Kirstin Ortner

Aqueous One‐Pot Synthesis of Derivatized Cyclopentadienyl–Tricarbonyl Complexes of 99mTc with an In Situ CO Source: Application to a Serotonergic Receptor Ligand

Instant radiopharmaceuticals-just add [(99m) TcO4 ](-) in water! Half-sandwich complexes of the type [(RCOCp)(99m) Tc(CO)3 ] (e.g. 1) were synthesized in a single step in water from [(99m) TcO4 ](-) . The acidification of the Cp ring by a carbonyl substituent and the use of K2 [H3 BCO2 ] as a reducing agent and in situ source of CO are instrumental in the synthesis.

Reactions of dichloro[2-(dimethylaminomethyl)phenyl-C1,N]gold(III), [Au(damp-C1,N)Cl2], with aromatic thiosemicarbazones. Structures and spectroscopical data of the first gold(III) thiosemicarbazone complexes

Abstract The reaction between dichloro[2-(dimethylaminomethyl)phenyl-C1,N]gold(III), [Au(damp-C1,N)Cl2], and the thiosemicarbazones of 2-acetylpyridine (HAPTSC) or 4-hydroxy-3-methoxybenzaldehyde, vanilline (HVTSC) leads to the formation of the first gold(III) thiosemicarbazone complexes. The reactions occur under cleavage of the AuN bond and protonation of the amino group. The heterocyclic tridentate ligand HAPTSC binds to gold by formation of two five-membered rings, the bidentate ligand HVTSC by formation of one five-membered ring. Crystal structures and spectroscopical data of the novel complexes are discussed.

Gold(III) complexes with diphenylthiocarbazonate. Synthesis and structures of [Au (Hdamp–C 1){PhNHNC (S)NNPh}Cl]Cl×H2O and [Au (Hdamp–C 1){PhNNC(S)NNPh} (Smetetraz)] (Hdamp-C 1=2- (dimethylammonium-methyl)phenyl; −Smetetraz=2-methylmercaptotetrazolate)

Abstract Dichloro [2- ( NN -dimethylaminomethyl)phenyl-C 1 N]gold(III) [Au (damp–C 1 N)Cl 2 ]reacts with diphenylthiocarbazone PhNHNHC(S)NNPhunder formation of the cationic species [Au (Hdamp–C 1 ){PhNHNC (S)NNPh}Cl]Cl The reaction goes along with cleavage of the Au–N bond and protonation of the dimethylamino group Diphenylthiocarbazonate coordinates singly deprotonated as N S-chelate There is no evidence for the formation of Au (I) species during this reaction.

Inclusion of Copper(I) into a Novel Bipyridine-Containing Tetraphosphadiplatinacyclophane

The 5,5′-bis(hydroxyalkyl)-2,2′-bipyridines 4a–c (Scheme 1) were prepared either in one step (4b, 4c) or in four steps (4a) starting with 5,5′-dimethyl-2,2′-bipyridine in each case. Reaction of 4a–c with mesyl chloride afforded the bis(mesylates) [–C5H3N–(CH2)n–CH2–OSO2Me]25a–c [n = 1 (a), 2 (b), 3 (c)], which could easily be transformed into the diphosphanes 6a–c by reaction with LiPPh2. Treatment of 6c, 6b with Cl2Pt(NCPh)2 and (RC6H4)2Pt(COD) according to the high-dilution method resulted in the formation of the tetraphosphadiplatinacyclophanes [–C5H3N–(CH2)4–PPh2PtCl2PPh2–(CH2)4–C5H3N–]2 (7c) and [–C5H3N–(CH2)3–PPh2Pt(C6H4R)2PPh2–(CH2)3–C5H3N–]2 (8b, 9b) (8b: R = H, 9b: R = tBu), respectively (Scheme 2). The molecular structures of 8b and 9b were elucidated by X-ray structural analyses. The noncoordinated bipyridine moieties in 8b were employed to encapsulate copper(I) to give the host/guest complex 10b (Scheme 3), which was investigated by FAB-MS, NMR spectroscopy, and cyclovoltammetry. 10b exhibited a quasi-reversible oxidation at E1/2 = –0.31 V and an electrodeposition-redissolution redox system at E1/2 = –0.79 V, owing to the formation of copper at the surface of the working electrode.

Structure, Stability, and Biodistribution of Cationic [M(CO)3]+ (M = Re, 99Tc, 99mTc) Complexes with Tridentate Amine Ligands

Bifunctional chelating molecules linking the fac‐[99mTc(CO)3]+ core with targeting biomolecules are required for the development of specific diagnostic radiopharmaceuticals. Diethylenetriamine (1) and N‐(pyridin‐2‐ylmethyl)ethane‐1,2‐diamine (2) both react readily with [99mTc(H2O)3(CO)3]+ in 0.9% saline at micromolar concentrations to form the cationic complexes [99mTc(1)(CO)3]+ (5) and [99mTc(2)(CO)3]+ (6) in quantitative yields. The crystal structures of the corresponding Re or 99Tc complexes were determined and exhibit in particular the small size of 5. Challenging both 99mTc complexes 5 and 6 with a 104 excess of histidine or cysteine showed no decomposition or ligand exchange after 24 hours and both compounds were also stable against reoxidation to [99mTcO4]−. In normal mice, complex 5 revealed a good and fast clearance from the blood, and most organs. Only limited accumulation in the large intestine was visible after 4 hours. Complex 6 was also excreted relatively quickly from the blood but retention was observed in some tissues after 4 h. In order to illustrate the potential of both ligands to be further functionalized, two derivatives containing potentially DNA binding functionalities, N‐(2‐Amino‐ethyl)‐N′‐pyren‐1‐ylmethyl‐ethane‐1,2‐diamine (3) and N‐(quinolin‐2‐ylmethyl)ethane‐1,2‐diamine (4) were synthesized. The respective Re or 99Tc complexes were fully characterized. Based on these results, it appears that functionalization of biomolecules with acyclic triamine ligands is biologically relevant. Complex 5 in particular could be used to mimic a terminal amino group in, e.g., a peptide due to its small size and positive charge. We thank Mallinckrodt Med. BV, Petten, NL for financial support.

Stabilisation of AuIII and AuI in the same complex molecule by a tridentate phosphinodithiolate ligand. Structures of [AuIIILCl] and [AuIL2AuIII] (L = {PhP(C6H3S-2-SiMe3-3)2}2−)

Abstract The reaction of the organometallic complex [AuIII(damp-CI,N)Cl2] (damp-C,N− = dimethylaminomethylphenyl) with PhP(C6H3SH-2-SiMe3-3) 2, H2L, results in cleavage of the AuC bond and the formation of [AuIIILCl] and [AuIL2AuIII] complexes. The square coordination environment of gold in [AuLCl] is noticeably distorted (maximum deviation from planarity: 0.326(1) A) by the steric requirements of the tridentate chelating ligand, but the oxidation state ‘+3’ of the metal is retained. [AuIL2AuIII] contains gold atoms in both square-planar (AuIII) and linear (AuI) coordination environments. The square-planar AuIII is bound by two trans-chelated PS units, and the two remaining thiolate groups provide the linear coordination of AuI. The Au-Au distance is 2.919(1) A, indicative of a weak bonding interaction.

Syntheses of a series of S6 thioether cages and their coordination chemistry with Ag

The syntheses of four S6-cages with different cavity sizes are described. In regard of potential applications for radioimmunotherapy with 111Ag, their coordination behaviour towards Ag(I) was evaluated by studies of their reactivity in solution and of their crystal structures. All cages reacted differently with Ag(I). Whereas S6-cages based on 3,8,12,17,20,25-hexathiabicyclo[8.8.8]-hexacosane (14) and on 5,9,17,21,28,31-hexathiabicyclo[11.11.11]pentatriacontane (18) showed only external Ag(I) coordination, successive adaptation of the cage size, yielded ligand 24, based on 4,7,13,21,24,25-hexathiabicyclo[8.8.8]hexacosane, which gave a complex with internal-peripheral Ag(I) binding.

Central vs. peripheral Ag(I) coordination in NS3-open chain and cage ligands

A series of NS3-open chain and cage ligands were synthesised and their complexation behaviour towards Ag(I) and Cu(I) studied. Crystal structures show that all open chain ligands form complexes in which the four donor atoms of the ligands coordinate the metal ions in a trigonal pyramidal geometry. For the NS3-cages, however, the ions are not in the centre of the cage, but show peripheral coordination resulting in polymeric crystal structures. The new NS3-aromatic cage ligand 18 binds Ag(I) peripherally giving a polymeric structure in the solid state and fluxional behaviour in solution. NMR evidence for equally populated central and peripheral coordination sites is coherent with results from DFT calculations.

Isothiocyanato complexes of rhenium VI. Synthesis, characterization and structures of cis-and trans-[ReCl2(NCS) (Me2PhP)3]☆

Abstract The reaction of [ReCl 3 (Me 2 PhP) 3 ] with excess KSCN or trimethylsilylisothiocyanate leads to the replacement of only one chloro ligand. Initially, mer,trans -[ReCl 2 (NCS) (Me 2 PhP) 3 ] is formed. The compound crystallizes in the monoclinic space group P 2 1 / n with unit cell of dimensions a = 14.992(2), b = 10.846(1), c = 19.117(6) A , β = 112.89(2)°, Z = 4 . The chloro ligands are coordinated in trans position to each other. An ReN bond length of 2.071(4) A was found for the nitrogen bound NCS − ligand. Mer,trans -[ReCl 2 (NCS) (Me 2 PhP) 3 ] isomerizes to mer,cis -[ReCl 2 (NCS) (Me 2 PhP) 3 ] at longer reaction periods. The cis complex crystallizes in the monoclinic space group P 2 1 / n , Z = 4. A unit cell of dimensions a=14.824(7), b = 13.158(2), c = 16.212(7) A , β = 112.92(2)° was determined for this compound. The rhenium atom is six-coordinate with cis -positioned chloro ligands. The ReN bond distance is shortened by 0.038 A with respect to mer,trans -[ReCl 2 (NCS) (Me 2 PhP) 3 ]. The coordination geometry of the two isomers of mer -[ReCl 2 (NCS) (Me 2 PhP) 3 ] can be derived from FAB-MS studies. Fragmentation occurs by the loss of complete ligands. It takes place in a strong dependence on the structural trans influences of the coordinated ligands. The relative intensities of the main fragments clearly indicate the geometry of the coordination sphere.