1.Formation, reactivity and redox properties of carbon- and sulfur-bridged diiron complexes derived from dibenzothienyl Schiff bases: effect of N,N- and N,P-chelating moieties.
Santo K1, Hirotsu M, Kinoshita I. Dalton Trans. 2015 Mar 7;44(9):4155-66. doi: 10.1039/c4dt03422h.
Dibenzothienyl Schiff bases, DBT-NN and DBT-NP, were derived from condensation of 4-formyldibenzothiophene with N,N-dimethylethylenediamine and 2-(diphenylphosphino)ethylamine, respectively. A photochemical reaction of [Fe(CO)5] with DBT-NN produced diiron complexes, [Fe2(μ-DBT-NN)(CO)6] (1) and [{Fe(μ-BPT-NN-κ(3)S,C,N)(CO)2}Fe(CO)3] (2). Complex 1 has π coordination of a Schiff base C=N bond and an N,N-chelate, while 2 has an S,C,N-tridentate ligand having an uncoordinated dimethylamino group. The corresponding reaction with DBT-NP produced a diiron complex of an S,C,N,P-tetradentate ligand, [{Fe(μ-BPT-NP-κ(4)S,C,N,P)(CO)}Fe(CO)3] (3), which has an N,P-chelate, via the DBT-NP complex [Fe(DBT-NP-κP)(CO)4] (4). Reactions of 2 and 3 with one equivalent of PMe2Ph gave the monosubstituted complexes [{Fe(μ-BPT-NN-κ(3)S,C,N)(CO)2}Fe(CO)2(PMe2Ph)] (5) and [{Fe(μ-BPT-NP-κ(4)S,C,N,P)(CO)}Fe(CO)2(PMe2Ph)] (6), respectively. The corresponding reactions with an excess of PMe2Ph produced mononuclear complexes, trans-[Fe(BPT-NN-κ(3)S,C,N)(CO)(PMe2Ph)2] (7) and [Fe(BPT-NP-κ(4)S,C,N,P)(CO)(PMe2Ph)] (8), respectively.
2.Catalytic ability of a cationic Ru(II) monochloro complex for the asymmetric hydrogenation of dimethyl itaconate and enamides.
Serrano I1, Rodríguez M, Romero I, Llobet A, Parella T, Campelo JM, Luna D, Marinas JM, Benet-Buchholz J. Inorg Chem. 2006 Mar 20;45(6):2644-51.
The synthesis of two Ru chloro complexes, Ru(III)Cl(3)(bpea), 1, and cis-fac-Delta-[Ru(II)Cl{(R)-(bpea)}{(S)-(BINAP)}](BF(4)), cis-fac-Delta-(R)-(S)-2, (bpea = N,N-bis(2-pyridylmethyl)ethylamine; (S)-BINAP = 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl), is described. Complex 2 is characterized in solution through UV-vis, cyclic voltammetry (CV), and 1D and 2D NMR spectroscopy. X-ray diffraction analysis indicates that in the solid state it possesses the same structure as in solution, as expected for a low-spin d(6) Ru(II)-type complex. The molecular structure of cis-fac-Delta-(R)-(S)-2, consists of a nonsymmetric complex, where the Ru metal center has a significantly distorted octahedral-type coordination because of the bulkiness of the (S)-BINAP ligand. cis-fac-Delta-(R)-(S)-2 has a remarkable catalytic performance at P = 6.8 atm of H2 and T = 70 degrees C toward the hydrogenation of prochiral double bonds both from efficiency and from stereoselectivity viewpoints.
3.Synthesis and structural characterisation of Pd(II) and Pt(II) complexes with a flexible, ferrocene-based P,S-donor amidophosphine ligand.
Tauchman J1, Císařová I, Stěpnička P. Dalton Trans. 2014 Jan 28;43(4):1599-608. doi: 10.1039/c3dt52760c.
1'-Diphenylphosphino-1-{[(2-(methylthio)ethyl)amino]carbonyl}ferrocene (1), accessible via amidation of 1'-(diphenylphosphino)ferrocene-1-carboxylic acid (Hdpf) with 2-(methylthio)ethylamine, reacts with [PdCl2(cod)] (cod = cycloocta-1,5-diene) at a 1 : 1 metal-to-ligand ratio to give trans-[PdCl2(1-κ(2)P,S)] (trans-2) as the sole product. A similar reaction with [PtCl2(cod)] affords a mixture of cis- and trans-[PtCl2(1-κ(2)P,S)] (cis- and trans-3), which can be separated by fractional crystallisation. Complexation reactions performed with 2 equiv. of the ligand are less selective, yielding mixtures of the expected bis-phosphine complexes (i.e., trans-[PdCl2(1-κP)2], or a mixture of cis- and trans-[PtCl2(-κP)2]) with the respective monophosphine complexes. The structures of 1, trans-2, cis-3 and trans-3 determined by X-ray diffraction demonstrate the ability of the title ligand to act as a flexible cis- or trans-P,S-chelate donor (the ligand bite angles are 174.
4.Template synthesis of iron(II) complexes containing tridentate P-N-S, P-N-P, P-N-N, and tetradentate P-N-N-P ligands.
Lagaditis PO1, Mikhailine AA, Lough AJ, Morris RH. Inorg Chem. 2010 Feb 1;49(3):1094-102. doi: 10.1021/ic901945c.
A series of mer-tridentate iron(II) complexes bearing P-N-S (3), P-N-P (4), and P-N-N (5) ligands have been prepared via the metal template effect in one pot involving air-stable phosphonium dimers [cyclo-(-PPh(2)CH(2)C(OH)H-)(2)](Br)(2) (1) and [cyclo-(-PCy(2)CH(2)C(OH)H-)(2)](Br)(2) (2), KOtBu, [Fe(H(2)O)(6)][BF(4)](2) and 2-aminothiolphenol (for 3), 2-(diphenylphosphino)ethylamine (for 4), and 2-(aminomethyl)pyridine (for 5). The new phosphonium dimer 2 was prepared via an S(N)2 reaction of PCy(2)H with BrCH(2)CH(OEt)(2). The complexes Fe{PR(2)CH(2)CH=N(2-C(6)H(4))S}(2)FeBr(2) (3a, R = Ph; 3b, R = Cy) are paramagnetic, and X-ray diffraction studies revealed that they are bimetallic, in which the S atoms of the bis-tridentate (PNS)(2)Fe unit bridge to a FeBr(2) fragment. Complexes [Fe(PR(2)CH(2)CH=NC(2)H(4)PPh(2))(NCMe)(3)]X(2) (4a, R = Ph; 4b, R = Cy; X(2) = FeBr(4) or (BF(4))(2)) form when 1 equiv of iron is reacted with PPh(2)CH(2)CH(2)NH(2) and 0.
