Showing papers by "Alan Davison published in 1988"
TL;DR: In this article, a neutral complex (TcO(emaR)) was crystallized as a monohydrate, and a single-crystal X-ray structure determination was performed.
Abstract: General methods for the preparation of ligands of the type R'SCH/sub 2/CONHCH/sub 2/CH/sub 2/NHCOCH/sub 2/SR, H/sub 2/ema(R)(R'), where R = alkyl, aminoalkyl, and carboxyalkyl and R' = H, benzoyl, acetamidomethyl, and benzamidomethyl are described. New methods for the protection and deprotection of thiols with triphenylmethyl and amidomethyl groups have been developed. These ligands have been reacted with (Bu/sub 4/N)(TcOCl/sub 4/) and Na(TcO(eg)/sub 2/) (eg = ethylene glycolato), and for the cases where R = Me, CH/sub 2/Ph,(CH/sub 2/)/sub 10/COOH, and CH/sub 2/CH/sub 2/(NC/sub 4/H/sub 8/O), neutral complexes, (TcO(emaR)), have been isolated and characterized. The complex (TcO(ema(CH/sub 2/CH/sub 2/NC/sub 4/H/sub 8/O))) was crystallized as a monohydrate, and a single-crystal X-ray structure determination was performed. For all of the (TcO(ema(CH/sub 2/CH/sub 2/NR/sub 2/))) complexes, an intramolecular dealkylation occurred to cleanly form (TcO(ema))/sup /minus//, which can be isolated as the AsPh/sub 4//sup +/ salt. Furthermore, (TcO(ema(CH/sub 2/Ph))) and (TcO(ema(Me))) were reacted with amines, water, and halides to give the dealkylated products. Crystal data for C/sub 12/H/sub 20/N/sub 3/O/sub 4/S/sub 2/Tc/center dot/H/sub 2/O: monoclinic, a = 12.120 (1) /angstrom/, b = 7.172 (1) /angstrom/, c = 18.933 (2) /angstrom/, /beta/ = 94.29 (1)/degree/, V = 1641.1 /angstrom//sup 3/, space group = P2/sub 1//n (No.more » 14), Z = 4, R = 0.042, R/sub w/ = 0.055. 34 references, 3 figures, 3 tables.« less
64 citations
TL;DR: The trioxotechnetium(VII) diolate complexes TcO 3 Cl(AA) (AA = phen, bpy, 5-NO 2 -phen, 3,4,7,8-Me 4 -phen) cleanly oxidize olefins (C 2 R 4 ) in solution at 22°C, forming in high yields the corresponding oxotechnetsium(V) dolate complexes, T cOCl(OCR 2 CR 2 O)(AA) as mentioned in this paper.
44 citations
TL;DR: In this paper, the authors describe the preparation and structure of cristalline de complexes Tc(SC 10 H 13 ) 3 (CH 3 CN) 2, Tc[SC 10H 13 ] 3 (CO) (C 5 H 5 N)
Abstract: Preparation et structure cristalline de complexes Tc(SC 10 H 13 ) 3 (CH 3 CN) 2 , Tc(SC 10 H 13 ) 3 (CO)(CH 3 CN) et Tc(SC 10 H 13 ) 3 (CO)(C 5 H 5 N)
33 citations
TL;DR: In this paper, two general routes for the preparation of technetium complexes with aromatic amine, chloride, and alkoxide ligands are presented, and the same isomer appears to result from either route.
Abstract: Two general routes for the preparation of technetium complexes with aromatic amine, chloride, and alkoxide ligands are presented. The reactions of the tetrachlorooxotechnetate(V) anion of (n-Bu{sub 4}N)(TcOCl{sub 4}) with pyridine in tetrahydrofuran/alcohol solvent or of the dioxotetrakis(pyridine)technetium(V) cation of (TcO{sub 2}(py){sub 4})Cl with LiCl in sulfuric acid/alcohol both yield a neutral alkoxydichlorooxobis(pyridine)technetium(V) complex. The same isomer appears to result from either route. The analogous thiazole derivatives may be prepared in a like manner. The complex chloro(1,2-ethanediolato)oxo(1,10-phenanthroline)technetium(V), TcOCl(C{sub 2}H{sub 4}O{sub 2})(C{sub 12}H{sub 8}N{sub 2}), is prepared from (n-Bu{sub 4}N)(TcOCl{sub 4}) with 1,2-ethanediol and 1,10-phenanthroline in methanol. This complex was characterized by ir, uv/vis, and {sup 1}H and {sup 99}Tc NMR spectroscopies and by fast atom bombardment mass spectrometry. Further insight into the bonding in this complex comes from the single-crystal x-ray structure determination. The space group is monoclinic, P2{sub 1}/c, with a = 7.440 (2) {angstrom}, b = 8.928 (3) {angstrom}, c = 21.355 (4) {angstrom}, {beta} = 92.48 (2){degree}, V = 1417.2 (7) {angstrom}{sup 3}, and Z = 4. The structure was solved by standard methods and refined to R = 0.051 and R{sub w} = 0.036 based on 1859 reflections. The oxo and chloride ligands are mutually cis inmore » the highly distorted octahedral coordination sphere. The unusually long Tc-Cl bond length (2.418 (2) {angstrom}) is attributed to a trans influence exerted by the coordinated diolate. This effect combined with short lengths for the C-C bond (1.491 (1) {angstrom}) and for the O-Tc-O linkage (1.924 (4), 1.902 (3) {angstrom}) suggests partial multiple bonding between the technetium and the diolate. 38 references, 2 figures, 3 tables.« less
25 citations
TL;DR: A range of diamagnetic complexes with technetium in valence states of +1 to +7 have been studied, and the results of some studies as discussed by the authors were reported, such as the resonance of a Tc(I) complex, (Tc(CNBu/sup t/)/sub 6/), was measured with several different spectrometers and was found to be /minus/1914 ppM.
Abstract: A range of diamagnetic complexes with technetium in valence states of +1 to +7 has been studied, and the results of some studies on technetium(I) complexes are reported. The resonance of a Tc(I) complex, (Tc(CNBu/sup t/)/sub 6/), was measured with several different spectrometers and was found to be /minus/1914 ppM. The spectra of more than 20 different analogs with substituted isocyanides have been measured, and all were found to fall within 50 ppM of the tert-butyl derivative. A great deal of difference in the resonance values reported for the Tc(I) complex, (Tc(dmpe)/sub 3/)/sup +/ (dmpe = 1,2-bis(dimethylphosphino)ethane) is noted. Results of studies of a mixed sample of (NH/sub 4/)(Tc/sub 4/) and (Tc(dmpe)/sub 3/)(PF/sub 6/) noted that the observed resonance attributable to pertechnetate is in the region of 500 ppM. 14 references, 1 figure.
15 citations
TL;DR: In this paper, the reaction of [TcNOCL4]− with acetylacetone was found to give the complex TcNO(acac)Cl3]−, which has been fully characterised by X-ray crystallography and FAB− Mass spectrometry.
10 citations
TL;DR: A cholesterol derivative was incorporated into small unilamellar phospholipid vesicles, and antibodies were bound covalently to the vesicle, showing good antibody activity and specificity.
1 citations
TL;DR: In this paper, two general routes for the preparation of technetium complexes with aromatic amine, chloride, and alkoxide ligands are presented, and the same isomer appears to result from either route.
Abstract: Two general routes for the preparation of technetium complexes with aromatic amine, chloride, and alkoxide ligands are presented. The reactions of the tetrachlorooxotechnetate(V) anion of (n-Bu{sub 4}N)(TcOCl{sub 4}) with pyridine in tetrahydrofuran/alcohol solvent or of the dioxotetrakis(pyridine)technetium(V) cation of (TcO{sub 2}(py){sub 4})Cl with LiCl in sulfuric acid/alcohol both yield a neutral alkoxydichlorooxobis(pyridine)technetium(V) complex. The same isomer appears to result from either route. The analogous thiazole derivatives may be prepared in a like manner. The complex chloro(1,2-ethanediolato)oxo(1,10-phenanthroline)technetium(V), TcOCl(C{sub 2}H{sub 4}O{sub 2})(C{sub 12}H{sub 8}N{sub 2}), is prepared from (n-Bu{sub 4}N)(TcOCl{sub 4}) with 1,2-ethanediol and 1,10-phenanthroline in methanol. This complex was characterized by ir, uv/vis, and {sup 1}H and {sup 99}Tc NMR spectroscopies and by fast atom bombardment mass spectrometry. Further insight into the bonding in this complex comes from the single-crystal x-ray structure determination. The space group is monoclinic, P2{sub 1}/c, with a = 7.440 (2) {angstrom}, b = 8.928 (3) {angstrom}, c = 21.355 (4) {angstrom}, {beta} = 92.48 (2){degree}, V = 1417.2 (7) {angstrom}{sup 3}, and Z = 4. The structure was solved by standard methods and refined to R = 0.051 and R{sub w} = 0.036 based on 1859 reflections. The oxo and chloride ligands are mutually cis inmore » the highly distorted octahedral coordination sphere. The unusually long Tc-Cl bond length (2.418 (2) {angstrom}) is attributed to a trans influence exerted by the coordinated diolate. This effect combined with short lengths for the C-C bond (1.491 (1) {angstrom}) and for the O-Tc-O linkage (1.924 (4), 1.902 (3) {angstrom}) suggests partial multiple bonding between the technetium and the diolate. 38 references, 2 figures, 3 tables.« less
TL;DR: In this paper, a neutral complex (TcO(emaR)) was crystallized as a monohydrate, and a single-crystal X-ray structure determination was performed.
Abstract: General methods for the preparation of ligands of the type R'SCH/sub 2/CONHCH/sub 2/CH/sub 2/NHCOCH/sub 2/SR, H/sub 2/ema(R)(R'), where R = alkyl, aminoalkyl, and carboxyalkyl and R' = H, benzoyl, acetamidomethyl, and benzamidomethyl are described. New methods for the protection and deprotection of thiols with triphenylmethyl and amidomethyl groups have been developed. These ligands have been reacted with (Bu/sub 4/N)(TcOCl/sub 4/) and Na(TcO(eg)/sub 2/) (eg = ethylene glycolato), and for the cases where R = Me, CH/sub 2/Ph,(CH/sub 2/)/sub 10/COOH, and CH/sub 2/CH/sub 2/(NC/sub 4/H/sub 8/O), neutral complexes, (TcO(emaR)), have been isolated and characterized. The complex (TcO(ema(CH/sub 2/CH/sub 2/NC/sub 4/H/sub 8/O))) was crystallized as a monohydrate, and a single-crystal X-ray structure determination was performed. For all of the (TcO(ema(CH/sub 2/CH/sub 2/NR/sub 2/))) complexes, an intramolecular dealkylation occurred to cleanly form (TcO(ema))/sup /minus//, which can be isolated as the AsPh/sub 4//sup +/ salt. Furthermore, (TcO(ema(CH/sub 2/Ph))) and (TcO(ema(Me))) were reacted with amines, water, and halides to give the dealkylated products. Crystal data for C/sub 12/H/sub 20/N/sub 3/O/sub 4/S/sub 2/Tc/center dot/H/sub 2/O: monoclinic, a = 12.120 (1) /angstrom/, b = 7.172 (1) /angstrom/, c = 18.933 (2) /angstrom/, /beta/ = 94.29 (1)/degree/, V = 1641.1 /angstrom//sup 3/, space group = P2/sub 1//n (No.more » 14), Z = 4, R = 0.042, R/sub w/ = 0.055. 34 references, 3 figures, 3 tables.« less