Electron-deficient Complexes Research Articles

Technetium(III) complexes with the tetradentate "umbrella" ligand tris(o-mercaptophenyl)phosphinate: x-ray structural characterization of Tc(P(o-C6H4S)3)(CNC3H7) and Tc(P(o-C6H4S)3)(CNC3H7)2

Tris(o-mercaptophenyl) phosphinate (PS3) binds to Tc(III) as a tetradentate ligand to form the formally 14-electron complex Tc(PS3)(CNMe). An x-ray single-crystal structure determination of the isopropyl isocyanide derivative Tc(PS3)(CN-i-Pr) shows sulfurs bound in the equatorial plane. The crystal data for MF = C{sub 22}H{sub 19}NPS{sub 3}Tc is presented. In the presence of a large excess of isonitrile, these electron-deficient complexes bind a sixth ligand. The six-coordinate complex Tc(PS3)(CN-i-Pr){sub 2}, was also structurally characterized and the crystal data is presented. 8 refs., 2 figs., 4 tabs.

A novel electrophilic N-amidation via electron deficient complexes : Action of ferric chloride on N-acetyloxyamides

The action of FeCl3 on N-acetyloxyamides leads to electron deficient species which can react intra or intermolecularly with an aromatic group to give oxindoles or analogues.

A metal ( 51V, 55Mn, 59Co) NMR investigation of the electron-deficient complexes V(CO) 3tmpo, Mn(CO) 3tmpo and Co(CO) 2tmpo (tmpo = 2,2,6,6-tetramethylpiperidyl-1-oxyl)

The diamagnetic, electron-deficient complexes V(CO) 3tmpo, Mn(CO) 3tmpo and Co(CO) 2tmpo, containing the tmpo ligand in the η 2-bond mode, have been investigated by metal NMR spectroscopy. The V and Mn compounds exhibit extremely low metal shieldings, which can be rationalized in terms of the low polarizability of the NO functionality of the 4-electron donating tmpo(1 −) or of low-lying electronic excitations between predominantly d-type moelcular orbitals associated with strained three-membered metallacycles.

Syntheses and characterization of the electron-deficient complex (TMPO)V(CO) 3

Syntheses and characterization of the electron-deficient complex (TMPO)V(CO) 3

Metal perfluoroalkane- and perfluoroarene-thiolates. Part V. The reactions of tricarbonyl(π-cyclopentadienyl)-molybdenum and -tungsten thiolates and acetylenes

The thiolates [(η5-C5H5)M(CO)3SRF](M = Mo or W; RF = CF3 or C6F5) react with acetylenes, RCCR (R = CF3, Me, or Ph) to give the formally electron-deficient π-acetylene complexes [(η5-C5H5)M(CO)(RC2R)SRF]. The bonding and isomerism in these complexes at low temperatures is discussed. On oxidation [(η-C5H5)MoO(CF3C2CF3)SC6F5] can be isolated. Trifluoropropyne reacts with the thiolates to give the acetylene complex [(η5-C5H5)Mo(CO)(CF3C2H)SC6F5] and cyclopentadienone complexes [(η5-C5H5)Mo(CO){(CF3C2H)2CO}SCF3] and [{(η5-C5H5)[(CF3C2H)2CO]SCF3}2].

The crystal structure of C12H16Ru4(CO)10: an open Ru4 cluster containing a novel three-carbon bridging group

The electron-deficient complex C12H16Ru4(CO)10 is shown to contain an open Ru4 cluster; the monocyclic C12 ring is attached to the cluster by a conventional π-allyl bond to one ruthenium atom, and by a novel bridging C3 unit, which is π-bonded to the two apical metal atoms, and σ-bonded to each of the “hinge” metal atoms.

Stereospecific polymerizations by means of coordinated anionic catalysis: Introductory Lecture

The phenomena stereoisomerism in the linear polymers of olefines and diolefines and the nature of the stereospecific polymerization processes are shortly discussed. They allowed the first synthesis of isotactic and syndiotactic polymers and of the four pure stereoisomers of polybutadiene, that is: the polymers having 1,2-isotactic, 1,2-syndiotactic, 1,4-cis, and 1,4-trans enchainments. The structure of catalytic complexes, that promove the stereospecific polymerization in the ionic coordinated catalysis, is pointed out. They are electron deficient complexes containing bridge-bonds between very electropositive transition metals, with valence less than the maximum, and very electropositive metals with very small ion diameter, to which electronegative carbon atoms are coordinated. Some soluble complexes, based on Titanium and Aluminum, are described, that act as catalysts in homogeneous solution. The best stereospecific catalysts for the synthesis of isotactic polymers are heterogeneous ones and their stereospecificity is connected with the presence of a crystalline substrate, formed by a layer lattice on which the active centers contain chemisorbed or epitattely bound metallorganic complexes (that may exist in enantiomorphous forms).