Synthesis and Structures of a Series of Bulky “Rind-Br” Based on a Rigid Fused-Ring s-Hydrindacene Skeleton

Abstract

A series of octa-R-substituted bromo-s-hydrindacenes, "Rind-Br," have been synthesized by a sequence of the Lewis acid catalyzed intramolecular FriedelCrafts reaction, bromination and vice versa. Their structural features and physical properties depend on the eight R-substituents at the four benzylic positions on the s-hydrindacenyl skeleton. The molecular structures of the Rind-Br have been confirmed by X-ray crystallography, indicating the unique structural diversities of the bulky Rind groups.

Synthesis and Magnetic Properties of Linear Two-coordinate Monomeric Diaryliron(II) Complexes Bearing Fused-ring Bulky “Rind” Groups

“…9 We have studied the low-coordinate compounds of the maingroup elements 10 and transition metals 11 with newly developed bulky aryl groups based on a fused-ring 1,1, 3,3,5,5,7,7-octa-Rsubstituted s-hydrindacene skeleton (Rind groups). 12,13 As part of these investigations, we anticipated that the bulky rigid Rind groups might provide a stable linear two-coordinate complex of transition metals. Herein, we report the synthesis, structural characterization, and magnetic properties of a new class of organoiron(II) compounds, Fe(Rind) 2 , in which the iron atom is directly connected to the two bulky Rind groups.…”

An Isolable Diborane(4) Compound with Terminal B–H Bonds: Structural Characteristics and Electronic Properties

“…The C 2v isomer is considered to have one BB σ-bond and two BHB 3c2e bonds, which are closely related to a canonical form as a doubly proton-bridged dianionic BB triple bond. 4 We recently obtained rather serendipitously, for the first time, a stable doubly H-bridged diborane(4), (¯-H) 2 (Eind)BB(Eind) (1b(br)), 5 containing the fused-ring bulky Eind groups (Eind: 1,1,3,3,5,5,7,7-octaethyl-s-hydrindacen-4-yl) 6 as a protecting group (Scheme 1). Soon after, we developed a new logical method for the selective formation of 1b(br), which involves BB σ-bond formation via the two-electron reduction of the readily available H-bridged dimer of monoborane 3b (Scheme 1).…”

“…We now report that the introduction of somewhat bulkier MPind groups (MPind: 1,1,7,7-tetramethyl-3,3,5,5-tetrapropyls-hydrindacen-4-yl) 6 leads to the selective formation of (MPind)HBBH(MPind) (1a(tm)) (Scheme 1), as the first example of an isolable H-terminal staggered diborane(4) compound. In this paper, we discuss the structural features and electronic properties of 1a(tm) in comparison to those of the H-bridged isomer 1b(br).…”

“…A toluene solution of the MPind-based diborane(6), (MPind)HB(¯-H) 2 -BH(MPind) (3a), which was prepared by the reduction of (MPind)BF 2 with LiAlH 4 in THF followed by treatment with trimethylchlorosilane (Me 3 SiCl), was treated with a sufficient amount (ca. 3.0 equiv) of a THF solution of lithium naphthalenide (LiNaph) to produce the diborane (6) …”

Sterically demanding imidazolinium salts through the activation and cyclization of formamides

“…19 We were able to synthesize several NHC salts 28-32 via their appropriate precursors 23-27, ranging in steric bulk, and were even able to incorporate the highly hindered EMind aniline (21) bearing two ortho tertiary carbons (Scheme 4). 20 The formamide activation strategy was shown to be general for the preparation of alkyl-and aryl-substituted imidazolinium Scheme 2 Triflic anhydride-promoted cyclization of formamide 8. Scheme 3 Process for formation/purification of imidazolinium salt 11.…”