Phosphorus-Bridged [1.1]Ferrocenophane with syn and anti Conformations

Abstract

Photolysis of PPh-bridged [1]ferrocenophane (1) in THF gave PPh-bridged [1.1]ferrocenophane (2) as a minor dimer along with major polymeric products. After subsequent sulfurization of the reaction mixture with elemental sulfur, both syn and anti isomers of P(S)Ph-bridged [1.1]ferrocenophane (3) were successfully isolated and characterized by X-ray analysis. syn-3 thus obtained was desulfurized stereoretentively to syn-2 with Si 2 Cl 6 in refluxing benzene, while anti-3 primarily gave the isomerized product, syn-2. Stereoretentive desulfurization of anti-3 to anti-2 was achieved with CF 3 SO 3 Me/P(NMe 2 ) 3 at room temperature. anti-2 thus obtained could be converted almost completely to syn-2 upon simple heating in toluene, indicative of the thermal instability of the anti isomer over the syn isomer. The yield of syn-2 was improved from 9% to 32% when THF used in the photolysis was replaced with ether and the reaction mixture was heated so as to isomerize anti-2, which had been formed concomitantly. A potential utility of syn-2 as a ligand was demonstrated by the formation of [CoCl 2 (syn-2)] (5) through a reaction of syn-2 with CoCl 2 .

Polyferrocenylsilane‐Based Polymer Systems

“…[91] The monomers that were used were the phosphorous-bridged showed only a sharp signal, the ROP process is completely regioselective. Nonchlorinated donor solvents (THF, acetonitrile) promote the regioselectivity, whereas apolar and chlorinated ones give rise to complicated 31 P{ 1 H} NMR spectra.…”

Comparison of Doubly Lithiated, Magnesiated, and Zincated Ferrocenes: [Fe(η5-C5H4)2]2Zn2(tmeda)2, the First Example of a [1.1]Ferrocenophane with Bridging First-Row Transition Metal Atoms

“…These structural features suggest the macrocyclic framework of 6 (C 6 H 6 ) 4 to be comparatively unstrained. According to empirical rules established by Miyoshi et al, the anti -conformation is preferred for [1.1]ferrocenophanes [Fe(η 5 -C 5 H 4 ) 2 ] 2 (ER x ) 2 with (i) bulky substituents R at the bridgehead positions and (ii) C 5 H 4 -E bond lengths exceeding 1.85 Å . Both conditions are met for 6 (C 6 H 6 ) 4 such that its anti -conformation is in accord with a priori expectations.…”

“…[1.1]Ferrocenophanes, which can be regarded as the cyclic analogs of poly(ferrocenylene)s, have been the subject of intense study and examples with the elements B, Si, − P, S or the main group metals Al, , Ga, − In, and Sn , are known in the literature.…”

Photoinduced FeCp Bond Cleavage and Insertion Reactions of Strained Silicon‐ and Sulphur‐Bridged [1]Ferrocenophanes in the Presence of Transition‐Metal Carbonyls

“…[20] Since the X-ray crystal structure of the first [1.1]ferrocenophane was reported by Watts et al in 1967, [52] such species have attracted significant attention, owing to their unusual structural and redox properties. [53] Analogous [1.1]ferrocenophanes bearing ER x bridging groups, in which E ranges from Group 13 (B, [54] Al, Ga, In [55] ), Group 14 (C [56] Si, [53,57] Sn [19] ) to Group 15 (P [58,59] ), have also been published and their properties extensively studied. Nonetheless, to the best of our knowledge, compound 10 is the first example of a Group- 16- [54,59] It has been previously noted that, in general, the greater the ring-strain in [1]ferrocenophanes, the more upfield shifted the ipso-Cp-C 13 C resonance.…”