of the relationship between the unusual intramolecular bond lengths and the very short intermolecular hydrogen bonds has been developed based on database analysis and computational modelling. In each of (3)-(5) there is an extensive network of intermolecular hydrogen bonds, generating three-dimensional frameworks in (3) and (5), and two-dimensional sheets in (4).

Journal Article↗