Showing papers by "Georgina M. Rosair published in 2013"
TL;DR: In this paper, a single thiocyanato bridged 1D polymeric zinc complex with dinuclear asymmetric unit was synthesized using two different Schiff bases N,N/-bis(3-methoxysalicylidenimino)-1,3-diaminopropane (L1H2) and N, N/-bis (3-ethoxyaliclyideniminos)-1.3-diagrams (L2H2), respectively.
58 citations
TL;DR: A number of structures are identified in which the Vertex-to-Centroid Distance (VCD) method suggests B/C disorder not previously recognised and some structures in which it appears that a cage C atom has been wrongly assigned.
Abstract: Replacing a boron vertex in a [BnHn]2− cluster with a smaller atom, e.g. carbon, results in the distance from that atom to the polyhedral centroid being shorter. This forms the basis of a simple but very effective method of distinguishing between B and C atoms in (hetero)carboranes that have been studied crystallographically, the Vertex-to-Centroid Distance (VCD) method. Examples of well-characterised icosahedral and sub-icosahedral closocarboranes, nidocarboranes, icosahedral metallacarboranes and supraicosahedral metallacarboranes are used to illustrate the generality of the VCD method. In this process a number of structures are identified in which the method suggests B/C disorder not previously recognised and some structures in which it appears that a cage C atom has been wrongly assigned. The largest sub-group of heterocarboranes is the family of 3,1,2-MC2B9 compounds, and for these species consideration of Exopolyhedral Ligand Orientation (ELO) can sometimes be used to quickly suggest when a literature structure is suspect in terms of cage C atom positioning. The crystal structure of one such compound, 3,3-NO3-3-PPh3-3,1,2-closo-RhC2B9H11, has been redetermined and the correct location of the cage C atoms established.
51 citations
TL;DR: The identity and activity of gold(I) catalysts in the presence of thiols and amines is investigated and all new isolated gold complexes were investigated for their catalytic activity in order to compare the level of deactivation in each species.
Abstract: Thiols and amines, which are common heteroatom nucleophiles in gold-catalysed reactions, are known to dampen the reactivity of gold catalysts. In this article, the identity and activity of gold(I) catalysts in the presence of thiols and amines is investigated. In the presence of thioacid, thiophenol and thiol, digold with bridging thiolate complexes [{Au(L)}2(μ-SR)][SbF6] are formed and have been fully characterised by NMR and X-ray crystallography. In the presence of amines and anilines, complexes [LAu-NH2R][SbF6] are formed instead. All new isolated gold complexes were investigated for their catalytic activity in order to compare the level of deactivation in each species.
28 citations
TL;DR: The tetranuclear nickel(II) complex [Ni4(OH)(L)(HL)2(CH3OH)1.5]·9H2O (1) has been synthesized by the reaction of NiCl2·6H 2O and the Schiff base ligand H3L (H3L).
25 citations
TL;DR: In this paper, a cubane-like Cu 4 O 4 subcore capped by two copper(II) atoms over opposite faces is shown to exhibit strong antiferromagnetic behavior.
15 citations
TL;DR: A high-yielding synthesis of the 13-vertex cobaltacarborane 4-Cp-4,1,12-closo-CoC(2)B(10)H(12) is described and this compound was used to prepare the known 14- Vertex species 1,14-CP(2)-1,14,2,10-closa-Co(2).
Abstract: A high-yielding synthesis of the 13-vertex cobaltacarborane 4-Cp-4,1,12-closo-CoC2B10H12 is described and this compound used to prepare the known 14-vertex species 1,14-Cp2-1,14,2,10-closo-Co2C2B10H12 (II) and 1-(p-cymene)-14-Cp-1,14,2,10-closo-RuCoC2B10H12 (IV), the latter by a new route. The related species 1,14-Cp2-2,10-Me2-1,14,2,10-closo-Co2C2B10H10 (1) and 1,14-(η-C9H7)2-1,14,2,10-closo-Co2C2B10H12 (2) are also reported. Polyhedral expansion of 4,1,8-CoC2B10 compounds affords a different isomer of the 14-vertex bimetallacarboranes, 1,14,2,9-Co2C2B10, and three examples, 1,14-Cp2-1,14,2,9-closo-Co2C2B10H12 (3), 1,14-Cp2-2,9-Me2-1,14,2,9-closo-Co2C2B10H10 (4) and 1,14-(η-C9H7)2-1,14,2,9-closo-Co2C2B10H12 (5), are prepared and characterised. Patterns in 11B NMR chemical shifts and in , the weighted average 11B chemical shift, within and between related isomers of the 14-vertex compounds II and 1–5 are discussed. Compounds II, IV, 2, 4 and 5 were studied crystallographically, with cage C atom positions in these and related bicapped hexagonal antiprismatic 1,14,2,x-M2C2B10 species analysed by the Vertex-to-Centroid Distance method.
13 citations
TL;DR: A range of molecular modelling techniques has been applied to predict optimized geometrical conformations and energies of the ring-closed oxazine form and ring-opened merocyanine forms of three azospirooxazines as mentioned in this paper.
8 citations
TL;DR: In this paper, the 11B NMR spectrum was assigned to the salt [HNEt3][7-nido-SB10H11] and its 11B X-ray diffraction was performed.
6 citations
TL;DR: An efficient, high yielding, chemo-and regioselective, five-step synthetic route to N2-Cbz-guanin-9-yl acetic acid has been developed, which avoids the use of triphosgene as discussed by the authors.
4 citations
TL;DR: The indenyl ligand conformation in 1 (cisoid between the bridgehead carbon atoms and cage heteroatoms) reveals that the structural trans effect in a phosphacarborane ligand is weakest for carbon and therefore varies in the order B > P > C as discussed by the authors.
Abstract: Two new metallaphosphacarboranes have been synthesised from [7, 8-nido-CPB9H11]– by deprotonation followed by treatment with a metal fragment. Starting with [HNMe3][7, 8-nido-CPB9H11] deprotonation and reaction with a source of {(indenyl)Co}2+ affords the η-bonded cobaltaphosphacarborane 3-(η-C9H7)-3,1,2-closo-CoCPB9H10 (1) the first “half-sandwich“ 3,1,2-metallaphosphacarborane. The indenyl ligand conformation in 1 (cisoid between the indenyl bridgehead carbon atoms and cage heteroatoms, with the cage carbon atom lying below the indenyl C–C bond) reveals that the structural trans effect in a phosphacarborane ligand is weakest for carbon and therefore varies in the order B > P > C. Starting with [HNC5H11][7, 8-nido-CPB9H11] deprotonation and reaction with half an equivalent of [Ru(p-cymene)Cl2]2 affords the σ-bonded ruthenaphosphacarborane 8-{Ru(p-cymene)Cl(C5H11N)}-7, 8-nido-CPB9H11 (2), the first example of a molecule with a phosphacarborane σ-bonded to a metal to be crystallographically characterised.
2 citations