A 15-vertex heteroborane.
Explore the source record for details and available documents.
Journal Article↗
Biomedical subjects
Georgina M Rosair
Publications and source records attributed to Georgina M Rosair.
Supramolecular binding of protonated amines to a receptor microgel in aqueous medium.
Polyanionic microgels containing negatively charged tetrazole binding sites show supramolecular binding of various protonated amines (e.g. dibucaine and spermine) in a competitive aqueous medium at millimolar concentration.
Amines↗
Weak metamagnetic-like 1D manganese(II) complex with a double mu(1,1)-azido bridge: a structure and magnetic study.
The azido-bridged manganese complex of formula [Mn(tptz)(mu(1,1)-N3)2]n [1; tptz = 2,4,6-tris(2-pyridyl)-1,3,5-triazine] has been synthesized and characterized by single-crystal X-ray diffraction analysis and a low-temperature magnetic study. The complex 1 crystallizes in the orthorhombic space group Pbcn, with a = 17.911(5) A, b = 15.804(5) A, c = 6.6538(18) A, and Z = 4. The Mn atoms are coordinated by three N atoms of the tptz ligands and connected to each other by double end-on (EO) azide ligands, forming a neutral 1D chain. The adjacent 1D chains are connected by face-to-face pi-pi-stacking interactions and C-H...pi interactions of pyridine rings of the tptz ligands, which leads to the formation of a supramolecular 2D sheet structure. Temperature- and field-dependent magnetic analyses reveal dominant intrachain ferromagnetic interactions with EO azide-bridge and weak interchain antiferromagnetic interactions with overall metamagnetic behavior having 3D magnetic ordering at 2.7 K. The critical field is approximately 80 G, at which the interlayer antiferromagnetic ground-state switches to a ferromagnetic state.
Journal Article↗
Unusually weak binding interactions in tetrazole-amidine complexes.
[reaction: see text] Tetrazoles frequently replace carboxylic acids in pharmaceutical drugs. However, while the binding modes of tetrazolate and carboxylate anions in amidinium complexes turns out to be similar, the association constant of the former is 2-3 orders of magnitude smaller in DMSO. Crystal structures revealed that the N...H-N hydrogen bonds in amidinium tetrazolates are bent (162 degrees and 169 degrees ) and noticeably longer (N...N 2.96 A) than corresponding hydrogen bonds in both amidinium carboxylates and ammonium tetrazolates.
Journal Article↗
A tuneable self-complexing molecular switch.
[reaction: see text] A new self-complexing donor-acceptor system has been synthesized that has the propensity to undergo intramolecular decomplexation under thermal and electrochemical perturbation and upon addition of a competitive guest for the cyclophane's cavity.
Journal Article↗
The synthesis and characterisation of 4,1,2-MC2B10 metallacarboranes.
Reduction of the tethered carborane 1,2-(CH2)3-1,2-closo-C2B10H10 followed by treatment with CoCl2/NaCp, [(p-cymene)RuCl2]2(p-cymene=C6H4MeiPr-1,4), (PMe2Ph)2PtCl2 or (dppe)NiCl2(dppe=Ph2PCH2CH2PPh2) affords reasonable yields of the new 13-vertex metallacarboranes 1,2-(CH2)3-4-Cp-4,1,2-closo-CoC2B10H10 (1), 1,2-(CH2)3-4-(p-cymene)-4,1,2-closo-RuC2B10H10 (2), 1,2-(CH2)3-4,4-(PMe2Ph)2-4,1,2-closo-PtC2B10H10 (3) and 1,2-(CH2)3-4,4-(dppe)-4,1,2-closo-NiC2B10H10 (4), respectively. All compounds were characterised spectroscopically and crystallographically. The cobalt and ruthenium species 1 and 2 have Cs symmetry in both solution and the solid state, having henicosahedral cage structures featuring a trapezoidal C1C2B9B5 face. The platinum and nickel compounds 3 and 4 have asymmetric docosahedral cage structures in the crystal (the more so for 4 than for 3) although both appear, by 11B and 31P NMR spectroscopy, to have Cs symmetry in solution. Low-temperature experiments on the more soluble platinacarborane could not freeze out the diamond-trapezium-diamond fluctional process that we assume is operating in solution, and we therefore conclude that this process has a relatively low activation barrier, probably <35 kJ mol-1.
Journal Article↗
Synthetic, spectroscopic, computational and structural studies of some 13-vertex ruthenacarboranes.
Reduction of 1,2-closo-C2B10H12 followed by treatment with [RuCl2(p-cymene)]2(p-cymene = C6H4MeiPr-1,4) affords the 13-vertex ruthenacarborane 4-(p-cymene)-4,1,6-closo-RuC2B10H12, characterised both spectroscopically and, in two crystalline forms, crystallographically. Although asymmetric in the solid state, having a docosahedral cage architecture with cage C atoms at vertices 1 and 6, this species clearly has Cs symmetry on the NMR timescale at room temperature. However, the fluctional process in operation can be arrested at low temperature, and an activation energy of 43.1 kJ mol(-1) is estimated. A computational study of the related species 4-(eta-C6H6)-4,1,6-closo-RuC2B10H12 reveals that the fluctionality is due to a double diamond-square-diamond process, first suggested by Hawthorne et al for the analogous CpCo species. These calculations yield an activation energy of 40.4 kJ mol(-1), in excellent agreement with that derived from experiment. Reduction of 1,2-Ph(2)-1,2-closo-C2B10H10 followed by treatment with [RuCl2(eta-C6H6)]2 or [RuCl2(p-cymene)]2 yields the analogous species 1,6-Ph2-4-(eta-C6H6)-4,1,6-closo-RuC2B10H10 and 1,6-Ph2-4-(p-cymene)-4,1,6-closo-RuC2B10H10, respectively. These C,C-diphenyl compounds were again studied spectroscopically and crystallographically, the p-cymene species again showing two crystalline modifications. In contrast to their CpCo and Cp*Co analogues all three ruthenacarboranes do not undergo isomerisation in refluxing toluene.
Journal Article↗
Isolation of a new two-dimensional honeycomb carbonato-bridged copper(II) complex exhibiting long-range ferromagnetic ordering.
Atmospheric CO2 fixation by an aqueous solution containing Cu(ClO4)2.6H2O and 4-aminopyridine (4-apy) yields a novel example of a two-dimensional mu3-CO3 bridged copper(II) complex {[Cu(4-apy)2]3(mu3-CO3)2(ClO4)2.(1/2)CH3OH}n that has been characterized by IR, UV and X-ray crystallography; preliminary magnetic measurements show that complex exhibits long-range ordered ferromagnetic coupling.
Carbonates↗
Fourteen-vertex homo- and heterobimetallic metallacarboranes.
Reduction of 4-(p-cymene)-4,1,12-closo-RuC2B10H12 followed by metallation with {M'} fragments (M' = {CpCo2+}, {(arene)Ru2+} or {(dppe)Ni2+}) affords 14-vertex bimetallic 1,14,2,10-RuM'C2B10 species having bicapped hexagonal antiprismatic structures.
Journal Article↗
The first 4,1,10-MC2B10 supraicosahedral metallacarboranes and a route to previously inaccessible 4,1,12-ruthenium arene species.
Reduction of 1,12-closo-C2B10H12 or its C,C-dimethyl analogue with sodium in liquid ammonia followed by metallation with {CpCo}2+, {(arene)Ru}2+ or {(dppe)Ni}2+ fragments affords the first examples of 4,1,10-MC2B10 species; thermolysis of these yields the appropriate 4,1,12-MC2B10 isomers, unavailable for (arene)Ru metallacarboranes by similar thermolysis of known 4,1,6-MC2B10 compounds.
Journal Article↗
Crystal engineering with heteroboranes. III. 2-Carboxy-1-methoxymethyl-1,2-dicarba-closo-dodecaborane(12).
The title compound, 1-CH(2)OCH(3)-2-COOH-1,2-closo-C(2)B(10)H(10) or C(5)H(16)B(10)O(3), forms a discrete centrosymmetric tetramer, via hydrogen bonding, involving two inner and two outer carborane molecules. One conventional eight-membered hydrogen-bonded ring [graph set R(2)(2)(8)] is formed between two carboxylic acid groups of the inner carboranes. This interaction is then supplemented by an open finite hydrogen bond (graph set D) between the ether O atom of the inner carborane and the carboxylic acid H atom of the outer carborane.
Journal Article↗
Crystal engineering with heteroboranes. II. 1,2-Dicarboxy-1,2-dicarba-closo-dodecaborane(12) ethanol hemisolvate.
The title compound, 1,2-(COOH)(2)-1,2-closo-C(2)B(10)H(10).0.5C(2)H(6)O or C(4)H(12)B(10)O(4).0.5C(2)H(6)O, forms a tetramer by incorporating ethanol (solvent) molecules through hydrogen bonding. Two eight-membered rings [graph set R(2)(2)(8)] are formed by hydrogen bonding between two carboxylic acid groups, whereas two ten-membered rings [R(3)(3)(10)] are formed by hydrogen bonding between two carboxylic acid groups and the OH group of an ethanol molecule (solvent). Two crystallographically independent tetramers are present in the crystal structure.
Journal Article↗
C.I. Pigment red 266.
C.I. Pigment Red 266, or 4-[[4-(aminocarbonyl)phenyl]hydrazono]-N-(2-methoxyphenyl)-3-oxo-3,4-dihydronaphthalene-2-carboxamide, C(25)H(20)N(4)O(4), adopts the keto-hydrazone tautomeric form with significant intramolecular hydrogen bonding. The molecules pack to form layers involving an extensive network of intermolecular hydrogen bonds, in which the primary amide group plays a prominent role. The good technical performance of this pigment in application may be attributed principally to the pattern of intra- and intermolecular hydrogen bonding.
Journal Article↗
Beyond the icosahedron: the first 13-vertex carborane.
Explore the source record for details and available documents.
Journal Article↗
Cyclodextrin-derived host molecules as reversal agents for the neuromuscular blocker rocuronium bromide: synthesis and structure-activity relationships.
A series of mono- and per-6-substituted cyclodextrin derivatives were synthesized as synthetic receptors (or host molecules) of rocuronium bromide, the most widely used neuromuscular blocker in anaesthesia. By forming host-guest complexes with rocuronium, these cyclodextrin derivatives reverse the muscle relaxation induced by rocuronium in vitro and in vivo and therefore can be used as reversal agents of the neuromuscular blocker to assist rapid recovery of patients after surgery. Because this supramolecular mechanism of action does not involve direct interaction with the cholinergic system, the reversal by these compounds, e.g., compound 14 (Org 25969), is not accompanied by cardiovascular side effects usually attendant with acetylcholinesterase inhibitors such as neostigmine. The structure-activity relationships are consistent with this supramolecular mechanism of action and are discussed herein. These include the effects of binding cavity size and hydrophobic and electrostatic interaction on the reversal activities of these compounds.
Androstanols↗
[5-Bromo-N-(2-carboxylatophenyl)salicylideniminato]dimethyltin(IV).
The structure of the title dimethyltin(IV) complex, [2-(5-bromo-2-oxidobenzylideneamino)benzoato-kappa3O,N,O']dimethyltin(IV), [Sn(CH(3))(2)(C(14)H(8)BrNO(3))], features centrosymmetric dimers disposed about a central Sn(2)O(2) core. Each Sn centre has seven-coordinate pentagonal-bipyramidal geometry, taking into account two moderately long Sn-O contacts about an inversion centre [2.679 (4) and 2.981 (4) A]. The methyl groups are in an axial orientation.
Journal Article↗
The first supraicosahedral p-block metallacarboranes.
Reaction of Na2[7,9-C2B10H12] or its C-dimethyl analogue with SnCl2 in THF affords 4,1,6-closo-SnC2B10H12 or 1,6-Me2-4,1,6-closo-SnC2B10H10 respectively, the first 13-vertex metallacarboranes involving p-block metals; spectroscopic, structural and theoretical studies, including an analysis of fluctionality in solution, are reported.
Journal Article↗