The galla[1]ferrocenophane {[dimethyl(2-pyridyl)silyl]bis(trimethylsilyl)methyl-κ²C,N}(ferrocene-1,1′-diyl)gallium(III)

Abstract

Key indicators: single-crystal X-ray study; T = 173 K; mean (C-C) = 0.005 Å; R factor = 0.044; wR factor = 0.088; data-to-parameter ratio = 18.6.

A Flexible Approach to Strained Sandwich Compounds: Chiral [1]Ferrocenophanes with Boron, Gallium, Silicon, and Tin in Bridging Positions

“…16 The most commonly discussed angle is the tilt angle α , as the tilting of the Cp ligand alone is responsible for the major portion of the intrinsic strain 16. 17 The gallium compound 4 a exhibits with α angles of 16.26(9) and 16.45(10)° similar values as those for the known Ga‐bridged [1]FCPs equipped with bulky trisyl ‐type ligands (Figure 2) [(Pytsi)Gafc: 15.4(2) and 16.4(2)°;18 (Me 2 Ntsi)Gafc: 15.83(19)°5c].…”

Synthesis of Intramolecularly Coordinated Aluminum and Gallium Compounds for the Preparation of [1]Ferrocenophanes

“…That the targeted strained species was formed in solution was evident from proton NMR spectroscopy. Aluminum- or gallium-bridged ferrocenophanes equipped with ligands capable of intramolecular donation ( C s point group symmetry) give rise to a typical pattern of the protons at the Cp moieties; i.e., the two signals for all α-protons appear upfield with significantly different chemical shifts, whereas both peaks for all β-protons appear downfield and are either overlapping or exhibit just a small difference in chemical shifts. ,,, For example, compound 7 shows three signals in the typical Cp range at δ 4.22 (2 α-H), 4.29 (2 α-H), and 4.62 (4 β-H), while the aluminum compound 8 shows four signals at δ 4.10 (2 α-H), 4.28 (2 α-H), 4.66 (2 β-H), and 4.68 (2 β-H). These patterns and the chemical shifts are comparable with those for other galla- or alumina[1]ferrocenophanes which were isolable (e.g., bridging moiety Ga(Pytsi), δ 4.08 (2 α-H), 4.45 (2 α-H), 4.61 (2 β-H), 4.65 (2 β-H); bridging moiety Al(Pytsi), δ 3.91 (2 α-H), 4.31 (2 α-H), 4.64 (2 β-H), 4.68 (2 β-H)).…”

“…The bulkiness of the ligand R plays a crucial role, not only for the outcome of these salt metathesis reactions but also for the reactivity of the resulting sandwich compounds. If the bulky, intramolecularly coordinating, trisyl- type ligands Pytsi and Me 2 Ntsi (Chart ) were employed, strained aluminum- or gallium-bridged [1]vanadarenophanes, [1]chromarenophanes, [1]ferrocenophanes, , [1]molybdarenophanes, and [1]ruthenocenophanes could be isolated. However, if nonbulky ligands of the “one-armed” phenyl type (Ar′; Chart ) were used to stabilize group 13 elements in bridging positions, nonstrained [1.1]metallacyclophanes resulted from respective salt metathesis reactions …”

The Dynamic Indium-Bridged [1.1]Ferrocenophane [(Me2Ntsi)In(C5H4)2Fe]2

“…Recently, we had shown that the steric requirements of the ligand that is attached to the group-13 element plays an important role for aluminum- and gallium-bridged metallacyclophanes. While the bulky trisyl -based ligands Pytsi and Me 2 Ntsi (Figure ) stabilized strained [1]metallacyclophanes, – the slimmer “one-armed phenyl” ligand Ar′ or p- t BuAr′ (Figure ) resulted exclusively in unstrained [1.1]metallacyclophanes (Figure ). ,, Against this background it was a surprise that a [1.1]ferrocenophane ( 3 ) instead of an expected [1]ferrocenophane was formed (eq ). How can this result be rationalized?…”

“…In the course of our investigation of aluminum- or gallium-bridged metallacyclophanes, we discovered that the bulkiness of the ligand that is attached to the bridging group-13 element plays a crucial role. When the bulky trisyl -based ligands Pytsi or Me 2 Ntsi (Figure ) were applied, strained [1]metallacyclophanes were formed; – the use of the slimmer “one-armed phenyl” ligand Ar′ or p- t BuAr′ (Figure ) resulted in unstrained [1.1]metallacyclophanes. ,, Among the latter species are the first [1.1]metallacyclophanes of bis(benzene) complexes, i.e., aluminum- and gallium-bridged [1.1]chromarenophanes and [1.1]molybdarenophanes (Figure ) …”