15038-48-9Relevant articles and documents
Reactions of tetracyclone molybdenum complexes with electrophilic alkynes: Cyclopentadienone-alkyne coupling and alkyne coordination
Adams, Harry,Booth, Yvonne K.,Cook, Elizabeth S.,Riley, Sarah,Morris, Michael J.
, p. 2254 - 2261 (2017)
The reactions of the complexes [Mo(CO)2(4-C4Ph4CO)2] and [Mo(CO)3(NCMe)(4-C4Ph4CO)] with the alkynes dimethyl acetylenedicarboxylate (DMAD; RC - CR where R = CO2Me) and methyl propiolate (RC - CH) have been studied. In the case of DMAD, the initial product is the green carbonyl complex [Mo(CO)(RC - CR)(5,σ-C4Ph4COCR - CR)] (3), in which two alkyne molecules have been incorporated: one is linked to the carbonyl group of the tetracyclone ligand, whereas the other is -bound to the metal as a four-electron donor. Oxidation of this compound affords yellow [Mo(O)(RC - CR)(5,σ-C4Ph4COCR - CR)] (8). When the -acceptor carbonyl ligand is replaced by the-donor oxo group, the alkyne ligand changes orientation: it lies parallel to the Mo-CO bond in 3 but perpendicular to the Mo - O group in 8. Analogous complexes (9, 10) were isolated in the case of methyl propiolate; each exists as a mixture of two isomers depending on the orientation of the unsymmetrical alkyne ligand.
Synthetic, structural, NMR, and computational study of a geminally bis(peri-substituted) tridentate phosphine and its chalcogenides and transition-metal complexes
Ray, Matthew J.,Randall, Rebecca A. M.,Arachchige, Kasun S. Athukorala,Slawin, Alexandra M. Z.,Buehl, Michael,Lebl, Tomas,Kilian, Petr
, p. 4346 - 4359 (2013)
Coupling of two acenaphthene backbones through a phosphorus atom in a geminal fashion gives the first geminally bis(peri-substituted) tridentate phosphine 1. The rigid nature of the aromatic backbone and overall crowding of the molecule result in a rather inflexible ligand, with the three phosphorus atoms forming a relatively compact triangular cluster. Phosphine 1 displays restricted dynamics on an NMR time scale, which leads to the anisochronicity of all three phosphorus nuclei at low temperatures. Strained bis- and tris(sulfides) 2 and 3 and the bis(selenide) 4 have been isolated from the reaction of 1 with sulfur and selenium, respectively. These chalcogeno derivatives display pronounced in-plane and out-of-plane distortions of the aromatic backbones, indicating the limits of their angular distortions. In addition, we report metal complexes with tetrahedral [(1)Cu(MeCN)][BF 4] (5), square planar [(1)PtCl][Cl] (6), trigonal bipyramidal [(1)FeCl2] (7), and octahedral fac-[(1)Mo(CO)3] (8) geometries. In all of these complexes the tris(phosphine) backbone is distorted, however to a significantly smaller extent than that in the mentioned chalcogenides 2-4. Complexes 5 and 8 show fluxionality in 31P and 1H NMR. All new compounds 1-8 were fully characterized, and their crystal structures are reported. Conclusions from dynamic NMR observations were augmented by DFT calculations.
Synthesis and structures of dinuclear iron, molybdenum and tungsten complexes derived from (PhCHCHPh)-coupled bis(cyclopentadiene)
Li, Bin,Wang, Baiquan,Xu, Shansheng,Zhou, Xiuzhong
, p. 5309 - 5317 (2005)
Reductive coupling of phenylfulvene with amalgamated calcium metal followed by hydrolysis yields CpPhCHCHPhCp (1) in high yield. Refluxing ligand 1 and Fe(CO)5 in xylene produces (PhCHCHPh)-coupled bis(cyclopentadienyl) tetracarbonyl diiron (PhCHCHPh)[(η5-C5H 4)Fe(CO)2]2 (2) as a mixture of meso (2-meso) and racemic isomers (2-rac). The pure racemic isomers of the Mo and W analogues (3-rac and 4-rac) have been synthesized by lithiation of ligand 1 and addition of (MeCN)3M(CO)3 (M = Mo, W) followed by oxidation with 2 equiv. of ferrocenium tetrafluoroborate. All the new complexes have been fully characterized. The molecular structures of 1-meso, 2-meso, 2-rac, 3-rac, and 4-rac have been determined by X-ray diffraction analysis.
Formation of clusters by oxidative addition of organic and inorganic disulfides. Molecular structures of (MeCN)2(CO)6Mo2(μ-SPh)2 and Mo2Fe7S8(CO)22
Eremenko, I. L.,Pasynskii, A. A.,Abdulaev, A. S.,Aliev, A. S.,Orazsakhatov, B.,et al.
, p. 297 - 308 (1989)
Reactions of the disulfides Ph2S2 and (CO)6Fe2S2 with (MeCN)3Mo(CO)3 (I) leading to the splitting of S-S bonds have been studied.Binuclear (MeCN)2(CO)6Mo2(μ-SPh)2 (II) is obtained from the reaction of I with Ph2S2.The X-ray diffraction data for II (space group P21, a 9.262(4), b 9.343(10), c 15.494(6), β 105.85(3), Z=2, R=0.037) show the Mo-Mo bond of length (2.982(1) Angstroem), to be supported by thiolate bridges (Mo-S 2.468(1) Angstroem).Interaction of I with the ferrosulfide dimer breaks the S-S and the Fe-Fe bonds to give an antiferromagnetic nonanuclear cluster Mo2Fe7S8(CO)22 (III) (μeff 2.61(298 K) - 1.92(78 K) BM).An X-ray diffraction study (space group P1, a 13.003(2), b 14.278(1), c 16.019(2) Angstroem, α=109.555(8), β 97.187(10), γ 113.006(7) deg, Z=2, R=0.045) has revealed that molecule III consists of two fragments (CO)9Fe3(S)4Mo(CO)2 (Mo-Fe 2.750(2) Angstroem, Fe-S 2.260(3) Angstroem, Mo-S 2.406(3) Angstroem) linked via the Fe atom (Mo-Fe 2.900(2) Angstroem, Fe-S 2.242(3) and 2.529(3) Angstroem), but without Fe-Fe bonds.
Carborane Stabilized 19-Electron Molybdenum Metalloradical
Jaiswal, Kuldeep,Malik, Naveen,Tumanskii, Boris,Ménard, Gabriel,Dobrovetsky, Roman
supporting information, p. 9842 - 9848 (2021/07/21)
Paramagnetic metal complexes gained a lot of attention due to their participation in a number of important chemical reactions. In most cases, these complexes are dominated by 17-e metalloradicals that are associatively activated with highly reactive paramagnetic 19-e species. Molybdenum paramagnetic complexes are among the most investigated ones. While some examples of persistent 17-e Mo-centered radicals have been reported, in contrast, 19-e Mo-centered radicals are illusive species and as such could rarely be detected. In this work, the photodissociation of the [Cp(CO)3Mo]2 dimer (1) in the presence of phosphines was revisited. As a result, the first persistent, formally 19-e Mo radical with significant electron density on the Mo center (22%), Cp(CO)3Mo·PPh2(o-C2B10H11) (5b), was generated and characterized by EPR spectroscopy and MS as well as studied by DFT calculations. The stabilization of 5b was likely achieved due to a unique electron-withdrawing effect of the o-carboranyl substituent at the phosphorus center.
Synthesis of a carbon analogue of scytonemin
Mukai, Chisato,Arima, Katsuya,Hirata, Shuichi,Yasuda, Shigeo
, p. 273 - 277 (2015/04/22)
The synthesis of a carbon analogue of scytonemin was accomplished on the basis of molybdenum-mediated intramolecular double Pauson-Khand type reaction of bis(allenyne), followed by the double aldol condensation of the formed double Pauson-Khand type adduct.
