ChemInform Abstract: PLATINUM(II) COMPLEX CONTAINING A SEVEN MEMBERED CHELATE RING- X-RAY MOLECULAR STRUCTURE OF CHLORO(DIMETHYLSULFOXIDE)(1,4-DIAMINOBUTANE)PLATINUM(II) CHLORIDE

The title compound, C25H20BNO2 · CH3OH, was examined by UV, IR, 1H, and 13C NMK spectroscopy as well as by thermogravimetry and X-ray structure analysis (Pbnb, a = 8.815, b = 17.309, c=28.992 Å, R= 5.5%). These investigations show the six-membered chelate ring (chelate A) to exist as formulated in [2] and not as a five-membered chelate ring B. One methanol molecule connects two chelate molecules by hydrogen bonds, resulting in an overall ratio of chelate to methanol of 1 : 1.

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Induction of Λ-helicity in a zinc complex with an alanine-appended aminopyridine ligand

Acta Crystallographica Section C Structural Chemistry ◽

10.1107/s2053229621006471 ◽

2021 ◽

Vol 77 (8) ◽

Author(s):

Berislav Perić ◽

Zoran Kokan ◽

Srećko I. Kirin

Keyword(s):

Zinc Complex ◽

Chelate Ring ◽

Ionic Interactions ◽

Stacking Interactions ◽

Neutral Ligand ◽

X Ray Diffraction ◽

X Ray ◽

The Third ◽

Membered Chelate Ring ◽

The Stability

The crystal structure of tris[dimethyl 5-({1-[(pyridin-2-yl-κN)carbamoyl-κO]ethyl}carbamoyl)benzene-1,3-dicarboxylate]zinc(II) dinitrate acetonitrile trisolvate, [Zn(C19H19N3O6)3](NO3)2·3CH3CN or [Zn(L)3](NO3)2·3CH3CN, (1), has been determined by single-crystal X-ray diffraction. The neutral ligand L coordinates to the Zn2+ cation in a bidentate fashion via the pyridine N atom and an amide O atom, forming a six-membered chelate ring. The Λ-helical chirality of the Zn2+ coordination sphere is induced by pendant L-alanine residues through stacking interactions between the arene groups of two coordinated ligands, assisted by a hydrogen bond between amide groups bonded to the stacked arene rings. The third ligand is coordinated to the Zn2+ cation by the same six-membered chelate ring, but in the opposite direction with respect to the analogous chelate rings of the first two coordinated ligands. Besides ionic interactions between [ZnL 3]2+ complexes and NO3 − anions, several types of hydrogen bonds and intermolecular stacking interactions contribute to the stability of the solid-state phase.

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Trifluoromethylaryl-Substituted Quinoxalines: Unusual Ruthenium- Amidininate Complexes and their Suitability for Anellation Reactions

Zeitschrift für Naturforschung B ◽

10.1515/znb-2005-0805 ◽

2005 ◽

Vol 60 (8) ◽

pp. 843-852 ◽

Cited By ~ 7

Author(s):

Frank Schramm ◽

Dirk Walther ◽

Helmar Görls ◽

Christian Käpplinger ◽

Rainer Beckert

Keyword(s):

Boron Trifluoride ◽

Chelate Ring ◽

Ruthenium Complex ◽

Structural Motif ◽

X Ray Diffraction ◽

Quinoxaline Derivative ◽

Imidazolium Salt ◽

X Ray ◽

Membered Chelate Ring ◽

Complex Fragment

The reaction of the 2,3-dianilino-quinoxaline 1 with an equivalent of triethyl orthoformiate results in a cyclic aminalester 2. An excess of triethyl orthoformate results in the carbene dimer 4. With the help of boron trifluoride, 2 can be transformed into the imidazolium salt 3. Reaction of 1 with KOtC4H9 leads to a quinoxaline derivative 5 under anellation of a benzene ring whereas the related pyrazino-quinoxaline 6 (formed from tetraaminobenzene tetrahydrochloride and bis-(3- trifluoromethylphenyl) oxalimidoyl chloride) does not react under similar conditions. However, 6 can be activated towards anellation by employing the complex fragment [(tbbpy)2Ru]2+, tbbpy: bis(4,4’-di-tert-butyl-2,2’-bipyridine). This generates an unusual ruthenium complex 9 which could be characterised by X-ray diffraction. Complex 9 contains a pentacene derivative and coordinates the ruthenium fragment at the amidinate moiety thus forming a four-membered chelate ring. Isolation of a second ruthenium complex 8 which contains an intact pyrazino-quinoxaline 6 in which the metal is also coordinated to an amidinato group supports the assumption that the anellation reaction occurs only after metal complexation at the amidinate group. In contrast to this, the smaller [(tmeda)2Pd]2+ fragment reacts with the pyrazino-quinoxaline 6 to form the mononuclear Pd complex 10. Its structural motif (X-ray diffraction) shows that the palladium centre coordinates at the 1,4-diamino group of the intact pyrazino-quinoxaline to form a five-membered chelate ring. This suggests that the bulkiness of the complex fragment determines whether or not an anellation reaction can take place.

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Crystal structure of unsymmetrical α-diimine palladium(II) complex cis-[{ArN=C(Me)–(Et)C=NAr}PdCl2] [Ar = 2,6-(iPr)2C6H3]

Acta Crystallographica Section E Crystallographic Communications ◽

10.1107/s2056989017009616 ◽

2017 ◽

Vol 73 (8) ◽

pp. 1148-1150

Author(s):

Shravan Kumar Ellandula ◽

Cosmos Opoku Amoako ◽

Joel T. Mague ◽

Perumalreddy Chandrasekaran

Keyword(s):

Molecular Structure ◽

Palladium Complex ◽

Crystal And Molecular Structure ◽

Chelate Ring ◽

X Ray Diffraction ◽

X Ray ◽

Square Planar ◽

Diimine Ligand ◽

Coordination Plane ◽

N Vector

The unsymmetrical α-diimine ligand N-{2-[2,6-bis(propan-2-yl)phenylimino]pentan-3-ylidene}-2,6-bis(propan-2-yl)aniline, [ArN=C(Me)—(Et)C=NAr] [Ar = 2,6-(iPr)2C6H3], (I), and the corresponding palladium complex, cis-(N-{2-[2,6-bis(propan-2-yl)phenylimino]pentan-3-ylidene}-2,6-bis(propan-2-yl)aniline)dichloridopalladium(II) 1,2-dichloroethane monosolvate, [PdCl2(C29H42N2)]·C2H4Cl2 or cis[PdCl2{I}], (II), have been synthesized and characterized. The crystal and molecular structure of the palladium(II) complex have been established by single-crystal X-ray diffraction. The compound crystallized along with a 1,2-dichloroethane solvent of crystallization. The coordination plane of the PdII atom shows a slight tetrahedral distortion from square-planar, as indicated by the dihedral angle between the PdCl2 and PdN2 planes of 4.19 (8)°. The chelate ring is folded along the N...N vector by 7.1 (1)°.

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A 4- to 7-membered chelate ring expansion in a Ph2PCH2PPh2(dppm) derivative: X-ray crystal structure of [(OC)4W{Ph2PNHNC(Ph)CH2PPh2}]

Journal of the Chemical Society Chemical Communications ◽

10.1039/c39820000287 ◽

1982 ◽

pp. 287-288 ◽

Cited By ~ 12

Author(s):

Subhi Al-Jibori ◽

Walter S. McDonald ◽

Bernard L. Shaw

Keyword(s):

Crystal Structure ◽

Chelate Ring ◽

Ring Expansion ◽

X Ray ◽

Membered Chelate Ring

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The Crystal and Molecular Structure of catena-{Aquabis[2-methyl-2-(phenylthio)-propanoato]cadmium(II) monohydrate}

Australian Journal of Chemistry ◽

10.1071/ch9881769 ◽

1988 ◽

Vol 41 (11) ◽

pp. 1769 ◽

Cited By ~ 9

Author(s):

G Smith ◽

EJ Oreilly ◽

CHL Kennard ◽

TCW Mak ◽

WH Yip ◽

...

Keyword(s):

Molecular Structure ◽

Crystal Structure ◽

Crystal And Molecular Structure ◽

Chelate Ring ◽

Propanoic Acid ◽

Cadmium Complex ◽

Carboxylate Group ◽

Orthorhombic Space Group ◽

X Ray ◽

Carboxylate Groups

The crystal structure of the cadmium complex of 2-methyl-2-(phenylthio) propanoic acid, [ Cd (C6H5SC(CH3)2CO2)2(H2O)]. H2O has been determined by X-ray diffration and refined to a residual R 0.051 for 2725 observed reflections. Crystals are orthorhombic, space group Pbca with a 10.819(2), b 9.030(1), c 47.24(2) A and Z 8. The stereochemistry about cadmium is distorted MO6S seven-coordinate with Cd -S 2.747(2)Ǻ and a Cd -O range 2.277-2.491(5)Ǻ. Bonds are from cadmium to a water, and to four oxygens from two bidentate carboxylate groups, one of which also forms a polymer link. The same carboxylate group is also involved in a five- membered (S,O) chelate ring.

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Crystal and Molecular Structure of the s-fac-[Co((S)-Asp)(medien)]ClO4 . H2O . HClO4 Isomer

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19930335 ◽

1993 ◽

Vol 58 (2) ◽

pp. 335-342 ◽

Cited By ~ 2

Author(s):

Jan Ondráček ◽

Jaroslav Maixner ◽

Jana Ondráčková ◽

František Jursík

Keyword(s):

Molecular Structure ◽

Crystal And Molecular Structure ◽

Chelate Ring ◽

Complex Cation ◽

Heavy Atom ◽

Boat Conformation ◽

Membered Chelate Ring ◽

Anisotropic Temperature ◽

Hydroxonium Cation ◽

Heavy Atom Method

The crystal and molecular structure of s-fac-[Co((S)-Asp)(medien)]ClO4 . H2O . HClO4 was elucidated by the heavy atom method. The positional parameters of the nonhydrogen atoms and their anisotropic temperature parameters were refined based on 2 474 observed reflection with final values of R = 0.0603 and wR = 0.0616. The substance crystallized in the orthorhombic system in the space group P212121, Z = 4, a = 8.536(1), b = 13.378(1), c = 16.899(2) Å. The structure comprises layers of the complex cation which alternate with layers containing two perchlorate anions and one hydroxonium cation. The five-membered chelate ring of 4-methyl-1,4,7-triazaheptane exist in the asymmetric λ, δ envelope conformations and the N-CH3 group of the triamine has the exo orientation. The five-membered ring of (S)-aspartic acid assumes the symmetric envelope conformation, the six-membered chelate ring, the skew boat conformation.

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