Structural and Theoretical Insights into Metal–Scorpionate Ligand Complexes

Soft Scorpionate Ligands Based on Imidazole‐2‐thione Donors

“…These observations have been further supported by the work of Hill on other Mo and W carbonyl complexes,38 Santos in her rhenium carbonyl complexes with Tm and Bm ligands39,40 and Rabinovich on a series of Mn(Tm R )(CO) 3 complexes 41. We have also undertaken DFT studies of the [M(Tm Me )(CO) 2 (NO)] complexes (M = Mo, W) and these confirm the π‐type interactions of the sulfur donors with the metal centre 42…”

“…This is a cautionary result, since on the face of it dichloromethane would otherwise appear to be a good solvent for complexation reactions of the Tm ligand. We have also observed that reaction of [M(Tm Me )(CO) 3 ] – (M = Mo, W) with NOBF 4 results not only in formation of the desired metal nitrosyl complexes, but also a neutral borane adduct, B(mt) 3 (dmf) 42. The NO + ion is oxidising and presumably is responsible for removing the hydride from boron thus allowing the solvent adduct to form.…”

“…The seven‐coordinate [W(Tm Me )(CO) 3 I] was also reported. The intermediates in these reactions are presumed to be the anions, [M(Tm Me )(CO) 3 ] – and these have also been reacted with either NOBF 4 42 or Diazald92 to yield the nitrosyl species [M(Tm Me )(CO) 2 (NO)] and with N , N ′‐dimethylthiocarbamoyl chloride to yield η 2 ‐thiocarbamoyl complexes,93 [Mo(η 2 ‐SCNMe 2 )(Tm Me )(CO) 2 ]. Reaction of the anion with tin halides yields molybdenum stannyl complexes.…”

The Thermal Stability of Tris(methimazolyl)borates and Their Germanium Complexes

“…Density Functional Theory (DFT) Molecular Orbital Calculations: 20 DFT calculations were performed using the Gaussian 03 program 21. The starting anions were generated from coordinates of known structures and subjected to geometry optimisation using B3LYP density functionals and the 6‐311G** basis set 22.…”

Technetium Complexes and Radiopharmaceuticals with Scorpionate Ligands

“…Most of the so-called homoscorpionates are nitrogen donor ligands where nitrogen atoms are incorporated in the aromatic system of a pyrazole ring. Although advanced theoretical analyses of the bonding between scorpionate ligands and metal atoms have been reported [ 23 ], for the purpose of this review a basic orbital picture could be useful to get some essential insight into the most relevant structural features of the interaction of these ligands with technetium cores. In this elementary picture, pyrazolyl nitrogen atoms can be considered as possessing sp 2 hybridization where one s - and two p -type atomic orbitals are involved in the σ bonding within the pyrazole ring, whereas the remaining p -type orbital perpendicular to the ring plane is involved in the delocalized aromatic π–bonding.…”