Manganese arene -complexes, preparation

Manganese allyl complexes, preparation, 5, 826 Manganese arenes, preparation and characteristics, 5, 830 Manganese aryl complexes, preparation and characteristics,... 

Scheme Cationic arene manganese tricarbonyl complexes prepared from the [Mn(CO)5] fragment. [Mn(CO)5] is generated in situ via Method A Mn(CO)5Br (58)/AlCl3/A Method B Mn2(CO)io/TFA/TFA-anhydride/reflux Method C Complex 58/AgBF4/CH2Cl2/reflux. In all cases the counteranion is either BF4" or PFg"...

The reactions of (arene)Cr(CO)j, (arene)Mn(CO)j and [(arene)MCp] (M = Fe or Ru) complexes have been studied extensively. Many of these arene compoimds have been prepared by heating the arene with Cr(CO)y but because dissociations of amines, nitriles or arenes from Cr(0) fragments are typically faster than dissociation of CO (see Chapter 5), reactions of arenes with Cr(CO)j(L)3 (L = NH or NCMej) or with (naphthalene) Cr(CO)j are milder than reactions with Cr(CO). Manganese-arene complexes [(arene) Mn(CO)3] - are typically generated from (CO)5MnBr, AgBF and arene, while the iron-and ruthenium-arene complexes [(arene)MCp] are typically generated by addition of arenes to [CpM(NCMe)3] (M = Fe or Ru). " ... 

Manganese carbenes, preparation, 5, 825 Manganese carbonyl complexes with 776-arene complexes, 5, 787 cyclopentadienyl complexes, 5, 783 with hydrocarbon ligands, complexes, 5, 776 synthesis and characteristics, 5, 761 Manganese carbonyl halides, applications and reactivity,... 

A variety of transition metals, for example, chromium, molybdenum, tungsten, iron, vanadium, manganese, and rhodium can be used to prepare relatively stable j -arene complexes (see Arene Complexes). Reactions of j -arene chromium tricarbonyl complexes have been extensively examined, and numerous reviews are available. Although chromium complexes are by far the most utilized in organic synthesis, complexes of iron and manganese are emerging as potentially useful alternatives. 

This method may be utilized for the preparation of most arene sandwich compounds as well as for many other arene complexes. However, it cannot be used for manganese arene derivatives. 

Softer nucleophiles N, for example, H or PBub, add directly (reversibly in the latter case) to the exo face of the arene to give the [Re(j7 -C6R6N-6-exo)(CO)3] (142) complexes without any participation of the metal center. Attempted extension to Re complexes of the well-established methodology for double functionalization of arenes earlier developed for the Mn analogs on the basis of [Mn(j -dienyl)(CO)2(NO)]+ (see Manganese Organometallic Chemistry) is thwarted by the limitations foimd in the preparation of the cations [Re()]5 -dienyl)(CO)2 (NO)]+. 

As indicated above, manganese and cobalt arene Ti-complexes could not be prepared by a direct method however, cyclization of 2-butyne provides a method of preparation of di(hexamethylbenzene) cobalt Ti-complex (2-14). 

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