Iron, carbonyl compounds structure

Tetraethylammoniumhis(tetracarbonyliron)bis(/i-tetracarbonyliron)dithal-late(2 — ), [Et4N]2[Tl2Fe4(CO)16], decomposes rapidly upon exposure to air and is soluble in MeOH, CH2C12, and most polar organic solvents. Its crystal structure shows it to be a weak dimer of [Tl Fe(CO)4 2] and it probably exists as the monomer in solution.15 IR (CH2C12, cm-1) 1985(m), and 1908(s). It may be oxidized or irradiated to yield higher nuclearity thallium-iron carbonyl compounds.14,15... 

There are a number of amine-catalyzed carbonylation reactions which are catalyzed by cobalt carbonyl and iron carbonyl. It seems to me that these are insertion reactions of metal amides, where carbon monoxide is inserted and then some kind of a reduction or subsequent reaction gives the observed products, urea derivatives or carbamates in alcohols. We do not know the structure of the iron compound it is probably similar to the cobalt species shown. 

One of the complexes formed in the reaction of diphenylacetylene and iron dodecacarbonyl is a red, crystalline compound of the composition [Fe2(CO)6(PhC2Ph)], which, on reduction with sodium in liquid ammonia, gives dibenzyl (117). By analogy with the cobalt carbonyl complex, structure (XXXV M = Fe) is proposed, in which the 7r-elcctrons of the triple... 

Many complexes involving iron are known, mostly clusters containing iron carbonyl fragments, and reports for some come from the early years of metal cluster chemistry. Perhaps the simplest compound is PbFe(CO)4 , described originally in I960 (59) and later in more detail by Marks in 1978 (60). The structure is unknown although it is postulated to be oligomeric on the basis of infrared spectroscopic data. 

Another class of tetrairon tin compounds, described by Stone (67) and Fritchie (73), are derived from reactions between alkylchlorostannanes and iron carbonyl species. The latter report describes the structure of [Sn Fe2-(CO)8( t-SnMe2) 2], 61, which contains a central tetrahedral tin atom bonded to two Fe2(CO)8(/i-SnMe2) fragments. 

A noteworthy work on complexes of this type has been on the oxyallyl complexes (171) and their related dimers (172). Despite the fact that only electrophilic substitution is observed in the reactions of these complexes and their derived (oxyallyl)Fe(CO)4 cations, these compounds, or structurally very similar ones, have been proposed as intermediates in iron carbonyl mediated [4 + 3] cycloaddition reactions of a ,a -dibromoketones and dienes. " ... 

Unstable metal nitrosyls are formed by Fe, Ru and Ni. Black Fe(NO)4, made by heating iron carbonyl with NO under pressure at 50°, is the most stable. The structure is unknown, but the ionic formula NO+[Fe(NO)3] has been suggested to explain its low volatility. Ruthenium tetranitrosyl, Ru(NO)4, is made as cubic, red crystals when NO is passed into Ru2(CO)g. A compound of empirical formula Ni(NO)2 is obtained as a blue powder when NO is passed into Ni(CO)4 dissolved in CHCI3. 

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