Mixed Boron(III) and Phosphorous(V) Complexes of <i>meso</i>‐Triaryl 25‐Oxasmaragdyrins

Emandi, Ganapathi; Kalita, Hemanta; Theophall, Gregory G.; Lakshmi, K. V.; Ravikanth, Mangalampalli

doi:10.1002/chem.201600131

Cited by 5 publications

(6 citation statements)

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“…Although 25-oxasmaragdyrin is a good macrocyclic ligand, most of the metal and nonmetal complexes described above clearly indicate that only nitrogen atoms of the dipyrromethene moiety of smaragdyrin are involved in coordination, whereas the other two donor nitrogen atoms, as well as the furan oxygen of the tripyrromethene moiety, remain uncoordinated. We made several attempts to involve the donor atoms of the tripyrrane moiety of 25-oxasmaragdyrin in coordination with metal/nonmetal atoms, and we succeeded in preparing the first examples of mixed B(III)/P(V) complexes of meso -triaryl 25-oxasmaragdyrins , containing one or two seven-membered heterocycles that are composed of five different atoms such as B, C, N, O, and P inside the macrocycle. The mixed B(III)/P(V) complexes of 25-oxasmaragdyrins 319 and 320 containing one and two seven-membered heterocycles were synthesized by reacting B(OH)(Ph)–smaragdyrin 318 and B(OH) 2 –smaragdyrin 287 , respectively, with POCl 3 in toluene at refluxing temperature (Scheme ).…”

Section: Smaragdyrinsmentioning

confidence: 99%

“…Overall, the P(V) ion in compound 319 was also tetracoordinated and was positioned at 1.64 Å above the mean plane bearing two chloro and oxo as axial groups. The other mixed B(III)/P(V) complex of 25-oxasmaragdyrin 320 , which contains two seven-membered heterocycles, has no crystallographic evidence, although the 1D and 2D NMR studies supported the presence of two seven-membered heterocycles inside the smaragdyrin macrocycle and involvement of four pyrrolic nitrogens of the smaragdyrin macrocycle in coordinating with B(III)/P(V) ions . Furthermore, the structure also revealed that the pyrrole ring bonded to P(V) ion was more deviated compared to other heterocyclic rings in the smaragdyrin macrocycle.…”

Section: Smaragdyrinsmentioning

confidence: 99%

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Smaragdyrins and Sapphyrins Analogues

et al. 2016

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Porphyrins and expanded porphyrins have attracted the attention of chemists for a long time in view of their diverse applications in catalysis; as anion, cation, and neutral substrate receptors; as ligands to coordinate large metal ions; as nonlinear optical materials, MRI contrasting agents, and sensitizers for photodynamic therapy (PDT); and more recently as models for aromaticity (both Huckel and Mobius). A diverse range of synthetic expanded porphyrins containing up to 96π electrons have been reported, and their properties have been exploited for various applications. The present Review is only confined to 22π electron expanded porphyrins containing five pyrrole/ heterocyclic rings such as sapphyrins and smaragdyrins. Even though these two macrocycles contain 22π electrons and five pyrrole/heterocyclic rings, they are structurally different. In sapphyrins, the five pyrrole/heterocyclic rings are connected through four meso-carbon bridges and one direct pyrrole−pyrrole bond, whereas in smaragdyrins, the five pyrrole/heterocyclic rings are connected through three mesocarbon bridges and two direct pyrrole−pyrrole bonds. The chemistry of sapphyrins has been well-established in recent years due to the availability of easy and efficient synthetic methods. On the other hand, smaragdyrins are not explored significantly because of their unstable nature. However, recently it was shown that smaragdyrins can be stabilized if one of the pyrrole rings is replaced with a furan ring to afford stable oxasmaragdyrin. The availability of oxasmaragdyrin allowed the exploration of smaragdyrin in recent years. Thus, an attempt has been made in this Review to describe the chemistry of both sapphyrins and smaragdyrins in terms of their synthesis, characterization, metal ion coordination, and anion-recognition properties.

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Section: Smaragdyrinsmentioning

confidence: 99%

Section: Smaragdyrinsmentioning

confidence: 99%

Smaragdyrins and Sapphyrins Analogues

et al. 2016

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“…The emission peaks of SM09 and SM-OR derivatives in tetrahydrofuran were observed at 701 and 704 nm, respectively. A bathochromic shift has been correlated with a higher intramolecular charge-transport ability in the literature. , …”

Section: Resultsmentioning

confidence: 93%

“…A bathochromic shift has been correlated with a higher intramolecular charge-transport ability in the literature. 32,33 The solid-state absorption spectra of studied compounds as thin films coated on FTO substrates were also collected in the reflectance mode. The absorption spectra of all the solid films showed broadened Soret and Q bands compared to those of the corresponding solution spectra in THF.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Tuning Alkyl Chain Lengths of Oxasmaragdyrins-B(OR)₂ for Optimizing Hole-Transport and Efficiency in Perovskite Solar Cells

Leonardus

Rameez

et al. 2021

ACS Appl. Energy Mater.

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A major challenge toward commercialization of perovskite solar cells (PSCs) is the development of cost-effective hole-transport materials (HTMs) with good hole mobility and long-term stability. Porphyrinoids such as metal-free oxasmaragdyrins as alternative HTMs in PSCs show promising power conversion at lower costs. In this study, a difluoroboryl oxasmaragdyrin, SM09, has been modified by introducing alkoxy chains with different chain lengths (methoxy (OMe), ethoxy (OEt), butoxy (OBu), and octyloxy (OOct)) at the central core position, affecting molecular packing, varying intermolecular distances, and consequently altering the hole mobility. These modified oxasmaragdyrins were used as HTMs for the planar PSCs. The device performance was evaluated and correlated with the alkyl chain length and was rationalized by photophysical characterizations. The device efficiencies decrease with an increase in the alkyl chain length from the highest PCE of 15.47% for SM-OMe to 13.35% for SM-OOct. The best performance was obtained in SM-OMe, due to its higher hole mobility (3.75 × 10–4 cm2 V–1 s–1) and stronger p-type character. In the future, a simple tuning of alkyl chain length at central core positions of oxasmaragdyrin HTMs can be an effective strategy to enhance the power conversion efficiency (PCE) of PSCs.

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“…Chandrashekar and co-workers reported the synthesis of the first stable 25-oxasmaragdyrin and stable Ni(II) and Rh(I) complexes of 25-oxasmaragdyrin . More recently, Ravikanth and co-workers reported the synthesis, reactivity, and electronic properties of BF 2 ,, B(OR) 2 ,, PO 2 ,, and mixed B(III)/P(V) complexes of 25-oxasmaragdyrin. However, the preparation of stable azasmaragdyrin has remained elusive, and this has prevented its potential application as a ligand to form metal complexes.…”

Section: Introductionmentioning

confidence: 99%

Calixsmaragdyrin: A Versatile Ligand for Coordination Complexes

et al. 2017

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The Ru(II) and BF complexes of calixsmaragdyrin were prepared under simple reaction conditions and characterized by HR-MS, 1D and 2D NMR spectroscopy, optical spectroscopy, and electrochemistry, and the structure of the Ru(II) complex of calixsmaragdyrin was elucidated by X-ray crystallography. The crystal structure of the Ru(II) complex revealed that the Ru(II) ion is hexacoordinate with the three pyrrole nitrogen ligands from the tripyrrin unit of the calixsmaragdyrin macrocycle, and the remaining coordination sites of Ru(II) ion were occupied by two carbonyl groups and one hydroxyl (-OH) group. The calixsmaragdyrin macrocycle in the Ru(II) complex was distorted with a dome-like structure. In the BF complex of calixsmaragdyrin, the BF unit was bound to two pyrrolic nitrogens of the dipyrrin moiety of calixsmaragdyrin as deduced by detailed 1- and 2-dimensional NMR spectroscopy studies. The Ru(II) complex displayed a strong Soret-like absorption band at 449 nm with the absence of Q-bands, whereas the BF complex showed a Soret-like band at 475 nm with two well-defined Q-bands at 787 and 883 nm, respectively. Quantum mechanical DFT calculations yielded relaxed equilibrium structures that were similar to the X-ray crystal structures, and the related charge density distributions indicated that the d orbital of the Ru(II) ion was contributing to the HOMO and LUMO states. In addition, TD-DFT calculations successfully reproduced the large bathochromic shifts, oscillator strengths, and electronic transitions that were observed in the experimental absorption spectra of all three complexes. Both the Ru(II) and the BF complexes of calixsmaragdyrin were stable under redox conditions.

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Mixed Boron(III) and Phosphorous(V) Complexes of meso‐Triaryl 25‐Oxasmaragdyrins

Cited by 5 publications

References 18 publications

Smaragdyrins and Sapphyrins Analogues

Smaragdyrins and Sapphyrins Analogues

Tuning Alkyl Chain Lengths of Oxasmaragdyrins-B(OR)₂ for Optimizing Hole-Transport and Efficiency in Perovskite Solar Cells

Calixsmaragdyrin: A Versatile Ligand for Coordination Complexes

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Mixed Boron(III) and Phosphorous(V) Complexes of meso‐Triaryl 25‐Oxasmaragdyrins

Cited by 5 publications

References 18 publications

Smaragdyrins and Sapphyrins Analogues

Smaragdyrins and Sapphyrins Analogues

Tuning Alkyl Chain Lengths of Oxasmaragdyrins-B(OR)2 for Optimizing Hole-Transport and Efficiency in Perovskite Solar Cells

Calixsmaragdyrin: A Versatile Ligand for Coordination Complexes

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Tuning Alkyl Chain Lengths of Oxasmaragdyrins-B(OR)₂ for Optimizing Hole-Transport and Efficiency in Perovskite Solar Cells