Search results for "bond"
showing 10 items of 3527 documents
The first authenticated example of triorganotin(IV) perchlorate complexes of some heterocyclic bases
1993
Abstract A convenient method is reported for the synthesis of some novel complexes of composition (R 3 SnL 2 ) ClO 4 where L represents pyridine, γ-picoline, 2,2′-bipyridine and 1,10-phenanthroline; and R n Bu or Ph. All of the new ionic complexes have been characterized by elemental analysis, molar conductance, infrared, multinuclear nuclear magnetic resonance ( 1 H, 13 C and 119 Sn) and 119 Sn Mossbauer spectroscopies. The complexes of composition (R 3 SnL 2 )ClO 4 exist both in solution and in the solid state with trans -trigonal bipyramidal structure where the R-groups occupy the equatorial positions while the ligands are in the axial position.
SYNTHESIS, LASER-RAMAN, INFRARED AND PROTON MAGNETIC RESONANCE SPECTRA OF (CH3)3PtX2- 3 IONS (X = Cl−, Br−) AND (CH3)3Ptiv ISOCYANIDE COMPLEXES
1976
Abstract The novel ionic complexes [(C6H5)4As]2 [(CH3)3PtX3](X = Cl− and Br−) and [(CH3)3Pt(bipy)L]+[B(C6H5)4]− (bipy = 2,2′-bipyridine, L = aliphatic and aromatic isocyanide) have been prepared. The structure of the complex ions has been inferred from Laser-Raman and infrared spectra in the solid state and 1H NMR in solution. These data are consistent with a facial configuration of the organometallic moiety. Trends in vibrational frequencies ν(Pt-C) and ν(Pt-X) indicate a “trans” influence sequence for the ligands, which in the case of (CH3)3PtX2- 3 is related with that found for (CH3)2AuX− 2 ions.
Complexes of Tin(IV) with Tridentate Ligands M�SSBAUER, Infrared, and Solution Phase Studies
1974
The configuration in the solid state and in solution phase of complexes of SuIV wit,li tridentate “planar” ligands, Sn(trid)2 and HNEt3Cl3 Sntrid, have been investigated by infrared and MOSSBAUER spectroscopy, as well as by osmometry, conductivity, and electronic and PMR spectroscopy. The presence of monomeric Sn(trid)2 and ionic [HNEt] [Cl3Sn trid−] species has been inferred. Octahedral type configurations are advanced for both classes of compounds. Komplexe des Zinn (IV) mit dreizahigen Liganden. Mossbauer- und IR-Spektren sowie Untersuchungen von Losungen Die Struktur von SnIV-Komplexen mit dreizahnigen “planaren” Liganden, Sn(trid)2 und HNEt3Cl2Sntrid, wurde in fester Phase und in Losun…
Bioconjugates of 1’-Aminoferrocene-1-carboxylic Acid with (S)-3-Amino-2-methylpropanoic Acid and L-Alanine
2010
Formal CH 2 insertion in bioconjugates composed of 1'-aminoferrocene-1-carboxylic acid (Fca) and alanine Boc-Ala-Fca-Ala-OCH 3 gives Fca bioconjugates with the β-amino acid (S)-3-amino-2-methylpropanoic acid (Aib). The novel homologous conjugates of ferrocene were fully characterized by spectroscopic and analytical methods. NMR, CD and IR spectroscopy in concert with DFT calculations suggest that the formal "L-Ala-to-(S)-β-Aib mutations" can exert ferrocene helix inversion due to the different stereogenic carbon atoms of L -Ala and (S)-β-Aib. Furthermore, the mutation (de-)stabilizes the conserved secondary structure with two intramolecular hydrogen bonds, depending on the "mutation site". …
Metal Phosphonates Based on {[(Benzimidazol‐2‐ylmethyl)imino]bis(methylene)}bis(phosphonic Acid): Syntheses, Structures and Magnetic Properties of th…
2006
Five compounds based on {[(benzimidazol-2-ylmethyl)imino]bis(methylene)}bis(phosphonic acid) [(C7H5N2)CH2N(CH2PO3H2)2], namely [M{(C7H5N2)CH2N(CH2PO3H)2}] [M = Mn (1), Fe (2), Co (3), Cu (4), Cd (5)] have been synthesized under hydrothermal conditions. These compounds are isostructural, crystallizing in the orthorhombic space group Pbca, with a = 15.331(2), b = 10.7150(16), and c = 16.715(2) A for 1; a = 15.320(3), b = 10.477(2), and c = 16.764(3) A for 2; a = 15.207(2), b = 10.4626(16), and c = 16.794(3) A for 3; a = 15.101(3), b = 10.3517(17), and c = 16.997(3) A for 4; and a = 15.4679(19), b = 10.8923(13), and c = 16.6175(19) for 5. Each compound shows a one-dimensional chain structure w…
Untersuchungen über das Benzothiiren
1984
Thermolyse und Photolyse von 1,2,3-Benzothiadiazol 10c, liefern die Produkte 11c – 15c. Mit Hilfe der 13C-Markierungstechnik wird gezeigt, das dabei kein intermediares Benzothiiren 1c gebildet wird. Isotopomere Reaktionsprodukte gehen auf H-Verschiebungen zuruck. Durch elektronenziehende Estergruppen in 6-Position wird der Ringschlus zu den substituierten Benzothiirenen 1d, e zwar nicht bei der Thermolyse, wohl aber bei der photochemischen Reaktionsfuhrung ermoglicht. Zum Nachweis dient eine eingehende Untersuchung der bei Thermolyse, Photolyse und auf einem unabhangigen Weg erhaltenen Disulfide 14d, e, bzw. 14d′, e′ und 14d˝, e˝. Die vorliegenden Ergebnisse basieren auf 13C- und 1H-NMR-Mes…
Synthesis and crystal structure of the low-spin iron(II) complex [Fe(bpym)3](ClO4)2·1/4H2O (bpym=2,2′-bipyrimidine)
1997
Abstract Single crystals of the mononuclear iron(II) complex of formula [Fe(bpym)3](ClO4)2·1/4H2O (bpym=2,2′-bipyrimidine) have been prepared and characterized crystallographically. The complex is monoclinic, P21/c, a=13.688(5), b=19.391(6), c=11.554(5) A, β=102.22(3)°, V=2997(2) A3, Z=4, R=0.063 and Rw=0.068. The structure analysis reveals a distorted octahedral geometry around the iron atom. The average Fe–N bond length and N–Fe–N bidentate angle are 1.970(5) A and 81.0(1)°, respectively. The value of the Fe–N distance and that of the room temperature magnetic moment are in agreement with its singlet 1A1 ground state.
Synthesis, crystal structure and magnetic properties of the spin crossover system [Fe(pq)3]2+
2008
Abstract Three new compounds formulated (ClO4)2[Fe(pq)3] (1), (BF4)2[Fe(pq)3] · EtOH (2) and {(ClO4)[MnCr(C2O4)3][Fe(pq)2(H2O)2]} (3), where pq is 2,2′-pyridylquinoline, have been synthesised and characterised. Despite the different crystal packing exhibited by 1 and 2, the cationic species [Fe(pq)3]2+ are structurally quite similar. At 293 K, the Fe–N bond lengths are characteristic of the iron(II) in the high-spin state. In contrast to 1, 2 undergoes a continuous spin transition. Indeed, at 95 K its structure experiences a noticeable change in the Fe–N bonds and angles, i.e. the Fe–N bonds shorten by 0.194 A on the average. The magnetic behaviour confirms that 1 is fully high-spin in the …
Synthesis and Physical Properties of K4[Fe(C5O5)2(H2O)2](HC5O5)2·4H2O (C5O52– = Croconate): A Rare Example of Ferromagnetic Coupling via H-bonds
2012
The reaction of the croconate dianion (C(5)O(5))(2-) with a Fe(III) salt has led, unexpectedly, to the formation of the first example of a discrete Fe(II)-croconate complex without additional coligands, K(4)[Fe(C(5)O(5))(2)(H(2)O)(2)](HC(5)O(5))(2)·4H(2)O (1). 1 crystallizes in the monoclinic P2(1)/c space group and presents discrete octahedral Fe(II) complexes coordinated by two chelating C(5)O(5)(2-) anions in the equatorial plane and two trans axial water molecules. The structure can be viewed as formed by alternating layers of trans-diaquabis(croconato)ferrate(II) complexes and layers containing the monoprotonated croconate anions, HC(5)O(5)(-), and noncoordinated water molecules. Both …
Syntheses, Crystal Structures, and Magnetic Properties of the Oxalato-Bridged Mixed-Valence Complexes [FeII(bpm)3]2[FeIII2(ox)5]·8H2O and FeII(bpm)3N…
2001
The preparation and crystal structures of two oxalato-bridged FeII-FeIII mixed-valence compounds, [FeII(bpm)3]2[FeIII2(ox)5].8H2O (1) and FeII(bpm)3Na(H2O)2FeIII(ox)(3).4H2O (2) (bpm = 2,2'-bipyrimidine; ox = oxalate dianion) are reported here. Complex 1 crystallizes in the triclinic system, space group P1, with a = 10.998(2) A, b = 13.073(3) A, c = 13.308(3) A, alpha = 101.95(2) degrees, beta = 109.20(2) degrees, gamma = 99.89(2) degrees, and Z = 1. Complex 2 crystallizes in the monoclinic system, space group P2(1)/c, with a = 12.609(2) A, b = 19.670(5) A, c = 15.843(3) A, beta = 99.46(1) degrees, and Z = 4. The structure of complex 1 consists of centrosymmetric oxalato-bridged dinuclear h…