Molecular Engineering of Ruthenium-based Photosensitizers with Superior Photovoltaic Performance in DSSC: Novel N-Alkyl 2-Phenylindole-based Ancillary Ligands

In this work, we report the design and successful synthesis of two new heteroleptic polypyridyl Ru(II) complexes (SD-5 and SD-6), by incorporating hetero-aromatic electron-donating N-alkyl-2-phenylindole moieties into the ancillary ligand....

Confronting the Challenging Asymmetric Addition of Vinyl Arene Pronucleophiles into Ketones: Ligand-Controlled Regiodivergent Processes Through a Dearomatized Allyl-Cu Species

The selective reductive coupling of vinyl arenes and ketones represents a versatile approach for the rapid construction of enantiomerically enriched tertiary alcohols. Herein, we demonstrate a CuH-catalyzed regiodivergent coupling of vinyl arenes and ketones, in which the selectivity is controlled by the ancillary ligand. This approach leverages an in situ generated benzyl- or dearomatized allyl-Cu intermediate, yielding either the dearomatized or exocyclic addition products, respectively. The method exhibits excellent regio-, diastereo- and enantioselectivity, and tolerates a range of common functional groups and heterocycles. Computational studies suggest that the regio- and enantioselectivity are controlled by the ancillary ligand, while the diastereoselectivity is enforced by steric interactions between the alkyl-Cu intermediate and ketone substrates in a six-membered cyclic transition state.

Synthesis and Study of the Physical and Photovoltaic Properties of Novel Heteroleptic Ruthenium(II) Complexes Ligated with Highly π-Conjugated Bipyridine Ancillary and Phenanthroline Anchoring Ligand for Dye-Sensitized Solar Cells

Six new heteroleptic ruthenium(II) complexes (JM1–JM6), each bearing a highly π-conjugated bipyridine ancillary ligand (a methoxy-substituted analog (L1) and a phenanthroline-type anchoring ligand (L2) (dcphen or dcvphen; [Ru(L)2(NCS)2][TBA]2; L1 = 4,4′-bis{2-(3,4-dimethoxyphenyl)ethenyl}-2,2′-bipyridine (dmpbpy), 4,4′-bis{2-(1,1′-biphenyl)-4-ylethenyl}-2,2′-bipyridine (bpbpy), or 4,4′-bis{2-(4′-methoxy-[1,1′-biphenyl]-4-ylethenyl}-2,2′-bipyridine (mbpbpy); L2 = 4,7-dicarboxy-1,10-phenanthroline (dcphen) or 4,7-bis(E-carboxyvinyl)-1,10-phenanthroline (dcvphen)) were synthesized, and their physical and photovoltaic properties were investigated. Various dye-sensitized solar cells (DSSCs) were fabricated using heteroleptic ruthenium(II) complexes. Ruthenium(II) complex JM1, ligated to dmpbpy (ancillary) and dcphen (anchoring) ligands, exhibited the maximum power conversion efficiency (PCE) value of 3.40%, which was approximately 71% of the efficiency exhibited by the commercially available N719-sensitized solar cells. Ruthenium(II) complex JM5, ligated to mbpbpy (ancillary) and dcphen (anchoring) ligands, exhibited the second-best PCE value (2.52%), and ruthenium(II) complex JM3, ligated to bpbpy (ancillary) and dcphen (anchoring) ligands, exhibited a PCE value of 1.45%. It was observed that the PCE values of the DSSCs could be significantly improved by introducing the electron-donating methoxy group at proper positions of the ancillary ligands present in the heteroleptic ruthenium(II) complexes (such as JM1 and JM5).

Confronting the Challenging Asymmetric Addition of Vinyl Arene Pronucleophiles into Ketones: Ligand-Controlled Regiodivergent Processes Through a Dearomatized Allyl-Cu Species

The selective reductive coupling of vinyl arenes and ketones represents a versatile approach for the rapid construction of enantiomerically enriched tertiary alcohols. Herein, we demonstrate a CuH-catalyzed regiodivergent coupling of vinyl arenes and ketones, in which the selectivity is controlled by the ancillary ligand. This approach leverages an in situ generated benzyl- or dearomatized allyl-Cu intermediate, yielding either the dearomatized or exocyclic addition products, respectively. The method exhibits excellent regio-, diastereo- and enantioselectivity, and tolerates a range of common functional groups and heterocycles. Computational studies suggest that the regio- and enantioselectivity are controlled by the ancillary ligand, while the diastereoselectivity is enforced by steric interactions between the alkyl-Cu intermediate and ketone substrates in a six-membered cyclic transition state.

Structural trends in a series of bulky dialkylbiarylphosphane complexes of CuI

CuI complexes containing the bulky dialkylbiarylphosphane 2-(di-tert-butylphosphanyl)-2′,4′,6′-triisopropylbiphenyl ( t BuXPhos, L) and an ancillary ligand (Cl−, Br−, I−, MeCN, ClO4 − or SCN−) have been structurally characterized, namely, chlorido[2-(di-tert-butylphosphanyl)-2′,4′,6′-triisopropylbiphenyl-κP]copper(I), [CuCl(C29H45P)], 1, bromido[2-(di-tert-butylphosphanyl)-2′,4′,6′-triisopropylbiphenyl-κP]copper(I), [CuBr(C29H45P)], 2, [2-(di-tert-butylphosphanyl)-2′,4′,6′-triisopropylbiphenyl-κP]iodidocopper(I), [CuI(C29H45P)], 3, (acetonitrile-κN)[2-(di-tert-butylphosphanyl)-2′,4′,6′-triisopropylbiphenyl-κP]copper(I) hexafluoridophosphate, [Cu(CH3CN)(C29H45P)]PF6, 4, [2-(di-tert-butylphosphanyl)-2′,4′,6′-triisopropylbiphenyl-κP](perchlorato-κO)copper(I), [Cu(ClO4)(C29H45P)], 5, and di-μ-thiocyanato-κ2 S:N;κ2 N:S-bis{[2-(di-tert-butylphosphanyl)-2′,4′,6′-triisopropylbiphenyl-κP]copper(I)}, [Cu2(NCS)2(C29H45P)2], 6. Iodide complex 3 shows significant CuI–arene interactions, in contrast to its chloride 1 and bromide 2 counterparts, which is attributed to the weaker interaction between the iodide ion and the CuI centre. When replacing iodide with an acetonitrile (in 4) or perchlorate (in 5) ligand, the reduced interaction between the CuI atom and the ancillary ligand results in stronger CuI–arene interactions. No CuI–arene interactions are observed in dimer 6, due to the tricoordinated CuI centre having sufficient electron density from the coordinated ligands.