The synthesis of the first alkoxide-bridged indium complex supported by a chiral dinucleating ligand platform (1), along with its zinc analogue (2), is reported. Both complexes are synthesized in a one-pot reaction starting from a chiral dinucleating bis(diamino)phenolate ligand platform, sodium ethoxide, and respective metal salts. The dinucleating indium analogue (7) based on an achiral ligand backbone is also reported. Indium complexes bearing either the chiral or achiral ligand catalyze the ring-opening polymerization of racemic lactide (rac-LA) to afford highly heterotactic poly(lactic acid) (PLA; Pr > 0.85). The indium complex bearing an achiral ligand affords essentially atactic PLA from meso-LA. The role of the dinucleating ligand structure in catalyst synthesis and polymerization activity is discussed.
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http://dx.doi.org/10.1021/acs.inorgchem.6b00358 | DOI Listing |
Organometallics
January 2025
Organic Chemistry and Catalysis, Institute for Sustainable and Circular Chemistry, Faculty of Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands.
We report the synthesis and characterization of a series of high- and low-spin dicobalt complexes of the PNNP expanded pincer ligand. Reacting this dinucleating ligand in its neutral form with two equiv of CoCl(tetrahydrofuran) yields a high-spin dicobalt complex featuring one Co inside and one Co outside of the dinucleating pocket. Performing the same reaction in the presence of two equivalents of KOtBu provides access to a high-spin dicobalt complex wherein both Co centers are bound within the PNNP pocket, and this complex also features a bridging OtBu ligand.
View Article and Find Full Text PDFChemistry
November 2024
Universität Göttingen, Institut für Anorganische Chemie, Tammannstrasse 4, D-37077, Göttingen, Germany.
Salt metathesis of dinickel(II) complex LNiBr (1; L is a dinucleating pyrazolate ligand with two β-diketiminato chelate arms) with Na(OCP) ⋅ (dioxane) yielded LNi(PCO) (2) with a P-bridging phosphaethynolate. Further reaction of 2 with benzyl isocyanide or with an N-heterocyclic carbene (NHC) triggered decarbonylation and gave LNi(PCN-CHPh) (3) and LNiP(NHC) (4) with P-bridging cyanophosphide and NHC-phosphinidenide, respectively. Electronic structure analysis indicated a μ-η : η binding mode of the PCO anion between the two Ni ions in 2, which is even more pronounced for the [PCN(-CHPh)] anion in 3.
View Article and Find Full Text PDFDalton Trans
November 2024
Research School of Chemistry, Australian National University, Canberra, ACT, 2601, Australia.
A new unsymmetrical dinucleating phosphino pyridyl 1,8-naphthyridine ligand PNNN is reported. Reaction with CuCl gave the dicopper complex [Cu(μ-Cl)(PNNN)] (1). In contrast, complexation of [RuCl(cymene)] yielded a monometallic species [RuCl(cymene)(PNNN)]Cl ([2]Cl) in which the Ru is bound to the κ-N,N, rather than κ-P,N, binding pocket.
View Article and Find Full Text PDFChem Commun (Camb)
August 2024
Department of Chemistry, University of California Berkeley, Berkeley, USA.
The selective synthesis of biomimetic Fe/Mn complexes able to mimic the geometry and catalytic activity of enzymes possessing this cofactor is still a challenge. Herein, we discuss the stepwise synthesis, characterization, and magnetic properties of a Fe(II)/Mn(II) species and related Fe(II)/Fe(II) complexes.
View Article and Find Full Text PDFOrganometallics
May 2024
Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States.
A dinucleating 1,8-naphthyridine ligand featuring fluorene-9,9-diyl-linked phosphino side arms (PNNP) was synthesized and used to obtain the cationic dicopper complexes , [(PNNP)Cu(μ-Ph)][NTf]; [NTf] = bis(trifluoromethane)sulfonimide, , [(PNNP)Cu(μ-CCPh)][NTf], and , [(PNNP)Cu(μ-OBu)][NTf]. Complex reacted with diboranes to afford dicopper μ-boryl species (, with μ-Bcat; cat = catecholate and , with μ-Bpin; pin = pinacolate) that are more reactive in C(sp)-H bond activations and toward activations of CO and CS, compared to dicopper μ-boryl complexes supported by a 1,8-naphthyridine-based ligand with di(pyridyl) side arms. The solid-state structures and DFT analysis indicate that the higher reactivities of and relate to changes in the coordination sphere of copper, rather than to perturbations on the Cu-B bonding interactions.
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