Metal-metal multiple bonds. Part 22. Addition reactions of organic azides and diethyl azodicarboxylate with Cp2Mo2(CO)4. Molecular structures of Cp2Mo2(CO)2(NAr)(.mu.-NNN(Ar)CO) (Ar = p-tert-BuC6H4) and [Cp'Mo(CO)2]2(.mu.-EtO2CN2CO2Et)

1987 ◽  
Vol 6 (10) ◽  
pp. 2151-2157 ◽  
Author(s):  
M. David. Curtis ◽  
John J. D'Errico ◽  
W. M. Butler
Keyword(s):  
Molecular Structures ◽  
Addition Reactions ◽  
Multiple Bonds ◽  
Organic Azides ◽  
Metal Metal ◽  
Diethyl Azodicarboxylate

Metal-metal multiple bonds. 18. Addition reactions of diazoalkanes with the molybdenum-molybdenum triple bond in R2Mo2(CO)4 (R = C5H5, C5H4Me, C5Me5)

1986 ◽  
Vol 5 (11) ◽  
pp. 2283-2294 ◽  
Author(s):  
M. David. Curtis ◽  
L. Messerle ◽  
John J. D'Errico ◽  
William M. Butler ◽  
Michael S. Hay
Keyword(s):  
Triple Bond ◽  
Addition Reactions ◽  
Multiple Bonds ◽  
Metal Metal

Characterizations of Novel Binuclear Transition Metal Polynitrogen Compounds: M2(N5)4 (M=Co, Rh and Ir)

2014 ◽  
Vol 924 ◽  
pp. 233-252 ◽  
Author(s):  
Li Hong Tang ◽  
Hui Bin Guo ◽  
Qian Shu Li ◽  
Jin Hui Peng ◽  
Jun Jie Gu ◽  
...  
Keyword(s):  
Transition Metal ◽  
Nbo Analysis ◽  
High Order ◽  
Multiple Bonds ◽  
Dissociation Energies ◽  
Nucleus Independent Chemical Shift ◽  
Metal Atoms ◽  
Metal Metal ◽  
Natural Bonding Orbital ◽  
Polynitrogen Compounds

Theoretical studies on a series of binuclear transition metal pentazolides M2(N5)4(M=Co, Rh and Ir) predict Paddlewheel-type structures with very short metal-metal distances suggesting high-order metal-metal multiple bonds. Natural Bonding Orbital (NBO) analysis have indicated that the bonding between the metal atom and the five-membered ring is predominantly ionic for each M2(N5)4species, and a high-order metal-metal multiple bonding exists between the two metal atoms, in addition, the presence of the delocalized π orbital plays an important role in the stabilization of this metal-polynitrogen species. Nucleus independent chemical shift (NICS) values confirm that the planar N5exhibits aromaticity in these M2(N5)4species. The values of NICS(0.0), NICS(0.5) and NICS(1.0) for Co2(N5)4are larger than those of the other two M2(N5)4species (M=Rh and Ir), with the order of Co2(N5)4>Rh2(N5)4>Ir2(N5)4. The dissociation energies into Mononuclear Fragments for M2(N5)4(M=Co, Rh and Ir) are predicted to be 82.9 (85.7), 139.9 (113.2), and 155.1 (149.7) kcal/mol, respectively. However, the dissociation energies for the loss of one pentazolato group from the M2(N5)4analysis have indicated that the Co2(N5)4is relatively higher at ~40 kcal/mol. Thermochemistry suggests Co2(N5)4to be a viable species.

First Examples of Homogeneous Catalytic Cyclotrimerization and Polymerization of Phenylacetylene and Copolymerization of Phenylacetylene and Norbonene with Dinuclear Complexes Containing Unbridged Metal-Metal Quadruple Bond

2003 ◽  
Vol 68 (6) ◽  
pp. 1094-1104 ◽  
Author(s):  
Konstantinos Mertis ◽  
Stavros Arbilias ◽  
Demos Argyris ◽  
Nikos Psaroudakis ◽  
Jiří Vohlídal ◽  
...  
Keyword(s):  
Dinuclear Complexes ◽  
Addition Reactions ◽  
Polymer Yield ◽  
Quadruple Bond ◽  
Metal Metal ◽  
Medium Activity ◽  
Copolymer Structure ◽  
Almost All ◽  
Ligand Addition ◽  
Low Activity

First examples of application of dinuclear complexes containing unbrigded metal-metal quadruple bond as catalysts in cyclotrimerization, oligomerization and polymerization of substituted acetylene are reported. The d4-d4 dinuclear complexes (Bu4N)2[Re2X8] (1) (1a, X = Cl; 1b, X = Br and 1c, X = I) show low activity and the complex [Mo2Cl4(MeOH)2(PPh3)2] (2) medium activity in cyclotrimerization and oligomerization of phenylacetylene (PA). In contrast, the tungsten-based d4-d4, complex Na4[W2Cl8] (3) exhibits high polymerization activity (polymer yield above 90%) and ca 75% cis-selectivity in tetrahydrofuran. The activity and cis-stereoselectivity of these single-component catalysts decrease in the order 3 >> 2 >> 1, which is proportional to the metal-metal quadruple bond propensity towards ligand addition reactions. Complex 3 induces metathesis polymerization of norbornene (NBE) to poly(cyclopentene-1,3-diylvinylene) with 82% cis-selectivity and copolymerization of PA and NBE to almost all-cis high-molecular-weight copolymer containing cyclopentene-1,3-diylvinylene units, which is free of longer sequences of both PA and NBE units. This suggests that also homopolymerization of PA with 3 proceeds by the metathesis mechanism and that the PA/NBE copolymer structure is close to the alternating one.

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