Structural Studies of Seven Compounds of Cobalt(III) With trans-6,13-Diamino-6,13-dimethyl-1,4,8,11-tetraazacyclotetradecane

1992 ◽  
Vol 45 (10) ◽  
pp. 1663 ◽  
Author(s):  
NF Curtis ◽  
WT Robinson ◽  
DC Weatherburn
Keyword(s):  
Chelate Ring ◽  
Chair Conformation ◽  
Boat Conformation ◽  
Structural Studies ◽  
Molecular Plane ◽  
X Ray ◽  
Membered Chelate Ring ◽  
Additional Ligand ◽  
Primary Amino ◽  
Amine Groups

The structures of seven compounds of trans-6,13-diamino-6,13-dimethyl-1,4,8,11-tetraacyclotetradecane (diam) with cobalt(III) have been determined by X-ray diffractometry: (1), trans-α-[{Co(diam-N5)}2(O2)](ClO4)4.2H2O (monoclinic, P21/n, a 10.673(2), b 22.924(8), c 19.332(5) Ǻ,β 114 19(2)°, R 0.044 for 4547reflections); (2), trans-α-[Co(diam-N5)Cl](ClO4)2 (orthorhombic, P 212121, a 9.043(4), b 11.214(4), c 21.431(8) A, R 0.055 for 1541 reflections); (3), trans-α- Co(diamH-N5)Cl] [ZnCl4] Cl.H2O (orthorhombic, Pna 21, a 25.26(5), b 9.866(2), c 9.457(2) 1, R 0.108 for 1686 reflections); (4), trans-α-[Co(diamH-N5)(H2O)Cl3.ClO4 (monoclinic, P 21/n, a 12.928(8), b 8.554(5), c 20.624(12) A, β 106.00(4)°, R 0.060 for 2094 reflections); (5), trans-γ-[Co(diamH-N5)Cl]Cl3.3H2O (orthorhombic, P212121, a 12.895(7), b 12.898(9), c 13 -417(4) Ǻ, R 0.062 for 860 reflections); (6), trans-β-[Co(diamHN5) Cl] [ZnCl4]CI.½H2O.½C3.H7OH(triclinic, P1, a 10.469(4), b 9.167(5), c 15.464(6) Ǻ, α 73.74(4), β 71.15(3), γ 73.70(1)°, R 0.045 for 3685 reflections); (7), trans-β-[Co(diamH2- N4)Cl2] [ZnCl4]Cl.½H2O.½C2.H5OH(triclinic, P1, a 10.138(2), b 12.011(3), c 12-451(2) Ǻ, α 79,87(2), β 66.64(1), γ 66.64(1)°, R 0.035 for 2637 reflections). The cations of compounds (1)-(6) all have pentadentate diam (diam-N5 or diamH-N5) with one primary amino substituent coordinated trans to the additional ligand. Compounds (1)-(4) have the pentadentate macrocycle in cyclam configuration (1). R,S,R,S, with all four secondary amine groups on the same side of the molecular plane, with one six-membered chelate ring in a boat conformation with the amino substituent coordinated, and the other in a chair conformation. Compound (5) has the pentadentate macrocycle in configuration (2), R,R,S,R, with one NH group alone on one side of the molecular plane with the six-membered chelate ring with the non-coordinated amrnonio substituent in a skew conformation. Compounds (6) and (7) have the R,R,S,S configuration (S'), (6) having diamH-N5 with one amine substituent coordinated, and (7) with planar tetradentate diamH2-N4 in the macrocycle conformation usual for planar coordinated cyclam compounds, the ammonio substituents being equatorially oriented.

The Dichloroplatinum(II) and Dichloropalladium(II) Complexes of 1,4-Diazacycloheptane: Preparative, Structural and Conformational Studies

1996 ◽  
Vol 49 (12) ◽  
pp. 1301 ◽  
Author(s):  
GW Allen ◽  
ECH Ling ◽  
LV Krippner ◽  
TW Hambley
Keyword(s):  
Crystal Structures ◽  
Chelate Ring ◽  
Chair Conformation ◽  
Monoclinic Space Group ◽  
Boat Conformation ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
Membered Chelate Ring ◽  
Alternative Conformation

The preparation and purification of [Pt( hpip )Cl2] and [Pd( hpip )Cl2] ( hpip = homopiperazine = 1,4-diazacycloheptane) are described. Crystal structures of [Pt( hpip )Cl2] and [Pd( hpip )Cl2] have been determined by X-ray diffraction methods and refined to R values of 0.023 (932 F) and 0.023 (948 F). The crystals of [Pt( hpip )Cl2] are orthorhombic, space group Pbcm , a 7.7019(8), b 9.8080(12), c 12.1944(14) Ǻ, and those of [Pd( hpip )Cl2] are monoclinic, space group P21/m, a 6.1001(9), b 11.527(2), c 6.458(I) Ǻ, β 106.30(2)°. The seven- membered rings of the ligands in both complexes adopt boat-like conformations in which the five- membered chelate ring has an eclipsed N-C-C-N group and the six- membered chelate ring adopts a chair conformation. Molecular mechanics methods were used to investigate whether this conformation was a crystallographic artefact but it was found to be real. An alternative conformation in which the six-membered chelate ring adopts a skew-boat conformation was also investigated. It was found to be less stable than the conformation observed in the crystal structures, but to a degree that depends on whether non-bonded interactions involving the metal atom were included or not.

Conformational analysis of coordination compounds. XIII. Complexes of 2-methylpentane-2,4-diamine

1981 ◽  
Vol 34 (12) ◽  
pp. 2525 ◽  
Author(s):  
TW Hambley ◽  
CJ Hawkins ◽  
JA Palmer ◽  
MR Snow
Keyword(s):  
Chelate Ring ◽  
Cobalt Complex ◽  
Platinum Complex ◽  
Chair Conformation ◽  
Geometrical Parameters ◽  
Boat Conformation ◽  
Space Group ◽  
X Ray ◽  
Strain Energy Minimization ◽  
Good Agreement

The crystal structures of tetraammine{(�)-2-methylpentane-2,4-diamine} cobalt(III) tetrachlorozincate chloride and 2,2'-bipyridine{(�)-2-methylpentane-2,4-diamine)platinum(II) nitrate semihydrate have been determined by X-ray structure analysis. The former crystals are orthorhombic with the space group P212121, with a 12.49, b 20.16 and c 7.68 �. The latter crystals are also orthorhombic but with the space group Pbca with a 14.96, b 28.69 and c 19.45 �. Both structures have been refined by least-squares methods to weighted R values of 0.034 (1407 reflections) and 0.055 (2301 reflections), respectively. The six-membered diamine chelate ring has a flattened chair conformation in the cobalt complex, and an unsymmetric boat conformation in the platinum complex. Strain-energy-minimization calculations show these structures correspond to energy minima and the calculated geometrical parameters are in good agreement with those observed for the chelate ring. Proton n.m.r. spectra are consistent with the chair conformation being almost exclusively populated in the ammine complex and in the tetracyanocobaltate(III) complex in aqueous solution, but the and 13C n.m.r. spectra of the platinum(II) complex show that, although the chair conformer predominates, the boat conformation is significantly populated in solution.

Crystal structure determination of the conformation of two bicyclo[3.3.1]nonan-ones

1985 ◽  
Vol 63 (6) ◽  
pp. 1166-1169 ◽  
Author(s):  
John F. Richardson ◽  
Ted S. Sorensen
Keyword(s):  
Crystal Structure ◽  
Direct Methods ◽  
Chair Conformation ◽  
Molecular Structures ◽  
Boat Conformation ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Final Agreement

The molecular structures of exo-7-methylbicyclo[3.3.1]nonan-3-one, 3, and the endo-7-methyl isomer, 4, have been determined using X-ray-diffraction techniques. Compound 3 crystallizes in the space group [Formula: see text] with a = 15.115(1), c = 7.677(2) Å, and Z = 8 while 4 crystallizes in the space group P21 with a = 6.446(1), b = 7.831(1), c = 8.414(2) Å, β = 94.42(2)°, and Z = 2. The structures were solved by direct methods and refined to final agreement factors of R = 0.041 and R = 0.034 for 3 and 4 respectively. Compound 3 exists in a chair–chair conformation and there is no significant flattening of the chair rings. However, in 4, the non-ketone ring is forced into a boat conformation. These results are significant in interpreting what conformations may be present in the related sp2-hybridized carbocations.

Boron Chelates and Boron-Metal Chelates, X [1]. 3-(2-Hydroxyphenyl)-2,2-diphenyl-1-oxa-3-azonia-2-borata-naphthalene-methanol (1/1): Synthesis, Spectroscopic Investigations and Crystal Structure

1982 ◽  
Vol 37 (11) ◽  
pp. 1450-1455 ◽  
Author(s):  
Rudolf Allmann ◽  
Eberhard Hohaus ◽  
Stanislaw Olejnik
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Structure Analysis ◽  
Title Compound ◽  
Chelate Ring ◽  
Boron Chelates ◽  
X Ray ◽  
Membered Chelate Ring ◽  
Compound C ◽  
Overall Ratio

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.

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

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.

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

2005 ◽  
Vol 60 (8) ◽  
pp. 843-852 ◽  
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.

scholarly journals Synthesis of Trithia-Borinane Complexes Stabilized in Diruthenium Core: [(Cp*Ru)2(η1-S)(η1-CS){(CH2)2S3BR}] (R = H or SMe)

Inorganics ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 21 ◽  
Author(s):  
Koushik Saha ◽  
Urminder Kaur ◽  
Rosmita Borthakur ◽  
Sundargopal Ghosh
Keyword(s):  
Mass Spectrometry ◽  
1H Nmr Spectroscopy ◽  
Chair Conformation ◽  
Membered Ring ◽  
Molecular Structures ◽  
Boat Conformation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Butterfly Cluster ◽  
Tellurium Powder

The thermolysis of arachno-1 [(Cp*Ru)2(B3H8)(CS2H)] in the presence of tellurium powder yielded a series of ruthenium trithia-borinane complexes: [(Cp*Ru)2(η1-S)(η1-CS){(CH2)2S3BH}] 2, [(Cp*Ru)2(η1-S)(η1-CS){(CH2)2S3B(SMe)}] 3, and [(Cp*Ru)2(η1-S)(η1-CS){(CH2)2S3BH}] 4. Compounds 2–4 were considered as ruthenium trithia-borinane complexes, where the central six-membered ring {C2BS3} adopted a boat conformation. Compounds 2–4 were similar to our recently reported ruthenium diborinane complex [(Cp*Ru){(η2-SCHS)CH2S2(BH2)2}]. Unlike diborinane, where the central six-membered ring {CB2S3} adopted a chair conformation, compounds 2–4 adopted a boat conformation. In an attempt to convert arachno-1 into a closo or nido cluster, we pyrolyzed it in toluene. Interestingly, the reaction led to the isolation of a capped butterfly cluster, [(Cp*Ru)2(B3H5)(CS2H2)] 5. All the compounds were characterized by 1H, 11B{1H}, and 13C{1H} NMR spectroscopy and mass spectrometry. The molecular structures of complexes 2, 3, and 5 were also determined by single-crystal X-ray diffraction analysis.

Structure cristalline et moléculaire de l'acétoxy-3β ursane olide-28,20βa

1987 ◽  
Vol 65 (4) ◽  
pp. 851-854 ◽  
Author(s):  
Danielle Druet ◽  
Louis Claude Comeau ◽  
Robert Viani ◽  
André Baldy ◽  
Jacques Estienne ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Chemical Analysis ◽  
Chair Conformation ◽  
Boat Conformation ◽  
X Ray ◽  
Crystallographic Study

An X-ray crystallographic study of the triterpene C32H50O4, isolated from Opiliaceltidifolia, confirms the chemical analysis of the molecular structure. The rings A, B, C, and D are in the chair conformation, but ring E, due to a bridging lactone between the C(17) and C(20) carbon atoms, adopts a boat conformation. All five six-membered rings are trans-fused.

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