A monoaqua zinc complex. Unique acid dissociation behaviour

Drew, Michael G. B.; Parui, Debarati; De, S. K.; Chowdhury, Shubhamoy; Datta, Dipankar

doi:10.1039/b706230n

Cited by 14 publications

(4 citation statements)

References 31 publications

(46 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This is due to the stabilizing effect of the extensive co-operative hydrogen bonding present in its crystal structure (both intra-and intermolecular hydrogen bonds exist; see Table 5). Nevertheless, the Ph-C N-N C-Ph moiety still exists in an anti conformation, which is the minimum energy conformation suggested by our DFT calculations and other similar structures (Patra & Goldberg, 2001, 2003a , 2007, 2008Bai et al, 2005). In the two Ph-C N-N C-Ph moieties, the interplanar angles of the benzene rings are 65.971 (5) and 20.021 (6) , which means that the moieties are not coplanar, owing to the stabilizing effect of various kinds ofinteractions present in its crystal structure ( Table 6).…”

Section: Crystal Structure Of Bdhocbsupporting

confidence: 73%

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

Section: Crystal Structure Of Bdhocbsupporting

confidence: 73%

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

show abstract

“…The reliability of density functional theory (DFT) and neglect of diatomic differential overlap (NDDO) semiempirical molecular orbital calculations for modeling and predicting geometric, electronic, and energetic features of zinc compounds is not well established, although several attempts to evaluate the accuracy of these methods have been published. [77][78][79][80][81][82][83][84][85][86][87][88][89][90][91] Benchmark databases containing Zn-ligand bond distances, dipole moments, and dissociation energies in Zn model compounds with H, O, OH, H 2 O, NH 3 , S, and SCH 3 were presented recently, 89 together with an evaluation of various density functional approximations. In that study, out of 39 density functionals and eight other molecular orbital methods that were tested, the M05-2X 92 density functional was recommended as the best affordable method to obtain accurate geometric parameters, dipole moments, and bond dissociation energies for the selected Zn centers.…”

Section: Introductionmentioning

confidence: 99%

Energies, Geometries, and Charge Distributions of Zn Molecules, Clusters, and Biocenters from Coupled Cluster, Density Functional, and Neglect of Diatomic Differential Overlap Models

Sorkin

Truhlar

Amin

2009

J. Chem. Theory Comput.

View full text Add to dashboard Cite

We present benchmark databases of Zn-ligand bond distances, bond angles, dipole moments, and bond dissociation energies for Zn-containing small molecules and Zn coordination compounds with H, CH3, C2H5, NH3, O, OH, H2O, F, Cl, S, and SCH3 ligands. The test set also includes clusters with Zn-Zn bonds. In addition, we calculated dipole moments and binding energies for Zn centers in coordination environments taken from zinc metalloenzyme X-ray structures, representing both structural and catalytic zinc centers. The benchmark values are based on relativistic-core coupled cluster calculations. These benchmark calculations are used to test the predictions of four density functionals, namely B3LYP and the more recently developed M05-2X, M06, and M06-2X levels of theory, and six semiempirical methods, including neglect of diatomic differential overlap (NDDO) calculations incorporating the new PM3 parameter set for Zn called ZnB, developed by Brothers and co-workers, and the recent PM6 parametrization of Stewart. We found that the best DFT method to reproduce dipole moments and dissociation energies of our Zn compound database is M05-2X, which is consistent with a previous study employing a much smaller and less diverse database and a much larger set of density functionals. Here we show that M05-2X geometries and single-point coupled cluster calculations with M05-2X geometries can also be used as benchmarks for larger compounds, where coupled cluster optimization is impractical, and in particular we use this strategy to extend the geometry, binding energy, and dipole moment databases to additional molecules, and we extend the tests involving crystal-site coordination compounds to two additional proteins. We find that the most predictive NDDO methods for our training set are PM3 and MNDO/d. Notably, we also find large errors in B3LYP for the coordination compounds based on experimental X-ray geometries.

show abstract

“…8,12,14,16,17 Researchers mainly focused on the design and construction of metal complexes with synthetic helical chelating ligands. [18][19][20] Recently, we have also directed our attention to Schiff bases comprising two pyridyl-imine functions obtained from benzyldihydrazone. [21][22][23][24][25][26][27] These ligands were found to be efficient for helical structures upon coordination to metal centers.…”

Section: Introductionmentioning

confidence: 99%

Structural versatility of the quasi-aromatic Möbius type zinc(ii)-pseudohalide complexes – experimental and theoretical investigations

et al. 2019

View full text Add to dashboard Cite

show abstract

A monoaqua zinc complex. Unique acid dissociation behaviour

Cited by 14 publications

References 31 publications

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

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

Energies, Geometries, and Charge Distributions of Zn Molecules, Clusters, and Biocenters from Coupled Cluster, Density Functional, and Neglect of Diatomic Differential Overlap Models

Structural versatility of the quasi-aromatic Möbius type zinc(ii)-pseudohalide complexes – experimental and theoretical investigations

Contact Info

Product

Resources

About