Übergangsmetallkomplexe mit Nitroxidradikalen: Palladium-, Platin-, Pentamethylcyclopentadienyl-rhodium- und -iridium-Komplexe sowie α-Aminocarboxylatkomplexe mit Donor-haltigen Derivaten des 2,5-Dihydroimidazol-l-oxyls / Transition Metal Complexes of Nitroxide Radicals, Palladium, Platinum, Pentamethylcyclopentadienyl Rhodium and Iridium Complexes, and α-Aminocarboxylate Complexes with Derivatives of 2,5-Dihydroimidazole-l-oxyls

1998 ◽  
Vol 53 (1) ◽  
pp. 101-109 ◽  
Author(s):  
Frank Hintermaier ◽  
Sylvia Helding ◽  
Leonid B. Volodarsky ◽  
Karlheinz Sünkel ◽  
Kurt Polbom ◽  
...  
Keyword(s):  
Nitrogen Atom ◽  
Molecular Structures ◽  
Iridium Complexes ◽  
X Ray Diffraction ◽  
Chelate Complexes ◽  
X Ray ◽  
Ring Nitrogen ◽  
Derivatives Of ◽  
Ring Nitrogen Atom ◽  
Palladium Platinum

2,5-Dihydroimidazoline-l-oxyl radicals I, II with imino substituents coordinate to Pd(II) and Pt(II) complexes with formation of the N,N chelate complexes 1-6. With oxygen containing substituents either monodentate N-coordination to give 8 or N ,O chelate formation to give 9 takes place, depending on the position of the oxygen atom relative to the ring nitrogen atom. With radicals III that also have the second ring nitrogen atom oxidized and the Rh(III) or Ir(III) complexes [Cp*MCl2]2 the O , O chelates 11 -13 could be obtained, while with Na2PdCl4 the heterocycle was destroyed with formation of a N,N chelate complex 10 of an α-nitrosooxime ligand. The orthopalladated 2,2,5,5 tetramethyl-4-phenyl-2,5-dihydroimidazoline-l-oxyl complex 7a reacts with several a-amino acidates under splitting of the dichloro bridge with formation of the C,N/N,O-bis-chelate complexes 7b-f. The molecular structures of 2 and 10 were determined by X-ray diffraction.

β-Hydroxydithiozimtsäurederivate als Liganden. Synthese und Charakterisierung neuartiger 1,1-Ethendithiolato- und O,S-Chelatkomplexe / Derivatives of β -Hydroxydithiocinnamic Acids as Ligands. Syntheses and Characterisation of Novel 1,1-Ethenedithiolato and O,S-Chelate Complexes

2007 ◽  
Vol 62 (3) ◽  
pp. 475-482 ◽  
Author(s):  
Karsten Schubert ◽  
Helmar Görls ◽  
Wolfgang Weigand
Keyword(s):  
Bidentate Ligand ◽  
Molecular Structures ◽  
X Ray Diffraction ◽  
Chelate Complexes ◽  
X Ray ◽  
H Nmr ◽  
Hexyl Ester ◽  
Elemental Analyses ◽  
Derivatives Of ◽  
C Nmr

Starting from 4-bromoacetophenone 1, the 4-bromo-β -hydroxydithiocinnamic acid 2 and the 4-bromo-β -hydroxydithiocinnamic acid hexyl ester 3 were prepared using carbon disulfide and potassium-tert-butylate as a base. Acting as a ligand, the acid gives 1,1-ethenedithiolato complexes with (Ph3P)2Pt(II) (4a), (Et3P)2Pt(II) (4b), dppePt(II) (4c), (Ph3P)2Pd(II) (4d), dppePd(II) (4e), and dppeNi(II) (4f). In contrast to the acid, the deprotonated ester 3 forms a monoanionic bidentate ligand. [O,S] Complexes of Pt(II) (5a), Pd(II) (5b) and Ni(II) (5c) were obtained. All complexes have been fully characterised using 1H NMR, 13C NMR and 31P NMR spectroscopy, mass spectrometry, infrared spectroscopy and elemental analyses. The molecular structures of the complexes 4b and 5a - 5c were determined by X-ray diffraction analyses.

scholarly journals Bis(dicarbollide) Complexes of Transition Metals as a Platform for Molecular Switches. Study of Complexation of 8,8′-Bis(methylsulfanyl) Derivatives of Cobalt and Iron Bis(dicarbollides)

Molecules ◽  
2020 ◽  
Vol 25 (23) ◽  
pp. 5745
Author(s):  
Sergey A. Anufriev ◽  
Sergey V. Timofeev ◽  
Alexei A. Anisimov ◽  
Kyrill Yu. Suponitsky ◽  
Igor B. Sivaev
Keyword(s):  
Solid State ◽  
Transition Metal ◽  
Molecular Switches ◽  
X Ray Diffraction ◽  
Chelate Complexes ◽  
X Ray ◽  
Complexes Of Transition Metals ◽  
Silver Palladium ◽  
Solid State Structures ◽  
Derivatives Of

Complexation of the 8,8′-bis(methylsulfanyl) derivatives of cobalt and iron bis(dicarbollides) [8,8′-(MeS)2-3,3′-M(1,2-C2B9H10)2]− (M = Co, Fe) with copper, silver, palladium and rhodium leads to the formation of the corresponding chelate complexes, which is accompanied by a transition from the transoid to the cisoid conformation of the bis(dicarbollide) complex. This transition is reversible and can be used in design of coordination-driven molecular switches based on transition metal bis(dicarbollide) complexes. The solid-state structures of {(Ph3P)ClPd[8,8′- (MeS)2-3,3′-Co(1,2-C2B9H10)2-κ2-S,S′]} and {(COD)Rh[8,8′-(MeS)2-3,3′-Co(1,2-C2B9H10)2-κ2-S,S′]} were determined by single crystal X-ray diffraction.

scholarly journals 2-Hetaryl-1,3-tropolones based on five-membered nitrogen heterocycles: synthesis, structure and properties

2015 ◽  
Vol 11 ◽  
pp. 2179-2188 ◽  
Author(s):  
Yury A Sayapin ◽  
Inna O Tupaeva ◽  
Alexandra A Kolodina ◽  
Eugeny A Gusakov ◽  
Vitaly N Komissarov ◽  
...  
Keyword(s):  
Density Functional ◽  
Acetic Acid Solution ◽  
Intramolecular Proton Transfer ◽  
Molecular Structures ◽  
X Ray Diffraction ◽  
Dft Methods ◽  
Functional Theory ◽  
X Ray ◽  
X Ray Crystallography ◽  
Derivatives Of

A series of derivatives of 2-hetaryl-1,3-tropolone (β-tropolone) was prepared by the acid-catalyzed reaction of 2-methylbenzoxazoles, 2-methylbenzothiazoles and 2,3,3-trimethylindoline with 3,4,5,6-tetrachloro-1,2-benzoquinone. The molecular structures of the three representative compounds were determined by X-ray crystallography. In crystal and (as shown by the DFT PBE0/6-311+G** calculations) in solution, 2-hetaryl-4,5,6,7-tetrachloro- and 2-hetaryl-5,6,7-trichloro-1,3-tropolones exist in the NH-tautomeric form with a strong resonance-assisted intramolecular N–H···O hydrogen bond. The mechanism of the formation of 1,3-tropolones in the reaction of methylene-active five-membered heterocycles with o-chloranil in acetic acid solution has been studied using density functional theory (DFT) methods. The reaction of 2-(2-benzoxa(thia)zolyl)-5,6,7-trichloro(4,5,6,7-tetrachloro)-1,3-tropolones with alcohols leads to the contraction of the seven-membered tropone ring with the formation of 2-(2-benzoxa(thia)zolyl)-6-alkoxycarbonylphenols. The molecular structure of 2-(2-ethoxycarbonyl-6-hydroxy-3,4,5-trichlorophenyl)benzoxazole has been determined by X-ray diffraction. 2-(2-Benzoxa(thia)zolyl)-6-alkoxycarbonylphenols display intense green fluorescence with anomalous Stokes shifts caused by the excited state intramolecular proton transfer (ESIPT) effects.

scholarly journals Exploring the Isomer Dependent SERS Spectra of (diphenylphosphoryl)(pyridin-2, -3, and -4-yl)methanol Adsorbed on Gold Nanocolloids

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Ewa Pięta ◽  
Edyta Proniewicz ◽  
Bogdan Boduszek ◽  
Tomasz K. Olszewski ◽  
Younkyoo Kim ◽  
...  
Keyword(s):  
Nitrogen Atom ◽  
Adsorption Process ◽  
Gold Surface ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering ◽  
Ring Nitrogen ◽  
Derivatives Of ◽  
Ring Nitrogen Atom ◽  
Surface Changes

The surface-enhanced Raman scattering (SERS) spectra of three aminophosphonate derivatives of pyridine: (diphenylphosphoryl)(pyridin-2-yl)methanol (α-Pyr), (diphenylphosphoryl)(pyridin-3-yl)methanol (β-Pyr), and (diphenylphosphoryl)(pyridin-4-yl)methanol (γ-Pyr) were measured after immobilization onto colloidal gold surface. Changes in the wavenumber, broadness, and enhancement between the corresponding Raman and SERS bands allowed to deduce orientation of theα-,β-, andγ-isomers (α-,β-, andγ-refer to the position of the substituent relative to the ring nitrogen atom) of aminophosphonate derivatives of pyridine on the gold surface. Briefly, it was demonstrated that theα-Pyr andβ-Pyr show the same mode of adsorption, whereas the adsorption process of theγ-Pyr isomer differs in this regard that pyridine assists in the interaction with the gold surface.

scholarly journals Synthesis and Reactivity of Pyrrolide-Diimine Complexes of Chromium

2007 ◽  
Vol 72 (5-6) ◽  
pp. 637-648 ◽  
Author(s):  
Brian A. Salisbury ◽  
John F. Young ◽  
Glenn P. A. Yap ◽  
Klaus H. Theopold
Keyword(s):  
Molecular Structures ◽  
Octahedral Coordination ◽  
Octahedral Complex ◽  
Coordination Geometry ◽  
X Ray Diffraction ◽  
X Ray ◽  
Alkyl Derivatives ◽  
Nitrogen Donors ◽  
Diimine Complexes ◽  
Derivatives Of

Lithium 2,5-bis{[(2,6-diisopropylphenyl)imino]methyl}pyrrol-1-ide (LiL) reacts with [CrCl3(thf)3] to yield the octahedral complex [(η2-L)CrCl2(thf)2] (1), in which only two of the three potential nitrogen donors are coordinated to chromium. In the presence of various alkyl aluminum cocatalysts, 1 catalyzes the polymerization of ethylene. Attempts to prepare alkyl derivatives of 1 were thwarted by an apparent disproportionation, yielding divalent [(η2-L)(η1-L)Cr(thf)] (2). The molecular structures of 1 and 2 have been determined by X-ray diffraction. The structure of 2 is unusual in that it features weak, but equivalent interactions of both imine groups of the η1-pyrrolide ligands with the chromium, giving rise to an approximately octahedral coordination geometry with two extremely long Cr-N distances.

Crystal and molecular structures of two aryldiazenato complexes of molybdenum of the type [Mo(N2Ar)(S2CNMe2)3]

1980 ◽  
Vol 33 (4) ◽  
pp. 717 ◽  
Author(s):  
GA Williams ◽  
ARP Smith
Keyword(s):  
Nitrogen Atom ◽  
Single Crystal ◽  
Crystal Lattice ◽  
Magnetic Moments ◽  
Nitro Derivative ◽  
Molecular Structures ◽  
Electron Donors ◽  
X Ray Diffraction ◽  
X Ray ◽  
Crystal And Molecular Structures

The crystal and molecular structures of the aryldiazenato complexes of molybdenum, [Mo(N2C6H5)(S2CNMe2)3],CH2Cl2 (1), and the m-nitro derivative [Mo{N2C6H4(m-NO2)}-(S2CNMe2)3]2,�CH2Cl2,�H2O (2), have been determined by single-crystal X-ray diffraction methods at 294 K. Crystals of (1) are monoclinic, P21/n, a 13.056(1), b 13.366(1), c 15.350(1) Ǻ, β 93.80(1)°, Z 4. Crystals of (2) are monoclinic, C2/c, a 32.442(8), b 17.670(4), c 17.867(3) Ǻ, β 99.03(1)°, Z 8. Automatic diffractometry has provided significant Bragg intensities for 2849 (1) and 3898 (2) independent reflections and the structures have been refined by least-squares methods to R 0.036 (1) and 0.053 (2). The two unique molybdenum complexes in (2) are essentially chemically equivalent. The complexes in (1) and (2) possess the expected seven-coordinate pentagonal bipyramidal structures with the aryldiazenato ligands, singly bent, occupying axial positions. The N=N-Mo units are linear, and the bonding can be represented by N=N→Mo with the aryldiazenato ligands three-electron donors. The m-nitro substituent in (2) interacts with a dithiocarbamate (dtc) nitrogen atom, thereby affecting the redox behaviour of this compound. The possible significance of this O(nitro)...N(dtc) interaction to the mechanism, whereby included nitrobenzene solvent in the crystal lattice lowers the magnetic moments of ferric dithiocarbamates, is discussed.

scholarly journals CO2 Derivatives of Molecular Tin Compounds. Part 1: Hemicarbonato and Carbonato Complexes

Inorganics ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 31
Author(s):  
Laurent Plasseraud
Keyword(s):  
Elevated Pressure ◽  
Molecular Structures ◽  
X Ray Diffraction ◽  
Tin Compounds ◽  
X Ray ◽  
Synthesis Conditions ◽  
Structural Database ◽  
Carbonate Salts ◽  
Derivatives Of ◽  
Nickel Cluster

This review focuses on organotin compounds bearing hemicarbonate and carbonate ligands, and whose molecular structures have been previously resolved by single-crystal X-ray diffraction analysis. Most of them were isolated within the framework of studies devoted to the reactivity of tin precursors with carbon dioxide at atmospheric or elevated pressure. Alternatively, and essentially for the preparation of some carbonato derivatives, inorganic carbonate salts such as K2CO3, Cs2CO3, Na2CO3 and NaHCO3 were also used as coreagents. In terms of the number of X-ray structures, carbonate compounds are the most widely represented (to date, there are 23 depositions in the Cambridge Structural Database), while hemicarbonate derivatives are rarer; only three have so far been characterized in the solid-state, and exclusively for diorganotin complexes. For each compound, the synthesis conditions are first specified. Structural aspects involving, in particular, the modes of coordination of the hemicarbonato and carbonato moieties and the coordination geometry around tin are then described and illustrated (for most cases) by showing molecular representations. Moreover, when they were available in the original reports, some characteristic spectroscopic data are also given for comparison (in table form). Carbonato complexes are arbitrarily listed according to their decreasing number of hydrocarbon substituents linked to tin atoms, namely tri-, di-, and mono-organotins. Four additional examples, involving three CO2 derivatives of C,N-chelated stannoxanes and one of a trinuclear nickel cluster Sn-capped, are also included in the last part of the chapter.

Metallkomplexe mit biologisch wichtigen Liganden, LXXV. Synthese metallorganischer Cobalt(III)-, Iridium(III)- und Ruthenium(II)-Komplexe mit α-Iminocarboxylat-Liganden Metal Complexes of Biologically Important Ligands, LXXV. Synthesis of Organometallic Cobalt(III), Iridium(III) and Ruthenium(II) Complexes with α-Iminocarboxylate Ligands

1995 ◽  
Vol 50 (2) ◽  
pp. 265-274 ◽  
Author(s):  
Kay Severin ◽  
Ralph Bergs ◽  
Michael Maurus ◽  
Sharam Mihan ◽  
Wolfgang Beck
Keyword(s):  
Metal Complexes ◽  
Iridium Complexes ◽  
X Ray Diffraction ◽  
Chelate Complexes ◽  
X Ray

The α-iminocarboxylato chelate complexes RuH(CO)[OOC-C(R1)=N-R2](PPh3)2 (1), η6-p-cymene)RuCl[OOC-C(R)=N-CH2CO2Me] (3) and Cp*CoI[OOC-C(R1)= N-R2] (4) have been obtained from RuHCl(CO)(PPh3)3, [(η6-p-cymene)RuCl2] and Cp*Co(CO)I2, respectively and 2-oxocarboxylate/amine. The structure of (η6-p-cymene)RuCl[OOC-C(CH3)= N-CH2CO2Me] (3a) has been determined by X-ray diffraction. By use of diamines the corresponding dinuclear cobalt and iridium complexes (5, 6) are formed from 2-oxocarboxylate and Cp*Co(CO)I2 or [Cp*IrCl2]2.

Reaction of Imidazoles with Cyanogen Bromide: Cyanation at N 1 or Bromination at C 2?

1999 ◽  
Vol 52 (3) ◽  
pp. 159 ◽  
Author(s):  
Peter B. W. McCallum ◽  
M. Ross Grimmett ◽  
Allan G. Blackman ◽  
Rex T. Weavers
Keyword(s):  
Nitrogen Atom ◽  
Cyanogen Bromide ◽  
Lone Pair ◽  
Alkyl Substituent ◽  
Acetonitrile Solution ◽  
Crystal Data ◽  
X Ray ◽  
Ring Nitrogen ◽  
Ring Nitrogen Atom

The reaction in acetonitrile solution of a number of imidazoles(1H-, 1-methyl-, 2-methyl-, 4-methyl-, 1,2-, 1,4- and1,5-dimethyl-, 1-ethyl-, 1-benzyl- and 1-butyl-imidazole) and imidazolecomplexes([Co(NH3)5(imH)](ClO4)3,[Co(NH3)5(im)](ClO4)2 and[Co(NH3)5(1-Meim)](ClO4)3) with BrCN has beenstudied. Those imidazoles bearing an N-alkyl substituent and having a hydrogenat C2 react to give the 2-bromo products, while the N-H imidazoles react togive N-cyano derivatives. The product(s) from thereaction of 1,2-dimethylimidazole with BrCN could not be characterized. Of thecomplexes, only[Co(NH3)5(im)](ClO4)2 reacts, giving the 2-bromoproduct. Our observations suggest a lone pair on a ring nitrogen atom isnecessary for an imidazole to react with BrCN, and a possible mechanism issuggested. The X-ray structure of 2-methylimidazole-1-carbonitrile isreported. Crystal data (–143°C) forC5H5N3:monoclinic, P21/c, a10·201(5), b 7·110(3),c 7·227(3) Å, β 100·47(2)°,V 515·4(4) Å 3 , Z 4,dcalcd 1·380 gcm¯3 . Refinement of the structure converged withR1 0·0444 for 1183reflections with Fo >4F(Fo) andwR2 0·1259 for all 1278data.

Structures of 4-Iminopyrido[1,2-a]pyrimidines, Pyrido[1,2-a]pyrimidin-4-ones, Pyridopyrimidinium Olates, and Thiazolo[3,2-a]pyrimidine Analogues

2012 ◽  
Vol 65 (4) ◽  
pp. 371 ◽  
Author(s):  
Paul V. Bernhardt ◽  
Curt Wentrup
Keyword(s):  
Nitrogen Atom ◽  
Ring Opening ◽  
Normal Range ◽  
X Ray ◽  
X Ray Crystallography ◽  
Structural Peculiarities ◽  
Ring Nitrogen ◽  
Structure Correlation ◽  
Pyrimidine Analogues ◽  
Ring Nitrogen Atom

The Structure-Correlation Principle of Bürgi and Dunitz is invoked in an analysis of the structures of 2-chloro-8-methyl-4-(2-(4-picolinyl)imino-4H-pyrido[1,2-a]pyrimidine 8, 7-chloro-5-(2-thiazolyl)imino-5H-thiazolo[3,2-a]pyrimidine 9, 2-methylamino-4H-pyrido[1,2-a]pyrimidin-4-one 10, 7-methylthio-5H-thiazolo[3,2-a]pyrimidin-5-one 11, 2,3-dihydro-7-methylthio-5H-thiazolo[3,2-a]pyrimidin-5-one 12, and 1-methyl-2-[(o-tert-butylphenyl)imino]-1,2-dihydropyrido[1,2-a]pyrimidin-1-ium-4-olate 13, which have been determined by X-ray crystallography. The most notable structural peculiarities are the long ‘amidine’ and ‘amide’ C–N bonds (1.40–1.50 Å) and the tilting of the ‘amidine’ C=N and ‘amide’ C=O groups towards a ring nitrogen atom (NCX = 114–118°). Also the ‘amidine’ C=N (1.28 Å) and ‘amide’ C=O bonds (1.22–1.24 Å) are long, i.e. in the normal range for resonance-stabilized amidines and amides in spite of the lack of such resonance in these compounds. These features mimic the transition states for ring opening to ketenes. The long amidine and amide C–N bonds and acute NCX angles are in accord with the observed thermal ring opening to ketenimines and ketenes, respectively.

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