Crystal structures of trans-acetyldicarbonyl(η⁵-cyclopentadienyl)(1,3,5-triaza-7-phosphaadamantane)molybdenum(II) and trans-acetyldicarbonyl(η⁵-cyclopentadienyl)(3,7-diacetyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane)molybdenum(II)

Abstract

The title compounds, [Mo(C5H5)(COCH3)(C6H12N3P)(CO)2], (1), and [Mo(C5H5)(COCH3)(C9H16N3O2P)(C6H5)2))(CO)2], (2), have been prepared by phosphine-induced migratory insertion from [Mo(C5H5)(CO)3(CH3)]. The molecular structures of these complexes are quite similar, exhibiting a four-legged piano-stool geometry with trans-disposed carbonyl ligands. The extended structures of complexes (1) and (2) differ substantially. For complex (1), the molybdenum acetyl unit plays a dominant role in the organization of the extended structure, joining the molecules into centrosymmetrical dimers through C—H...O interactions with a cyclopentadienyl ligand of a neighboring molecule, and these dimers are linked into layers parallel to (100) by C—H...O interactions between the molybdenum acetyl and the cyclopentadienyl ligand of another neighbor. The extended structure of (2) is dominated by C—H...O interactions involving the carbonyl groups of the acetamide groups of the DAPTA ligand, which join the molecules into centrosymmetrical dimers and link them into chains along [010]. Additional C—H...O interactions between the molybdenum acetyl oxygen atom and an acetamide methyl group join the chains into layers parallel to (101).

Crystal structures of phosphine-supported (η5-cyclopentadienyl)molybdenum(II) propionyl complexes

“…Use of tri(2-furyl)phosphine, which features heteroatoms as potential hydrogen-bond acceptors, leads to an unusual structure with the acetyl oriented down, away from the cyclopentadienyl ring rather than up toward it as observed in other cases (Whited et al, 2013), and a similar effect was observed by incorporation of a Lewis-acidic manganese unit to interact with the acetyl ligand (Adatia et al, 1986). Recent use of other potentially hydrogen-bonding phosphine ligands did not lead to the same solid-state effect (Anstey et al, 2020).…”

“…CpMo(CO) 3 (CH 2 CH 3 ). This compound was prepared by modification of the method used of Gladysz et al (1979), as previously reported by and Anstey et al (2020). In a 20 ml scintillation vial equipped with a flea-sized stir bar, [CpMo(CO) 3 ] 2 (0.1908 g, 0.39 mmol) was dissolved in THF (10 ml).…”