Formation and reactivity of metal-ligand bonds: platinum(I) dimers and cobalt and chromium alkyls

Thesis/Dissertation · Mon Dec 31 23:00:00 EST 1984

OSTI ID:5815827

Blau, R J

(Pt/sub 2/(..mu..-dppm)/sub 2/Cl(PPh/sub 3/))/sup +/ is formed from a rate-limiting bimolecular reaction of PPH/sub 3/ with (Pt(..mu..-dppm)/sub 2/Cl/sub 2/) in CH/sub 2/Cl/sub 2/. Alternatively, it and its bromo and chloro derivatives can be formed from the reaction of halides with (Pt(..mu..-dppm)/sub 2/-PPh/sub 3/)/sub 2/)/sup 2 +/ by (a) rate-limiting PPH/sub 3/ dissociation, or (b) rate-limiting Pt/sub 2/(..mu..-dppm) ring opening at a Pt-P bond. Formation of product by (b) occurs after the formation of two observable intermediates, one of which, (Pt/sub 2/)eta/sup 2/-dppm)(..mu..-dppm)X(PPh/sub 3/))/sup +/, is readily characterized by /sup 31/P(/sup 1/H) NMR spectroscopy. Rates of these ligand substitution reactions are very sensitive to the anions present in solution. Atropisomers due to hindered rotation around the Pt-PPh/sub 3/ bond of (Pt/sub 2/(..mu..-dppm)/sub 2/Cl(PPh/sub 3/))/sup +/ are caused by phenyl-phenyl repulsions and can be distinguished by /sup 31/P(H) NMR spectroscopy. Such repulsions also retard the rate of positional interchange of axial and equatorial substitutents on its Pt/sub 2/(..mu..-dppm)/sub 2/ ring as observed by /sup 1/H NMR spectroscopy. Several correlations between /sup 195/Pt-/sup 31/P coupling constants and Pt-P and Pt-Pt bond lengths were observed. The synthesis, characterization, and reactivity of((Pt/sub 2/(..mu..-dppm)/sub 2/Cl)(di-eta/sup 2/-P/sub 4/))/sup 2 +/ is reported. This complex is a dimer of platinum dimers bridged by tetra-phosphorus. One platinum of each dimer is bound to two phosphorus atoms of P/sub 4/. The formation and reactivity of the metal-carbon bonds in benzylcobalamin and chromium alkyls, ((H/sub 2/O)/sub 5/CrR/sup 2 +/; R = CH/sub 2/Ph, CH(CH/sub 3/)OC/sub 2/H/sub 5/, CH/sub 2/OCH/sub 9/), were also investigated.

• Research Organization: Iowa State Univ. of Science and Technology, Ames (USA)
• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 5815827
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
400301 -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
CHEMICAL PREPARATION
CHEMICAL REACTIONS
CHROMIUM COMPLEXES
COBALT COMPLEXES
COMPLEXES
DIMERS
HETEROCYCLIC COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
ORGANOMETALLIC COMPOUNDS
PLATINUM COMPLEXES
SYNTHESIS
TRANSITION ELEMENT COMPLEXES