1,2-Disubstituted Aryl-Based Ferrocenyl Phosphines

Ferrocenylaryl- or ferrocenylheteroarylphosphines [Fe­{1-PPh₂(spacer)-2-NMe₂CH₂C₅H₃}­(C₅H₅)] (spacer = 1,4-phenylene (<i>rac</i>-<b>6</b>), 1,3-phenylene (<i>rac</i>-<b>7</b>), 4,4′-biphenylene (<i>rac</i>-<b>8</b>), 2,5-thienylene (<i>rac</i>-<b>9</b>)) were prepared in a facile two-step sequence starting with Negishi cross-coupling between <i>N</i>,<i>N</i>-dimethylaminomethylferrocene and aryl halide phosphine oxides, Br-spacer-P­(O)­Ph₂, followed by reduction with trichlorosilane. All products were characterized spectroscopically (¹H, ¹³C, and ³¹P NMR, MS, FTIR), and <i>rac</i>-<b>6</b>, the corresponding phosphine oxide <i>rac</i>-<b>2</b>, and <i>rac</i>-<b>9</b> were also characterized by X-ray crystallography. Furthermore, the redox properties of <i>rac</i>-<b>2</b>–<b>9</b> were studied by cyclic voltammetry

Cross-dehydrocoupling: A Novel Synthetic Route to P–B–P–B Chains

Transition-metal-catalyzed dehydrocoupling of <i>tert</i>-butylferrocenylphosphine–borane (<b>2</b>) with [{Rh­(μ-Cl)­(1,5-cod)}₂] (cod = cyclooctadiene) as the catalyst gave the homocoupled product [Fc­(<i>t</i>Bu)­(H)­P­(BH₂)­P­(Fc)­(<i>t</i>Bu)­(BH₂X)] [<b>3</b>; Fc = Fe­(C₅H₅)­(C₅H₄), X = H/Cl], while cross-dehydrocoupling with the tertiary phosphine–boranes P­(<i>t</i>Bu)­(<i>n</i>Bu)₂(BH₃) (<b>2a</b>) and PPh­(<i>n</i>Bu)₂(BH₃) (<b>2b</b>) using [Rh­(1,5-cod)₂]­OTf (OTf = trifluoromethanesulfonate) gave the first cross-dehydrocoupled products reported to date, [Fc­(<i>t</i>Bu)­(BH₃)­P­(BH₂)­P­(<i>t</i>Bu)­(<i>n</i>Bu)₂] (<b>4</b>) and [Fc­(<i>t</i>Bu)­(BH₃)­P­(BH₂)­PPh­(<i>n</i>Bu)₂] (<b>5</b>), in moderate yields. Compounds <b>2</b>–<b>5</b> were characterized by NMR spectroscopy (¹H, ¹³C, ³¹P, and ¹¹B), IR spectroscopy, mass spectrometry, and single-crystal X-ray structure determination

1,2-Disubstituted Aryl-Based Ferrocenyl Phosphines

Ferrocenylaryl- or ferrocenylheteroarylphosphines [Fe­{1-PPh₂(spacer)-2-NMe₂CH₂C₅H₃}­(C₅H₅)] (spacer = 1,4-phenylene (<i>rac</i>-<b>6</b>), 1,3-phenylene (<i>rac</i>-<b>7</b>), 4,4′-biphenylene (<i>rac</i>-<b>8</b>), 2,5-thienylene (<i>rac</i>-<b>9</b>)) were prepared in a facile two-step sequence starting with Negishi cross-coupling between <i>N</i>,<i>N</i>-dimethylaminomethylferrocene and aryl halide phosphine oxides, Br-spacer-P­(O)­Ph₂, followed by reduction with trichlorosilane. All products were characterized spectroscopically (¹H, ¹³C, and ³¹P NMR, MS, FTIR), and <i>rac</i>-<b>6</b>, the corresponding phosphine oxide <i>rac</i>-<b>2</b>, and <i>rac</i>-<b>9</b> were also characterized by X-ray crystallography. Furthermore, the redox properties of <i>rac</i>-<b>2</b>–<b>9</b> were studied by cyclic voltammetry

1,2-Disubstituted Aryl-Based Ferrocenyl Phosphines

Ferrocenylaryl- or ferrocenylheteroarylphosphines [Fe­{1-PPh₂(spacer)-2-NMe₂CH₂C₅H₃}­(C₅H₅)] (spacer = 1,4-phenylene (<i>rac</i>-<b>6</b>), 1,3-phenylene (<i>rac</i>-<b>7</b>), 4,4′-biphenylene (<i>rac</i>-<b>8</b>), 2,5-thienylene (<i>rac</i>-<b>9</b>)) were prepared in a facile two-step sequence starting with Negishi cross-coupling between <i>N</i>,<i>N</i>-dimethylaminomethylferrocene and aryl halide phosphine oxides, Br-spacer-P­(O)­Ph₂, followed by reduction with trichlorosilane. All products were characterized spectroscopically (¹H, ¹³C, and ³¹P NMR, MS, FTIR), and <i>rac</i>-<b>6</b>, the corresponding phosphine oxide <i>rac</i>-<b>2</b>, and <i>rac</i>-<b>9</b> were also characterized by X-ray crystallography. Furthermore, the redox properties of <i>rac</i>-<b>2</b>–<b>9</b> were studied by cyclic voltammetry

1,2-Disubstituted Aryl-Based Ferrocenyl Phosphines

Ferrocenylaryl- or ferrocenylheteroarylphosphines [Fe­{1-PPh₂(spacer)-2-NMe₂CH₂C₅H₃}­(C₅H₅)] (spacer = 1,4-phenylene (<i>rac</i>-<b>6</b>), 1,3-phenylene (<i>rac</i>-<b>7</b>), 4,4′-biphenylene (<i>rac</i>-<b>8</b>), 2,5-thienylene (<i>rac</i>-<b>9</b>)) were prepared in a facile two-step sequence starting with Negishi cross-coupling between <i>N</i>,<i>N</i>-dimethylaminomethylferrocene and aryl halide phosphine oxides, Br-spacer-P­(O)­Ph₂, followed by reduction with trichlorosilane. All products were characterized spectroscopically (¹H, ¹³C, and ³¹P NMR, MS, FTIR), and <i>rac</i>-<b>6</b>, the corresponding phosphine oxide <i>rac</i>-<b>2</b>, and <i>rac</i>-<b>9</b> were also characterized by X-ray crystallography. Furthermore, the redox properties of <i>rac</i>-<b>2</b>–<b>9</b> were studied by cyclic voltammetry

Synthesis of 1,1′,2-Trisubstituted Aryl-Based Ferrocenyl Phosphines as Precursors for Immobilized Ligands

Ferrocenylaryl or ferrocenylheteroaryl phosphines bearing a carboxaldehyde group, [Fe­{1-PPh₂(spacer)-2-NMe₂CH₂C₅H₃}­(C₅H₄CHO)] (spacer = none (<i>rac</i>-<b>12</b>), 1,4-phenylene (<i>rac</i>-<b>13</b>), 1,3-phenylene (<i>rac</i>-<b>14</b>), 2,5-thienylene (<i>rac</i>-<b>15</b>)), were prepared in a facile four-step sequence starting with dibromination of <i>N</i>,<i>N</i>-dimethylaminomethylferrocene (<b>1</b>) followed by Negishi cross-coupling between 1,1′-dibromo-2-<i>N,N</i>-dimethylaminomethylferrocene (<i>rac</i>-<b>2</b>) and aryl or heteroaryl bromide phosphine oxides, Br-spacer-P­(O)­Ph₂ (spacer = 1,4-phenylene, 1,3-phenylene, 2,5-thienylene), reduction with trichlorosilane, and functionalization of the 1′-position of the cyclopentadienyl ring. All products were fully characterized by spectroscopy (¹H, ¹³C, and ³¹P NMR, MS, IR) and for <i>rac</i>-<b>3</b>, <i>rac</i>-<b>7</b> and <i>rac</i>-<b>11</b> also by X-ray crystallography. Furthermore, preliminary studies on the grafting of <i>rac</i>-<b>12</b> on silica were conducted

Synthesis of 1,1′,2-Trisubstituted Aryl-Based Ferrocenyl Phosphines as Precursors for Immobilized Ligands

Ferrocenylaryl or ferrocenylheteroaryl phosphines bearing a carboxaldehyde group, [Fe­{1-PPh₂(spacer)-2-NMe₂CH₂C₅H₃}­(C₅H₄CHO)] (spacer = none (<i>rac</i>-<b>12</b>), 1,4-phenylene (<i>rac</i>-<b>13</b>), 1,3-phenylene (<i>rac</i>-<b>14</b>), 2,5-thienylene (<i>rac</i>-<b>15</b>)), were prepared in a facile four-step sequence starting with dibromination of <i>N</i>,<i>N</i>-dimethylaminomethylferrocene (<b>1</b>) followed by Negishi cross-coupling between 1,1′-dibromo-2-<i>N,N</i>-dimethylaminomethylferrocene (<i>rac</i>-<b>2</b>) and aryl or heteroaryl bromide phosphine oxides, Br-spacer-P­(O)­Ph₂ (spacer = 1,4-phenylene, 1,3-phenylene, 2,5-thienylene), reduction with trichlorosilane, and functionalization of the 1′-position of the cyclopentadienyl ring. All products were fully characterized by spectroscopy (¹H, ¹³C, and ³¹P NMR, MS, IR) and for <i>rac</i>-<b>3</b>, <i>rac</i>-<b>7</b> and <i>rac</i>-<b>11</b> also by X-ray crystallography. Furthermore, preliminary studies on the grafting of <i>rac</i>-<b>12</b> on silica were conducted

Copper(I) Complexes of a Flexible Bis-phospholane Ligand: Route to Paddle-Wheel- and Box-Type Macrocycles

Two bis-phospholane copper­(I) metallamacrocycles were selectively synthesized starting from the same two building blocks, namely, ligand <b>1</b> and [Cu­(NCCH₃)₄]­BF₄. Reaction conditions (ligand:metal (L:M) ratio and dilution) can be tuned to obtain either a paddle-wheel- (<b>2</b>, L:M = 3:2) or box-type complex (<b>3</b>, L:M = 8:4). Their structures were unequivocally determined by X-ray crystallography. The solution ³¹P­{¹H} NMR spectrum of complex <b>2</b> consists of a broad signal, as is common for such complexes, whereas complex <b>3</b> shows splitting of the ³¹P­{¹H} NMR signal into a pseudoquartet due to ^63,65Cu–³¹P coupling, a rare occurrence exhibited only by highly symmetrical copper­(I) phosphine complexes

Versatile Coordination Modes of Triphospha-1,4-pentadiene-2,4-diamine

1,3,5-Triphospha-1,4-pentadiene-2,4-diamine reacts with [M­(CO)₄L] (M = Mo, L = nbd (norbornadiene); M = W, L = 2 CH₃CN) to give the chelate complexes [M­(CO)₄(PMes­{C­(NHCy)­PMes}₂-κ<i>P</i>¹<i>,P</i>³)]. In contrast, an unusual intramolecular rearrangement occurred with [Cu­(CH₃CN)₄]­PF₆ leading to the dimeric copper­(I) complex [Cu­(CNCy)­{PHMesP­MesC­(NHCy)­PMes-κ<i>P</i>¹<i>,P</i>³}]₂(PF₆)₂. The mechanism of the rearrangement was supported by quantum-mechanical calculations. The transition-metal complexes were characterized by multinuclear NMR spectroscopy, mass spectrometry, infrared spectroscopy, and X-ray crystallography

Facile One-Step Synthesis of MPHMes from MesPCl₂ (M = Li, Na, K; Mes = 2,4,6-Me₃C₆H₂)

Reaction of alkali metals (Li, Na, K) with mesityldichloro­phosphane (MesPCl₂, Mes = 2,4,6-Me₃C₆H₂) in ethereal solvents leads to formation of the corresponding mesitylphosphanides MPHMes in good purity and yield. ³¹P NMR spectroscopic studies in deuterated solvents strongly support a mechanism of the reaction that involves protonation/disproportionation steps in which the solvent is the only possible proton source. Li­(thf)­(tmeda)­PHMes (<b>1</b>), [Na­(tmeda)­(μ-PHMes)]_∞ (<b>2</b>), and [K­(pmdeta)­(μ-PHMes)]₂ (<b>3</b>) (tmeda = <i>N,N,N</i>′<i>,N</i>′-tetramethylethylenediamine, pmdeta = <i>N,N,N</i>′<i>,N</i>″<i>,N</i>″-pentamethyldiethylenetriamine) were obtained; in the solid state, <b>2</b> forms zigzag chains while <b>3</b> is a dimeric compound