Präparative, spektroskopische und kristallographische Untersuchungen an Phosphinato-Komplexen des Rheniums mit verschiedenen einzähnigen Liganden /Preparative, Spectroscopic and Crystallographic Investigations on Phosphinato Complexes of Rhenium with Various Unidentate Ligands

Abstract

<jats:title>Abstract</jats:title><jats:p>The stable phosphinato complexes [μ-R<jats:sub>2</jats:sub>PO<jats:sub>2</jats:sub>Re(CO)<jats:sub>3</jats:sub>L]<jats:sub>n</jats:sub> (1, 2b-f) [L = THF (a), py (b), NH<jats:sub>3</jats:sub> (c), P(C<jats:sub>6</jats:sub>H<jats:sub>5</jats:sub>)<jats:sub>3</jats:sub> (d), As(C<jats:sub>6</jats:sub>H<jats:sub>5</jats:sub>)<jats:sub>3</jats:sub> (e), P(C<jats:sub>6</jats:sub>H<jats:sub>11</jats:sub>)<jats:sub>3</jats:sub> (f), O(C<jats:sub>2</jats:sub>H<jats:sub>5</jats:sub>)<jats:sub>2</jats:sub> (g)] are obtained by addition of the ligands L to the compounds [μ-R<jats:sub>2</jats:sub>PO<jats:sub>2</jats:sub>Re(CO)<jats:sub>3</jats:sub>]<jats:sub>n</jats:sub> (1, 2) [R = CH<jats:sub>3</jats:sub> (1), C<jats:sub>6</jats:sub>H<jats:sub>5</jats:sub> (2)] at 20-40 °C (1, 2c: -35 °C). 1, 2b, d, e are also formed when THF in 1, 2a is substituted by the ligands b, d, and e. The unstable ether adducts 1, 2 g which result photochemically from Re<jats:sub>2</jats:sub>(CO)<jats:sub>10</jats:sub> and the acids R<jats:sub>2</jats:sub>PO<jats:sub>2</jats:sub>H, are transformed to 1, 2 by elimination of ether. At 20 °C 1, 2 a react with liquid ammonia to give the ionic complexes [(OC)<jats:sub>3</jats:sub>Re(NH<jats:sub>3</jats:sub>)<jats:sub>3</jats:sub>][O<jats:sub>2</jats:sub>PR<jats:sub>2</jats:sub>] (1, 2h). On the basis of their mass and vibrational spectra, and a crystallographic in­vestigation, the methyl [1a-f] and phenyl compounds [2a-f] are dimeric and oligomeric, respectively. The rhenium atoms are bridged via R<jats:sub>2</jats:sub>PO<jats:sub>2</jats:sub><jats:sup>-</jats:sup> ligands (phosphinato-O,O′). 1a crystallizes monoclinic in the space group C2/m with Z = 2.</jats:p>

Reactions of the Re(CO)3(H2O)3 + Synthon with Monodentate Ligands under Aqueous Conditions

“…The aqueous synthesis of [ 2 ]Br greatly improves on previously reported preparations of [ 2 ]X ( X = Cl − , O 2 PR 2 − ; R = Me, Ph), – which required multiple steps, or the treatment of Re(CO) 6 + with liquid ammonia in a sealed tube at 120 °C; Scheme shows the reaction pathways explored in this Article. Simply heating an aqueous ammonia solution of [ 1 ]Br at 60 °C for a few hours produces [ 2 ]Br in high yield.…”

“…Herein, we report the results of the interaction of ammonia, three heterocyclic amines, and a thioether with 1 + under aqueous conditions. We discovered that the synthesis of [Re(CO) 3 (NH 3 ) 3 ]Br ([ 2 ]Br) can be accomplished using more moderate conditions than previously employed. – Application of [ 1 ]Br in water with other monodentate ligands led to mixtures of products resulting from complications with the bromide competing for space in the coordination sphere, and therefore, solutions of [ 1 ][PF 6 ] were utilized instead. The development of an aqueous solution of [ 1 ][PF 6 ] and its quantitative application as a synthetic reagent are discussed.…”

1,2-eq,eq-[Re2(CO)8(THF)2]: A Reactive Re2(CO)8Fragment That Easily Activates H−H and C−H Bonds

“…The equatorial ligands adopt a staggered rotational conformation between the symmetry-related halves of the molecule (of C 2 point symmetry), with the THF ligands on the two Re centers staggered with a torsion angle between the oxygens of 125.8(2)°. The Re−O distance, 2.238(3) Å, is slightly longer than the values observed in rhenium(I) compounds (range 2.13−2.21 Å). 10c-f No Re(0)−THF compounds are reported in the database. The THF-oxygen coordination is pyramidal, with the oxygen atom 0.294 Å from the Re,C(11),C(14) plane, suggesting that sp 3 hybridization is retained upon binding.…”

“…As far as the tetrahydrofuran ligand is concerned, the affinity of the hard donor oxygen atom for hard metallic centers accounts for the high number of THF adducts exhibited by transition-metal cations. , However, tetrahydrofuran is also able to bind metals in low oxidation states, as attested by the number of THF adducts displayed by Re(I) carbonyl complexes . The only example of a THF molecule bonded to a Re(0) center is provided by the [Re 2 (CO) 9 (THF)] species; this is formed, mixed with the corresponding [Re 2 (CO) 9 (H 2 O)] aquo species, by protonation of [HRe 2 (CO) 9 ] - or by Me 3 NO-induced decarbonylation of [Re 2 (CO) 10 ], in THF solution. , The THF lability in this complex is much higher than that of MeCN in the related [Re 2 (CO) 9 (MeCN)] derivative, allowing the synthesis of open-chain tri- 12 and tetranuclear 11 clusters by replacement of THF with hydridic complexes able to act as “ligands” through their M−H σ-bond electron density …”