Terpyridine Cobalt Research Articles

A simple terpyridine–cobalt(II) complex sensitized by connective mpg–C3N4 for improved CO2 photoreduction

A noble metal–free hybrid photocatalysts (Cotpy@mpg–C3N4) composed of mesoporous carbon nitride (mpg–C3N4) and a simple molecular terpyridine–Co(II) complex (Co(ptpy)Cl2) has been synthesized for CO2 photoreduction. The hybrid photocatalyst exhibited high and durable CO formation (3.41 × 104 μmol g–1) after 48 h of visible light irradiation, which is much better than corresponding separated system without a covalent connection. The introduction of Co(ptpy)Cl2 to mpg–C3N4 via a covalent amido bond in Cotpy@mpg–C3N4 improved the reducing ability of conduction bond (–1.58 V vs. SCE) and CO2 adsorption capacity (3.23 mmol g–1). Further mechanistic studies revealed that the efficient cooperation between light–absorbing mpg–C3N4 and catalytic site Co(ptpy)Cl2 was crucial and facilitated electron transfer and charge separation during photocatalysis. This work highlights the synergistic effect of constituent components in the hybrid photocatalyst for CO2 photoreduction.

Correction to “Cobalt-Catalyzed C(sp2)–H Borylation with an Air-Stable, Readily Prepared Terpyridine Cobalt(II) Bis(acetate) Precatalyst”

ADVERTISEMENT RETURN TO ISSUEPREVAddition/CorrectionNEXTORIGINAL ARTICLEThis notice is a correctionCorrection to “Cobalt-Catalyzed C(sp2)–H Borylation with an Air-Stable, Readily Prepared Terpyridine Cobalt(II) Bis(acetate) Precatalyst”Nadia G. LéonardNadia G. LéonardMore by Nadia G. Léonardhttps://orcid.org/0000-0002-0949-5471, Máté J. BezdekMáté J. BezdekMore by Máté J. Bezdekhttps://orcid.org/0000-0001-7860-2894, and Paul J. Chirik*Paul J. ChirikMore by Paul J. Chirikhttps://orcid.org/0000-0001-8473-2898Cite this: Organometallics 2021, 40, 15, 2761Publication Date (Web):July 14, 2021Publication History Published online14 July 2021Published inissue 9 August 2021https://doi.org/10.1021/acs.organomet.1c00395Copyright © 2021 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views866Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (477 KB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

Remote, Diastereoselective Cobalt-Catalyzed Alkene Isomerization–Hydroboration: Access to Stereodefined 1,3-Difunctionalized Indanes

The remote, diastereoselective hydroboration of 2- and 3-substituted indenes with a 2,2′:6′,2″-terpyridine cobalt alkyl precatalyst is described that maintains high regio- and stereoselectivity independent of the starting position of the alkene. Several 1,2- and 1,3-disubstituted indanyl boronate esters were obtained with exclusive (>20:1 dr) selectivity for the trans diastereomer including synthetically versatile, stereodefined diboron derivatives. Alkene isomerization by a putative cobalt hydride intermediate precedes carbon–boron bond formation, leading to the observed regioselectivity for boron incorporation at the unsubstituted C(sp3)–H benzylic site. The regio- and diastereoselectivity of the transformation were maintained independent of the starting position of the alkene, as demonstrated by hydroboration of three isomers of methyl-substituted indene. Deuterium-labeling experiments support rapid and reversible insertion and β-hydride elimination to isomerize 3-methylindene and 1-exo-methylene-indane, accounting for the isotopic distribution observed in the products. Mechanistic studies, including stoichiometric experiments, density functional theory calculations, and kinetic analysis, support a mechanism in which 2,3-alkene insertion into a cobalt hydride intermediate determines both the regio- and diastereoselectivity of the catalytic reaction. Synthetic applications of the indanyl boronate esters were demonstrated through the elaboration of the products to several examples of 1,3-disubstituted indanes, important carbocyclic structural motifs in both pharmacological and bioactive molecules.

Molecular Assemblies of Metal Complexes via Base-Pairing of Nucleic Acids in the Crystalline State.

The nature of the molecular assemblies formed in the crystalline state by cobalt(II) terpyridine (terpy) complexes incorporating appended adenine (A) or thymine (T) bases was found to be controlled by which bases are present. Single-crystals of the cobalt(II) complexes [Co(A-C6-terpy)2 ](BF4 )2 (1) and [Co(T-C6-terpy)2 ](BF4 )2 (2) have needle and block habits, respectively. Subsequent mixing of 1 and 2 in MeOH resulted in isolation of [Co(A-C6-terpy)1.5 (T-C6-terpy)0.5 ](BF4 )2 (3) as plate-like crystals. A 3D network structure is present in 1 that incorporates 1D chains, whereas 2 adopts a 2D stacked structure constructed from ladder-type assemblies. For 3, "dimer-rings" consisting of [Co(A-C6-terpy)2 ]2+ and [Co(A-C6-terpy)(T-C6-terpy)]2+ units are generated by means of base-pairing between A and T. Notably, 3 displays the first crystal structure of a heteroleptic cobalt(II) complex of [Co(A-C6-terpy)(T-C6-terpy)](BF4 )2 . These assembly differences involving the terpyridine cobalt(II) complex units in 1-3 affect the cooperativities influencing their spin crossover (SCO) behavior. The influence of the terminal nucleobases on the resulting assembly has been probed by investigating the co-crystallization of [Co(terpy)2 ](BF4 )2 (4) with [Co(C6-terpy)2 ](BF4 )2 (5) and 1 with 5.

A redox- and photo-responsive quadri-state switch based on dimethyldihydropyrene-appended cobalt complexes

A multi-addressable quadri-state molecular switch based on the redox and photochromic properties of a dimethyldihydropyrene-substituted terpyridine cobalt complex has been designed and fully characterized.

A new terpyridine cobalt complex redox shuttle for dye-sensitized solar cells

A new cobalt-terpyridine redox shuttle ([Co(Cl-phenyl-terpyridine)2]2+/3+) has been synthesized, characterized, computationally investigated and then tested in photovoltaic devices, in conjunction with the prototypical N719 and Z907 ruthenium dyes. Lower efficiencies compared to the reference [Co(bpy)3]2+/3+ redox couple were obtained, probably due to increased recombination processes. Improvements in the devices performances were obtained by using chenodeoxycholic acid as surface co-adsorbent and as an electrolyte additive. Moreover, to better rationalize the photovoltaic results, the effect of two different counterions (TFSI and PF6) has been investigated for the reference [Co(bpy)3]2+/3+ electrolyte, finding a reduced efficiency for the TFSI-based electrolyte.

Magnetic Behavior and Liquid‐Crystal Properties in Spin‐Crossover Cobalt(II) Compounds with Long Alkyl Chains

AbstractLong‐chain‐alkylated terpyridine cobalt(II) complexes provide an opportunity for the study not only of their unique physical properties but also of the synchronicity between spin‐state transitions and crystal–liquid‐crystal phase transitions because the thermal motion of the long alkyl chains leads to a synergetic effect exerted by external stimuli. This microreview presents recent results of terpyridine cobalt(II) complexes bearing a variety of long alkyl chains with a particular focus on the structural features as well as magnetic and liquid‐crystalline properties. In addition, various influences, such as the size of the counter anion, the polarity of the terminal substituent, and mixed metal‐ion systems, on the magnetic properties of these complexes are also discussed.

Synthesis and DNA binding properties of a cationic 2,2′:6′,2″-terpyridine cobalt(II) complex containing an oligopeptide

The first example of DNA metallointercalator containing an oligopeptide moiety is presented. The ternary cobalt(II) complex [(DOTA)Co(II)(TPY)](ClO 4) 2 (DOTA=1,4,7,10-tetraaza-cyclododecane-2,9-dione, TPY=2, 2′:6′,2″-terpyridine) was found to be efficient in binding ct-DNA. The binding constant was determined by spectrophotometric titration. In vitro antitumor studies shows that this complex has significant antitumor activity. The single-crystal of a six coordinated oligopeptide cobalt(II) complex [Co(II)(DOTA) 2](ClO 4) 2 is also reported. The stabilities and species distributions of Co(II)–DOTA (1:1) and DOTA–Co(II)–TPY (1:1:1) systems were investigated by potentiometry titration.