Synthesis, x-ray structural determination and coordination chemistry of 4′-ferrocenyl-2,2′:6′,2″-terpyridine

Farlow, Brian; Nile, Terence A.; Walsh, Jerry L.; McPhail, Andrew T.

doi:10.1016/s0277-5387(00)80074-1

Cited by 47 publications

(33 citation statements)

References 16 publications

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“…Essentially the same holds true for Fc-tpy', in the single crystal of which the cyclopentadienyl ring forms an angle of 19.28 with the central C 5 N ring. [26] Similar to [(Fc-tpy') 2 (Table 5). Experiments in the picosecond time regime with l exc 532 nm revealed that a short-lived transient with a mean lifetime of about 2 ns is formed for all Fc-functionalised complexes (Table 6).…”

Section: Mlct State Of [(1 A)ru(tpy)]mentioning

confidence: 76%

“…Single-crystal X-ray structure determinations were performed for ligands 1 a ± d, and two representative molecular structures are shown in Figure 1 and Figure 2. Bond lengths [8]: N(1)ÀC(23) 133.5 (5), N(1)ÀC(24) 134.5 (5), N(2)ÀC (26) 132.8 (6), N(2)ÀC(30) 134.1 (6) [8] for this molecule: N(1)ÀC (21) 136.8 (9), N(1)ÀC(22) 135.2 (8), N(2)ÀC (24) 135.3 (9), N(2)ÀC(28) 128.2 (12), N(3)ÀC(29) 130.2 (9), N(3)ÀC (33) 135.3(9), C(10)ÀC(11) 142.7(12), C(11)ÀC(12) 118.9(12), C(12)ÀC (13) 146.4(10), C(16)ÀC (19) and angles are generally unexceptional. The acetylene groups are almost linear with CC distances of about 119 pm.…”

Section: Introductionmentioning

confidence: 99%

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Ferrocenyl‐Functionalised Terpyridines and Their Transition‐Metal Complexes: Syntheses, Structures and Spectroscopic and Electrochemical Properties

Siemeling

Brüggen

Vorfeld

et al. 2003

Chemistry A European J

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Terpyridine ligands of the type Fc'-X-tpy (Fc'=ferrocenyl or octamethylferrocenyl, X=rigid spacer, tpy'=4'-substituted 2,2':6',2''-terpyridine) were prepared, crystallographically characterised and used for the synthesis of di- and trinuclear bis(terpyridine) complexes of RuII, FeII and ZnII. Donor-sensitiser dyads and triads based on RuII were thoroughly investigated by (spectro)electrochemistry, UV/Vis, transient absorption and luminescence spectroscopy, and an energy level scheme was derived on the basis of the data collected. Intramolecular quenching of the photoexcited RuII complexes by the redox-active Fc' groups can occur reductively and by energy transfer. Both the redox potential of the donor Fc' and the nature of the spacer X have a decisive influence on excited-state lifetimes and emission properties of the complexes. Some of the compounds show room-temperature luminescence, which is unprecedented for ferrocenyl-functionalised compounds of this kind.

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Section: Mlct State Of [(1 A)ru(tpy)]mentioning

confidence: 76%

Section: Introductionmentioning

confidence: 99%

Ferrocenyl‐Functionalised Terpyridines and Their Transition‐Metal Complexes: Syntheses, Structures and Spectroscopic and Electrochemical Properties

Siemeling

Brüggen

Vorfeld

et al. 2003

Chemistry A European J

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“…lation between the interannular bond length and the ring twist angle in such compounds: For the two independent molecules of crystalline 4-biphenylylferro~ene the corresponding values are 1.56 k2.1" and 1.54 A/9.7"["1; for 4'-ferrocenyl-2,2' :6',2"-terpyridine 1.47 k19.2° [12] It is also smaller than the mean distance between the cyclopentadienyl ring planes of 3.32 A in this compound.…”

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confidence: 99%

Pyridyl‐Functionalised Cyclopentadienyl Ligands: Building Blocks for Oligonuclear Organometallic Assemblies

et al. 1995

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Lithiated 2-methylpyridine reacts with 2,3,4,5-tetramethylfulvene (TMF) to give 2-[2-(2,3,4,5-tetramethylcyclopenta-1,4-dien-l-yl)ethyl]pyridine (2H) after aqueous work-up. Similarly, a mixture of 2-methyl-6-[2-(2,3,4,5-tetramethylcyclopenta-1,4-dien-l-yl)ethyl]pyridine (3H) and 2,6-bis[2-(2,3,4,5-tetramethylcyclopenta-l,4-dien-1 -yl)ethyl]pyridine (4H2) was obtained from monolithiated 2,6-dimethylpyridine (and TMF. All three compounds were obtained as a roughly :statistical mixture of double-bond isomers. 2-Lithiopyridine reacts with 2,3,4,5-tetramethylcyclopent-2-enone to yield 2-(2,3,4,5-tetramethylcyclopenta-l,3-dien-l-yl)pyridine (5H) after acidic work-up. This compound was obtained as a nonstatistical mixture of double-bond isomers, which is presumably due to intramolecular hydrogen-bond interactions. The lithiated derivatives 2Li, 3Li and 5Li react with iron(I1) chloride to afford the respective ferrocenes (2),Fe ( 8 ) , (3),Fe (9) and (5),Fe (10). The structure of 10 was determined by a single-crystal X-ray diffraction study. The cyclopentadienyl ligands adopt a staggered conformation; the pyridyl rings are arranged in a stacked fashion with the closest ring-ring contact being 3.16 A. The distance between the iron atom and the cyclopentadienyl ring centroids is 1.66 A.We have recently described the first example of a pentamethylcyclopentadiene functionalised with a pendant pyridyl unit"]; compound 1H could be obtained in 60% yield by the addition of lithiated 4-tert-butyl-2-isopropylpyridine to tetramethylfulvene (TMF)L2] and subsequent aqueous work-up. + (mixture of isomers)Donor-functionalised cyclopentadienyl systems such as 1 are of great current interestI31. They belong to the rapidly growing class of hemilabile ligands['x41 and have, for example, proved useful for the "reversible" stabilisation of reactive metal-ligand fragments (serving, for example, as Results and DiscussionThe strategy for the synthesis of l H , which is based on the use of TMF as synthetic equivalent for the cyclopentadienyl moiety, was extended to the preparation of compounds 2H and 3H. These cyclopentadienes were obtained as yellow oils in 38% (2H) and 45% (3H) yield, respectively, after vacuum distillation. Owing to deprotonation equilibria, the bis(cyc1opentadiene) 4H2 was obtained as a side product (1 ~Y o yield) in the latter case (Scheme 1). Chem Bev 1995,128,481 -485 The steric and electronic properties of cyclopentadienyl ) H20This strategy cannot be extended, however, to the preparation of pyridyl-functionalised cyclopentadienes containing a single methylene spacer group between the pyridine and cyclopentadiene ring: When 2-lithiopyridine (prepared

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“…This charge-transfer band is associated with the ferrocenyl moiety and the terpyridyl vanadium(IV) moiety. [46][47][48] The low-energy d-d absorption band for 1-4 was not observed possibly due to the presence of this intense band. Complex 5, which lacks the ferrocenyl moiety, showed a low-energy oxidovanadium(IV)-centred d-d band at 720 nm in DMF (Figure 2).…”

Section: +mentioning

confidence: 97%

Ferrocene‐Conjugated Oxidovanadium(IV) Complexes as Potent Near‐IR Light Photocytotoxic Agents

et al. 2011

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Ferrocene‐conjugated oxidovanadium(IV) complexes [VO(Fc‐tpy)(B)](ClO4)2 (1–4) and [VO(Ph‐tpy)(dppz)](ClO4)2 (5) as a control [Fc = (η5‐C5H4)FeII(η5‐C5H5), Fc‐tpy = 4′‐ferrocenyl‐2,2′:6′,2″‐terpyridine, Ph‐tpy = 4′‐phenyl‐2,2′:6′,2″‐terpyridine, B = heterocyclic base: 2,2′‐bipyridine (bpy in 1), 1,10‐phenanthroline (phen in 2), dipyridoquinoxaline (dpq in 3), dipyridophenazine (dppz in 4)] were prepared and their DNA binding, DNA photocleavage activity and photocytotoxicity studied. The crystal structure of [VO(Fc‐tpy)(bpy)](PF6)2·3Me2CO shows a vanadyl group in six‐coordinate VIVON5 coordination geometry, in which Fc‐tpy and bpy display tridentate meridional and bidentate N‐donor axial–equatorial binding modes, respectively. The one‐electron paramagnetic complexes exhibit a charge‐transfer band near 590 nm in DMF. The VIV/VIII redox couple in 1–4 appears near –0.7 V, whereas the Fc moiety shows a response near 0.6 V vs. SCE in DMF/0.1 M TBAP. The complexes are good binders to calf thymus DNA with Kb values of 104–106 M–1. DNA melting and viscometric data suggest groove and/or partial intercalative DNA binding of the complexes. Complexes 3–5 display DNA photocleavage activity in near‐IR light of 785 nm. Complex 4 shows significant photocytotoxicity in visible light (400–700 nm) in HeLa cells with low dark toxicity.

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Synthesis, x-ray structural determination and coordination chemistry of 4′-ferrocenyl-2,2′:6′,2″-terpyridine

Cited by 47 publications

References 16 publications

Ferrocenyl‐Functionalised Terpyridines and Their Transition‐Metal Complexes: Syntheses, Structures and Spectroscopic and Electrochemical Properties

Ferrocenyl‐Functionalised Terpyridines and Their Transition‐Metal Complexes: Syntheses, Structures and Spectroscopic and Electrochemical Properties

Pyridyl‐Functionalised Cyclopentadienyl Ligands: Building Blocks for Oligonuclear Organometallic Assemblies

Ferrocene‐Conjugated Oxidovanadium(IV) Complexes as Potent Near‐IR Light Photocytotoxic Agents

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