Studies on phosphaamidines, phosphinodiimines, and diphosphanes

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Mokhtabad Amrei, Leila
University of Lethbridge. Faculty of Arts and Science
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Lethbridge, Alta : University of Lethbridge, Dept. of Chemistry and Biochemistry
The synthesis of a new neutral phosphaamidine (Dipp)N=C(CH3)P(Dipp) and new protonated phosphaamidines ((Dipp)HN+=C(R)PH(Dipp), R = tBu, CH3, pCH3O-Ph and Dipp = 2,6-diisopropylphenylphosphane are described. The protonated phosphaamidines have Z-anti(N=C) geometry in the solid state. A new phosphinodiimine (Dipp)P((tBu)C=N(Dipp))2 and a new amidinophosphaalkene (Dipp)P=C(CH3)-N(Dipp)-C(CH3)=N(Dipp) are described which were synthesized by using the related phosphaamidines as starting materials. The substitution at the carbon backbone plays a significant role in isomerisation and for the geometric preference of these compounds in solution and in the solid state. A new diphosphane (Dipp)HP-PH(Dipp), which was first observed as a side product while making phosphaamidines, was crystallographically characterized. All of these compounds, including phosphaamidines, phosphinodiimines, and diphosphanes, display isomerism in solution which has been studied through 1D and 2D (1H, 13C, 31P) nuclear magnetic resonance and solid-state NMR spectroscopies, X-ray crystallography, IR and Raman in the case of (Dipp)HP-PH(Dipp), spectroscopies and Hybridge Density Functional Theory calculations.
amidinophosphaalkene , carbon backbone , isomerisation , neutral phosphaamidine , protonated phosphaamidine , synthesis