Tricarbonylrhenium(I) and ‐technetium(I) Complexes with Tris(1,2,3‐triazolyl)phosphine Oxides

Abstract

Two potentially tripodal ligands, tris(1-phenyl-1H-1,2,3-triazol-4yl)phosphine oxide (OP( 1,2,3 Tz 1À Ph ) 3 ) and tris(1-benzyl-1H-1,2,3triazol-4-yl)phosphine oxide (OP( 1,2,3 Tz 1À benz ) 3 ), were used in reactions with [Re(CO) 5 Br] and (NEt 4 ) 2 [Tc(CO) 3 Cl 3 ]. While the formation of rhenium complexes with bidentate and tridentate coordinated phosphine oxides was observed, for technetium only cationic complexes with tripodal coordinated OP( 1,2,3 Tz 1À R ) ligands were isolated. The products have been characterized spectroscopically and by single crystal X-ray diffraction.

[Tc(OH2)(CO)3(PPh3)2]+: A Synthon for Tc(I) Complexes and Its Reactions with Neutral Ligands

“…The NOESY spectrum is shown in Figure 14. The shielding of the 99 Figure 15 shows the structures of the complex cations of [Tc(SeMe 2 )(CO) 3 (PPh 3 ) 2 ](BF 4 ) (19) and [Tc(thse)(CO) 3 -(PPh 3 ) 2 ](BF 4 ) (20). The technetium atoms in both compounds are coordinated octahedrally.…”

“…[Tc(thse)(CO) 3 (PPh 3 ) 2 ](BF 4 ) (20). A solution of freshly distilled tetrahydroselenophene (0.25 mL) in CH 2 Cl 2 (0.5 mL) was added to a suspension of [Tc(OH 2 )(CO) 3 (PPh 3 ) 2 ](BF 4 ) (41 mg, 0.05 mmol) in CH 2 Cl 2 (1 mL) under an argon atmosphere and stirred for 5 min.…”

“…The high intrinsic stability of organometallic technetium­(I) complexes makes them exceptional candidates for potential radiopharmaceutical applications with the medicinally relevant nuclear isomer 99m Tc. This is impressively demonstrated by 99m Tc sestamibi–a highly inert d 6 hexakisisonitrile complex, which has been used extensively for myocardial imaging since the 1990s. − Modern approaches toward novel technetium radiopharmaceuticals also address bis­(arene) compounds − and cyclopentadienyl complexes. − Particularly the latter group of compounds is frequently stabilized by the {Tc I ­(CO) 3 } + core, which can be provided in aqueous solution as the [Tc­(CO) 3 ­(OH 2 ) 3 ] + complex for 99 Tc as well for the clinically relevant gamma emitter 99m Tc. − The aqua ligands of this compound can be readily exchanged by biologically relevant ligands and give, thus, access to potential pharmaceuticals. − …”

Light-Driven Ring Slippage in [Re(η7-C7H7)(η5-C7H9)]+ and the Inertness of Its Technetium Homologue

“…Consequently, there is therefore a clear difference in the chemistry of Re­(I) and Tc­(I). This confirms similar findings as described for fac -[Re­(CO) 3 ] + and fac -[Tc­(CO) 3 ] + complexes with tris­(1,2,3-triazolyl)­phosphine oxides: while complexes with tripodal coordinated phosphine oxides are easily prepared with technetium, the reaction with rhenium leads to lower yield due to the formation of many side species …”

Binding Small Molecules to a cis-Dicarbonyl 99TcI-PNP Complex via Metal–Ligand Cooperativity

“…Reactions with H 2 and CO 2 substantiated equivalent reactivities of Re and 99 Tc in low oxidation states. We emphasize that this is not a necessity given the similarity between 4d and 5d elements, as distinct differences have been reported in the literature. , The concept of MLC was applied to an extended substrate scope with a focus on weakly acidic ligands. The dearomatized pincer backbone of cis -[ 99 Tc I ( Pyr PNP t Bu *)­(CO) 2 ] acts as the internal base in reactions with H 2 , CO 2 , terminal alkynes, an imidazolium cation, pyrrole, and pyrazole.…”