Calcium Amido Complexes Coordinated by Tridentate Amidinate Ligands: Synthesis, Structures and Catalytic Activity in Olefin Hydrophosphination and Polymerization of Cyclic Esters

Abstract

The reactions of [(Me 3 Si) 2 N] 2 Ca(thf ) 2 with amidines 2-(Ph 2 P=NPh)C 6 H 4 NHC(tBu)=N(2,6-R 2 C 6 H 3 ) {R = iPr (L 1 H); R = Me (L 2 H)} afford heteroleptic calcium amido complexes (1); R = Me (2)} featuring tridentate coordination of the amidinate ligands. Complexes 1 and 2 proved to be efficient catalysts for intermolecular hydrophosphination of styrene, αmethylstyrene, divinylbenzene and phenylacetylene with Ph 2 PH and PhPH 2 . Compounds 1 and 2 exhibit high catalytic activity in the ring-opening polymerization of ε-caprolactone and enable quantitative conversion of 500 equiv. of monomer in 5 seconds [a] G. A. Razuvaev

Preparation and Reactivity Studies of Four and Five coordinated Amidinate Aluminum Compounds

“…Dark red crystals of 6 were obtained from the concentrated toluene solution at À 32°C. 1-4 were characterized by 1 H, 13 C and 27 Al NMR shows the resonances at À 131 and À 134 ppm (Figure S13 in Supporting Information) indicating that the two fluorine atoms are magnetically not equivalent. Compounds 5 and 6 did not give good NMR characterization due to their instability in solution.…”

“…Dark red crystals of 6 were obtained from the concentrated toluene solution at À 32 °C. 1-4 were characterized by 1 H, 13 C and 27 Al NMR…”

“…C 6 D 6 was dried by stirring for 2 days over Na/K alloy followed by distillation in vacuum and degassed. 1 H, 13 C{ 1 H} NMR spectra were recorded on Bruker Avance 200, Bruker Avance 300, and Bruker Avance 500 MHz NMR spectrometers and were referenced to the TMS. Elemental analysis was performed by the Analytisches Labor für Anorganische Chemie für Universität Göttingen.…”

“…In recent times, amidinates with the general formula [R 1 C-(NR) 2 ] À are widely used to develop compounds from f-group metals to main group elements such as silicon, [1][2][3][4][5][6][7][8][9][10] germanium, [9,11] strontium, [12] calcium, [13] magnesium, [14] tin, [15] gallium, [16][17][18] indium [19][20][21][22] etc. This class of ligands is easy to synthesize and known to increase the stability of the resulting compounds.…”

Photocatalytic Hydrophosphination with Air-Stable and Commercially Available Bis(acetylacetonato)copper(II) (Cu(acac)2)

“…Hydrophosphination of styrene was examined first due to its common use in recent studies. 41,42,43,44 A chloroform-d1 solution of styrene was treated with 2 equiv. of phenylphosphine in the presence of 5 mol % of 1.…”