Photochemistry of [Ru(I)(iPr)(CO)2(iPr-DAB)] (iPr-DAB = N,N'-diisopropyl-1,4-diaza-1,3-butadiene): Homolysis of the Metal-Alkyl Bond from the .sigma.b(Ru-iPr).pi.* State. Crystal Structure of the Photoproduct [Ru(I)2(CO)2(iPr-DAB)]

FT-EPR study of alkyl radicals formed in the photochemical reaction of Re(alkyl)(α-diimine) and Ru(alkyl)(α-diimine) complexes

“…1) and [Ru(E)(R)(CO) 2 (a-diimine)] (II) complexes, where R = alkyl or benzyl, E = I or SnPh3, and a-diimine = 4,4'-dimethyl-2,2'-bipyridine (DMB) or N,N'-diisopropyl-1,4-diazabutadiene (iPr-DAB) have been subject of detailed spectroscopic (UVNis, IR, Raman, NMR, EPR) studies [1][2][3][4][5][6][7]. It has been shown that photoexcitation of these complexes can trigger homolysis of the metal-alkyl (benzyl) bond.…”

“…It appears, therefore, that excitation to the 'MLCT state of [Re(CH 3 ) (CO)3(DMB)] is followed by two independent deactivation pathways, one producing a nonreactive 3 MLCT state and another giving a short-lived excited state from which bond dissociation occurs [7]. Spectroscopic and theoretical studies indicate that bond dissociation requires that photoexcitation populates a state with a(metal-alkyl)ic'(a-diimine) character [1][2][3][4][5][6][7]. According to this interpretation, variations in photoreactivity stems from changes in the quantum yield of formation of reactive ait excited states.…”

Synthesis and spectroscopic properties of Re(R)(CO)3(α-diimine) (R  alkyl; α-diimine  R′-pyCa, R′-DAB) complexes. Crystal structure of Re(Me) (CO)3 (iPr-DAB)

“…The spectroscopic, photophysical and photochemical properties of the first set of complexes have been described elsewhere [12][13][14], while the synthesis, structural and spectroscopic properties of the second set are reported here. A preliminary account of the photochemistry of these Re complexes has appeared [15].…”

Photochemistry of the metal-metal-bonded complexes [(CO)5MnRu(Me)(CO)2(α-diimine)]. Crystal structure of the photoproduct [(CO)4Mn-μ-(σ(N),σ(N′),ν2(CN)-iPr-PyCa)Ru(Me)(CO)2]

“…complexes can lead to the formation of radicals if the metal-a-diimine moiety is covalently bonded to another metal fragment or an alkyl group; examples are the complexes [LnM-M'(CO)3(a-diimine)] (LnM = (CO)5Mn , (CO)5Re , (CO)4C0, Ph3Sn ' etc. ; M' = Mn, Re) [1][2][3][4][5][6][7][8], [Re(R)(CO)3(a-diimine)] [9], [RuI(ipr)(CO)2(iPr-DAB)] [10] and [Zn(R)2(R'-DAB) ] [11]. With exception of the Zn compounds, all these complexes are characterized by strongly allowed metalto-o~-diimine (MLCT) transitions in the visible region.…”

“…Studies of the complexes [Re(R)(CO)3(a-diimine)] [9] and [Rul(R)(CO)2(ipr-DAB)] [10] (R = alkyD, for which the occurrence of the homolysis reaction strongly depends on R, have shown that these reactions probably occur from a 3~rbTr * state in which one electron has been transferred from the metal-alkyl bond to the a-diimine. With exception of the [Zn(R)z(R'-DAB)] [11] complexes, such a or b ~ 17" * transition has never been observed for any of these metal-metal and metal-alkyl complexes.…”