The Four-Step, Double-Autocatalytic Mechanism for Transition-Metal Nanocluster Nucleation, Growth, and Then Agglomeration: Metal, Ligand, Concentration, Temperature, and Solvent Dependency Studies

2008 ◽  
Vol 20 (5) ◽  
pp. 1956-1970 ◽  
Author(s):  
Eric E. Finney ◽  
Richard G. Finke
Keyword(s):  
Transition Metal ◽  
Ligand Concentration ◽  
Metal Nanocluster ◽  
Metal Ligand ◽  
Autocatalytic Mechanism ◽  
Nucleation Growth

ChemInform Abstract: Fragmentation of Realgar, As4S4, Controlled by Transition Metal-Ligand Systems.

ChemInform ◽  
1987 ◽  
Vol 18 (51) ◽  
Author(s):  
M. DI VAIRA ◽  
P. STOPPIONI ◽  
M. PERUZZINI
Keyword(s):  
Transition Metal ◽  
Metal Ligand

Symmetry Violations in Partially Oxidized One-Dimensional (1D)Transition Metal Polymers. Metal-Ligand-Metal(M-L-M) Bridged Systems

1984 ◽  
Vol 39 (9) ◽  
pp. 807-829
Author(s):  
Michael C. Böhm
Keyword(s):  
Transition Metal ◽  
Density Wave ◽  
Tight Binding ◽  
Mean Field ◽  
Valence Bond ◽  
Hole State ◽  
One Dimensional ◽  
Metal Derivatives ◽  
A Charge ◽  
Metal Ligand

The band structure of the metal-ligand-metal (M-L-M) bridged quasi one-dimensional (1D) cyclopentadienylmanganese polymer, MnCp 1, has been studied in the unoxidized state and in a partly oxidized modification with one electron removed from each second MnCp fragment. The tight-binding approach is based on a semiempirical self-consistent-field (SCF) Hartree-Fock (HF) crystal orbital (CO) model of the INDO-type (intermediate neglect of differential overlap) combined with a statistical averaging procedure which has its origin in the grand canonical ensemble. The latter approximation allows for an efficient investigation of violations of the translation symmetries in the oxidized 1D material. The oxidation process in 1 is both ligand- and metal-centered (Mn 3d-2 states). The mean-field minimum corresponds to a charge density wave (CDW) solution with inequivalent Mn sites within the employed repeat-units. The symmetry adapted solution with electronically identical 3d centers is a maximum in the variational space. The coupling of this electronic instability to geometrical deformations is also analyzed. The ligand amplitudes encountered in the hole-state wave function prevent extremely large charge separations between the 3d centers which are found in ID systems without bridging moieties (e.g. Ni(CN)2-5 chain). The symmetry reduction in oxidized 1 is compared with violations of spatial symmetries in finite transition metal derivatives and simple solids. The stabilization of the valence bond-type (VB) solution is physically rationalized (i.e. left-right correlations between the 3d centers). The computational results derived for 1 are generalized to oxidized transition metal chains with band occupancies that are simple fractions of the number of stacking units and to 1D systems that deviate from this relation. The entropy-influence for temperatures T ≠ 0 is shortly discussed (stabilization of domain or cluster structures).

Metal-Ligand Cooperative Approaches in Homogeneous Catalysis Using Transition Metal Complex Catalysts of Redox Noninnocent Ligands

2021 ◽  
Author(s):  
Rakesh Mondal ◽  
Amit Kumar Guin ◽  
Gargi Chakraborty ◽  
Nanda D Paul
Keyword(s):  
Transition Metal ◽  
Metal Complex ◽  
Homogeneous Catalysis ◽  
Transition Metal Complex ◽  
Raw Materials ◽  
Value Added ◽  
Catalytic Reactions ◽  
Redox Noninnocent ◽  
Metal Ligand ◽  
Metal Complex Catalysts

Catalysis offers a straightforward route to prepare various value-added molecules starting from readily available raw materials. The catalytic reactions mostly involve multi-electron transformations. Hence, compared to the inexpensive and readily...

By Alcoholysis of Transition and Inner Transition Metal-Ligand Bonds

2007 ◽  
pp. 67-69
Author(s):  
R. C. Mehrotra ◽  
B. S. Saraswat
Keyword(s):  
Transition Metal ◽  
Metal Ligand

Retaining Alkyl Nucleophile Regiofidelity in Transition-Metal-Mediated Cross-Couplings to Aryl Electrophiles

Synthesis ◽  
2018 ◽  
Vol 50 (20) ◽  
pp. 3974-3996 ◽  
Author(s):  
Josep Cornella ◽  
Matthew O’Neill
Keyword(s):  
Transition Metal ◽  
Functional Group ◽  
Chemical Space ◽  
Cross Coupling ◽  
Transition Metal Catalysis ◽  
Metal Catalysis ◽  
Substantial Progress ◽  
Tertiary Alkyl ◽  
Metal Ligand

While the advent of transition-metal catalysis has undoubtedly transformed synthetic chemistry, problems persist with the introduction of secondary and tertiary alkyl nucleophiles into C(sp2) aryl electrophiles. Complications arise from the delicate organometallic intermediates typically invoked by such processes, from which competition between the desired reductive elimination event and the deleterious β-H elimination pathways can lead to undesired isomerization of the incoming nucleophile. Several methods have integrated distinct combinations of metal, ligand, nucleophile, and electrophile to provide solutions to this problem. Despite substantial progress, refinements to current protocols will facilitate the realization of complement reactivity and improved functional group tolerance. These issues have become more pronounced in the context of green chemistry and sustainable catalysis, as well as by the current necessity to develop robust, reliable cross-couplings beyond less explored C(sp2)–C(sp2) constructs. Indeed, the methods discussed herein and the elaborations thereof enable an ‘unlocking’ of accessible topologically enriched chemical space, which is envisioned to influence various domains of application.1 Introduction2 Mechanistic Considerations3 Magnesium Nucleophiles4 Zinc Nucleophiles5 Boron Nucleophiles6 Other Nucleophiles7 Tertiary Nucleophiles8 Reductive Cross-Coupling with in situ Organometallic Formation9 Conclusion

Ligand K-edge X-ray absorption spectroscopic studies: metal-ligand covalency in transition metal tetrathiolates

1997 ◽  
Vol 263 (1-2) ◽  
pp. 315-321 ◽  
Author(s):  
Kendra Rose Williams ◽  
Britt Hedman ◽  
Keith O. Hodgson ◽  
Edward I. Solomon
Keyword(s):  
Transition Metal ◽  
Spectroscopic Studies ◽  
X Ray ◽  
X Ray Absorption ◽  
Metal Ligand
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