Pnicogen and chalcogen bonds in cyclometalated iridium(III) complexes

Kinzhalov, Mikhail A.; Popova, E. A.; Petrov, M. L.; Khoroshilova, Olesya V.; Mahmudov, Kamran T.; Pombeiro, Armando J. L.

doi:10.1016/j.ica.2018.02.029

Cited by 5 publications

(3 citation statements)

References 23 publications

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“…The difference in stabilities of 3 a − c and the latter complexes in solution could be an indication of weak coordinating bond between dialkylcyanamide ligands and the iridium center. A similar observation was previously done for other N ‐donor ligands in the [Ir(ppy) 2 Cl(L)] complexes (L – N 2 ‐coordinated 4‐(2‐bromophenyl)‐1,2,3‐thiodiazole and 4‐(2‐bromophenyl)‐1,2,3‐selenadiazole). Taking into account this instability, solution 1 H NMR spectra were not measured for 3 a – c , and these compounds were characterized by elemental analyses (C, H, N), HRESI + ‐MS, FTIR, and studied by single‐crystal X‐ray diffraction.…”

Section: Resultssupporting

confidence: 83%

Cyclometalated Iridium(III) Complexes Featuring Disubstituted Cyanamides

et al. 2018

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The neutral cyclometalated iridium(III) complexes [Ir(ppy) 2 Cl (NCNR 2 )] [ppy = 2-phenylpyridinato-C 2 ,N, R = Me 3 a, Et 3 b, 1 = 2 C 5 H 10 3 c] were prepared via the reaction of the chlorobridged dimer [Ir 2 (ppy) 4 (μ-Cl) 2 ] (1) with corresponding dialkylcyanamides NCNR 2 (2 a-c) and 3 a-c were isolated in 74-85% yields. The cationic cyclometalated iridium(III) complex [Ir (ppy) 2 (NCNMe 2 ) 2 ](OTf) (4) was obtained by replacement of chloride ligands with NCNMe 2 in 1 in the presence of AgOTf. UV/Vis absorption and emission properties of 3 a À c and 4 were studied; these complexes exhibit luminescence in the solid state upon photoexcitation (340 nm, 77 K). The characteristic feature of the X-ray structures of 3 a-c is a deviation of the fragment Ir-N-C from linearity by 13.8(5)-22.8(3)°. Quantum chemical DFT calculations and topological analysis of the electron density distribution within the formalism of Bader's theory (AIM method) performed for 3 a-c demonstrated that the Ir-N-C fragments in the optimized equilibrium structures of [Ir(ppy) 2 Cl(NCNR 2 )] significantly deviate from the linearity (by 19.8-30.7°) and indicated that the Ir-N contacts between the metal centers and dialkylcyanamide ligands are relatively weak (24-30 kcal/mol) and have a closed-shell dative interactions character. The charge decomposition analysis (CDA) shows existence of {M} ! L donation with almost negligible contribution of the {M}!L back-donation in 3 a-c.

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Section: Resultssupporting

confidence: 83%

Cyclometalated Iridium(III) Complexes Featuring Disubstituted Cyanamides

et al. 2018

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“…Quite the opposite from representing exotic or unusual contacts, these bonds make important contributions to numerous fields of chemistry and biology. As examples, understanding the forces behind crystal engineering and supramolecular chemistry benefits from a knowledge of σ-hole interactions due to their directionality, strength, and self-organization properties which promote formation of adducts in the solid state [ 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 ]. The importance of σ-hole bonding has also been verified in the context of anion recognition processes [ 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 ], materials chemistry [ 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 ], or biochemistry [ 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 ].…”

Section: Introductionmentioning

confidence: 99%

Noncovalent Bonds through Sigma and Pi-Hole Located on the Same Molecule. Guiding Principles and Comparisons

2021

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Over the last years, scientific interest in noncovalent interactions based on the presence of electron-depleted regions called σ-holes or π-holes has markedly accelerated. Their high directionality and strength, comparable to hydrogen bonds, has been documented in many fields of modern chemistry. The current review gathers and digests recent results concerning these bonds, with a focus on those systems where both σ and π-holes are present on the same molecule. The underlying principles guiding the bonding in both sorts of interactions are discussed, and the trends that emerge from recent work offer a guide as to how one might design systems that allow multiple noncovalent bonds to occur simultaneously, or that prefer one bond type over another.

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“…Due to its high directionality, chalcogen bonding is particularly important in crystal engineering and self-assembly of supramolecular structures. Evidence of chalcogen bond-like motifs in crystalline structures is frequently seen in the literature. ,,− An often repeated example is the structure of Ebselen, an essential biological compound, which is stabilized by short Se···O noncovalent contacts . Selenocyanate crystals have recently come under intense investigation ,, as the substitution of the cyano group strongly enhances one of the σ-holes over the other on the Se atom .…”

Section: Introductionmentioning

confidence: 99%

Experimental and Theoretical Studies of Dimers Stabilized by Two Chalcogen Bonds in the Presence of a N···N Pnicogen Bond

et al. 2021

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The structure of the 5,6-dichloro-2,1,3-benzoselenadiazole homodimer, obtained by adding the ligand, 4,5-dichloro-o-phenylenediamine, to the methanolic solution of SeCl4, was determined by X-ray crystallography, augmented by Fourier transform infrared, Raman, and NMR spectroscopy. The binding motif involves a pair of Se···N chalcogen bonds, with a supplementary N···N pnicogen bond. Quantum calculations provide assessments of the strengths of the individual interactions as well as their contributing factors. All together, these three bonds compose a total interaction energy between 5.4 and 16.8 kcal/mol, with the larger chalcogen atom associated with the strongest interactions. Replacement of the Se atoms by S and Te analogues allows analysis of the dependence of these forces on the nature of the chalcogen atom. Calculations also measure the importance to the binding of the presence of a second N atom on each diazole unit as well as the substituted phenyl ring to which it is fused.

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Pnicogen and chalcogen bonds in cyclometalated iridium(III) complexes

Cited by 5 publications

References 23 publications

Cyclometalated Iridium(III) Complexes Featuring Disubstituted Cyanamides

Cyclometalated Iridium(III) Complexes Featuring Disubstituted Cyanamides

Noncovalent Bonds through Sigma and Pi-Hole Located on the Same Molecule. Guiding Principles and Comparisons

Experimental and Theoretical Studies of Dimers Stabilized by Two Chalcogen Bonds in the Presence of a N···N Pnicogen Bond

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