Air-stable fluorescent primary phosphine complexes of molybdenum and tungsten

Abstract

Here we report a study on the reactivity of the fluorescent air-stable primary phosphine 8-((4-phosphino)phenyl)-4,4-dimethyl-1,3,5,7-tetramethyl-2,6-diethyl-4-bora-3a,4a-diaza-s-indacene 4 with [Mo (CO) 6 ], [W(CO) 6 ], [Mo(CO) 4 (piperidine)] and [W(CO) 4 (piperidine)] which yields the mono-phosphine [Mo(CO) 5 (4)] 5, [W(CO) 5 (4)] 6 and di-phosphine cis-[Mo(CO) 4 (4) 2 ] (7) and cis-[W(CO) 4 (4) 2 ] (9) complexes as the predominant products. In addition to the characterisation of these complexes by multinuclear NMR and IR spectroscopy, and mass spectrometry, the solid state structures of 6 and cis-7 have also been determined by single crystal X-ray diffraction. The photophysical properties of the complexes show that the incorporation of the phosphorus ligand has a limited effect on the absorption and emission profile of the Bodipy core and that they retain similar quantum yields to their parent Bodipy dyes. Small quantities of the by-products trans-[Mo(CO) 4 (4) 2 ] (7), cis-[Mo(CO) 4 (piperidine)(4)] (8) and cis-[W(CO) 4 (piperidine)(4)] (10) were also isolated and characterized.

Synthesis and Structure of Metal Complexes of P-Stereogenic Chiral Phosphiranes: An EDA-NOCV Analysis of the Donor–Acceptor Properties of Phosphirane Ligands

“…Higham and co-workers suggested that the observations for rhodium complexes could be explained if the PCH 2 CH 2 group in phosphiranes, because of the pyramidalized structure and increased s-character of the donor orbitals, was a poorer σ-donor than PMe 2 . , A similar rationalization is plausible for the Mo complexes. In contrast, no difference in the CO stretching frequencies for W­(CO) 5 complexes was observed. , However, this system is particularly insensitive to phosphine structure, so that electronic differences among PPh 3 , PMe 3 , and the mixed arylmethylphosphines PPh 3– n Me n ( n = 0–3) could not be determined by vibrational spectroscopy …”

New Developments on the Hirao Reactions, Especially from “Green” Point of View

“…KOAc and NaOAc were also applied as ionic additives in the Hirao reaction [ 58 - 62 ]. In the presence of Pd(OAc) 2 or Pd(dba) 2 as the Pd precursor, dppf [ 58 - 65 ], dppb [ 58 , 66 - 70 ], dppp [ 58 ] and BINAP [ 58 ] could also be used as ligands. Pd(dppf) 2 Cl 2 was also a suitable catalyst to promote the coupling reaction of dialkyl phosphites [ 71 , 72 ].…”