Sonja Abram

Synthesis and characterization of indium(III) complexes with tri- and pentadentate thiosemicarbazones. Crystal and molecular structure of [InCl2(HDAPTSC)] · 2 DMSO, {O[In(HDAPTSC)(OH)]2} · 5MeOH, [InCl2(APTSC)(MeOH)], [In(APTSC)2]PF6 and (H2APTSC)][InCl(APTSC)(mnt)] · 0.5 H2O (H2DAPTSC = 2,6-diacetylpyridine-bis(thiosemicarbazone), HAPTSC = 2-acetylpyridine-thiosemicarbazone, mnt2 = 1,2-dicyanoethene-1,2-dithiolate)

Abstract The synthesis and characterization of novel indium(III) complexes with pyridine-thiosemicarbazone ligands are reported as well as ligand exchange reactions on the products. 2,6-Diacetylpyridine-bis(thiosemicarbazone), C5H3N(C3N3SH6)2 (H2DAPTSC), and 2-acetylpyridine-thiosemicarbazone, C5H4N(C3N3SH6) (HAPTSC), were reacted with indium(III) halides and indium(III) nitrate, respectively, to give [InX2(HDAPTSC)], {O[In(HDAPTSC)(OH)]2}, [InX2(APTSC)(MeOH)] and [In(APTSC)2]PF6.

Ligand exchange reactions starting from [Re(CO)3Br3]2−. Synthesis, characterization and structures of rhenium(I) tricarbonyl complexes with thiourea and thiourea derivatives

The anionic rhenium(I) complex fac-[Re(CO)3Br3]2− has been reacted with thiourea (tu), N,N-dialkylbenzoylthioureas (HR2btu) and N,N-dialkylthiocarbamoylbenzamidines (HR12tcbR2) to give novel mono- and binuclear rhenium(I) complexes. All new compounds are air-stable and non-sensitive against aqueous media. Fac-[Re(CO)3(tu)3] (NO3) is formed from the bromo complex by precipitation of AgBr after addition of AgNO3 and subsequent reaction with thiourea. The compound co-crystallizes with one molecule of (Et4N) NO3 in the monoclinic space group P21/n,a = 143675(3), b = 13.372(1), c = 28.841 (7) A, s = 102.53(1)°, Z = 8. The mean ReS bond length is 2.529 A. N,N-Dialkylbenzoylthioureas react with (Et4N)2[Re(CO)3)Br3] to form neutral [Re(CO)3Br(HR2btu)] complexes. With the rhenium(I) centers under study they coordinate bidentately, but without deprotonation, which is unusual for this class of chelate ligands. [Re(CO)3Br(HEt2btu)] crystallizes in the triclinic space group P1, a = 8.080(2), b = 9.254(3), c = 13.761(5) Aα = 76.60(2), s = 88.66(2), γ = 70.92(3)°, Z = 2. The chelate ring shows significant deviations from planarity which underline the absence of an extended π-system. Complexes of different composition are formed with thiocarbamoylbenzamidines depending on the sterical requirements of the individual ligands. A binuclear compound could be isolated with N,N-diethylthiocarbamoylbenzamidinate (Et2tcbH−). [Re2(CO)6−(Et2tcbH)2] crystallizes in the monoclinic space group P21/c, a = 10.859(4), b = 17.409(2), c = 9.159(5) A, s = 79.15(2)°, Z = 2. Both rhenium atoms are coordinated by three facially arranged carbonyls and a singly deprotonated Et2tcbH− ligand. The sulfur atoms of these ligands act as bridges between the metal centers forming a four-membered Re2S2 ring. Two slightly different ReS bond lengths are observed in this ring system (2.507(2) and 2.545(2) A). Only a mononuclear, anionic complex is formed with the more bulky benzamidine ligand N(N-morpholinylthiocarbonyl)-N′-phenylbenzamidine (Hmorphtcbph). (Et4N) [Re(CO)3Br(morphtcbph)] crystallizes in the triclinic space group P1, a = 10.018(4), b = 10.065(4), c = 16.720(7) A, α = 80.90(3), s = 79.82(3), γ = 70.81(4)°, Z = 2. The rheniumsulfur distance is 2.476(2) A.

Application of technetium and rhenium carbonyl chemistry to nuclear medicine. Preparation of [NEt4]2[TcCl3(CO)3] from [NBu4][TcO4] and structure of [NEt4][Tc2(μ-Cl)3(CO)6]; structures of the model complexes [NEt4][Re2(μ-OEt)2(μ-OAc)(CO)6] and [ReBr({-CH2S(CH2)2Cl}2)(CO)3]

A detailed investigation of the one-pot synthesis of [NEt4]2[MX3(CO)3] [M=Tc (1a) or Re (1b); X= Cl−, Br−] is presented. The intermediates [NEt4][Tc2-(μ-Cl)3(CO)6] (2a), [NBu4][Tc3(μ3-H)(μ-H)3(CO)9] (3) and [Tc3(μ-H)3(CO)12] (4) have been isolated and characterized. The X-ray structure of (2a) is described. Complex (2a) crystallizes in the monoclinic space group P21/c with a=19.491(6), b=18.323(2) and c=17.497(9)AÅ, and β=97.59(2)°. Quantitative conversion of (2a), (3) and (4) into the aqua-ion [M(OH2)3(CO)3]+ [M=Tc (5a) or Re (5b)] is described. To evaluate an optimal and simple chelating group for the “fac-M(CO)3” moiety, the reaction with the bidentate thioether ligand Cl(CH2)2S(CH2)2S(CH2)2Cl (qyp) has been investigated and the structure of the neutral complex [ReBr(qyp)(CO)3] (6) is described. Complex (6) crystallizes in the monoclinic space group P21/c with a=15.935(6), b=2.788(4) and c= 7.955(10)AÅ, and β=98.57(1)°. To extend the knowledge about substitution chemistry of organometallic complexes in aqueous solution, the acetato ligand [OOCCH3]− has been reacted with (1b), resulting in the formation of the dinuclear, acetato-bridged complex [NEt4][Re2(μ-OH)2(μ-OAc)(CO)6], which converted into [Re2(μ-OEt)2(μ-OAc)(CO)6]− (7) after recrystallization from EtOH. The X-ray structure of (7) has been determined. Complex (7) crystallizes in the monoclinic space group P21/c with a=16.288(3), b=12.4272(10) and c=13.620(3)AÅ, and β=76.63(1)°. For a future application of the small “fac-M(CO)3” moiety, it seems thus advantageous to combine these two ligand groups in one simple chelating function.

Steps towards [(C5Me5)TcO3]: Novel synthesis of [(C5Me5)Tc(CO)3] from [{Tc(μ3−OH)(CO)3}4] and oxidation of [(C5Me5)M(CO)3] (M = Tc, Re) with Br2

Abstract [NEt4]2[Tc(Cl)3(CO)3] was prepared directly from [NBu4][TcO4]. Dissolution of [NEt4]2[Tc(Cl)3(CO)3] in water yielded the aqua ion [Tc(OH2)3(CO)3]+ which, upon titration with 1 eq. of OH−, gave the tetranuclear complex [{Tc(μ3-OH)(CO)3}4] in quantitative yield and of which the structure could be elucidated. Reaction of [{Tc(μ3−OH)(CO)3}4] with HC5Me5 gave the important starting material [(C5Me5)M(CO)3] (M = Tc, Re). To achieve complexes in higher oxidation states with the C5Me5− ligand, oxidation was performed with [Br2] for the rhenium and the corresponding technetium complex. Oxidation in trifluoroacetic acid yielded cis/trans-[(C5Me5)M(Br)2(CO)2] (M = Tc, Re). Oxidation in dichloromethane gave in both cases the seven co-ordinate, 18e− M(III) complex [(C5Me5)MBr(CO)3]+. The structure of the rhenium complex was elucidated. It was found that oxidation took place at the metal centre and the C5Me5− ring to yield [(CO)3M(μ−Br)3M(CO)3] as the counterion.

Indium(III) complexes with tridentate nitrogen donor ligands. Synthesis, characterization and crystal structure of complexes with pyridine-2,6-bis(acetyloxime) and 2,6-bis(1-phenyliminoethyl)pyridine

Abstract 2,6-Bis(acetyloxime)pyridine, 2,6-C5H3N(C2H3NOH)2 (L1), reacts with indium(III) chloride in methanol to give the seven-coordinate complex [InCl3(L1)(MeOH)]. The structurally similar Schiff base ligand 2,6-bis(1-phenyliminoethyl)pyridine (L2), 2,6-C5H3N(C2H3NC6H5)2, however, forms a six-coordinate indium(III) complex of the composition [InCl3(L2)]. The InN bond distances are longer by 0.03–0.12 A in the seven-coordinate compound compared with those in the Schiff base complex. The MeOH ligand in [InCl3(L1)(MeOH)] can be replaced by Cl− or H2O to give the complex anion [InCl4(L1)]− and [InCl3(L1)(OH2)], respectively. The pentagonal-bipyramidal coordination environment of the metal is preserved during these reactions.

Rhenium(V) and technetium(V) complexes with N-[2(1H-pyrolylmethyl)]-N'-(4-pentene-3-one-2)ethane 1,2-diaminate (C12H16N3O, MRP 20). X-ray crystal structures of H3MRP 20 and TcO(MRP 20)

Synthesis of N-[2(1H-pyrolylmethyl)]-N′-(4-pentene-3-one-2)ethane-1, 2-diamine has been effected and the compound characterised by X-ray diffraction. Crystal data for C12H19N3O: space group P21/c: a=10.358(3), b=7.953(1), c=15.640(4) A, β=101.63(1)°, V=1261(2) A3 to give Z=4 for D=1.165 g cm−3. Structure solution and refinement based on 2114 reflections converged at R=0.064, Rw=0.079. Reaction of this molecule with Bu4N[TcO(ethylene glycolate)2] results in the formation of a neutral technetium(V) complex [TcOL]. The X-ray structure of this complex confirms a five-coordinate, square based pyramidal geometry with no crystallographic axes of symmetry. Crystal data: orthorhombic space group P212121; a=11.701(1), b=14.949(2), c=7.516(1) A, V=1314.6 A3 to give Z=4 for D=1.68 g cm−3. Structure resolution and refinement based on 2115 reflections converged at R=0.037, Rw=0.033. Reaction of N-[2(1H-pyrolylmethyl)]-N′-(4-pentene-3-one-2)ethane-1,2-diamine with rhenium(V) oxotrichlorobistriphenylphosphine [ReOCl3(PPh3)2] or a rhenium(V) glycolato precursor yields the [ReOL] complex. The compounds have been studied by NMR, UVVis, IR spectroscopy as well as by mass spectrometry. The obtained results have been discussed in terms of the complex formation and the different transition metals.

Mixed-ligand complexes of indium(III). Reactions of [InCl3(L1)(MeOH)] with bidentate ligands. Synthesis, characterization and X-ray structures of [In(L1)Cl(ox)(OH2)]·2H2O, [In(L1)Cl(mnt)]·MeOH and [In(pythio)3] [L1 = pyridine-2,6-bis(acetyloxime), ox2− = oxalate, mnt2− = 1,2-dicyanoethene-1,2-dithiolate, pythio− = pyridine-2-thiolate]

[InCl 3 (L 1 )(MeOH)] [L 1 = pyridine-2,6-bis(acetyloxine), 2,6-C 5 H 3 N(C 2 H 3 NOH) 2 ] reacts with bidentate ligands by ligand exchange. A seven-coordinate complex of the composition [In(L 1 )Cl(ox)(OH 2 )] is formed with potassium oxalate (K 2 ox). The oxalato ligand occupies the equatorial plane of a pentagonal bipyramid together with the tridentate amine oxime. With sodium 1,2-dicyanoethene-1,2-dithiolate (Na 2 mnt) the analogous reaction produces a six-coordinate mixed ligand complex, [In(L 1 )Cl(mnt)], which has a distorted octahedral coordination sphere. Ligands which form four-membered chelate rings like dialkyldithiocarbamates, R 2 dtc − , or pyridine-2-thiolate, pythio − , are able to replace all ligands of [InCl 3 (L 1 )(MeOH)] to form neutral tris chelates. The structure of [In(pythio) 3 ] has been elucidated showing a strong distortion of the coordination polyhedron from the idealized octahedral geometry.

Mixed-ligand complexes of technetium Part XI. Nitridotechnetium complexes with tri- and tetradentate azomethines. X-ray molecular and crystal structure of [N-(2-ethoxycarbonyl-3-oxo-but-1-en(1)yl)-2-aminophenolato](triphenylphosphine)nitridotechnetium(V), TcN(ecbap)(Ph3P)

Diamagnetic nitridotechnetium(V) complexes with tri- and tetradentate azomethine ligands which possess electron withdrawing groups in their periphery can be prepared starting from TcNCl 2 (Ph 3 P) 2 or (in the case of the tetradentate ligands) TcNX 4 − (X = Cl, Br). The products are air stable compounds which have been characterized by elemental analysis, infrared and UV-Vis spectroscopy, NMR and mass spectrometry. The mixed-ligand complex [ N -(2-Ethoxycarbonyl-3-oxo-but-l-en(1)yl)-2-aminophen- olato](triphenylphosphine)nitridotechnetium(V) (C 31 H 28 N 2 O 4 PTc, M r = 622.5) crystallizes monoclinic in the space group C 2/ c . The coordination geometry is a distorted square pyramid with the nitrido ligand at the apex.

113mIn chelate complexes—I. In vitro investigations on a series of alkylvaried dithiocarbamato complexes with 113mIn

Abstract A series of 7 indiumdialkyldithiocarbamates (R = ethyl, n-propyl, i-propyl, n-butyl, i-butyl, (CH 2 ) 5 , (CH 2 ) 2 O(CH 2 ) 2 ) has been prepared by reacting InCl 3 with aqueous solutions of the ligands. The products have been investigated at various concentration levels. The properties of the products at the lower concentration levels have been studied by thin-layer chromatography, electrophoresis and by determination of the octanol/water partition. A comparison of the results with the behaviour of the well-characterized tris(dialkyldithiocarbamato)indium(III) complexes is given.

Synthesis, Characterization and Crystal Structure of {N-(2-Mercaptoacetyl)-N′-[4-(pentene-3-one-2)]ethane-1,2-diaminato } oxotechnetium(V)

{ N-(2-Mercaptoacetyl)-N′-[4-(pentene-3-one-2)]ethane-1,2-diaminato} oxotechnetium(V) has been prepared by the reaction of (Bu4N)TcOX4 complexes (X = Cl, Br) with N-(mercaptoacetyl)-N′-[4-(pentene-3-one-2)]ethane-1,2-diamine in methanolic solution. The compound forms dark red crystals which were characterized by elemental analysis, IR and 1H NMR spectroscopy, mass spectrometry, as well as an X-ray structure determination. The compound crystallizes triclinic in the centrosymmetric space group PĪ with a = 776.50(3), b = 819.69(6), c = 1040.43(7) pm, α = 92.944(6)°, β = 110.805(5)° and γ = 109.957(5)°. The final R value is 0.023. In the monomeric complex the five coordinate technetium atom exhibits a square pyramidal environment with the donors of the tetradentate ligand in the basal plane and the oxo ligand in the apical position. The bond length Tc–O = 165.7(2) is within the normal range of Tc=O double bonds.