Synthesis and Characterization of New Trimeric Rhenium(I) Complexes. The Influence of Steric Factors on the Size of Pyrazolonaterhenium(I) Metallomacrocycles

Abstract

The reaction of [ReX(CO)5] with thiosemicarbazones H2L(R) derived from beta-keto esters (X = Cl, Br; R = Me, Ph) allowed the isolation of cyclic trimeric complexes [Re3(pyz(R))3(CO)9], where pyz(R) is the pyrazolonate corresponding to the thiosemicarbazone. Electron spray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICR-MS) monitoring of the reactions of H2L(Ph) in toluene confirmed that the trimer was formed in the reaction mixture and no higher oligomer was detected. These studies, together with the X-ray structures of the trimeric complexes, afford new insight into the factors influencing the self-assembly of pyrazolonaterhenium(I) complexes.

Neutral discrete metal–organic cyclic architectures: Opportunities for structural features and properties in confined spaces

“…Trimeric rhenium metallacycle, [Re 3 (L84) 3 (CO) 9 ] (101) (L84 = 2,5-dihydro-3-methyl-5-oxo-1-methyl or 1-phenylpyrazole-1-carbothiamide, Hpyz R ; R = Me, Ph), was synthesized by refluxing the reaction mixture of L84 and [ReCl(CO) 5 ] in toluene (Scheme 38) [205]. Nonsolvated compound of 101 was also prepared by using methanol as the solvent.…”

“…Scheme 38. Synthesis of metallacycle 101 [205]. X-ray crystallographic data showed that a five membered chelate ring was formed by the coordination of the pyrazolonato ligand to the Re center through its S and N3 atoms (Fig.…”

Coordination modes of 5-pyrazolones: A solid-state overview

“…All these carbothioamide-5-pyrazolones were obtained by elimination-cyclization processes involving ␤-keto ester or ␤-keto amide thiosemicarbazones (H␤TSCs) in the presence of a metal cation (although other factors such as pH, temperature and the nature of the solvent may influence the process) [109][110][111][112][113][114] (see Scheme 15).…”

“…Br) in chloroform at room temperature and then reacting the resulting complex {[ReBr(CO) 3 (HTSC)]} with NaOMe. However, [Re(L 57 )(CO) 3 ] 3 ·0.5PhCH 3 , [Re(L 59 )(CO) 3 ] 3 ·2PhCH 3 and [Re(L 59 )(CO) 3 ] 3[114], which were isolated from the reaction of [ReCl(CO) 5 ] withFig. 48.…”

Sterically‐Directed Consecutive and Size‐Selective Self‐Assembly of Palladium Diphosphane Complexes with an Ar‐BIAN Ligand: Unexpected Formation of Pentameric and Hexameric Aggregates

“…In this respect, a notable study with N , N ′‐diphenylamidinates has clearly demonstrated that ligands without ortho substituents on the aryl moieties establish a dimer/tetramer equilibrium in solution with copper(I) ions, whereas replacement of the ortho ‐hydrogen atoms by methyl groups produces only a dimeric assembly 8. The size of the metallamacrocycle has been shown to depend on the substituent (R) of the pyrazolonate ligand in the pyrazolonate rhenium(I) complexes that appeared as tetramers (R=H) or trimers (R=Me, Ph) 9. Interestingly, the phenoxy groups attached to the diazadibenzoperylene ligands (L) in [Pd(dppp)(L)] n 2 n + ( n =3, 4; dppp=bis(diphenylphosphanyl)propane) complexes induce steric congestion between L on the edges rather than increasing repulsion with the chelating dppp units.…”