Darstellung und Kristallstrukturen einiger mit N,N'‐Dimethylharnstoff verbrückter Diphosphorverbindungen; NMR‐Untersuchung einer λ4P+λ4P+‐Diphosphorverbindung

Abstract

Preparation and Single‐Crystal X‐ray Structure Investigations of some N,N′‐Dimethylurea‐Bridged Diphosphorus Compounds: NMR Studies of a λ4P+ λ4P+ ‐Diphosphorus CompoundThe synthesis of N,N′‐dimethylurea‐bridged diphosphorus compounds involving the structural elements λ3Pλ4P+ (3b, 3c, and 7) and λ4P+λ4P+ (4 and 8) is described. The salts 4 and 8 were obtained by methylation of the λ3Pλ4P+ compounds 3c and 7 with MeOSO2CF3. The λ3P atom in 3c and 7 coordinates to tungsten(0) with formation of the ionic pentacarbonyl derivatives 9 and 10. The NMR spectra of the diphosphonium salt 4 were completely analyzed using NOE and 2D shift correlation experiments (13C,1H and 31P,1H). The single crystal X‐ray structure determinations of 3b and 9 are reported. 3b found to crystallize as a hemisolvate with dichloromethane. The RR/SS diastereomer is present in the crystal. The PP distance amounts to 219.1 pm. Both phosphorus atoms interact weakly with the chloride ion (293, 312 pm). 9 crystallizes as a hemisolvate with toluene, the RS/SR diastereomer being present. A PP distance of 224.7 pm and weak interactions between the phosphorus atoms and an oxygen atom of the anion (305, 308 pm) are found.