Reactions of 4-methylidene-bis(1-phenyl-3-methylpyrazol-5-one) with trimethylaluminum: Synthesis, structure and catalysis for the ring-opening polymerization of ε-caprolactone

Bis- and Tris(2-oxobenzimidazolyl)hydroborato Complexes of Sodium and Thallium: New Classes of Bidentate and Tridentate Oxygen Donor Ligands

A series of bis- and tris(oxobenzimidazolyl)hydroborato compounds, namely, [Bo^RBenz]Na and [To^RBenz]-Na (R = Me, Bu^t, Ad), which feature uncommon sterically demanding LX [O₂] and L₂X [O₃] donor ligands, have been obtained via the reactions of NaBH₄ with 1-R-1,3-dihydro-2H-benzimidazol-2-ones. Evidence that the alkyl substituents are suitably located to have a significant impact on the coordination environment is provided by the observation that the methyl derivative [To^MeBenz]Na(κ³-diglyme) exhibits κ³-coordination of the diglyme, whereas the t-butyl and adamantyl derivatives, [To^ButBenz]Na(κ²-diglyme) and [To^AdBenz]Na(κ²-diglyme), exhibit κ²-coordination. The [Bo^RBenz] and [To^RBenz] ligands also allow for isolation of discrete mononuclear thallium compounds, [Bo^RBenz]Tl and [To^RBenz]Tl, for which the steric demands of the ligands have been quantified in terms of both cone angle and buried volume concepts.

Efficient ring-opening polymerization (ROP) of ε-caprolactone catalysed by isomeric pyridyl β-diketonate iron(iii) complexes

A series of FeL3 complexes of dipyridyl β-diketones were structurally characterized and their catalytic properties investigated.

Synthesis and catalytic application of magnesium complexes bearing pendant indolyl ligands

Three novel indole-based ligand precursors [HIndPh(R), R = methoxy, HIndPh(OMe) (); thiomethoxy, HIndPh(SMe) (); and N,N'-dimethylamino, HIndPh(NMe2) ()] have been synthesized via Sonogashira and cyclization reactions with moderate to high yield. Reactions of these ligand precursors with 0.6 equivalent of Mg(n)Bu2 in THF afforded the magnesium bis-indolyl complexes , respectively. All the ligand precursors and related magnesium complexes have been characterized by NMR spectroscopy and elemental analyses. The molecular structures are reported for compounds and . Under optimized conditions, compound demonstrates efficient catalytic activities towards the ring opening polymerization of l-lactide and ε-caprolactone in the presence of BnOH.

The ring-opening polymerization of ε-caprolactone and l-lactide using aluminum complexes bearing benzothiazole ligands as catalysts

A series of aluminum complexes bearing benzothiazole ligands was synthesized and the ring-opening polymerization of ε-caprolactone (CL) and l-lactide (LA) using these aluminum complexes as catalysts was studied.

Well-controlled ring-opening polymerization of cyclic esters initiated by dialkylaluminum β-diketiminates

A series of aluminum alkyl complexes nacnacRAlMe2 (2a-2h) bearing aliphatic N-substituted β-diketiminate ligands (nacnacRH = N,N'-dialkyl-2-amino-4-iminopent-2-enes), were prepared from the reaction of trialkyl aluminum and the corresponding β-diketimines. All these aluminum complexes were characterized by NMR, elemental analysis and HRMS spectroscopy. The molecular structures of complexes 2a, 2c and 2h were confirmed by single-crystal X-ray diffraction. These aluminum alkyl complexes show notable activity towards the ring-opening polymerization of ε-caprolactone in the absence and presence of alcohol, and the resulting polymers have narrow molecular weight distributions.

Synthesis and structural characterization of bis(2-oxoimidazolyl)hydroborato complexes: a new class of bidentate oxygen-donor ligands

A new class of bidentate ligands that feature oxygen donors, namely, the bis(2-oxo-1-tert-butylimidazolyl)hydroborato and bis(2-oxo-1-methylbenzimidazolyl)hydroborato ligands, [Bo(Bu(t))] and [Bo(MeBenz)], have been synthesized via the reactions of MBH4 with 2 equiv of the respective 2-imidazolone. Chelation of [Bo(Bu(t))] and [Bo(MeBenz)] to a metal center results in a flexible eight-membered ring that is capable of adopting a "boatlike" conformation that allows for secondary M···H-B interactions.

Experimental and DFT studies on the vibrational and electronic spectra of 9-anthracenemethanol

Vibrational spectral measurements were made for 9-anthracenemethanol. Optimized geometrical structure and harmonic vibration frequencies were computed based on ab initio and density functional theory B3LYP methods using 6-311G(**) and LANL2DZ basis sets. The equilibrium geometries got from all of the methods and basis were compared with X-ray diffraction results. The IR and UV-vis spectra of the title compound were computed using all of the methods and choose the most appropriate way to discuss. And the absorption spectra were calculated both in gas phase and in CH(3)CH(2)OH and CH(3)CN solution. The calculated results matched well with the experimental values. On the basis, the first excited state electronic transition energy has been calculated using time-dependent density functional theory.