Areneruthenium(II) Complexes with Functionalized Phosphines Coordinating as Mono-, Bi- or Tridentate Ligands

Abstract

Dedicated to the Memory of Luigi M. Venanzi, one of the pioneers of modern coordination chemistry Areneruthenium(II) compounds [Ru(p-cym)Cl 2 {k-P-i PrP(CH 2 CH 2 OMe) 2 }], 3, and [Ru(arene)Cl 2 {k-P-RP(CH 2 CO 2 Me) 2 }] 4 ± 7 (arene p-cym ( 1-methyl-4-isopropylbenzene), mes ( 1,3,5-trimethylbenzene); R i Pr, t Bu) were prepared from the dimers [Ru(arene)Cl 2 ] 2 and the corresponding functionalized phosphine. Treatment of 6 and 7 with 1 equiv. of AgPF 6 affords the monocationic complexes [Ru(mes)Cl{k 2 -P,O-RP(CH 2 C(O)OMe)(CH 2 CO 2 Me)}]PF 6 , 10 and 11, while the related reaction of 5 ± 7 with 2 equiv. of AgPF 6 produces the dicationic compounds [Ru(p-cym){k 3 -P,O,O-t BuP(CH 2 C(O)OMe) 2 }](PF 6 ) 2 (12) and [Ru(mes)-{k 3 -P,O,O-RP(CH 2 C(O)OMe) 2 }](PF 6 ) 2 , 13 and 14. Partial hydrolysis of one hexafluorophosphate anion of 12 ± 14 leads to the formation of [Ru(arene){k 2 -P,O-RP(CH 2 C(O)OMe)(CH 2 CO 2 Me)}(k-O-O 2 PF 2 )]PF 6 , 15 ± 17, of which 17 (arene mes; R t Bu) has been characterized by X-ray crystallography. Compounds 13 and 14 react with 2 equiv. of KO t Bu in t BuOH/toluene to give the unsymmetrical complexes [Ru(mes){k 3 -P,C,O-RP-(CHCO 2 Me)(CHC(O)OMe)}], 18 and 19, containing both a five-membered phosphinoenolate and a threemembered phosphinomethanide ring. The molecular structure of compound 18 has been determined by X-ray structure analysis. The neutral bis(carboxylate)phosphanidoruthenium(II) complexes [Ru(arene){k 3 -P,O,O-RP-(CH 2 C(O)O) 2 }], 20 ± 23 are obtained either by hydrolysis of 18 and 19, or by stepwise treatment of 4 and 5 with KO t Bu and basic Al 2 O 3 . Novel tripodal chelating systems are generated via insertion reactions of 19 with PhNCO and PhNCS.Introduction. ± In the search of finding useful ligands for catalytically active transition-metal complexes, the chemistry of substituted phosphines of general composition R 2 P(CH 2 ) n Y has become an area of great interest in recent years (for reviews, see [1]). By far, the most attention was given to compounds where the functional group Y is MeO, C(O)R' or C(O)OR', since it was anticipated that the Odonors temporarily are able to protect a vacant coordination site and thus allow the addition of more powerful ligands to the metal center under fairly mild conditions. Moreover, with b-phosphino ketones or esters as coordinating groups, a number of Ometallated phosphinoenolate metal complexes have been prepared and found to be appropriate starting materials for C,C coupling reactions with activated alkynes and isocyanates [2], for the generation of metal acetylides from alk-1-ynes [3], and for reversibly binding CO 2 [4].As a continuation of our work on the reactivity of phosphino esters R 2 PCH 2 CO 2 R' toward d 6 and d 8 metal centers [5], we have recently developed a synthetic route to the trifunctional phosphines RP(CH 2 CO 2 R') 2 [6] and started to investigate their coordination capabilities [7]. In this paper, we describe the synthesis of a series of areneruthenium(II) complexes containing the potentially tridentate m...

Base-Assisted Cyclometalation and Phosphorus−Carbon Bond Cleavage in (Arene)ruthenium(II) Complexes Containing Functionalized Iminophosphorane-Phosphine Ligands Ph2PCH2P{NP(X)(OR)2}Ph2 (X = O, S; R = Et, Ph)

“…In addition, the bond distances within the three-membered Ru−P−C metallacycle (Ru−P(1) = 2.244(1) Å, Ru−C(11) = 2.204(4) Å, and P(1)−C(11) = 1.759(4) Å) compare well with those found in the related (η 6 -arene)-ruthenium(II) complexes [RuCl{κ 2 - P,C - i Pr 2 PCH(CO 2 Me)}(η 6 -1,3,5-C 6 H 3 Me 3 )] ( E ) (Ru−P = 2.2694(8) Å, Ru−C = 2.201(2) Å, P−C = 1.761(2) Å),14a [Ru(κ 3 - P,C,O - i PrP{CH(CO 2 Me)}C(H)CO 2 Me)(η 6 -1,3,5-C 6 H 3 Me 3 )] ( F ) (Ru−P = 2.301(2) Å, Ru−C = 2.217(4) Å, P−C = 1.727(4) Å),14b and [Ru(κ 3 - P,C,O -Ph 2 PCH{C(Ph)C(H)C(O) t Bu})(η 6 -1,3,5-C 6 H 3 Me 3 )][BF 4 ] ( G ) (Ru−P = 2.243(2) Å, Ru−C = 2.211(8) Å, P−C = 1.761(4) Å) 12a (see Chart ). P−N and P−O bond lengths are also similar to those found in other species containing −R 2 PNP(X)(OR‘) 2 units (X = O, S). 3f,, Cyclometalations leading to the formation of a strained three-membered M−P−C ring are well documented, ,, butno example is known in the chemistry of iminophosphorane-phosphine ligands R 2 PCH 2 P(NR‘)R 2 1 ORTEP-type view of the structure of [RuCl(κ 2 - P,C -Ph 2 PCHP{NP(O)(OPh) 2 }Ph 2 )(η 6 - p -cymene)] ( 3b ) showing the crystallographic labeling scheme.…”

“…In the case of 3 − 4a , b the concomitant chloride abstraction leaves a free coordination site, allowing the attachment of the phosphoryl or thiophosphoryl unit. We note that such P−C bond cleavage has no precedent in the chemistry of the three-membered metallacyclic compounds of the type [M]-(κ 2 - P,C -R 2 PCHR). ,,

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Positional and compositional disorder in a ruthenium(II) piano-stool complex

“…In Fig. 3(d Werner et al, 2001). Among these three complexes, the [PO 2 F 2 ] À anion is monodentate and well refined only in (II), with an Ru-O bond length of 2.117 (3) Å , a value in excellent agreement with the corresponding distance of 2.1130 (15) Å in (I).…”

Coordination of the Ester Group – Hydrido‐Rhodium(III) and Iridium(III) Complexes of Orthometallated Diphenylmethylene Glycine Esters [1]

“…Further remarkable ligands are Werner ’s trifunctional phosphines RP(CH 2 CO 2 R′) 2 which are coordinated by two ester groups in several complexes 19 in e.g. Cl 2 Ru[RP(CH 2 COOR′) 3 ] 29b. In metal complexes of 3‐carboxyethyl‐substituted trispyrazolylborates the ester carbonyl stretching frequency proved to be highly diagnostic for the interaction of the ester groups with coordinated water (hydrogen bonding) or with the metal ion 47.…”