1
|
Seikh L, Dhara S, Shukla A, Singh A, Lahiri GK. Fine Tuning between Radical versus Nonradical States of Azoheteroarenes on Selective Osmium Platforms. Inorg Chem 2024; 63:12175-12189. [PMID: 38870544 DOI: 10.1021/acs.inorgchem.4c01384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2024]
Abstract
The article highlights the cooperative impact of azoheteroarenes [abbt: 2,2'-azobis(benzothiazole), L1-L3; bmpd: (E)-1,2-bis(1-methyl-1H-pyrazole-3-yl) diazene, L4] and coligands [bpy: 2,2'-bipyridine; pap: 2-phenylazopyridine] in tuning radical (N-N•-) versus nonradical (N═N0) states of L on selective OsII-platforms in structurally/spectroscopically characterized monomeric [1]ClO4-[6]ClO4 and [1](ClO4)2-[2](ClO4)2/[7](ClO4)2-[8](ClO4)2, respectively. The preferred syn-configuration of L in the complexes prevented obtaining ligand bridged dimeric species. It revealed that {Os(bpy)2} facilitated the stabilization of both nonradical ([1](ClO4)2-[2](ClO4)2) and radical ([1]ClO4-[2]ClO4) states of L1/L2, while it delivered exclusively the radical form for L3 in [3]ClO4. In contrast, {Os(pap)2} generated radical states of L1-L3 in [4]ClO4-[6]ClO4, respectively, without any alteration of the redox state of OsII and azo (N═N0) function of the pap coligand. The neutral state of L4 was, however, ascertained in [7](ClO4)2 or [8](ClO4)2 irrespective of the nature of the metal fragment {Os(bpy)2} or {Os(pap)2}, respectively. Switching between radical and nonradical forms of L in the complexes as a function L and coligand could be addressed based on their relative FMO (frontier molecular orbital) energies. Multiple close redox steps of the complexes extended a competitive electron transfer scenario between the redox active components including metal/L/bpy/pap, leading to delicate electronic forms in each case.
Collapse
Affiliation(s)
- Liton Seikh
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Suman Dhara
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Anuj Shukla
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Aditi Singh
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Goutam Kumar Lahiri
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| |
Collapse
|
2
|
Seikh L, Sutradhar S, Dhara S, Bera SK, Panda S, Paine TK, Lahiri GK. Sequential Oxygenation of Bis(β-diketiminate) on a Selective Diruthenium Platform. Inorg Chem 2024; 63:10312-10323. [PMID: 38776455 DOI: 10.1021/acs.inorgchem.4c01029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2024]
Abstract
This article demonstrated the redox-noninnocent phenylene-linked bis(β-diketiminate) (L2-)-bridged first example of isomeric diruthenium(III)-acac species (acac = acetylacetonate) and its ability to activate dioxygen. The coordination of deprotonated L2- to the {Ru(acac)2} in bis(bidentate) mode led to isomeric {(acac)2RuIII}2(μ-L2-) (S = 1, 1-trans/1-cis, green). 1 displayed Ru(III)-based anisotropic EPR in CH3CN but without the resolution of the forbidden (ΔMs = 2) g1/2 signal at 77 K. 1-cis, however, slowly transformed to the energetically favored 1-trans form. 1 underwent two-step oxygenation at the Cβ sites of L2- to form the β-diketiminate/α-ketodiimine (L'-)-bridged mixed valent (acac)2RuIII(μ-L'-)RuII(acac)2 (2, S = 1/2, pink) followed by bis(α-ketodiimine) (L″)-bridged isovalent (acac)2RuII(μ-L″)RuII(acac)2 (3, S = 0, red). The role of O2 toward 1 → 2/3 was corroborated by 18O2 labeling experiment. Redox steps of 1-3 varied as a function of isomeric identity, bridge, and metal oxidation state. The calculated MOs and Mulliken spin densities attributed to the noninnocence of L2-, L'-, and L″ in the respective complexes. Spectrophotometric monitoring of 1 → 2 revealed pseudo-first-order rate constants (105k s-1) of 1.8 (303 K), 3.5 (313 K), 7.7 (323 K), and 17.0 (333 K) and ΔH⧧/ΔS⧧/ΔG⧧ of 14.3 kcal mol-1/-33.1 cal mol-1 K-1/24.2 kcal mol-1 (298 K), respectively. Moreover, characterization of the short-lived blue intermediate obtained during the conversion of 1 → 2/3 upon exposure to O2 supported its valence tautomeric form (VT1, RuIII-L2--RuIII ↔ RuIII-L•--RuII, S = 1), which in effect facilitated oxygen activation at the ligand backbone.
Collapse
Affiliation(s)
- Liton Seikh
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Subhankar Sutradhar
- School of Chemical Sciences, Indian Association for the Cultivation of Sciences (IACS), Jadavpur, Kolkata 700032, India
| | - Suman Dhara
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Sudip Kumar Bera
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Sanjib Panda
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Tapan Kanti Paine
- School of Chemical Sciences, Indian Association for the Cultivation of Sciences (IACS), Jadavpur, Kolkata 700032, India
| | - Goutam Kumar Lahiri
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| |
Collapse
|
3
|
Biswas M, Dey S, Dhara S, Panda S, Lahiri GK. Metal-ligand synergy driven functionalisation of alkylene linked bis(aldimine) on a diruthenium(II) platform. Cyclisation versus oxygenation. Dalton Trans 2024; 53:2167-2180. [PMID: 38192265 DOI: 10.1039/d3dt03730d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2024]
Abstract
This article addresses the impact of metal-ligand redox cooperativity on the functionalisation of coordinated ligands. It demonstrates the structure-reactivity correlation of bis(aldimine) derived bis-bidentate L (Py-CHN-(CH2)n-NCH-Py, with n = 2 (L1), 3 (L2), 4 (L3)) as a function of the conformation (syn/anti) of its alkylene linker as well as the overall structural form (cis/trans) of (acac)2RuII(μ-L)RuII(acac)2 complex moieties (1-5) possessing an electron-rich acetylacetonate (acac) co-ligand. A systematic variation of the bridging alkylene unit of L in RuII/RuII-derived 1-5 led to the following reactivity/redox events, which were validated through structural, spectroscopic, electrochemical and theoretical evaluations: (i) Cyclisation of the ethylene linked (syn conformation) bis-aldimine unit of L1 via C-C coupling yielded pyrazine bridged (acac)2RuII(μ-L1')RuII(acac)2, 1a, while the corresponding anti-form (ethylene linker) of the metal-bound L1 in 2 ((acac)2RuII(μ-L1)RuII(acac)2) led to oxygenation at the ligand backbone (bis-aldimine (L) → bis(carboxamido) (L'')) via O2 activation to generate RuIIIRuIII-derived (acac)2RuIII(μ-L1''2-)RuIII(acac)2 (2a). (ii) Consequently, propylene and butylene linked L2 and L3 bridged between two {Ru(acac)2} units in 3 and 4/5 underwent oxygenation of L to L'' to yield diruthenium(III) complexes 3a and 4a/5a, respectively. (iii) In contrast, analogous L bridged oxidised [(acac)2RuIII(μ-L)RuIII(acac)2](ClO4)2 ([2](ClO4)2-[5](ClO4)2) and [{(PPh3)2(CO)(H)RuII}2(μ-L)](ClO4)2 ([6](ClO4)2-[8](ClO4)2) involving electron poor co-ligands failed to undergo the oxygenation of L irrespective of its n value, reemphasising the effective role of redox interplay between RuII and L particularly in the presence of an electron-rich acac co-ligand in the functionalisation of the latter in 1a-5a.
Collapse
Affiliation(s)
- Mitrali Biswas
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400076, India.
| | - Sanchaita Dey
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400076, India.
| | - Suman Dhara
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400076, India.
| | - Sanjib Panda
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400076, India.
| | - Goutam Kumar Lahiri
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400076, India.
| |
Collapse
|
4
|
Singh A, Singh B, Dey S, Indra A, Lahiri GK. Ruthenium Azobis(benzothiazole): Electronic Structure and Impact of Substituents on the Electrocatalytic Single-Site Water Oxidation Process. Inorg Chem 2023; 62:2769-2783. [PMID: 36719385 DOI: 10.1021/acs.inorgchem.2c03906] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The present article deals with the structurally and spectroelectrochemically characterized newer class of ruthenium-azoheteroarenes [RuII(Ph-trpy)(Cl)(L)]ClO4, [1]ClO4-[3]ClO4 (Ph-trpy: 4'-phenyl-2,2':6',2″-terpyridine; L1: 2,2'-azobis(benzothiazole) ([1]ClO4); L2: 2,2'-azobis(6-methylbenzothiazole) ([2]ClO4); L3: 2,2'-azobis(6-chlorobenzothiazole) ([3]ClO4)). A collective consideration of experimental (i.e., structural and spectroelectrochemical) and theoretical (DFT calculations) results of [1]ClO4-[3]ClO4 established selective stabilization of (i) the unperturbed azo (N═N)0 function of L, (ii) the exclusive presence of the isomeric form involving the N(azo) donor of L trans to Cl, and (iii) the presence of extended, hydrogen-bonded trimeric units in the asymmetric unit of [2]ClO4 (CH---O) via the involvement of ClO4- anions. The detailed electrochemical studies revealed metal-based oxidation of [RuII(Ph-trpy)(Cl)(L)]+ (1+-3+) to [RuIII(Ph-trpy)(Cl)(L)]2+ (12+-32+); however, the electronic form of the first reduced state (1-3) could be better represented by its mixed RuII(Ph-trpy)(Cl)(L•-)/RuIII(Ph-trpy)(Cl)(L2-) state. Both native (1+-3+) and reduced (1-3) states exhibited weak lower energy transitions within the range of 1000-1200 nm. Further, [1]ClO4-[3]ClO4 delivered an electrochemical OER (oxygen evolution reaction) process in alkaline medium on immobilizing them to a carbon cloth support, which divulged an amplified water oxidation feature for [2]ClO4 due to the presence of electron-donating methyl groups in the L2 backbone. The faster OER kinetics and high catalytic stability of [2]ClO4 could also be rationalized by its lowest Tafel slope (85 mV dec-1) and choronoamperometric experiment (stable up to 12 h), respectively, along with high Faradic efficiency (∼97%). A comparison of [2]ClO4 with the reported analogous ruthenium complexes furnished its excellent intrinsic water oxidation activity.
Collapse
Affiliation(s)
- Aditi Singh
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Baghendra Singh
- Department of Chemistry, Indian Institute of Technology (BHU), Varanasi, Uttar Pradesh 221005, India
| | - Sanchaita Dey
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Arindam Indra
- Department of Chemistry, Indian Institute of Technology (BHU), Varanasi, Uttar Pradesh 221005, India
| | - Goutam Kumar Lahiri
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| |
Collapse
|
5
|
Naskar S, Halder S, Kanrar G, Jana D, Dinda S, Pramanik K, Ganguly S. Role of ligand disposition and oxime…oximato hydrogen bonding upon redox non-innocent character of rhodium(III) phenylazooximates. Polyhedron 2023. [DOI: 10.1016/j.poly.2023.116342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
|
6
|
Panda S, Dhara S, Singh A, Dey S, Kumar Lahiri G. Metal-coordinated azoaromatics: Strategies for sequential azo-reduction, isomerization and application potential. Coord Chem Rev 2023. [DOI: 10.1016/j.ccr.2022.214895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
7
|
Khan FF, Bera SK, Dey S, Lahiri GK. Redox activity as a tool for bond activations and functionalizations. INORGANIC CHEMISTRY IN INDIA 2023. [DOI: 10.1016/bs.adioch.2022.07.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
|
8
|
Biswas M, Dey S, Das A, Kanti Paine T, Panda S, Kumar Lahiri G. Dioxygen Activation by Redox-Active Bis(aldimine) Ligand Bridged Diruthenium Complex Possessing Singlet Ground State. Chemistry 2022; 28:e202202088. [PMID: 35947006 DOI: 10.1002/chem.202202088] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Indexed: 01/08/2023]
Abstract
The unexplored 'actor' behavior of redox-active bis(aldimine) congener, p-phenylene-bis(picoline)aldimine (L1), towards dioxygen activation and subsequent functionalization of its backbone was demonstrated on coordination with {Ru(acac)2 } (acac= acetylacetonate). Reaction under aerobic condition led to the one-pot generation of dinuclear complexes with unperturbed L1, imino-carboxamido (L2- ), and bis(carboxamido) (L32- )-bridged isovalent {RuII (μ-L1)RuII }, 1/ {RuIII (μ-L32- )RuIII }, 3 and mixed-valent {RuII (μ-L2- )RuIII }, 2. Authentication of the complexes along with the redox non-innocence behavior of their bridge have been validated through structure, spectroelectrochemistry and DFT calculations. Kinetic and isotope labelling experiments together with DFT analyzed transition states justified the consideration of redox shuttling at metal/L1 interface for 3 O2 activation despite of the closed shell configuration of 1 (S=0) to give carboxamido derived 2/3.
Collapse
Affiliation(s)
- Mitrali Biswas
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Sanchaita Dey
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Abhishek Das
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, 700032, India
| | - Tapan Kanti Paine
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, 700032, India
| | - Sanjib Panda
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Goutam Kumar Lahiri
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| |
Collapse
|
9
|
Arya Y, Bera SK, Priego JL, Jiménez-Aparicio R, Lahiri GK. Bidirectional noninnocence of hinge-like deprotonated bis-lawsone on selective ruthenium platform: a function of varying ancillary ligands. Dalton Trans 2022; 51:10441-10456. [PMID: 35762823 DOI: 10.1039/d2dt01466a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The present work aimed to obtain discrete heavier metal complexes of unperturbed deprotonated bis-lawsone (hinge-like H2L = 2,2'-bis(3-hydroxy-1,4-napthoquinone). This is primarily due to its limited examples with lighter metal ions (Co, Zn, and Ga) and the fact that our earlier approach with the osmium ion facilitated its functionalisation. Herein, we demonstrated the successful synthesis and structural characterisation of L2--derived diruthenium [(bpy)2RuII(μ-L2-)RuII(bpy)2](ClO4)2 [1](ClO4)2 (S = 0), (acac)2RuIII(μ-L2-)RuIII(acac)22 (S = 1) and monoruthenium (pap)2Ru(L2-) 3 (S = 0) derivatives (bpy = 2,2'-bipyridine, acac = acetylacetonate, and pap = 2-phenylazopyridine). The crystal structures established that (i) O,O-/O,O- donating five-membered bis-bidentate and O-,O- donating seven-membered bidentate chelating modes of deprotonated L2- in rac (ΔΔ/ΛΛ) diastereomeric [1](ClO4)2, 2 and 3, respectively. (ii) The L2- bridging unit in [1](ClO4)2, 2 and 3 underwent twisting its two naphthoquinone rings with respect to the ring connecting C-C bond by 73.01°, 62.15° and 59.12°, respectively. (iii) Intermolecular π-π interactions (∼3.5 Å) between the neighbouring molecules. The paramagnetic complex 2 (S = 1) with two non-interacting Ru(III) (S = 1/2) ions exhibited weak antiferromagnetic coupling only at very low temperatures. In agreement with the magnetic results, 2 displayed typical RuIII-based anisotropic EPR in CH3CN (<g>/Δg: 2.314/0.564) but without any forbidden g1/2 signal at 120 K. The complexes exhibited multiple redox processes in CH3CN in the experimental potential window of ± 2.0 V versus SCE. The analysis of the redox steps via a combined experimental and theoretical (DFT/TD-DFT) approach revealed the involvement of L2- to varying extents in both the oxidative and reductive processes as a consequence of its bidirectional redox non-innocent feature. The mixing of the frontier orbitals of the metal ion and L2- due to their closeness in energy indeed led to the resonating electronic form in certain redox states instead of any precise electronic structural state.
Collapse
Affiliation(s)
- Yogita Arya
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
| | - Sudip Kumar Bera
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
| | - José Luis Priego
- Departamento de Química Inorgánica, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Ciudad Universitaria, E-28040 Madrid, Spain
| | - Reyes Jiménez-Aparicio
- Departamento de Química Inorgánica, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Ciudad Universitaria, E-28040 Madrid, Spain
| | - Goutam Kumar Lahiri
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
| |
Collapse
|
10
|
Dinda S, Pramanik S, Basu J, Patra SC, Pramanik K, Ganguly S. Azo-oximate metal-carbonyl to metallocarboxylic acid via the intermediate Ir(III) radical congener: quest for co-ligand driven stability of open- and closed-shell complexes. Dalton Trans 2022; 51:10121-10135. [PMID: 35731229 DOI: 10.1039/d2dt00345g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The redox non-innocent behavior of the diaryl-azo-oxime ligand LNOH1 has been accentuated via the synthesis of metastable anion radical complexes of type trans-[Ir(LNO˙-)Cl(CO)(PPh3)2] 2 (CO is trans to azo group of the ligand) by the oxidative coordination reaction of 1 with Vaska's complex. The stereochemical role of co-ligands vis-à-vis the interplay of π-bonding has been found to be decisive in controlling the aptitude of the coordinated redox non-innocent ligand to accept or reject an electron. This has been clarified via the isolation of quite a few complexes as well as the failure to synthesize some others. The oxidized analogues of type trans-[Ir(LNO-)Cl(CO)(PPh3)2]+2+ (CO and azo group of the ligand are trans) as well as its cis isomer cis-[Ir(LNO-)Cl(CO)(PPh3)2]+3+ (CO and azo group of the ligand are cis) have been structurally characterized but the radical anion congener of the latter could not be synthesized. Furthermore, the closed shell complexes [Ir(LNO-)Cl2(PPh3)2] 4 and [Ir(LNO-)2Cl(PPh3)] 5 have been well characterized by diffraction as well as spectral techniques but their corresponding azo anion radical complexes could not be isolated and this is attributed to the trans influence of ancillary ligands. The anion radical complexes trans-[Ir(LNO˙-)Cl(CO)(PPh3)2] 2 may be rapidly transformed to the metallocarboxylic acids trans-[Ir(LNO-)Cl(CO2H)(PPh3)2] 6via a proton-coupled electron transfer (PCET) process, thereby demonstrating the role of odd electron over the coordinated ligand framework to trigger metal-mediated carbonyl to carboxylic acid functionalization. Complexes 6 are further stabilized via intramolecular -CO2H⋯ON- (carboxylic acid⋯oximato) H-bonding. The optoelectronic properties as well as the origin of transitions in the complexes were analyzed by TD-DFT and theoretical analysis, which further disclose that the odd electron in trans-[Ir(LNO˙-)Cl(CO)(PPh3)2] 2 is primarily azo-oxime centric with very low contribution from the iridium center.
Collapse
Affiliation(s)
- Soumitra Dinda
- Department of Chemistry, St. Xavier's College (Autonomous), Kolkata - 700016, India.
| | - Shuvam Pramanik
- Department of Chemistry, Jadavpur University, Kolkata 700032, India
| | - Jaydeep Basu
- Department of Chemistry, St. Xavier's College (Autonomous), Kolkata - 700016, India.
| | | | | | - Sanjib Ganguly
- Department of Chemistry, St. Xavier's College (Autonomous), Kolkata - 700016, India.
| |
Collapse
|
11
|
Volpi G. Luminescent imidazo[1,5‐a] pyridine scaffold: synthetic heterocyclization strategies overview and promising applications. ASIAN J ORG CHEM 2022. [DOI: 10.1002/ajoc.202200171] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Giorgio Volpi
- University of Turin: Universita degli Studi di Torino Chemistry ITALY
| |
Collapse
|
12
|
SINGH KIRTI, Singh R, Hazari AS, Adhikari D. Bimodal photocatalytic behaviour of a Zinc β-diketiminate: Application to trifluoromethylation reaction. Chem Commun (Camb) 2022; 58:4384-4387. [DOI: 10.1039/d2cc00397j] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A photoactive Zinc β-diketiminate complex spans a wide redox window of 3.97 V at its excited state. Having a highly reducing excited-state potential, it generates electrophilic trifluoromethyl radical by the...
Collapse
|
13
|
Lahiri GK, Panda S, Huang KW, Singh A, Dey S. Inner-sphere electron transfer at the ruthenium-azo interface. Dalton Trans 2022; 51:2547-2559. [DOI: 10.1039/d1dt03934b] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Metal complexes exhibiting multiple reversible redox states have drawn continuing research interest due to their electron reservoir features. In this context, the present article described ruthenium-acac complexes (acac=acetylacetonate) incorporating redox-active...
Collapse
|
14
|
Singh A, Dey S, Panda S, Lahiri GK. Radical versus Nonradical States of Azobis(benzothiazole) as a Function of Ancillary Ligands on Selective Ruthenium Platforms. Inorg Chem 2021; 60:18260-18269. [PMID: 34762800 DOI: 10.1021/acs.inorgchem.1c02883] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The paper deals with the electronic impact of ancillary ligands on the varying redox features of azobis(benzothiazole) (abbt) in the newly introduced mononuclear ruthenium complexes [Ru(pap)2(abbt)]n (1n) and [Ru(bpy)2(abbt)]n (2n), where pap = 2-phenylazopyridine and bpy = 2,2'-bipyridine. In this regard, the complexes [RuII(pap)2(abbt•-)]ClO4 ([1]ClO4), [RuII(pap)2(abbt0)](ClO4)2 ([1](ClO4)2), [RuII(bpy)2(abbt0)](ClO4)2 ([2](ClO4)2), and [RuII(bpy)2(abbt•-)]ClO4 ([2]ClO4) were structurally and spectroscopically characterized. Unambiguous assignments of the aforestated radical and nonradical forms of abbt in 1+/2+ and 12+/22+, respectively, were made primarily based on their redox-sensitive azo (N═N) bond distances as well as by their characteristic electron paramagnetic resonance (EPR)/NMR signatures. Although the radical form of abbt•- was isolated as an exclusive product in the case of strongly π-acidic pap-derived 1+, the corresponding moderately π-acidic bpy ancillary ligand primarily delivered an oxidized form of abbt0 in 22+, along with the radical form in 2+ as a minor (<10%) component. The oxidized abbt0-derived [1](ClO4)2 was, however, obtained via the chemical oxidation of [1]ClO4. Both 1+ and 22+ displayed multiple closed by reversible redox processes (one oxidation O1 and four successive reductions R1-R4) within the potential window of ±2.0 V versus saturated calomel electrode. The involvement of metal-, ligand-, or metal/ligand-based frontier molecular orbitals along the redox chain was assigned based on the combined experimental (structure, EPR, and spectroelectrochemisry) and theoretical [density functional theory (DFT): molecular orbitals, Mulliken spin densities/time-dependent DFT] investigations. It revealed primarily ligand (abbt/pap or bpy)-based redox activities, keeping the metal ion as a simple spectator. Moreover, frontier molecular orbital analysis corroborated the initial isolation of the radical and nonradical species for the pap-derived 1+ and bpy-derived 22+ as well as facile reduction of pap and abbt in 1+ and 2+, respectively.
Collapse
Affiliation(s)
- Aditi Singh
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Sanchaita Dey
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Sanjib Panda
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Goutam Kumar Lahiri
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| |
Collapse
|
15
|
Panda S, Baliyan R, Dhara S, Huang KW, Lahiri GK. Redox induced oxidative C-C coupling of non-innocent bis(heterocyclo)methanides. Dalton Trans 2021; 50:16647-16659. [PMID: 34755157 DOI: 10.1039/d1dt03310g] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Redox driven C-C bond formation has gained recent attention over the traditional sequence of oxidative addition, insertion and reductive elimination reactions. In this regard, the transient radical mediated diverse reactivity profile of bis(heterocyclo)methanes (H-BHM: HL1-HL4) has been demonstrated as a function of varying metal ions and ligand backbones. It highlighted the following events: (a) redox induced homocoupling of deprotonated HL1 and HL4 on coordination to M(OAc)2 precursors (M = CuII, ZnII, PdII, AgI), including the effective role of molecular oxygen in the transformation process; (b) steric inhibition of C-C coupling of HL1 or HL4 on inserting the substituent at the bridged methylene centre (Ph in HL2 or CH3 in HL3); (c) competitive C-C coupling versus oxygenation of free HL1 with varying concentrations of PdII(OAc)2 as the ease of oxygenation over dimerisation of the deprotonated HL1 was corroborated by the DFT calculated lower activation barrier and greater thermodynamic stability of the former; and (d) redox non-innocence of BHMs on a coordinatively inert ruthenium platform, which in turn favored the involvement of a radical pathway for the aforestated coupling or oxygenation process. A combined structural, spectroscopic and DFT calculated transition state analysis demonstrated the mechanistic outline for the metal assisted oxidative coupling of BHMs.
Collapse
Affiliation(s)
- Sanjib Panda
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, Powai, 400076, India. .,KAUST Catalysis Centre and Division of Chemical and Life Sciences and Engineering, KAUST, Saudi Arabia
| | - Rupal Baliyan
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, Powai, 400076, India.
| | - Suman Dhara
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, Powai, 400076, India.
| | - Kuo-Wei Huang
- KAUST Catalysis Centre and Division of Chemical and Life Sciences and Engineering, KAUST, Saudi Arabia
| | - Goutam Kumar Lahiri
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, Powai, 400076, India.
| |
Collapse
|
16
|
Sousa SF, Ertem MZ, Faustino LA, Machado AEH, Concepcion JJ, Maia PIS, Patrocinio AOT. Mechanistic investigation of the aerobic oxidation of 2-pyridylacetate coordinated to a Ru(II) polypyridyl complex. Dalton Trans 2021; 50:15248-15259. [PMID: 34632989 DOI: 10.1039/d1dt02461b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new ruthenium polypyridyl complex, [Ru(bpy)2(acpy)]+ (acpy = 2-pyridylacetate, bpy = 2,2'-bipyridine), was synthesized and fully characterized. Distinct from the previously reported analog, [Ru(bpy)2(pic)]+ (pic = 2-pyridylcarboxylate), the new complex is unstable under aerobic conditions and undergoes oxidation to yield the corresponding α-keto-2-pyridyl-acetate (acpyoxi) coordinated to the RuII center. The reaction is one of the few examples of C-H activation at mild conditions using O2 as the primary oxidant and can provide mechanistic insights with important implications for catalysis. Theoretical and experimental investigations of this aerobic oxidative transformation indicate that it takes place in two steps, first producing the α-hydroxo-2-pyridyl-acetate analog and then the final product. The observed rate constant for the first oxidation was in the order of 10-2 h-1. The reaction is hindered in the presence of coordinating solvents indicating the role of the metal center in the process. Theoretical calculations at the M06-L level of theory were performed for multiple reaction pathways in order to gain insights into the most probable mechanism. Our results indicate that O2 binding to [Ru(bpy)2(acpy)]+ is favored by the relative instability of the six-ring chelate formed by the acpy ligand and the resulting RuIII-OO˙- superoxo is stabilized by the carboxylate group in the coordination sphere. C-H activation by this species involves high activation free energies (ΔG‡ = 41.1 kcal mol-1), thus the formation of a diruthenium μ-peroxo intermediate, [(RuIII(bpy)2(O-acpy))2O2]2+via interaction of a second [Ru(bpy)2(acpy)]+ was examined as an alternative pathway. The dimer yields two RuIVO centers with a low ΔG‡ of 2.3 kcal mol-1. The resulting RuIVO species can activate C-H bonds in acpy (ΔG‡ = 23.1 kcal mol-1) to produce the coordinated α-hydroxo-2-pyridylacetate. Further oxidation of this intermediate leads to the α-keto-2-pyridyl-acetate product. The findings provide new insights into the mechanism of C-H activation catalyzed by transition-metal complexes using O2 as the sole oxygen source.
Collapse
Affiliation(s)
- Sinval F Sousa
- Laboratory of Photochemistry and Materials Science, Institute of Chemistry, Universidade Federal de Uberlandia, 38400-902, Uberlandia, Brazil.
| | - Mehmed Z Ertem
- Chemistry Division, Energy & Photon Sciences Directorate, Brookhaven National Laboratory, Upton, USA.
| | - Leandro A Faustino
- Laboratory of Photochemistry and Materials Science, Institute of Chemistry, Universidade Federal de Uberlandia, 38400-902, Uberlandia, Brazil.
| | - Antonio Eduardo H Machado
- Laboratory of Photochemistry and Materials Science, Institute of Chemistry, Universidade Federal de Uberlandia, 38400-902, Uberlandia, Brazil.
| | - Javier J Concepcion
- Chemistry Division, Energy & Photon Sciences Directorate, Brookhaven National Laboratory, Upton, USA.
| | - Pedro I S Maia
- Núcleo de Desenvolvimento de Compostos Bioativos (NDCBio), Universidade Federal do Triângulo Mineiro, Av. Dr. Randolfo Borges 1400, 38025-440 Uberaba, MG, Brazil
| | - Antonio Otavio T Patrocinio
- Laboratory of Photochemistry and Materials Science, Institute of Chemistry, Universidade Federal de Uberlandia, 38400-902, Uberlandia, Brazil.
| |
Collapse
|
17
|
Chen C, Tang LH, Zhou WY, Jia AQ, Zhang QF. Photocatalytic Properties and Electronic Effects of Incorporation Bis(acetylacetonato) Ruthenium(II/III) Complexes with Bidentate Nitrogen and Sulfur Ancillaries. ChemistrySelect 2021. [DOI: 10.1002/slct.202102846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Chong Chen
- Institute of Molecular Engineering and Applied Chemistry Anhui University of Technology Ma'anshan Anhui 243002 P. R. China
| | - Li H. Tang
- Institute of Molecular Engineering and Applied Chemistry Anhui University of Technology Ma'anshan Anhui 243002 P. R. China
| | - Wen Y. Zhou
- Institute of Molecular Engineering and Applied Chemistry Anhui University of Technology Ma'anshan Anhui 243002 P. R. China
| | - Ai Q. Jia
- Institute of Molecular Engineering and Applied Chemistry Anhui University of Technology Ma'anshan Anhui 243002 P. R. China
| | - Qian F. Zhang
- Institute of Molecular Engineering and Applied Chemistry Anhui University of Technology Ma'anshan Anhui 243002 P. R. China
| |
Collapse
|
18
|
Dhara S, Panda S, Lahiri GK. Redox induced S-S bond cleavage of 2,2'-dithiobisbenzothiazole - leading to a [2Ru-2S] core analogous to [2Fe-2S] cluster. Dalton Trans 2021; 50:12408-12412. [PMID: 34378605 DOI: 10.1039/d1dt02211c] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Facile reduction of 2,2'-dithiobisbenzothiazole by the mediation of metal-to-ligand charge transfer or by internal reducing equivalent is demonstrated. It leads to various binding modes of thiolates (κ1, κ2, μ) in a series of mononuclear and dinuclear ruthenium complexes. The dinuclear complex exhibited electron transfer processes similar to a [2Fe-2S] cluster.
Collapse
Affiliation(s)
- Suman Dhara
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
| | - Sanjib Panda
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
| | - Goutam Kumar Lahiri
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
| |
Collapse
|
19
|
Stubbe J, Suhr S, Beerhues J, Nößler M, Sarkar B. The transformations of a methylene-bridged bis-triazolium salt: a mesoionic carbene based metallocage and analogues of TCNE and NacNac. Chem Sci 2021; 12:3170-3178. [PMID: 34164084 PMCID: PMC8179415 DOI: 10.1039/d0sc06957d] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 02/02/2021] [Indexed: 12/11/2022] Open
Abstract
Unusual and unexpected chemical transformations often provide access to completely new types of functional molecules. We report here the synthesis of a methylene-bridged bis-triazolium salt designed as a precursor for a new bis-mesoionic carbene (MIC) ligand. The direct metalation with silver oxide led to the isolation and crystallographic characterization of a cationic tetranuclear octacarbene-silver(i) complex. During metalation the formal bis-MIC precursor undergoes significant structural changes and chemical transformations. A combined synthetic, crystallographic and (spectro-)electrochemical approach is used to elucidate the mechanistic pathway: starting from the methylene-bridged bis-triazolium salt a single deprotonation leads to a NacNac analogue, which is followed by a redox-induced radical dimerization reaction, generating a new tetra-MIC ligand coordinated to silver(i) central atoms. Decomplexation led to the isolation of the corresponding tetratriazoliumethylene, a profoundly electron-poor alkene, which is an analogue of TCNE.
Collapse
Affiliation(s)
- Jessica Stubbe
- Institut Für Chemie und Biochemie, Anorganische Chemie, Freie Universität Berlin Fabeckstraße 34-36 14195 Berlin Germany
| | - Simon Suhr
- Lehrstuhl für Anorganische Koordinationschemie, Institut für Anorganische Chemie, Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Julia Beerhues
- Lehrstuhl für Anorganische Koordinationschemie, Institut für Anorganische Chemie, Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Maite Nößler
- Institut Für Chemie und Biochemie, Anorganische Chemie, Freie Universität Berlin Fabeckstraße 34-36 14195 Berlin Germany
| | - Biprajit Sarkar
- Institut Für Chemie und Biochemie, Anorganische Chemie, Freie Universität Berlin Fabeckstraße 34-36 14195 Berlin Germany
- Lehrstuhl für Anorganische Koordinationschemie, Institut für Anorganische Chemie, Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
| |
Collapse
|
20
|
Kumari M, Bera SK, Lahiri GK. Noninnocence of the deprotonated 1,2-bis((1 H-pyrrol-2-yl)methylene)hydrazine bridge in diruthenium frameworks - a function of co-ligands. Dalton Trans 2021; 50:9891-9903. [PMID: 34196336 DOI: 10.1039/d1dt01488a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The article deals with the sensitive electronic forms in accessible redox states of structurally and spectroscopically authenticated deprotonated 1,2-bis((1H-pyrrol-2-yl)methylene)hydrazine (H2LR, R = H) or 1,2-bis((3,5-dimethyl-1H-pyrrol-2-yl)methylene)hydrazine (H2LR, R = Me), a BODIPY analogue bridged diruthenium complex as a function of varying ancillary ligands. It involved rac-(acac)2RuIII(μ-LR 2-)RuIII(acac)21a, R = H; 1b, R = Me (S = 1, acac = acetylacetonate), rac-[(bpy)2RuII(μ-L2-)RuII(bpy)2](ClO4)2 [2](ClO4)2 (S = 0, bpy = 2,2'-bipyridine) and diastereomeric [(pap)2RuII(μ-L2-)RuII(pap)2](ClO4)2meso-[3a](ClO4)2/rac-[3b](ClO4)2 (S = 0, pap = phenylazopyridine). The crystal structure established the linkage of the conjugated -C5[double bond, length as m-dash]N2-N3[double bond, length as m-dash]C6- central unit with the two terminal deprotonated pyrrole units of coordinated L2-. The bridging L2- in 1a, 1b, [2](ClO4)2, [3b](ClO4)2 and [3a](ClO4)2 was slightly twisted and planar with torsional angles of 41.54°, 42.91°, 37.38°, 35.33° and 0°, respectively, with regard to the central N2-N3 bond. The extent of twisting of the bridge followed an inverse relationship with the RuRu separation: 4.935/4.934 Å 1a/1b < 5.141 Å [2](ClO4)2 < 5.201 Å [3b](ClO4)2 < 5.351 Å [3a](ClO4)2. This is also attributed to the intermolecular ππ/CHπ interactions between the nearby aromatic rings of L and bpy or pap in [2](ClO4)2 or [3](ClO4)2, respectively. The multiple redox steps of the complexes varied appreciably based on the σ-donating (acac) and π-acidic (bpy, pap) characteristics of the ancillary ligands. Experimental (structure, EPR) and theoretical (DFT) evaluation pertaining to the electronic forms of 1n, 2n and 3n demonstrated the preferential involvement of L based frontier orbitals in electron transfer processes even in combination with the redox facile ruthenium ion. This in turn highlighted its redox non-innocent feature as in the case of well-documented metal coordinated quinonoid, formazanate, diimine (bpy), azo (pap) and β-diketiminate functions.
Collapse
Affiliation(s)
- Maya Kumari
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400076, India.
| | - Sudip Kumar Bera
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400076, India.
| | - Goutam Kumar Lahiri
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400076, India.
| |
Collapse
|
21
|
Singh A, Dey S, Panda S, Lahiri GK. Redox Induced Tunable Functionalization of Picolylamines on Selective Ru‐Platform. Eur J Inorg Chem 2020. [DOI: 10.1002/ejic.202000918] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Aditi Singh
- Department of Chemistry Indian Institute of Technology Bombay, Powai Mumbai 400076 India
| | - Sanchaita Dey
- Department of Chemistry Indian Institute of Technology Bombay, Powai Mumbai 400076 India
| | - Sanjib Panda
- Department of Chemistry Indian Institute of Technology Bombay, Powai Mumbai 400076 India
| | - Goutam Kumar Lahiri
- Department of Chemistry Indian Institute of Technology Bombay, Powai Mumbai 400076 India
| |
Collapse
|
22
|
Dey S, Panda S, Lahiri GK. Ruthenium-Hydride Assisted Remarkable Diversity Towards Non-Spectator Feature of Benzodifuroxan. Chem Asian J 2020; 15:3281-3295. [PMID: 32779852 DOI: 10.1002/asia.202000849] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 08/09/2020] [Indexed: 11/07/2022]
Abstract
The present article demonstrates that ruthenium-hydride [RuII (H)(Cl)(CO)(PPh3 )3 ] mediated diverse functionalization modes of benzodifuroxan (BDF) encompassing two furoxan rings. Hydride transfer from the metal precursor facilitated multiple cascade reactions involving unsymmetrical cleavage of the furoxan rings of BDF, leading to the one-pot formation of a series of ruthenium (II) coordinated functionalized ligands exhibiting bidentate κ2 -N,O, κ2 -N,N' and bis-bidentate μ-bis(κ2 -N,O) modes. Further, a moderately stable intermediate species was also encountered in the reaction sequence in which the transformed deoxygenated ligand coordinated to the metal ion via the rarely manifested furazan ring (κ2 -N,N'' mode). The products were authenticated by their single-crystal X-ray structures and other spectroscopic/analytical techniques. Redox non-innocence of the functionalized ligands in the complexes was illustrated by spectroelectrochemistry (cyclic voltammmetry, UV-Vis. and EPR) in conjunction with DFT/TD-DFT calculations. Mechanistic outline for the facile ring opening processes of BDF including interconversions of complexes (e. g. reductive ring opening) were also addressed.
Collapse
Affiliation(s)
- Sanchaita Dey
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Sanjib Panda
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Goutam Kumar Lahiri
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| |
Collapse
|
23
|
Panda S, Goel P, Lahiri GK. Non-Spectator Feature of α-Diimine Mimicked Di/tetrahydro-bisisoquinoline and Biimidazopyridine on {Ru(acac)2
} Platform. Eur J Inorg Chem 2020. [DOI: 10.1002/ejic.202000230] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Sanjib Panda
- Department of Chemistry; Indian Institute of Technology Bombay; 400076 Mumbai Powai India
| | - Puneet Goel
- Department of Chemistry; Indian Institute of Technology Bombay; 400076 Mumbai Powai India
| | - Goutam Kumar Lahiri
- Department of Chemistry; Indian Institute of Technology Bombay; 400076 Mumbai Powai India
| |
Collapse
|
24
|
Khan FF, Chowdhury AD, Lahiri GK. Bond Activations Assisted by Redox Active Ligand Scaffolds. Eur J Inorg Chem 2020. [DOI: 10.1002/ejic.202000005] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Farheen Fatima Khan
- Department of Chemistry; Indian Institute of Technology Bombay; Powai 400076 Mumbai India
| | | | - Goutam Kumar Lahiri
- Department of Chemistry; Indian Institute of Technology Bombay; Powai 400076 Mumbai India
| |
Collapse
|
25
|
Panda S, Singha Hazari A, Gogia M, Lahiri GK. Diverse Functionalization of Ruthenium-Chelated 2-Picolylamines: Oxygenation, Dehydrogenation, Cyclization, and N-Dealkylation. Inorg Chem 2020; 59:1355-1363. [DOI: 10.1021/acs.inorgchem.9b03065] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sanjib Panda
- Department of Chemistry, Indian Institute of Technology (IIT) Bombay, Powai, Mumbai 400076, India
| | - Arijit Singha Hazari
- Department of Chemistry, Indian Institute of Technology (IIT) Bombay, Powai, Mumbai 400076, India
| | - Manish Gogia
- Department of Chemistry, Indian Institute of Technology (IIT) Bombay, Powai, Mumbai 400076, India
| | - Goutam Kumar Lahiri
- Department of Chemistry, Indian Institute of Technology (IIT) Bombay, Powai, Mumbai 400076, India
| |
Collapse
|
26
|
Murugesapandian B, Ganguly R, Lee PTK, Petković M, Clyburne JAC, Vidović D. Electronically Induced Steric Clash: Synthesis of NMe2-Modified β-Diketiminate-Supported Boron Difluoride Compounds. Aust J Chem 2020. [DOI: 10.1071/ch20188] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
We report on the synthesis and structural features of NMe2-modified β-diketiminate-supported boron difluoride compounds (LArBF2: LAr=[HC(NAr)2(CNMe2)2]–; LPh: Ar=Ph; LTol: Ar=p-tolyl; LXyl: Ar=m-xylyl). The title compounds were prepared in moderate yields (~65%) by insitu deprotonation of the corresponding ligands LArH using KH, followed by the addition of BF3OEt2. According to solid-state and theoretical analyses of the BF2 compounds, the lone pair at each NMe2 group is involved in electron delocalization within the central BC3N2 ring. As a result, the N-aryl substituents sterically clash with the NMe2 groups, causing this central ring to pucker. Several attempts were made to prepare heavy analogues (e.g. LArBX2, X=Cl, Br, I) but only unidentifiable product mixtures were observed. It appears that the observed steric clash between the N-aryl substituents and the NMe2 groups prevented the formation of these heavy analogues.
Collapse
|
27
|
Kumar Bera S, Panda S, Baksi SD, Kumar Lahiri G. Redox Non‐Innocence and Isomer‐Specific Oxidative Functionalization of Ruthenium‐Coordinated β‐Ketoiminate. Chem Asian J 2019; 14:4236-4245. [DOI: 10.1002/asia.201901093] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 09/13/2019] [Indexed: 11/06/2022]
Affiliation(s)
- Sudip Kumar Bera
- Department of ChemistryIndian Institute of Technology Bombay, Powai Mumbai 400076 India
| | - Sanjib Panda
- Department of ChemistryIndian Institute of Technology Bombay, Powai Mumbai 400076 India
| | - Sourajit Dey Baksi
- Department of ChemistryIndian Institute of Technology Bombay, Powai Mumbai 400076 India
| | - Goutam Kumar Lahiri
- Department of ChemistryIndian Institute of Technology Bombay, Powai Mumbai 400076 India
| |
Collapse
|