Synthesis, Structure and Cu‐Phenylacetylide Coordination of an Unsymmetrically Substituted Bulky dppf‐Analog

Abstract

The donor properties of a set of bulky ferrocene based bisphosphanes (Fe(C5H4PMes2)2 and (C5H4PMes2)Fe(C5H4PtBu2 with Mes= mesityl and tBu=tert‐butyl) were probed by exploring the NMR parameters of the corresponding selenophosphoranes amended by cyclovoltammetry. The ligand properties were explored in the complexation of copper phenylacetylide which is relevant as intermediate in the Cu(I) catalyzed CO2 addition to phenylacetylene. Owing to the poor solubility of the resulting complexes their characterization was performed with solid state NMR spectroscopy amended by IR spectroscopy, mass spectrometry and elemental analysis. Remarkably, these complexes feature luminescent properties, albeit with limited quantum yield.

Tailoring the Fe → Pd interaction in cationic Pd(ii) complexesviastructural variation of the ligand scaffold of sterically demanding dppf-analogs and their P,N-counterparts

“…2). This observation is consistent with related sterically demanding dppf analogs, Fc′(PMes 2 )(PPh 2 ) and Fc′(PMes 2 ) 2 , 82,83 for which better donor ability has been found for Mes 2 P- than for Ph 2 P- groups, based on variation of the s-character of the lone pair at phosphorus with the geometry at this atom. 23,82,83…”

“…This observation is consistent with related sterically demanding dppf analogs, Fc′(PMes 2 )(PPh 2 ) and Fc′ (PMes 2 ) 2 , 82,83 for which better donor ability has been found for Mes 2 P-than for Ph 2 P-groups, based on variation of the s-character of the lone pair at phosphorus with the geometry at this atom. 23,82,83 To examine how the diarylphosphanyl groups in 3a and 3b are influenced by the amino unit in the molecule, we set out to determine the 1 J P-Se values as a measure for their donating properties. To this end, 3a and 3b were reacted with red selenium forming selenophosphoranes 4a and 4b (Scheme 1B) featuring 1 J P-Se coupling values of 757 Hz and 719 Hz (in Toluene-D8), respectively, which are ca.…”

“…4-6 Hz lower than those reported for Fc′(PSePh 2 ) 2 (761 Hz), Fc′(PSeMes 2 )(PSePh 2 ) (763 PSePh2 and 723 PSeMes2 Hz), and Fc′(PSeMes 2 ) 2 (723 Hz) in the same solvent. 23,82 The lower values for 1 J P-Se in 4a and 4b indicate a better donor ability of the phosphanyl units as compared to their counterparts without the NMe 2 unit. Moreover, by careful evaluation of the structure of 4a (Fig.…”

“…Reagents and chemicals were purchased from commercial suppliers (Sigma-Aldrich, ABCR, Alfa-Aesar) and used as received. Ligands Fc′(PMes 2 )(PPh 2 ) 83 and Fc′(PMes 2 )(P t Bu 2 ) 82 were synthesized following procedures, reported by Pietschnig et al 94 Although Fc′(NH 2 )Br has previously been synthesized following various procedures in yields of 71%, 74 and 50% (calculated on the basis of starting Fc′Br 2 ), 73,77 in the current report, a recently published procedure was employed, due to its simplicity and higher yield (ca. 70-80%, calculated on the basis of Fc′Br 2 ).…”

“…Crystallized yield 23%. 1 On the basis of a known procedure, 82,83 a suspension of red Se (0.5 mmol) and Fc′(NMe 2 )(PPh 2 ) or Fc′(NMe 2 )(PMes 2 ) (0.2 mmol) in thf (20 mL) was stirred for 1 h at r.t. All the volatiles were removed under high vacuum (10 −3 mbar) and the product was extracted with hot toluene. Analytically pure compound was precipitated from hot toluene by slow cooling.…”