Coordination chemistry of pendant aniline aza-macrocycles

The selective functionalisation of triazamacrocycles is investigated herein, with the focus on 1, 4, 7-triazacyclononane (tacn) The ligands tris (5-fluoro, 2- aminophenyl) 1, 4, 7-triazacyclononane (L1), tris (4-fluoro, 2-aminophenyl) 1,4, 7- triazacyclononane (L") and tris (3-fluoro, 2-ammophenyl) 1, 4, 7-triazacyclononane (L ) were studied. X-Ray crystal data was obtained for (L,)M (C104)2.x:MeCN where M=Mn,,/FeII/Ni"/CuII/Znn/CdII/Hgn, (L2)M (C104)2 xMeCN where M=Mn1I/Fe,I/NiII/CuII/ZnII/Cdn and (L3)M (C104)2 xMeCN where M=Mn,1/NiI,/Cun/Zn,I/Cd,,/Pb11 complexes. The (L,)Cu (C104)2 complex exhibits a rare dynamic Jahn-Teller effect in the solid state. Selected compounds exhibit an interesting capping mode by their perchlorate counterions, with threefold-hydrogen bonding through the oxygen to the amine protons. The (L3)Pb (C104)2 crystal structure exhibits a typical geometry which accommodates a stereoactive lone pair from the lead centre. The variable temperature 'H NMR of tris 1, 4, 7-(2- aminophenyl) 1, 4, 7-triazacyclononane zinc bis tetraphenylborate was carried out over 298K-193K and spectra are included within. All complexes characterized by 'H NMR, 13C NMR, 19F NMR, IR, UV and where appropriate Mossbauer spectroscopy. The investigation into the synthesis and chemistry of the novel sulphonamide pentaazamacrocycles 1 -(/-tolylsulphonyl), bis 4, 7-(2-aminophenyl) - 1, 4, 7-triazacyclononane (L4), l-(/7-methoxyphenylsulphonyl), bis 4, 7-(2- aminophenyl) -1,4, 7-triazacyclononane (L5), l-(p-fluorophenylsulphonyl), bis 4, 7-(2-aminophenyl) -1,4, 7-triazacyclononane (L6) and 1-(2-mesitylsulphonyl) bis 4, 7-(2-aminophenyl) 1, 4, 7- tnazacyclononane (L7). The complexation with differing transition metals afforded the relevant complexes and X-Ray data was obtained for (L4)Ni/Zn/Cd.MeCN (C104)2.MeCN, (L4)Pb(C104) (C104).2(MeCN), 2 (L4)Cu (C104)4,4MeCN MeOH, (L5)Ni/Zn MeCN (C104)2.MeCN, and (L6)Ni MeCN (C104)2 MeCN H20. The (L4)Zn/Hg/Pb.MeCN (C104)2 MeCN, (L5)Zn/Hg MeCN (C104)2.MeCN, (L6)Zn MeCN (C104)2 MeCN and (L7)Zn MeCN (C104)2 MeCN compounds exhibit an unusual amine pattern in the 'H NMR. This was further studied by variable temperature *H NMR over the range of 298K-418K. The (L4)Cu(C104)2 crystal structure shows two complexes of the same compounds crystallizing in the same cell, each with slightly differing dimensions, but both of square based pyramidal geometry. The (L4)Pb(C104) C104.2.MeCN crystal structure exhibits a typical geometry which accommodates a stereoactive lone pair from the lead centre The bis sulphonamide l-(2-aminophenyl)-bis 4, 7-(/xira-tolylsulphonyl) 1, 4, 7- triazacyclononane (L8) was also prepared and its complexation of L8Ni/Cu/Zn/Cd coordination chemistry expanded. The fluorinated 7V-aryl tacn class was expanded by producing bis and tris ortho meta para-fluorinated phenyl ligands. This selective methodology led to the development of a tri substituted tacn ring with meta and /wra-fluorinated aromatic rings. We report the electronic spectroscopic examination of the autocatalytic oxidative degradation of the macrocyclic aniline moiety over 120hrs. The synthesis of mono l-(5-fluoro, 2-aminophenyl) bis 4, 7, (2-aminophenyl) 1, 4, 7- tnazacyclononane (L9), and mono l-(4-fluoro, 2-aminophenyl) bis 4, 7, (2- aminophenyl) 1, 4, 7-triazacyclononane (L10) are reported. The X-Ray single crystal data was collected for (L9)Mn/Zn (C104)2 The synthesis of 1, 4-bis-(2-amino, 4-fluorophenyl) homopiperizene (Ln) and its X-Ray crystal structure of (LnNi 2 MeCN)(C104)2 is described The conversion of N, N' bis (2-aminophenyl) 1, 4-diazacycloheptane by reaction with p- toluenesulphonyl chloride afforded N, AT bis (2-tosylaminophenyl) 1, 4- diazacycloheptane (Lu). Reaction with nickel perchlorate afforded the neutral complex (L')Ni . This dianionic ligand is proposed as a porphyrin analogue

Microbial biopesticides for integrated crop management : an assessment of environmental and regulatory sustainability

Herbivorous insects and mites, plant diseases and weeds are major impediments to the production of food crops and are increasingly difficult to control with conventional chemicals. This paper focuses on microbial control agents with an emphasis on augmentation. There are marked differences in the availability of products in different countries which can be explained in terms of differences in their regulatory systems. Regulatory failure arises from the application of an inappropriate synthetic pesticides model. An understanding of regulatory innovation is necessary to overcome these problems. Two attempts at remedying regulatory failure in the UK and the Netherlands are assessed. Scientific advances can feed directly into the regulatory process and foster regulatory innovation

Swallowing Disorders in Trauma Patients: Impact of Tracheostomy

Tracheostomy is associated with increased aspiration rates, and swallowing disorders have not been well-studied in trauma patients with tracheostomy. Swallowing evaluations were conducted in 224 patients (102 trauma and 122 nontrauma patients). Half of the patients in each group had tracheostomies. Bedside swallow studies were conducted in 40 patients, videofluoroscopy swallow studies in 100 patients, and both studies in 84 patients. χ2, Fisher\u27s exact test, Cramer\u27s V, and descriptive statistics were used for data analysis. Aspiration occurred in 35 per cent (36 of 102) of trauma patients with or without tracheostomy and in 36 per cent (22 of 61) of nontrauma patients with tracheostomy. Aspiration with and without penetration was observed in 54 per cent of trauma patients (55% with tracheostomy) compared with 67 per cent of all nontrauma patients (61% with tracheostomy). Trauma patients with head injuries exhibited 41 per cent (26 of 63) aspiration and 68 per cent (43 of 63) dysphagia compared with 26 per cent (10 of 39) and 59 per cent (23 of 39) in trauma patients with other injuries. There was a lower incidence of dysphagia in trauma patients (65% versus 81% in nontrauma) and in patients with tracheostomy (71% versus 77% without tracheostomy). Tracheostomy was not associated with increased dysphagia or aspiration

Aqueous solutions of transition metal containing micelles

Incorporation of d- or f-block metals into ligand systems that renders a metal complex surface-active or drives its partitioning into surfactant phases enables the localisation of chemical functionality at interfaces. This article discusses a number of fundamental aspects of these interesting materials and examines potential applications

Structure and pulsed EPR characterization of N,N′-bis(5-tert-butylsalicylidene)-1,2-cyclohexanediamino-vanadium(IV) oxide and its adducts with propylene oxide

The role of steric hindrance in controlling the binding mode of propylene oxide to a novel vanadyl salen-type complex N,N′-bis(5-tert-butylsalicylidene)-1,2-cyclohexanediamino-vanadium(IV) oxide, [VO(3)], has been investigated using CW/pulse EPR, ENDOR and HYSCORE spectroscopy and compared to that of the parent complex N,N′-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexanediamino-vanadium(IV) oxide, [VO(1)]. The single-crystal X-ray structure of [VO(3)]·HCCl3 has been determined by X-ray analysis and is complemented by DFT calculations and circular dichroism measurements. The structure of the complex in frozen solution, as revealed by the EPR methods, is in good agreement with the X-ray and DFT analyses. Removal of the ‘inner’ tert-butyl groups from the salicylidene rings reduces the steric hindrance between the ligand and epoxide substrate. As a result the selectivity for binding single enantiomers of propylene oxide in these complexes is reversed in [VO(3)] relative to [VO(1)]