Transition metal complexes of triphosphorus macrocycles: A new class of homogeneous olefin polymerisation catalysts

Abstract

Some early transition metal (Ti, V, Cr) complexes of the triphosphorus macrocycle 1,5,9-triethyl-1,5,9-triphosphacyclododecane, [12]aneP 3 Et 3 , and related derivatives [12]aneP 3 R 3 (R = Ph, C 3 H 6 OMe) have been examined for their reactivity towards ethene and propene. All complexes of the type [12]aneP 3 Et 3 MCl 3 display moderate catalytic activity in the homogeneous polymerisation of ethene when combined with an alkyl aluminium co-catalyst to give very high molecular weight polymers. Preliminary activation of chromium complexes with alkylating agents was also studied but these were inactive in the absence of a co-catalyst. Substitution of the P-borne alkyl group with a pendant ether function was found to switch the catalytic activity of chromium() complexes from polymerisation to oligomerisation. A nickel halide complex of [12]aneP 3 Et 3 was also found to be active in alkene polymerisation.

Chromium(III) complexes bearing 2-benzoxazolyl-6-arylimino-pyridines: Synthesis and their ethylene reactivity

“…On the other hand, chromium catalysts are still being the only practicing catalysts for the on-purpose process for ethylene trimerization or tetramerization [11][12][13][14][15][16][17][18][19]. Therefore it has attracted for designing homogeneous catalysts of chromium complexes through developing multidentate ligands, such as N^N (iminopyrrolide [20,21], b-diketiminate [21][22][23][24][25], bis(phosphoranimine)methanide [26] and bis(imidazole) [27,28]), N^O [29][30][31], P^P or P^N^P [32][33][34][35][36][37][38][39], P^P^P [40], N^P^N [41], S^N^S [34,35,42], N^S^N [43], C^N^C [44], N^N^O [45,46] and N^N^N^N [47], as well as N^N^N ligands such as (2-pyridylmethyl)amines [48], bis(imino)pyridines (A, Scheme 1) [45,[49][50][51], bis(oxazolinyl)pyridine (B, Scheme 1) …”

Chromium(III) complexes ligated by 2-(1-isopropyl-2-benzimidazolyl)-6-(1-(arylimino)ethyl)pyridines: Synthesis, characterization and their ethylene oligomerization and polymerization

“…The rapid progress has recently been focused on synthesizing new chromium complexes and investigating their catalytic behaviors toward ethylene reactivity, the numerous chromium complexes have been explored with numerous ligands in several chelate models such as N^O [11,12], N^N [13-15], N^N^N [16,17], P^P^P or P^N^P [18][19][20][21][22], S^N^S [21], C^N^C [23], N^S^N [24], N^N^N^N [25] along with half-metallocene [26]. In order to understand the active species and alternative intermediates of chromium complexes, some chromium complexes containing O^N^N [27] and N^N^N [28] ligands were investigated in our group as the extensive researches of late-transition metal analogues as catalysts in ethylene reactivity [29].…”

Facile Synthesis of Hyper‐Branched Tetraphosphanes and Tetraphosphane Chalcogenides

“…Diphosphanes such as dipamp, duphos, prophos, xyliphos, xantphos, josiphos, biphep, binap, bpe, dppe, and dppf are widely used ligands for organometallic catalysts, [1] anticancer drugs, [2] and fluorescent sensors for heavy metals. [3] Triphosphanes are ligands of catalysts for homogeneous olefin polymerization [4] and hydrogenolysis of benzothiophene. [5] They are also employed in Wittig reactions.…”