Metal-assisted electrocyclic reaction in a CN–NC–CN system

Pal, Pankaj Kumar; Chowdhury, Shubhamoy; Drew, Michael G. B.; Datta, Dipankar

doi:10.1039/b006547l

Cited by 25 publications

(16 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The X-ray crystal structure of the ligand HL has been reported earlier by us. [16] Abstract: HL and MeL are prepared by condensing benzil dihydrazone with 2-formylpyridine and 2-acetylpyridine, respectively, in 1:2 molar proportions. + .…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Metallo‐Organic Domino Reactions: CH versus CC Bond Breaking

Tocher

Drew

Nag

et al. 2007

Chemistry A European J

Self Cite

View full text Add to dashboard Cite

HL and MeL are prepared by condensing benzil dihydrazone with 2-formylpyridine and 2-acetylpyridine, respectively, in 1:2 molar proportions. While in a reaction with [Ru(C(6)H(6))Cl(2)]2, HL yields the cation [Ru(C(6)H(6)){5,6-diphenyl-3-(pyridin-2-yl)-1,2,4-triazine}Cl]+, MeL gives the cation [Ru(C(6)H(6))(MeL)Cl]+. Both the cations are isolated as their hexafluorophosphate salts and characterised by X-ray crystallography. In the case of HL, double domino electrocyclic/elimination reactions are found to occur. The electrocyclic reaction occurs in a C=N-N=C-C=N fragment of HL and the elimination reaction involves breaking of a C-H bond of HL. Density functional calculations on model complexes indicate that the identified electrocyclic reaction is thermochemically as well as kinetically feasible for both HL and MeL in the gas phase. For a double domino reaction, similar to that operative in HL, to occur for MeL, breaking of a C-C bond would be required in the elimination step. Our model calculations show the energy barrier for this elimination step to be much higher (329.1 kJ mol(-1)) for MeL than that for HL (96.3 kJ mol(-1)). Thus, the domino reaction takes place for HL and not for MeL. This accounts for the observed stability of [Ru(C(6)H(6))(MeL)Cl]+ under the reaction conditions employed.

show abstract

Section: Resultsmentioning

confidence: 99%

“…[16] [Ru-A C H T U N G T R E N N U N G (C 6 H 6 )Cl 2 ] 2 was prepared by a literature procedure. [26] Microanalyses were performed by a Perkin-Elmer 2400II elemental analyser.…”

Section: Methodsmentioning

confidence: 99%

Metallo‐Organic Domino Reactions: CH versus CC Bond Breaking

Tocher

Drew

Nag

et al. 2007

Chemistry A European J

Self Cite

View full text Add to dashboard Cite

show abstract

“…The main source of the helical twist is the torsion angle of À94.29 (6) about the bonds N1 C7-C21 N3 ( Fig. 2a) (Pal et al, 2000;De et al, 2006). For comparison, the O C-C O torsion angle in benzil in the solid state is 70 (Brown & Sadanaga, 1965).…”

Section: Crystal Structure Of Bdhocbmentioning

confidence: 99%

Experimental and theoretical studies of the products of addition–elimination reactions between benzil dihydrazone and three isomeric chlorobenzaldehydes

et al. 2015

View full text Add to dashboard Cite

A series of mono- and di-Schiff bases formed between benzil dihydrazone {BDH; systematic name: (1Z)-[(2E)-2-hydrazinylidene-1,2-diphenylethylidene]hydrazine} and three isomeric chlorobenzaldehydes were designed and synthesized to be used as model compounds to help to explain the reaction mechanisms for the formation of Schiff bases. These compounds are 1-(2-chlorobenzylidene)-2-{2-[2-(2-chlorobenzylidene)hydrazin-1-ylidene]-1,2-diphenylethylidene}hydrazine (BDHOCB), and the 3-chloro (BDHMCB) and 4-chloro (BDHPCB) analogues, all having the formula C28H20Cl2N4. Surprisingly, only di-Schiff bases were obtained; our attempts to push the reaction in favour of the mono-Schiff bases all failed. Density functional theory (DFT) calculations were performed to explain the trend in the experimental results. In the case of the systems studied, the type of Schiff base produced exhibits a clear dependence on the HOMO-LUMO energy gaps (ΔE(HOMO-LUMO)), i.e. the product is mainly governed by its stability. The compounds were characterized by single-crystal X-ray diffractometry, elemental analysis, melting point, (1)H NMR and (13)C NMR spectroscopy. The structural features of the three new Schiff bases are similar. For instance, they have the same chemical formula, all the molecules have a symmetrical double helix structure, with each Ph-C=N-N=C-Ph arm exhibiting an anti conformation, and their supramolecular interactions include intermolecular π-π and weak C-H...π stacking interactions. The crystal systems are different, however, viz. triclinic (space group P1¯) for BDHPCB, monoclinic (space group P2(1)/n) for BDHOCB and orthorhombic (space group Pnna) for BDHMCB.

show abstract

“…For background to polyimine ligands, see: Bai et al (2005); Chowdhury et al (2003); Drew et al (2006); Pal et al (2000); Sun et al (2006).…”

Section: Related Literaturementioning

confidence: 99%

“…Research of polyimmine compound is well established currently of great interest because of their potential applications as useful organic ligands, in which the amine nitrogen atoms have strong coordination ability to transition metal ions and recongnition function (Bai et al, 2005;Pal et al, 2000;Chowdhury et al, 2003;Drew et al, 2006;Sun et al, 2006). In this paper, we report the synthesis and crystal structure of the title compound.…”

Section: Commentmentioning

confidence: 99%

catena-Poly[[(benzil bis{[(pyridin-2-yl)methylidene]hydrazone}-κ⁴N,N′,N′′,N′′′)mercury(II)]-μ-chlorido-[dichloridomercury(II)]-μ-chlorido]

Akkurt¹,

Khandar²,

Tahir³

et al. 2012

Acta Cryst E

View full text Add to dashboard Cite

In the title coordination polymer, [Hg2Cl4(C26H20N6)]n, one HgII ion is coordinated by four N atoms from the benzylbis((pyridin-2-yl)methylidenehydrazone) ligand and two Cl− ions in a very distorted cis-HgCl2N4 octahedral geometry. The other HgII ion is coordinated in a distorted tetrahedral geometry by four Cl− ions. Bridging chloride ions link the HgII ions into a chain propagating in [010]: the Hg—Cl bridging bonds are significantly longer than the terminal bonds. The dihedral angle between the central benzene rings of the ligand is 83.3 (2)°. The packing is consolidated by weak C—H⋯Cl hydrogen bonds and C—H⋯π interactions.

show abstract

Metal-assisted electrocyclic reaction in a CN–NC–CN system

Cited by 25 publications

References 6 publications

Metallo‐Organic Domino Reactions: CH versus CC Bond Breaking

Metallo‐Organic Domino Reactions: CH versus CC Bond Breaking

Experimental and theoretical studies of the products of addition–elimination reactions between benzil dihydrazone and three isomeric chlorobenzaldehydes

catena-Poly[[(benzil bis{[(pyridin-2-yl)methylidene]hydrazone}-κ⁴N,N′,N′′,N′′′)mercury(II)]-μ-chlorido-[dichloridomercury(II)]-μ-chlorido]

Contact Info

Product

Resources

About

Metal-assisted electrocyclic reaction in a CN–NC–CN system

Cited by 25 publications

References 6 publications

Metallo‐Organic Domino Reactions: CH versus CC Bond Breaking

Metallo‐Organic Domino Reactions: CH versus CC Bond Breaking

Experimental and theoretical studies of the products of addition–elimination reactions between benzil dihydrazone and three isomeric chlorobenzaldehydes

catena-Poly[[(benzil bis{[(pyridin-2-yl)methylidene]hydrazone}-κ4N,N′,N′′,N′′′)mercury(II)]-μ-chlorido-[dichloridomercury(II)]-μ-chlorido]

Contact Info

Product

Resources

About

catena-Poly[[(benzil bis{[(pyridin-2-yl)methylidene]hydrazone}-κ⁴N,N′,N′′,N′′′)mercury(II)]-μ-chlorido-[dichloridomercury(II)]-μ-chlorido]