Showing papers on "Cyclobutadiene published in 1978"
90 citations
63 citations
62 citations
53 citations
TL;DR: In this paper, infrared evidence was presented for the formation of co-ordinatively unsaturated species [ML(CO)2][ML = Cr-(C6H6), Mn(η-C5H5), or Fe{C(C4H4), or F(CH2)H3}] on the u.v. photolysis of dinitrogen complexes at 12 K.
Abstract: Infrared evidence is presented for the formation of co-ordinatively unsaturated species [ML(CO)2][ML = Cr-(η-C6H6), Mn(η-C5H5), or Fe(η-C4H4), or Fe{C(CH2)H3}] on the u.v. photolysis of [ML(CO)3] complexes in argon and methane matrices, and dinitrogen complexes [ML(CO)2(N2)] in nitrogen matrices at 12 K. The primary photolysis step is readily reversed by visible light for [ML(CO)2] species of Cr and Fe, but not for Mn. The results are discussed in relation to the postulate of co-ordinatively unsaturated species as intermediates in the solution-phase substitution reactions.
34 citations
TL;DR: In this paper, reaction products from the thermal rearrangement of cobalt complexed 1,2-diethynyl-cyclobutadienes were tentatively identified by spectral investigation of mixtures resulting from the photodesilation of all acetylenic silyl groups followed by column chromatography on neutral alumina.
Abstract: Reaction products from the thermal rearrangement of cobalt complexed 1,2-diethynyl-cyclobutadienes were tentatively identified by spectral investigation of mixtures resulting from the photodesilation of all acetylenic silyl groups followed by column chromatography on neutral alumina. Mass spectral and chemical properties were used for the relative structure assignments. Several mechanisms are suggested but the true identity of the intermediates will require further research.
34 citations
TL;DR: In this paper, a cyclobutadiene derivative stabilized by steric effects which is isolable at room temperature is presented. But its properties are not discussed, except that it is not stable in the presence of sterics.
25 citations
24 citations
TL;DR: In this paper, the mixed sandwich complex (η5-cyclopentadienyl)(η4-1,3-diferrocenyl-2,4-diphenylcyclobutadiene) cobalt, c41H33CoFe2, is monoclinic, P21/c with a = 10.551, b = 16.345, c = 19.796, A and B = 93.19°.
22 citations
TL;DR: In this article, a d6 system was found for the cyclobutadiene ligand → charge donation, in which the mainly d-orbitals follow the sequence dz2 < dx2-y2 < dxy < dxz, dyz.
18 citations
TL;DR: This article showed that cycloheptatriene is about 10 4 times more electrophilic towards phosphine nucleophiles than is coordinated benzene, while cyclohexadecane is about 1.
TL;DR: The crystal structure of dicarbonylbis(tetraphenylcyclobutadiene)molybdenum has been determined from three-dimensional X-ray data collected by counter methods.
TL;DR: For the rhodium analogue, a cyclobutadiene-type structure containing a unique trapezoidal η4-C4-ring has been unequivocally established by means of X-ray diffraction techniques.
Abstract: Interactions of the diacetylene 2,2′-bis(phenylethynyl)biphenyl with the metal carbonyls [(η5-C5H5)-Co(CO)2], [(η5-C5H5)Rh(CO)2], and [Fe(CO)5] proceed via intramolecular cyclodimerization to form the respective η4-1,2-diphenylcyclobuta[l]phenanthrene complexes in each case; for the rhodium analogue, a cyclobutadiene-type structure containing a unique trapezoidal η4-C4-ring has been unequivocally established by means of X-ray diffraction techniques.
TL;DR: In this article, the tricarbonyliron group was removed from the symmetrical tropone derivative (1,7,8,9-η-bicyclo[5,2,0]nona-1(7),2,5,8-tetraen-4-one), which can be trapped as a Diels-Alder adduct with cyclopentadiene.
Abstract: The compounds (1,7,8,9-η-bicyclo[5,2,0]nonatetraenyl hexafluorophosphate)tricarbonyliron (9), (1,7,8,9-η-bicyclo[5,2,0]nona- 1(7),2,5,8-tetraen-4-one)tricarbonyliron (10), and (1,7,8,9-η-bicyclo- [5,2,0]nona-1(7),3,5,8-tetraen-2-one)tricarbonyliron (11) have been prepared. The cation (9) undergoes nucleophilic capture at C2, the position α to the coordinated cyclobutadiene ring. Oxidative removal of the tricarbonyliron group from the symmetrical tropone derivative (10) generates bicyclo-[5,2,0]nona-1(7),2,5,8-tetraen-4-one, which can be trapped as a Diels-Alder adduct with cyclopentadiene.
TL;DR: In this paper, the synthesis and properties of the first unsubstituted cyclobutadiene complex of an early transition metal, η4-C4H4)(η5-C5H5)V(CO)2, were described.
Abstract: The synthesis and properties of [(η4-C4H4)(η5-C5H5)V(CO)2], the first unsubstituted cyclobutadiene complex of an early transition metal, are described.
TL;DR: In this paper, the authors compared the INDO SCF MO calculations for π-cyclopentadienyl-π-cyclobutadiene ligand to the metal.
TL;DR: The crystal structure of the title compound, [Fe(CO)3(C9H6O), has been determined from single-crystal X-ray diffraction data at 295 K and refined by full-matrix least squares to a residual of 0.039 as mentioned in this paper.
Abstract: The crystal structure of the title compound, [Fe(CO)3(C9H6O)], has been determined from single-crystal X-ray diffraction data at 295 K and refined by full-matrix least squares to a residual of 0.039 (2160 'observed' reflections). Crystals are monoclinic, P21/c, a 9.326(5), b 12.293(5), c 10.342(4) Ǻ, β 115.77(3)°, Z 4. The iron atom is symmetrically bound to the four atoms of the cyclobutadiene ring ( 2.055 Ǻ).
TL;DR: In this paper, the NMR spectrum of 6b,10b-dihydrobenzo[j]cyclobut[a]acenaphthylene 1a produces a monoanion 2 or a condensed cyclobutadiene dianion 3 depending on reaction conditions.
TL;DR: The far-i.r., Raman and Inelastic Neutron Scattering spectra of solid C 4 H 4 Fe(CO) 3 have been obtained.
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01 Jan 1978
TL;DR: The crystal structure of the title compound, [Fe(CO),(C,H,O)], has been determined from single-crystal X-ray diffraction data at 295 K and refined by full-matrix least squares to a residual of 0.039 as mentioned in this paper.
Abstract: The crystal structure of the title compound, [Fe(CO),(C,H,O)], has been determined from singlecrystal X-ray diffraction data at 295 K and refined by full-matrix least squares to a residual of 0.039 (2160 'observed' reflections). Crystals are monoclinic, P2,/c, a 9.326(5), b 12.293(5), c lO.342(4) A, ,B 115.77(3)", Z 4. The iron atom is symmetrically bound to the four atoms of the cyclobutadiene ring ((FeC) 2.05, A).
TL;DR: In this paper, the tricarbonyliron group was removed from the symmetrical tropone derivative (1,7,8,9-η-bicyclo[5,2,0]nona-1(7),2,5,8-tetraen-4-one), which can be trapped as a Diels-Alder adduct with cyclopentadiene.
Abstract: The compounds (1,7,8,9-η-bicyclo[5,2,0]nonatetraenyl hexafluorophosphate)tricarbonyliron (9), (1,7,8,9-η-bicyclo[5,2,0]nona- 1(7),2,5,8-tetraen-4-one)tricarbonyliron (10), and (1,7,8,9-η-bicyclo- [5,2,0]nona-1(7),3,5,8-tetraen-2-one)tricarbonyliron (11) have been prepared. The cation (9) undergoes nucleophilic capture at C2, the position α to the coordinated cyclobutadiene ring. Oxidative removal of the tricarbonyliron group from the symmetrical tropone derivative (10) generates bicyclo-[5,2,0]nona-1(7),2,5,8-tetraen-4-one, which can be trapped as a Diels-Alder adduct with cyclopentadiene.
TL;DR: In this article, the synthesis and properties of the first unsubstituted cyclobutadiene complex of an early transition metal, η4-C4H4)(η5-C5H5)V(CO)2, were described.
Abstract: The synthesis and properties of [(η4-C4H4)(η5-C5H5)V(CO)2], the first unsubstituted cyclobutadiene complex of an early transition metal, are described.