Phosphine-functionalized amidinate ligated rare-earth metal complexes for highly 3,4-selective living polymerization of 1,3-conjugated dienes.

A series of rare-earth metal bis(alkyl) complexes have been prepared protonolysis reactions of tris(aminobenzyl) complexes (Ln(CHCHN(Me)-)) with phosphine-functionalized amidinated ligands (NCN(CH)PPh, = 2 (L1-H) and = 3 (L2-H)). The X-ray diffraction of P2-Sc (NCN(CH)PPhSc(CHCHN(Me)-)) showed the un-coordination of the diphenylphosphine group due to the inherent saturation of the central metal ion. In conjunction with [PhC][B(CF)], all the rare-earth metal complexes showed a high catalytic activity for the polymerization of 1,3-conjugated dienes (isoprene, β-myrcene and β-farnesene), affording highly 3,4-regular polymers (up to 100% 3,4-) with high molecular weight and narrow molecular weight distribution.

Wavelength-tunable noise-like fiber laser based on PbS quantum dot saturable absorber film.

A wavelength-tunable noise-like pulse (NLP) erbium-doped fiber laser incorporating PbS quantum dot (QD) polystyrene (PS) composite film as a saturable absorber (SA) is experimentally demonstrated. The wavelength tuning is implemented via a Lyot filter consisting of a segment of polarization-maintaining fiber (PMF) and a 45° tilted fiber grating. By adjusting the polarization state of the ring cavity, the laser can deliver NLP with a continuous wavelength-tunable range from 1550.

Polymerization of Bio-Derived Conjugated Dienes with Rare-Earth-Metal Complexes.

The reliance of both our life and industry on fossil resource and the alarming accumulation of polymeric materials in the environment have presented huge challenges to sustainable society. Nowadays, utilization of renewable monomers as building blocks for polymeric materials has emerged as a hot topic and increasingly gained attention from chemists. As a class of biomass with abundance and low cost, terpenes are typical hydrocarbon-rich natural compounds, and some of them, such as myrcene and farnesene, are inherently suitable for coordination polymerization.

Rare-Earth-Metal Complexes Bearing an Iminodibenzyl-PNP Pincer Ligand: Synthesis and Reactivity toward 3,4-Selective Polymerization of 1,3-Dienes.

A PNP-pincer ligand provides a versatile ligation framework, which is highly useful in organometallic chemistry and catalytic chemistry. In this work, by a strategy, a simple and efficient synthetic pathway, has been developed to prepare the new iminodibenzyl-based PNP pincer proligand PNP(Li or H) (R = isopropyl, phenyl). By employing salt metathesis or direct alkyl elimination, we successfully synthesized a series of iminodibenzyl-PNP rare-earth-metal (Ln = Sc, Y, Dy, Ho, Er, Tm, Lu) complexes and characterized them by NMR and X-ray diffraction analyses.

Access to Derivatizable Octahydrofluorenyl Ligand: Half-Sandwich Rare-Earth Metal Complexes for Highly Syndiospecific (Co)Polymerization of Styrene.

A simple and facile synthetic pathway for accessing new derivatizable bulky-demanding octahydrofluorenyl (OHF) ligands has been developed, and a series of half-sandwich rare-earth metal (Sc, Y, Lu) complexes bearing the OHF ancillary ligands have been synthesized. In conjunction with a borate, the OHF-ligated Sc complexes exhibited high catalytic activity for styrene (co)polymerization to afford polymers with highly syndiotactic polystyrene sequence (>99% ).

Rigid Acridane-Based Pincer Supported Rare-Earth Complexes for -1,4-Polymerization of 1,3-Conjugated Dienes.

A convenient synthetic route has been developed for preparing the novel rigid 4,5-(PR)2-2,7,9,9-tetramethylacridane-based pincer ligands (PNP; R = Pr and Ph), and the first rare-earth (Ln = Y, Lu) alkyl complexes bearing the PNP ligands were synthesized by a salt metathesis reaction (for the isopropyl-substituent PNP complexes, ) or direct alkylation (for the phenyl-substituent PNP complexes, ). For both and , the NMR spectroscopy and X-ray diffraction study confirmed the successful coordination of the PNP ligand to the central metal ion in a tridentate manner via the two phosphine and the nitrogen donors. In contrast to that are solvent-free complexes, the metal centers in are each coordinated with one tetrahydrofuran molecule.

Unsymmetrical diarylamido-based rare-earth alkyl complexes: their synthesis and catalytic performance in isoprene polymerization.

A family of rare-earth complexes bearing diarylamido-based pincer ligands with phosphino-, phenylthio- and quinolino-sidearms have been synthesized and fully characterized. Upon activation by [PhC][B(CF)], the scandium (P-Sc and S-Sc) and yttrium complexes (P-Y and S-Y) could catalyze the polymerization of isoprene with cis-1,4 selectivity (up to 98.8%), while the lutetium analogues P-Lu and S-Lu produced trans-1,4 selective polyisoprene (up to 83.

Tridentate diarylamido-based pincer complexes of nickel and palladium: sidearm effects in the polymerization of norbornene.

Nickel and palladium complexes bearing new diarylamido-based unsymmetrical [NNN] and [SNN] pincer ligands were synthesized and tested for the polymerization of norbornene. Upon the activation of MAO, all the palladium complexes showed high catalytic activities for the vinyl-addition polymerization of norbornene up to 5.32 × 10 g of PNB (mol of Pd) h, while the corresponding nickel complexes exhibited unsatisfactory catalytic activities.