Reaktionen kationischer η2-phosphinocarben-komplexe des wolframs mit anionischen nukleophilen

Stable Carbenes

“…Protic acids react with 155 affording the corresponding 1,2-adducts 158 . With Lewis acids such as MeS + , an electrophilic attack occurs at the metal−carbon double bond, affording the dicationic tungstaphosphathiabicyclo[1.1.0]butane complexes 159 . 316a,b On the other hand, nucleophiles such as trialkyl phosphines and the cyclopentadienyl anion C 5 H 5 - add at the carbene center, affording the tungstaphosphacyclopropane complexes 160 316b and 161 ,316c respectively. Last, a third reaction pathway is observed on reaction with the thiocyanate anion or isonitriles: cationic tungstaphosphabicyclo[1.1.0]butane complexes 162 are formed, the CO ligand now bridging the metal center and the C−R fragment …”

η2-Alkynyl and Vinylidene Transition Metal Complexes. 6.1 Reaction of Tungsten Vinylidene Complexes with Chlorophosphines as Nucleophile. Preparation and Crystal Structural Analysis of Neutral η2-Phosphinovinyl Complexes

“…The 1 H NMR spectra of 3a and 5 show characteristic signals of the magnetically nonequivalent methylene protons. Because of their different 3 J ( 31 P− 1 H) coupling constants [ 3a , δ 7.65 ppm ( 3 J H - P = 15 Hz) and 6.55 ppm ( 3 J H - P = 35 Hz); 5 , δ 7.47 ppm ( 3 J H - P = 13 Hz) and 6.49 ppm ( 3 J H - P = 32 Hz)], they can be assigned to the cis - and trans -position relative to the phosphor atom. 12b, The 3 J ( 31 P− 13 C) coupling constants of the E and Z isomers of 3b and 3c also differ significantly: the carbon atoms of the Z isomers of 3b and 3c couple in both cases with 3 J C - P = 17 Hz, while the E isomers have a coupling constant of 9 and 6 Hz, respectively.…”