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![The synthesis, structure and reactivity of bimetallic cycloheptatrienyl complexes için kapak resmi The synthesis, structure and reactivity of bimetallic cycloheptatrienyl complexes için kapak resmi](/client/assets/d79c3e4af2b6d196/ctx/images/no_image.png)
The synthesis, structure and reactivity of bimetallic cycloheptatrienyl complexes
Başlık:
The synthesis, structure and reactivity of bimetallic cycloheptatrienyl complexes
Yazar:
Davies, Edward Stephen, author.
ISBN:
9780438084865
Yazar Ek Girişi:
Fiziksel Tanımlama:
1 electronic resource (229 pages)
Genel Not:
Source: Dissertation Abstracts International, Volume: 76-08C.
Özet:
An X-ray crystallographic study of [Ru(CO)2(eta5-C5H5)Mo(CO)2(eta7-C7H7)] showed this complex to have an unsupported Ru-Mo bond of length 2.952(1)A and a cis arrangement of cyclopentadienyl and cycloheptatrienyl rings in the solid state. Attempts to synthesize the sterically more congested pentamethylcyclopentadienyl derivative [Ru(CO)2 (eta5-C5Me5)Mo(CO)2(eta7-C7H7)] via treatment of [MoBr(CO)2(eta7-C7H7)] with K[Ru(CO)2(eta5-C5Me5)] unexpectedly gave [Mo(CO)3(eta-eta6: C7H7)Ru(CO)2 (eta5-C5Me5)] as the major product. The minor reaction product [Ru(CO)2(eta5-C5Me5) Mo(CO)2(eta7-C7H7)] gave a solid state infrared spectrum in the v(CO) region which suggested the possibility of a trans structure. An X-ray crystallographic study of [Mo(C0)3(11-116:T11-C7117)Ru(CO)2(n5-05Me5)] established the presence of a bridging cycloheptatrienyl ring to which the Mo(CO)3 unit is bonded eta6, and the Ru(CO)2(eta5-C5Me5) fragment is bonded eta1 in a trans orientation. Treatment of [M(CO)3(eta7-C7H7)]+ (M = Cr, Mo, W) with [M'(CO)2(eta5-C5R5)- (M' = Fe, Ru; R = H, Me) yielded a series of complexes of the type [M(CO)3(eta- eta6:- eta1-C7H7) M'(CO)2(eta5-C5R5)], the stabilities of which are dependent upon the identity of the eta1-coordinated metal centre. 1H nmr spectroscopic investigations determined the presence of dynamic fluxional processes involving migration of the eta1-coordinated metal centre around the cycloheptatrienyl ring, while thermal decomposition of [M(CO)3(eta- eta6:eta1-C7H7) Ru(CO)2(eta5-C5R5)] (M = Mo, W; R = H, Me) resulted in an unusual synthesis of the metal-metal bonded complexes [Ru(CO)2(eta5-C5R5)M(CO)2(eta7-C7H7)]. Treatment of thermally rearranged bicycloheptatriene, C14H14, with [Ph3C][PF6] at -20°C allowed the isolation of [C14H13][PF6] from which [C14H12][PF6]2 was derived upon further treatment with [Ph3C][PF6] in refluxing dichloromethane. Reaction of [C14H12][PF6]2 with [Mo(NCMe)3(CO)3] gave the bimetallic bicycloheptatrienyl complex [{Mo(CO)3}2(eta-eta7:eta7-C14H12)][PF6]2, which is a precursor to [ (Mo(eta6-toluene)}2 (eta-eta7: eta7-C14H12)][PF6]2 and [{MoX(CO)2)2(eta-eta7:eta7-C14H12)] (X = Br, I). Investigations into eta7etaeta3 hapticity interconversions in [{Mo(NCMe)(CO)2)2 (eta-eta7: eta7-C14H12)][BF4]2 demonstrated a temperature dependent equilibrium between [Mo(NCMe)3(CO)2(eta-eta3: eta7-C14H12)Mo(NCMe)(CO)2]2+ and [{Mo(NCMe)3(CO)2}2 (eta-eta3: eta3-C14H12)]2+, while reaction of [Mo(eta6-toluene)}2(eta-eta7: eta7-C14H12)][PF6]2 with dppe in acetonitrile gave [{Mo(NCMe)(dppe))2(eta-eta7: eta7-C14H12)][BF4]2 which exhibits localized mixed valence character as evident from cyclic voltammetric studies. Treatment of [C14H13][PF6] with [Mo(NCMe)3(CO)3] gives [Mo(CO)3(eta7-C14H13)]+ which has been converted sequentially to [MoI(CO)2(eta7-C14H13)] then [MoI(CO)2(eta7-C14H12)]+. Reaction of [MoI(CO)2(eta7-C14H12)]+ with [Mo(NCMe)3(CO)3] gave [MoI(CO)2(eta-eta7:eta7-C14H12)Mo(CO)3]+from which the novel iodide bridged complex [(Mo(CO)2)2(eta-I)(eta-eta7:eta7-C14H12)][PF6] was formed on heating. An X-ray crystal structure of [{Mo(CO)2}2(eta-I)(eta-eta7:eta7-C14H12)][PF6] revealed two independent molecules in the asymmetric unit, with the Mo atoms occupying cis sites and bridged both by the iodide and bicycloheptatrienyl framework. Significant twisting of the bicycloheptatrienyl framework (35 and 400) is observed. Reactions of [{Mo(CO)2}2 (eta-I)(eta-eta7:eta7-C14H12)][PF6] generally involve fission of the iodide bridge, although treatment of [{Mo(CO)2}2(eta-I)(eta-eta7:eta7-C14H12)][PF6] with dppe gave the eta7: eta3 complex [Mo(CO)2(eta-I)(eta-eta7:eta3-C14H12)M0(dppe)(CO)2)[PF6].
Notlar:
School code: 1543
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Yer Numarası | Demirbaş Numarası | Shelf Location | Lokasyon / Statüsü / İade Tarihi |
---|---|---|---|
XX(686912.1) | 686912-1001 | Proquest E-Tez Koleksiyonu | Arıyor... |
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