Manganese compounds carbonyls

Some metal carbonyls, such as nickel, cobalt and manganese compounds have been used to produce metallic deposition. The decomposition occurs in a stepwise manner, producing one CO(g) molecule at each step. 

Optically active organometallic compounds in which the transition metal is the center of chirality have been known since 1969, when the first manganese compounds were reported1. In the meantime cyclopentadienyl and carbonyl transition metal complexes with 4, 5 and 6 ligands have been obtained in optically active form for the following types of compounds (Scheme 1) ... 

The most studied reaction involves the replacement of carbonyl groups by tertiary phosphines. This proceeds most readily in the case of cobalt derivatives, manganese compounds must usually be heated, and iron compounds require irradiation (except in the case of entry 13). 

Structural features of the compounds in entries 1-6 have already been discussed in Section IV,A. The manganese compound in entry 2 (and its rhenium analog) were prepared by heating Ph2SiH2 with the metal carbonyl M2(CO)i0 similar germanium- and tin-manganese derivatives have been made via Eq. (144) (263, 414). 

Dipole moment measurements, first carried out in our Munich Institute by E. Weiss (108), provided evidence of the very slight polar character of the metal-CO and metal-NO bonds. Similar measurements supplied information about stereochemistry for example, of cw-I2Fe(CO)4 (108), (Ph3P)3Fe(CO)2 (51), and [Fe(CO)3SEt]2 (90), as well as of the phosphine-containing nitrosyl carbonyl manganese compounds (105). 

OSHA PEL TWA 0.2 mg(Mn)/m3 (skin) ACGIH TLV TWA 5 mg(Mn)/m3 SAFETY PROFILE Poison by ingestion, inhalation, skin contact, intravenous, and intraperitoneal routes. A skin irritant. When heated to decomposition it emits toxic fumes of CO. See also MANGANESE COMPOUNDS and CARBONYLS. 

Compared with cluster complexes of lower nuclearities, the number of mixed chalcogen/carbonyl complexes having more than six metal atoms is small. Besides some complexes containing iron and cobalt, no manganese compound within this class of complexes is known. 

Although relatively few alkyl halides react with [M(CO)s] to form straightforward RM(CO)s derivatives, almost all acyl chlorides, RCOCl, react with [M(CO)s] to form the acyl derivatives RCOM(CO)5. Approximately fifteen acyl derivatives of manganese alone have been reported. Acyl derivatives of transition metals such as these manganese compounds appear to be especially stabilized by resonance structures such as (XX), in which the metal-carbon bond has appreciable double bond character, as in the metal carbonyls themselves. The rarity and instability of acyl derivatives of nontransition metals such as tin especially emphasizes the importance of structures analogous to (XX) in stabilizing acyl derivatives of transition metals. 

A wide variety of additives is available to refiners to improve gasoline quality, including octane number. Although lead has been banned in most western Countries, other octane-enhancers like MMT (Methyl-Cyclopentadienyl Manganese Tri-carbonyl) are widely used. Gibbs, (1989), presents a review of the various types of additives currently employed. Oxidation inhibitors and metal deactivators are normally added in the refinery or processing plant to prevent oxidation and gum formation. Dyes for product identification and antiknock compounds can be added prior... 

---