Influence of bidentate phosphine ligands on the chemistry of [FeFe]-hydrogenase model: insight into molecular structures and electrochemical characteristics

Substitution of carbonyl ligands of the hydrogenase model complex [Fe₂(μ-SeCH₂CH(Me)CH₂Se-μ)(CO)₆] ( A ), by 1,1′-bis (diphenylphosphino)ferrocene (dppf), 1,2-bis (diphenylphosphino)benzene (dppbz) or 1,2-bis (diphenylphosphino)acetylene (dppac) is investigated. It is found that the reaction product depends on the diphosphine used. In the case of dppf, the product is an intramolecular bridged disubstituted complex [Fe₂{μ-SeCH₂CH(Me)CH₂Se-μ}(CO)₄{μ,κ¹,κ¹(P,P)-dppf}] ( 1 ), while the dppac-reaction produces an intermolecular bridged tetra-iron model [Fe₂{μ-SeCH₂CH(Me)CH₂Se-μ}(CO)₅]₂{μ,κ¹,κ¹(P,P)-dppac} ( 2 ). However, the dppbz-reaction gives [Fe₂{μ-SeCH₂CH(Me)CH₂Se-μ}(CO)₄{κ²(P,P)-dppbz}] ( 3 ) in which the dppbz ligand is bonded to one Fe atom in a chelated manner. The newly prepared complexes ( 1 – 3 ) have been characterized by elemental analysis, IR, ¹H-, ¹³C{H}-, ³¹P{H}-, ⁷⁷Se{H}-NMR spectroscopy and X-ray structure determination. The electrochemical behavior of 2 and 3 , in absence and presence of acid, is described by cyclic voltammetric measurements in CH₂Cl₂.     

Cyclopentadienyl tungsten complexes with thiocarboxylate and thiosulfonate ligands: Structures of CpW(CO)3SCOPh and CpW(CO)3SSO2-4-C6H4Cl

Treatment of the hydrosulfido tungsten complex CpW(CO)₃SH with acid chlorides (RCOCl) or sulfonyl chlorides (RSO₂Cl) affords CpW(CO)₃SCOR (1) [R = Me (a), CH₂Cl (b), Ph (c), 4-C₆H₄NO₂ (d)] and CpW(CO)₃SSO₂R (2) [R = Me (a), Ph (b), 4-C₆H₄Cl (c), 4-C₆H₄NO₂ (d)], respectively. The novel complexes, 1 and 2, were fully characterized by elemental analyses, IR and ¹H NMR spectroscopy. The solid state structures of CpW(CO)₃SCOPh (1c) and CpW(CO)₃SSO₂-4-C₆H₄Cl (2c) were determined by an X-ray crystal structure analysis.     

Ruthenium(II) 2,2′-bipyridine complexes incorporating substituted phenylazo-(2-(phenylthio))phenylmethine ancillary ligands. Synthesis,crystal structure,spectroscopic and redox properties

Abstract  

Five ruthenium complexes bearing phenylazo-(2-(phenylthio))phenylmethine ligands of the general type trans-[Ru^II(bpy)(L)(Cl)₂] (C1–C5) {L = YC₆H₄N=NC(COCH₃)=NC₆H₄(2-SC₆H₅), H (L1), Cl (L2), OCH₃ (L3), Br (L4), or NO₂ (L5)} have been synthesized. The crystal structure of trans-[Ru(bpy)(L1)(Cl)₂] (C1) is reported and shows no direct metal–S interaction. The complexes have been characterized through spectroscopic (IR, UV/vis and NMR) and electrochemical (CV) techniques. The electrochemical parameters (E _L(L)) of the azoimine ligands are reported.     

Ruthenium heterocyclic thiolate complexes: CpRu(L)(L′)SR, [L = L′ = PPh3, 1/2 dppm, 1/2 dppe; L = PPh3, L′ = CO]

The synthesis and characterization of several new ruthenium complexes containing heterocyclic thiolate ligands are described. CpRu(PPh₃)₂Cl reacts with thiolate anions to give CpRu(PPh₃)₂SR, (1) [R = 2-mercaptobenzimidazolyl (a), 2-mercaptobenzothiazolyl (b), and 2-mercaptobenzoxazolyl (c)] in good yields. The CpRu(PPh₃)-(CO)SR (2) complexes are obtained by treating (1) with CO gas in THF at room temperature. The one-pot reaction of CpRu(PPh₃)₂Cl, thiolate anions with chelate bisphosphine ligands (P–P), gave CpRu(P–P)SR where P–P = Ph₂PCH₂PPh₂ (dppm) (3); Ph₂PCH₂CH₂PPh₂ (dppe) (4).     

Synthesis and reactivity of cyclopentadienyl iron complexes containing ferrocenyl selenolates

New homo-trimetallic complexes of general formula?1,1??-fc[SeFeCp(CO)₂]₂ (fc?=?Fe(??⁵-C₅H₄)₂) are accessible in high yield by the reaction of 1,1??-fc(SeLi)₂, which is generated from 1,1??-fc(SeSiMe₃)₂ and n-BuLi, with two equivalents of CpFe(CO)₂I. Photolytic CO-substitution reactions of the organoiron diselenolate with bis-phosphines at ?50?°C using 1:2 (metal/ligand) molar ratio afforded 1,1??-fc(SeFeCp(P^P)₂. All these complexes were characterized by physicochemical and spectroscopic methods.     

Half-sandwich ruthenium complexes of pentafluorobenzenethiolato ligands

A synthetic study of ruthenium complexes containing pentafluorobenzenethiolato ligand is presented. The bis(triphenylphosphine) complex CpRu(PPh₃)₂SC₆F₅ (1) is prepared from CpRu(PPh₃)₂Cl and C₆F₅S⁻ in high yield. This complex is readily reacted with CO gas to give the mixed carbonyl-phosphine complex CpRu(PPh₃)(CO)SC₆F₅ (2) and with NOBF₄ at room temperature to give [CpRu(PPh₃)(NO)SC₆F₅]BF₄ (3). The one-pot reaction of CpRu(PPh₃)₂Cl, dppa ligands, and C₆F₅S⁻ produces CpRu(dppa)SC₆F₅ [dppa = bis(diphenylphosphino)methane: dppm (4); bis(diphenylphosphino)ethane: dppe (5)]. Complexes (1)–(5) have been characterized by spectroscopic techniques (i.r., ¹H-n.m.r., ³¹P-n.m.r.) and by elemental analysis. The X-ray structural analysis of (5) is reported. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.