ISSN:
0009-2940
Keywords:
Manganese complexes
;
Insertion processes
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Mn(NO)2L2H complexes [L = PMe3 1a, PEt3 1b, P(OMe)3 1c, P(OEt)3 1d, P(OiPr)3 1e] have been prepared by the reaction of the corresponding Mn(NO)2L2Br compounds with NaBH4 in ethanol. The reactivity of 1a and 1b is compared to that of Mn(CO)3L2H species (L = PMe3 2a, L = PEt3 2b). Compound 1b reacts with weak acids like PhOH, (CF3)2CHOH and CH3COOH to yield Mn(NO)2(PEt3)2X complexes [X = OPh 3a, OCH(CF3)2 3b, OC(O)CH3 3c] and H2. Compound 2b does not undergo reaction with these acids. At room temperature in toluene 1a, b undergo facile CO2 insertion processes, while 2a, b do not show this reactivity even under more rigorous reaction conditions. From 1a, b and CO2 formato complexes Mn(NO)2L2[OC(O)H] (L = PMe3 4a, L = PEt3 4c) are obtained. The reaction of 1b with salicylaldehyde in toluene proceeds with the formation of a [2-(hydroxymethyl)-phenoxy]dinitrosylbis(triethylphosphane) manganese complex 5b, which exchanges the phenoxy ligand in the presence of excess of salicylaldehyde to give (2-formylphenoxy)-dinitrosylbis(triethylphosphane)manganese (6b) and α,2-dihydroxytoluene. p-Hydroxybenzaldehyde, vanilline, and 4-hydroxy-3,5-dimethoxybenzaldehyde and 1b also afford phenoxy derivatives Mn(NO)2(PEt3)2(OAr) [Ar = p-OC6H4-CHO 7a; OC6H3-2-OCH3-4-CHO 7b; OC6H2-2,6-(OCH3)2-4-CHO 7c] and H2. Compounds 2a, b do not react with any of these hydroxybenzaldehydes. Compounds 1a, b have been converted into Mn(NO)2L2 [(Z)-C(COOR′)≡C(R)H] species (L = PMe3, R = H, R′ = Me 8a; L = PEt3, R = H, R′ = Me 8b; L = PMe3 R, R′ = Me 9a; L = PMe3, R = Ph, R′ = Et 10a; L = PMe3, R = COOMe, R′ = Me 11a; L = PEt3, R = COOMe, R′ = Me 11b) in the presence of alkyl propiolates RC≡CCOOMe (R = H, Me, Ph, COOMe; R′ = Me, Et). Similarly, but under more rigorous conditions, insertion of RC≡CCOOMe (R = H, COOMe) into 2a, b occurs and α metalation products Mn(CO)3(PMe3)2[(Z)-C(COOMe) = CHR] (L = PMe3, R = H 12a; L = PEt3, R = H 12b; L = PMe3, R = COOMe 13a; L = PEt3, R = COOMe 13b) are formed. In the case of the methyl propiolate insertion into 2a, 10% of an additional β-metalation compound Mn(CO)3(PMe3)2[(Z)-CH = CH(COOMe)] (12c) have been detected spectroscopically. Compounds 11b and 13a, b have been transformed into manganacyclic complexes MN[C(COOMe)=CH(COOMe)]-(NO)2(PEt3)2 (14b) and MN[C(COOMe)=CH(COOMe)]-(CO)2L2 (L = PMe3 15a; L = PEt3, CO 15b; L = PEt3 15c). Compound 15c has been identified spectroscopically, and 1a, 8a, and 9a have been characterized by X-ray structure determinations.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19941271211
