On the Donor Ability of the Phosphaneiminato Substituent and Cube Formation with Transition Metal Fragments

Abstract

The particular role of the phosphaneiminato ligand as a donor is investigated for a) nitrenes (phosphinidenes) and carbenes and b) cubane formation with transition metals. Accordingly, and as shown for the case a) the ligand is a stronger π‐donor than an amino group and can be considered as a special case of imine‐type substituents. The latter are very effective in π‐donation. In the case b), i.e. the cubane formation with transition metals, one has to consider transition metals with a partially or completely filled d‐shell (with electrons). Hence depending on the transition metal, cubanes are build with weak ferromagnetic coupled or closed shell systems. For the cubanes with closed shell character the matter of insertion of halide anions is discussed. In the last chapter of the review the bond stretching in the dithionitrosyl complexes with rhenium is characterized.

Powerful Bispyridinylidene Organic Reducing Agents with Iminophosphorano π‐Donor Substituents

“…Although tables of substituent constants27, 28 indicate that amino groups are the premier π‐donor groups, we were aware of some theoretical and experimental evidence that N‐bound iminophosphorano groups (R 3 P=N)29–33 should be regarded as stronger electron‐donating substituents. Indeed, calculations by Schoeller have shown a greater stabilization of the singlet state of the corresponding phosphanylnitrenes (R 2 PN) for R=H 3 P=N over R=H 2 N 34. 35 In addition, whereas diaminochloroboranes [(R 2 N) 2 BCl] are covalent species with discrete BCl bonds,36 the isolation of the chloride salt of a dicoordinate borinium cation [ t Bu 3 P=N) 2 B][Cl] by Stephan et al 29.…”

Conformational Composition of Cyclopentadienylphosphine Investigated by Microwave Spectroscopy and Quantum Chemical Calculations

“…Such compounds are subject to circumambulatory (walk) rearrangement caused by rapid migration of substituents, which make them particularly interesting. [13][14][15][16] This unique fluxional phenomenon is in many cases easily observed by NMR spectroscopy via the temperature dependence of chemical shifts. [17][18][19][20] Numerous 5-substituted 1,3-cyclopentadienyl derivatives have therefore been prepared to study this effect.…”

“…[17][18][19][20] Numerous 5-substituted 1,3-cyclopentadienyl derivatives have therefore been prepared to study this effect. Experimental and theoretical investigations of circumambulatory behavior have been reported for silicon, 19,[21][22][23] germanium, 19,[23][24][25] phosphorus, [13][14][15][16]26 and arsenic 27,28 derivatives. The title compound, which was recently synthesized, 13 has also been the subject of such an investigation.…”

“…The title compound is a 5-substituted 1,3-cyclopentadienyl derivative with a heteroatom (phosphorus) attached to the allylic carbon atom via a σ-bond. Such compounds are subject to circumambulatory (walk) rearrangement caused by rapid migration of substituents, which make them particularly interesting. − This unique fluxional phenomenon is in many cases easily observed by NMR spectroscopy via the temperature dependence of chemical shifts. − Numerous 5-substituted 1,3-cyclopentadienyl derivatives have therefore been prepared to study this effect. Experimental and theoretical investigations of circumambulatory behavior have been reported for silicon, ,− germanium, ,− phosphorus, − , and arsenic , derivatives.…”

Synthesis and Characterization of Primary Cyclopentadienylphosphines and Cyclopentadienylarsines

“…The circumambulatory rearrangement easily observed by NMR spectroscopy for numerous derivatives leads to signals at chemical shifts dependent on the temperature and the nature of the substituents . Numerous experimental studies and theoretical calculations have been reported on silicon, − germanium, , phosphorus, , or arsenic derivatives. , …”