Preparation and characterization of a new series of Cr(II) hydroborates

1995 ◽  
Vol 73 (7) ◽  
pp. 1126-1134 ◽  
Author(s):  
Michel Dionne ◽  
Shoukang Hao ◽  
Sandro Gambarotta
Keyword(s):  
Trinuclear Complex ◽  
Synthesis And Characterization ◽  
Crystal Data ◽  
X Ray ◽  
X Ray Crystallography ◽  
Quadruple Bond ◽  
Quadruple Bonds ◽  
Reaction Proceeds

The synthesis and characterization of a new series of mono-, di-, and trinuclear Cr(II) borohydride compounds is described. The reaction of CrCl2(TMEDA) with two equivalents of NaBH4 afforded the thermally unstable (TMEDA)Cr(BH4)2 (1), which was converted by treatment with pyridine into the octahedral monomeric (Py)4Cr(BH4)2 (2). The reaction proceeds via formation of an intermediate trinuclear complex {[(TMEDA)(Py)Cr(η2-BH4)]2[(Py)2Cr(η2-BH4)2]}(µ,η1-BH4)2 (3), which was isolated and characterized by X-ray crystallography. Reaction of 1 and 2 with both CO2 and RN=C=NR (R = Cy, iPr) afforded hydride insertion and formation of the corresponding diamagnetic lantern-type Cr(II) formate (HCO2)4Cr2Py2 (4) and formamidinate compounds [RNC(H)NR]2Cr2(µ-BH)4 (R = Cy (5a), iPr (5b)), respectively, with supershort Cr—Cr quadruple bonds. The structures of 1, 2, 3, and 5b were elucidated by X-ray analysis. Crystal data are as follows. 1: C6H24N2B2Cr, monoclinic, Cc, a = 8.517(2) Å, b = 15.921(5) Å, c = 9.624(2) Å, β = 115.59(1)°, Z = 4, R = 0.022, Rw = 0.029; 2: C28H44N4B2O2Cr, monoclinic, P21/n, a = 12.021(1) Å, b = 15.555(1) Å, c = 15.723(1) Å, β = 90.13(2)°, Z = 4, R = 0.074, Rw = 0.086; 3: C32H76N8B6Cr3, monoclinic, P21/n, a = 8.515(1) Å, b = 14.525(1) Å, c = 18.286(2) Å, β = 91.38(1)°, Z = 2, R = 0.051, Rw = 0.060; 5b: C21H49N6BCr2, monoclinic, C2/c, a = 17.000(1) Å, b = 9.033(1) Å, c = 19.160(1) Å, β = 105.579(9)°, Z = 4, R = 0.069, Rw = 0.078. Keywords: divalent chromium, borohydride, Cr—Cr quadruple bond.

Synthesis and characterization of the binuclear diamido titanium chalcogenides [(Ar)NCH2CH2CH2N(Ar)]2Ti(µ-E)2 (E = Se, Te)

2002 ◽  
Vol 80 (11) ◽  
pp. 1524-1529 ◽  
Author(s):  
Tianle Zhang ◽  
Warren E Piers ◽  
Masood Parvez
Keyword(s):  
Solid State ◽  
Key Words ◽  
Synthesis And Characterization ◽  
Catalyst Precursor ◽  
Tellurium Atom ◽  
Titanium Complex ◽  
X Ray ◽  
X Ray Crystallography ◽  
Atom Source

Reaction of McConville's chelating amido titanium complex [(Ar)NCH2CH2CH2N(Ar)]Ti(CH3)2 (Ar = 2,6-i-Pr2C6H3) with either elemental Se or the tellurium atom source Te=PBu3 resulted in the formation of bis-µ-chalcogenido dimers [(Ar)NCH2CH2CH2N(Ar)]2Ti(µ-E)2 (E = Se, 2; Te, 3) with concommitant loss of EMe2. The dimers 2 and 3 were characterized spectroscopically and via X-ray crystallography. The two compounds are isostructural in the solid state. The tellurido dimer 3 may also be synthesized by reduction of the diamido dichloride [(Ar)NCH2CH2CH2N(Ar)]2TiCl2 with Na–Hg amalgam followed by treatment with Te=PBu3. This dimer is unreactive toward further Te=PBu3 or stannanes such as HSnBu3. Unlike decamethyltitanocene derivatives, the diamido complex is not an effective catalyst precursor for the heterohydrodecoupling of Te=PBu3 and HSnBu3.Key words: diamido titanium complexes, selenides, tellurides.

scholarly journals CAAC Boranes. Synthesis and characterization of cyclic (alkyl) (amino) carbene borane complexes from BF3 and BH3

2010 ◽  
Vol 6 ◽  
pp. 709-712 ◽  
Author(s):  
Julien Monot ◽  
Louis Fensterbank ◽  
Max Malacria ◽  
Emmanuel Lacôte ◽  
Steven J Geib ◽  
...  
Keyword(s):  
Silica Gel ◽  
Synthesis And Characterization ◽  
Gel Chromatography ◽  
Nmr Analysis ◽  
X Ray ◽  
X Ray Crystallography ◽  
In Situ Formation ◽  
Silica Gel Chromatography

In situ formation of two cyclic (alkyl) (amino) carbenes (CAACs) followed by addition of BF3•Et2O provided the first two examples of CAAC–BF3 complexes: 1-(2,6-diisopropylphenyl)-3,5,5-trimethyl-3-phenylpyrrolidin-2-ylidene trifluoroborane, and 2-(2,6-diisopropylphenyl)-3,3-dimethyl-2-azaspiro[4.5]decan-1-ylidene trifluoroborane. These CAAC–BF3 complexes are robust compounds that are stable to ambient laboratory conditions and silica gel chromatography. They were characterized by spectroscopy and X-ray crystallography. In contrast, a CAAC complex with borane (BH3) was readily formed in situ according to 1H and 11B NMR analysis, but did not survive the workup conditions. These results set the stage for further studies of the chemistry of CAAC boranes.

scholarly journals Synthesis and characterization of novel bioactive 1,2,4-oxadiazole natural product analogs bearing the N-phenylmaleimide and N-phenylsuccinimide moieties

2013 ◽  
Vol 9 ◽  
pp. 2202-2215 ◽  
Author(s):  
Catalin V Maftei ◽  
Elena Fodor ◽  
Peter G Jones ◽  
M Heiko Franz ◽  
Gerhard Kelter ◽  
...  
Keyword(s):  
Natural Product ◽  
Synthesis And Characterization ◽  
Aminobenzoic Acid ◽  
One Pot ◽  
X Ray ◽  
X Ray Crystallography ◽  
Quisqualic Acid ◽  
Oxobutanoic Acid

Taking into consideration the biological activity of the only natural products containing a 1,2,4-oxadiazole ring in their structure (quisqualic acid and phidianidines A and B), the natural product analogs 1-(4-(3-tert-butyl-1,2,4-oxadiazol-5-yl)phenyl)pyrrolidine-2,5-dione (4) and 1-(4-(3-tert-butyl-1,2,4-oxadiazol-5-yl)phenyl)-1H-pyrrole-2,5-dione (7) were synthesized starting from 4-(3-tert-butyl-1,2,4-oxadiazol-5-yl)aniline (1) in two steps by isolating the intermediates 4-(4-(3-tert-butyl-1,2,4-oxadiazol-5-yl)phenylamino)-4-oxobutanoic acid (3) and (Z)-4-(4-(3-tert-butyl-1,2,4-oxadiazol-5-yl)phenylamino)-4-oxobut-2-enoic acid (6). The two natural product analogs 4 and 7 were then tested for antitumor activity toward a panel of 11 cell lines in vitro by using a monolayer cell-survival and proliferation assay. Compound 7 was the most potent and exhibited a mean IC50 value of approximately 9.4 µM. Aniline 1 was synthesized by two routes in one-pot reactions starting from tert-butylamidoxime and 4-aminobenzoic acid or 4-nitrobenzonitrile. The structures of compounds 1, 2, 4, 5 and 6 were confirmed by X-ray crystallography.

Synthesis and characterization of 5,12-dimethyl-7,14-diphenyl-1,4,8,11- tetraazacyclotetradecane-4,11-diacetic acid and its transition metal complexes; crystal structure of the copper(II) complex of the macrocycle

1993 ◽  
Vol 71 (11) ◽  
pp. 1805-1809 ◽  
Author(s):  
Liqin Chen ◽  
Laurence K. Thompson ◽  
John N. Bridson ◽  
Jide Xu ◽  
Shisheng Ni ◽  
...  
Keyword(s):  
Transition Metal Complexes ◽  
Esr Spectra ◽  
Synthesis And Characterization ◽  
Diacetic Acid ◽  
X Ray ◽  
X Ray Crystallography ◽  
Carboxylate Oxygen ◽  
Spin Resonance ◽  
Oxygen Donors

The synthesis and characterization of a new 14-membered tetraazamacrocyclic ligand 5,12-dimethyl-7,14-diphenyl-1,4,8,11-tetraazacyclotetradecane-4,11-diacetic acid (H2L1) is reported. Cobalt(III), nickel(II), and copper(II) complexes with this ligand were prepared and characterized by infrared, electronic, and electron spin resonance (esr) spectra and in one case by X-ray crystallography. The complex CuL1•2CH3CH2OH (3) crystallized in the triclinic system, space group[Formula: see text], with a = 8.440(2), b = 13.445(2), c = 7.523(1) Å, α = 99.30(1), β = 106.57(1), γ = 87.00(1)° and Z = 2 (R = 0.027, Rw = 0.028 for 2618 reflections). The complex shows a distorted trans-octahedral geometry with four amino nitrogens in a plane and two apical carboxylate oxygen donors.

scholarly journals Synthesis and Characterization of Bidentate Isonitrile Iron Complexes

2021 ◽  
Author(s):  
Marion Till ◽  
John A. Kelly ◽  
Christoph G. P. Ziegler ◽  
Robert Wolf ◽  
Tianao Guo ◽  
...  
Keyword(s):  
New Species ◽  
Ir Spectroscopy ◽  
Iron Complexes ◽  
Molecular Structures ◽  
Synthesis And Characterization ◽  
Carbonyl Complexes ◽  
Subsequent Reduction ◽  
X Ray ◽  
X Ray Crystallography

Divalent iron complexes trans-[FeBr2(BINC)2], [Cp*FeCl(BINC)] (Cp* = Me5C5) and [FeBr2(CNAr3NC)2] with chelat-ing bis(isonitrile) ligands BINC (bis(2-isocyanophenyl)phenylphosphonate) and CNAr3NC (2,2’’-diisocyano-3,5,3’’,5’’tetramethyl-1,1’:3’,1’’-terphenyl) have been prepared and characterized. Their subsequent reduction yields di- and trinuclear compounds [Fe3(BINC)6], [Cp*Fe(BINC)]2, [Fe(CNAr3NC)2]2 and [K(Et2O)]2[Fe(CNAr3NC)2]2. The molecular structures of all new species were determined by X-ray crystallography. The molecular structures are compared to related iron carbonyl complexes. The complexes were further characterized by NMR and IR spectroscopy, and the electrochemical properties of selected compounds were analyzed by UV-Vis-NIR spectroelectrochemistry. <br>

Molecular Second-Order Optical Nonlinearity of Push-Pull Bisdithiolene Nickel Complexes

1997 ◽  
Vol 488 ◽  
Author(s):  
Chin-Ti Chen ◽  
Sish-Yuan Liao ◽  
Kuan-Jiuh Lin ◽  
Long-Li Lai
Keyword(s):  
Nonlinear Optical ◽  
Nickel Complexes ◽  
Optical Nonlinearity ◽  
Second Order ◽  
Synthesis And Characterization ◽  
Crystal Data ◽  
X Ray ◽  
Donor Acceptor ◽  
First Time

AbstractThe synthesis and characterization of donor-acceptor substituted unsymmetrical bisdithiolene nickel complexes are described for the first time. X-ray single crystal data indicate that the complexes exist with two types of bonding structures, namely, the π-localized and π-delocalized structures. The relation between bonding structures and the molecular second-order nonlinear optical properties, i.e., solvatochromism, dipole moment, and molecular first hyperpolarizability is discussed.

Syntheses, electrochemistry and photophysical properties of a series ofmeso-pyridylpentafluorophenylporphyrins

2010 ◽  
Vol 14 (11) ◽  
pp. 975-984 ◽  
Author(s):  
Emmanuel Z. Moreira ◽  
Alba D.Q. Ferreira ◽  
Cláudio Roberto Neri ◽  
Sumitra Mukhopadhyay ◽  
Sérgio Dovidauskas ◽  
...  
Keyword(s):  
Electrochemical Properties ◽  
Photophysical Properties ◽  
Synthesis And Characterization ◽  
Redox Potentials ◽  
Trans Isomers ◽  
X Ray ◽  
X Ray Crystallography ◽  
Cis And Trans Isomers ◽  
Cis And Trans

This work presents the synthesis and characterization of a series of substituted pyridylpentafluroporphyrins, including the separation of the cis- and trans-isomers, the latter being characterized by X-ray crystallography. The spectroscopic and electrochemical properties of the series are dependent on the number of electron withdrawing pentafluorophenyl substituent, but they do not depend on the symmetry of the molecule. Ongoing from the monosubstituted to the more substituted pentafluorophenyl porphyrin H2(MPyTFPP) derivative, the Soret bands are slightly red-shifted and their quantum fluorescence yields range from 0.035 to 0.046, consistent with the value of 0.045 for the fully substituted 5,10,15,20-tetrapentafluorophenylporphyrin (dichloromethane solutions). The redox potentials of the reductive processes of monoanion and dianion formation are also sensitive to the number of pentafluoro substituents, shifting 180 mV to more positive values for the P0/P-1process ongoing from the monopentafluoro to the tris-pentafluorophenyl substituted derivative.

Synthesis and Reactivity of Novel Alkali Metal Stannides

2004 ◽  
Vol 59 (11-12) ◽  
pp. 1462-1470 ◽  
Author(s):  
Thorsten Schollmeier ◽  
Ulrich Englich ◽  
Roland Fischer ◽  
Ingo Prass ◽  
Karin Ruhlandt ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Alkali Metal ◽  
Synthesis And Characterization ◽  
Metal Compounds ◽  
X Ray ◽  
X Ray Crystallography ◽  
Multinuclear Nmr Spectroscopy ◽  
Alkali Metal Compounds ◽  
Potassium Hydride

Reactivity and side products of reactions of diorganodihydridostannanes (R2SnH2, R = Me, nBu, tBu)) with various alkali metal compounds have been discussed. Alternatively, the synthesis and characterization of a family of novel potassium stannides are described as well. The compounds of type (RR’2Si)R”2SnK (R, R’= Me, Ph; R”= , Me, tBu, Ph) 4 - 9 were synthesized by reaction of potassium hydride with bis(silyl)stannides ((RR’2Si)2SnR”2). All compounds were characterized by multinuclear NMR spectroscopy. In addition, the tri-tert-butyltin compound 3 (LiSntBu3) and the unsymmetrical silyl substituted stannane 10 were characterized by X-ray crystallography.

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