Synthesis of a stable 1,2-bis(ferrocenyl)diphosphene

Sasamori, Takahiro; Sakagami, Michiyasu; Niwa, Masatoshi; Sakai, Heisuke; Furukawa, Yukio; Tokitoh, Norihiro

doi:10.1039/c2cc33277a

Cited by 25 publications

(23 citation statements)

References 42 publications

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“…In contrast to the d³* electron transitions of the previously reported 1,2-bis(ferrocenyl)diphosphene, Fc¤P=PFc¤, showing a little solvent dependency (546 nm in hexane, 556 nm in THF, ¦ max = 9 nm), 14 those of diphosphene 1 showed no apparent solvent dependency in hexane and THF solution. In the UVvis spectra of distibene 2 and dibismuthene 3, two characteristic absorption bands were observed around 500 and 600 nm in either THF or hexane solution.…”

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confidence: 47%

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1,2-Bis(ferrocenyl)dipnictenes: Bimetallic Systems with a Pn=Pn Heavy π-Spacer (Pn: P, Sb, and Bi)

Sakagami

Sasamori

Sakai

et al. 2013

Bulletin of the Chemical Society of Japan

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1,2-Bis(ferrocenyl)dipnictenes bearing a Pn=Pn ³-spacer (Pn: P (1), Sb (2), and Bi (3)) between two ferrocenyl units have been synthesized as stable compounds. Not only their molecular structures and fundamental properties but also their redox behavior have been systematically disclosed. Interestingly, in the reduction region, the dipnictenes showed two pseudo-reversible one-electron redox couples at low temperature, suggesting possible generation of the corresponding radical anion and dianion species. On the other hand, they showed three-step one-electron oxidation processes in the oxidation region. The first two oxidation steps would correspond to those of the two ferrocenyl moieties, while the third step would be that of the Pn=Pn ³-spacer moiety, respectively. Thus, these 1,2-bis(ferrocenyl)dipnictenes with a Pn=Pn ³-spacer should be stable multiredox systems reflecting unique properties of a double bond between heavier 15 group elements. As a result, all Pn=Pn units (Pn: P, Sb, and Bi) were found to work as a more effective ³-spacer than those of 2nd row elements such as C=C and N=N.Organometallic ³-conjugated systems are attracting much interest from the viewpoint of showing interesting electronic, optical, and magnetic properties. In this research field, d³ conjugated systems of bimetallic complexes tethered with a ³-electron spacer, [M(Ligand)](³-electron spacer)[M(Ligand)] (M: transition metal), have been actively investigated.1 These compounds are a unique class of appropriate models of mixedvalence states giving insight on the ability of the ³-electron system as a ³-spacer in the context of fundamental organic electronic materials such as molecular switches and molecular wires.2 In this background, ferrocene is frequently used as an effective d-electron moiety in such d³ conjugated systems, because it should be a promisingly stable and effective redox system and amenable to modification with a variety of established substituents.3 Thus, ferrocenyl-based bimetallic d³ electron systems should be a touchstone for investigating the ability of a ³-electron system as a "³-spacer." Although several numbers of d³ conjugated systems with two ferrocenyl groups bridged by a ³-electron spacer have been reported to be investigated, e.g., Ph(Fc)C=C(Fc)Ph, 4 FcC¸CFc, 5 FcN=NFc 6 (Fc: ferrocenyl), and bis(ferrocenyl)thiophene derivatives, 7 the ³-electron systems in these compounds are limited to those consisting of 2nd row main group elements. The advantageous and required properties as a d³ electron system toward organometallic electronic materials should be (i) relatively low redox potential, (ii) stable multistep redox behavior, and (iii) controllable redox system. Regarding all of these points, ³-bonds between heavier main group elements are thought to be superior to those of 2nd row elements as a ³-spacer in d³ electron systems, because ³-bond compounds between heavier main group elements are known to exhibit smaller ³³* energy gaps than those of 2nd row elements due to the smaller overlapping of np orbitals. ...

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“…14,15 The systematic evaluation of the ³-electron units of heavier main group elements as a ³-spacer should be of great interest and importance. In this paper, we describe systematic studies of the properties of 1,2-bis(ferrocenyl)dipnictenes 13 including structural features and redox behavior (Figure 1).…”

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confidence: 99%

1,2-Bis(ferrocenyl)dipnictenes: Bimetallic Systems with a Pn=Pn Heavy π-Spacer (Pn: P, Sb, and Bi)

Sakagami

Sasamori

Sakai

et al. 2013

Bulletin of the Chemical Society of Japan

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“…The UV/vis spectra of distibene 4 and dibismuthene 5 in THF or hexane showed two characteristic absorption bands around 500 and 600 nm. Similar to diphosphenes 3, 31,32 and based on a comparison with previously reported diaryldistibenes and dibismuthenes, 41,42 the absorptions at shorter wavelengths were assigned to symmetry allowed π π transitions of the Sb Sb and Bi Bi chromophores, whereas the absorptions at longer wavelengths should most likely be interpreted in terms of an overlap of several d π electron transitions from lled d orbitals of Fe to the π orbitals of the E E π spacers. The absorption associated with the d π electron transitions in dibismuthene 5 showed no apparent solvent dependency.…”

Section: Synthesis Of D π Electron Systems Bearing Two Bulky Fc Groupmentioning

confidence: 99%

“…Reaction of 31 with Fc PHLi, which was obtained from the treatment of 32 with n BuLi, followed by dehydrochlorination with DBU afforded the rst example of a stable 1,2 bis(ferrocenyl)diphosophene (3a) as a purple, crystalline solid in 40% yield (Scheme 8). 31 Since our synthetic attempts to generate the corresponding 1,2 bis(ferrocenyl)distibene Fc Sb Sb Fc and 1,2 bis(ferrocenyl)dibismuthene Fc Bi Bi Fc via analogous routes were unsuccessful, we decided to employ the signicantly bulkier Fc group [Fc 2,5 (3,5 di t butylphenyl) 2 1 ferrocenyl]. 33 Iodoferrocene 28b was treated with t BuLi, and the corresponding ferrocenyldihalopnictanes Fc PCl 2 (33), Fc SbCl 2 (34), and Fc BiBr 2 (35) were obtained from the addition of PCl 3 , SbCl 3 , and BiBr 3 , respectively.…”

Section: Synthesis Of D π Electron Systems Bearing Two Bulky Fc Groupmentioning

confidence: 99%

“…The reduction of 24 with NaI and (CF 3 CO) 2 O afforded sul de 25, and was followed by an oxidation with mCPBA to give sulfoxide 26, which is a structural isomer of 24. The inversion of sulfoxide 24 to 26 is the key step for the following procedures: a second Negishi cross coupling reaction under similar conditions between 26 and ArX (DmpI or DtpBr) produced sulfoxide 27, which was treated consecutively with t BuLi and I 2 to give Fc I (28a) 31,32 and Fc I (28b), 32,33 respectively. Treatment of these bulky ferrocenyliodides with n BuLi should correspondingly afford Fc Li or Fc Li, to which a wide variety of substituents should be easily introduced.…”

Section: Design and Synthesis Of Bulky Fc Groups: Steric Protection Fmentioning

confidence: 99%

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The Synthesis and Properties of Bimetallic d-^|^pi; Electron Systems Containing Metallocenyl Substituents of Fe or Ru, and ^|^pi;-Electron Spacers of Heavier Main Group Elements from Group 14 or 15

Sasamori

2014

J. Synth. Org. Chem. Jpn.

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Abstract:Relative to π electron systems between elements from the second row of the periodic table, those between heavier main group elements should exhibit higher HOMO and lower LUMO levels. Moreover, such π electron systems between heavier main group elements are expected to be good electron acceptors and donors, and they should also exhibit good electron transporting properties. With the ultimate goal to create unprecedented π electron systems between heavier main group elements in mind, we designed d π electron systems containing heavier main group elements in the π electron moiety and transition metals in the d electron moiety. In this account article, we present our recent progress on the generation of bimetallic ferrocenyl and ruthenocenyl based d π electron systems containing π bond spacers of heavier main group elements from group 14 or 15.

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