0000000000024057
AUTHOR
Michael B. Hursthouse
A new series of π-extended tetrathiafulvalene derivatives incorporating fused furanodithiino and thienodithiino units: a joint experimental and theoretical study
A new family of tetrathiafulvalenes has been prepared. The materials exhibit complex redox behaviour related to the electronic influence of the 1,4-dithiin moieties embedded within the framework of the molecules. The X-ray crystal structure of compound 4 reveals an unusual non-planar conformation of the heterocyclic compound, with the TTF fragment adopting a boat conformation. Theoretical calculations, performed at the DFT level (B3P86/6-31G*), confirm the boatlike structure (C2v symmetry) as the most stable conformation for this family of tetrathiafulvalenes. Upon oxidation, electrons are extracted from the whole molecule and the radical cations and dications remain highly distorted from p…
Synthesis and characterisation of polymeric metal-ion carboxylates from benzene-1,3,5-tricarboxylic acid with Mn(II), Co(II) or Zn(II) and 2,2-bipyridyl, phenanthroline or a pyridyl-2-(1-methyl-1H-pyrazol-3-yl) derivative
A total of 13 new co-ordination solids have been prepared of composition [Co(HBTC)(PHEN)(H2O)] (12), [Mn-3(BTC)(2)(PHEN)(3)] (13), [Mn(HBTC)(6)(H2O)] (14), [Mn(HBTC)(7)(H2O)] (15), [Zn-3(BTC)(2)(6)(3)(H2O)(3)]. 4H(2)O (16), [Zn-(HBTC)(6)(H2O)] (17), [Zn(H2BTC)(2)(6)] (18), [Zn(HBTC)(7)(H2O)] (19), [Zn(HBTC)(8)(H2O)] (20), [Zn-2(HBTC)(2)(9)(2)]. 2H(2)O (21), [Zn(HBTC)(10)(H2O)].H2O (22), [Co(HBTC)(10)(H2O)].H2O (23) and [Co(HBTC)(11)(H2O)] (24) 6 = pyridine-2-(1-methyl-1H-pyrazol-3-yl); 7 = pyridine-2-(1-methyl-4-bromo-1H-pyrazol-3-yl); 8 = pyridine-2-(1-methyl-4-nitro-1H-pyrazol-3-yl); 9 = pyridine-2-(1-methyl-5-trifluoromethyl-1H-pyrazol-3-yl); 10 = pyridine-2-(1-methyl-5-tert-butyl-1H-pyr…
Experimental and theoretical studies into the structural perturbations between neutral, oxidised and reduced forms of 1,4-dithiinoquinoxaline derivatives
The syntheses and electrochemistry of thieno[3',4'r5,6][1,4]dithiino[2,3-b]quinoxaline (9), 2,3-bis(methylsulfanyl)[1,4]dithiino[2,3-b]quinoxaline (16) and 2,3-ethylenedisulfanyl[1,4]dithiino[2,3-b]quinoxaline (17) are reported, together with the X-ray crystal structures of 9, 16 and the charge-transfer complex 9.TCNQ. In the thieno derivative 9, the molecular structure undergoes a significant change from a boat conformer to a planar system, upon oxidation with TCNQ. Theoretical calculations show that oxidation leads to planarisation of the molecular structure due to the aromatisation of the dithiine moiety. The study of the oxidised/reduced species helps to rationalise the electrochemical …
Triazolopyridines. 14. Substitution reactions of 7-amino[1,2,3]triazolo[1,5-a]pyridines.
Abstract Reaction between 7-aminotriazolopyridines 1 or 2 and sulphuric acid gives hydroxyalkylpyridines 3 and 4 ; bromination gives brominated pyridine 5 or triazolopyridine 6. The anions from amines 1 or 2 are ambident, acylating on N but alkylating on N or on C6; in the latter case triazolylalkenylcyanides 16 – 20 or the 6,6-dialkylated derivative 19 are obtained. An X-ray diffraction study has confirmed structure 19.
A remarkable rearrangement during reaction between triazolopyridinium ylides and dimethyl acetylenedicarboxylate
Abstract The ylides from 2-acylmethyltriazolopyridinium salts ( 1 ) react with dimethyl acetylenedicarboxylate in toluene solution to give the 7-pyrroleninylpyrazolo[1,5-a]pyridines ( 5 ).
New Tetrahydro-1,2,4,5-Tetrazinan-3-Ones and Oxoverdazyl Free Radicals
A series of tetrahydro-1,2,4,5-tetrazinan-3-ones have been prepared by the reaction of carbonic acid bis (1-methylhydrazide) with aromatic aldehydes. These were oxidised to oxoverdazyl free radicals and used immediately for ESR spectroscopy studies that indicate that the unpaired electron is delocalised over the verdazyl ring. The ESR spectra can be very well simulated considering hyperfine couplings with the four nitrogen atoms of the verdazyl ring and the six hydrogen atoms of the two methyl groups bonded to it.