Mario Scotti

Synthesis and characterization of manganese and rhenium tricarbonyl complexes with (O,O,O)-donor ligands

Abstract Complexes of the type [(C 5 H 5 )Co{P(O)R 2 } 3 ] − , R = OCH 3 , OC 2 H 5 , react as tridentate oxygen ligands L − with [MBr(CO) 5 ], M = Mn, Re, in hexane or tetrahydrofuran to give the tricarbonyl derivatives [LM(CO) 3 ]. The slightly volatile yellow crystalline compounds have been characterized by elemental analysis, 1 H NMR, IR and mass spectra. The low CO stretching frequencies indicate that the ligands L − are good π-donor ligands.

[Cp*Ir{P(O)(OMe)2}3]−, an iridium(III) phosphonate complex acting as a chelating oxygen ligand: synthesis and coordination chemistry

Abstract The anionic iridium complex [(C 5 Me 5 )Ir{P(O)(OMe) 2 } 3 ] − (L − ) has been prepared as sodium salt from the corresponding trimethyl phosphite complex [(C 5 Me 5 )Ir{P(OMe) 3 } 3 ](ClO 4 ) 2 . L − reacts with metal ions M 2+ to give ML 2 . With [PtMe 3 ] 2 SO 4 ·4H 2 O in water and with [{RhCl(cod)} 2 ], cod=1,5-cyclooctadiene, in cyclohexane solution the air-stable heterobimetallic complexes [LPtMe 3 ] and [LRh(cod)] are formed. The rhodium complex [(C 5 Me 5 )Rh{P(O)(OMe) 2 } 3 ] − (L′ − ) similarly gives [L′PtMe 3 ] and [L′Rh(cod)]. [LRh(cod)] and [L′Rh(cod)] react with CO gas (1 atm.) to yield [LRh(CO) 2 ] and [L′Rh(CO) 2 ]. Partial decarbonylation of these dicarbonyl complexes at room temperature leads to the tetranuclear complexes [L′Rh(μ-CO) 3 RhL′](Rh-Rh) and [LRh(μ-CO) 3 RhL](Rh- Rh).

Unusually stable trimethylplatinum(IV) complexes with an O3PtC3 coordination sphere. The crystal and molecular structure of (C5H5Co[P(O)(OEt)2]3PtMe3)

Abstract The reaction of [Me3PtI]4 with {C5H5Co[P(O)(OR)2]3}Na (R = Me, Et) gives the heterometallic dinuclear complexes {C5H5Co[P(O)(OR)2]3PtMe3} (3a: R = Me; 3b: R = Et) in almost quantitative yield. Compounds 3a, 3b are fairly robust and do not react with [CPh3]PF6 by hydride abstraction. On treatment with HC1 in benzene, stable adducts of composition 2{C5H5Co[P(O)(OR)2]3PtMe3} · 3HC1 (4a, 4b) are formed which presumably contain two PtMe3 units in different environments. The structure of 3b has been determined by single-crystal X-ray diffraction studies. 3b is monoclinic, space group P21/n with a = 1415.6(3), b = 1896.6(5), c = 1148.4(3) pm and β = 92.07(2)°. The structure was solved via Patterson synthesis and refined by least-squares to R and Rw 0.032 for 3355 unique reflections. The platinum atom is octahedrally surrounded by the three PO oxygen atoms of the phosphonate units and by the carbon atoms of the three methyl groups with PtO and PtC distances similar to those in [Me3Pt(μ-OH)]4. The structural parameters of the {C5H5Co[P(O)(OEt)2]3} unit in 3b do not differ from those in other complexes containing this moiety as a tripod ligand.

Bis-olefin-rhodium(I) complexes of a tripod ligand with an O,O,O-donor set

Abstract The organometallic anion [(C 5 H 5 )Co{P(O)(OC 2 H 5 ) 2 } 3 ] − reacts as a tridentate oxygen ligand L − with [{RhCl(diolefin)} 2 ] (diolefin = 1,5-cyclooctadiene, norbornadiene, tetrafluorobenzobarrelene, trimethyltetrafluorobenzobarrelene, duroquinone) and with [{RhCl(C 2 H 4 ) 2 } 2 ] in hexane or in acetone in the presence of AgClO 4 to give air stable compounds of the type [LRh(diolefin)] and [LRh(C 2 H 4 ) 2 ]. These novel five-coordinate Rh 1 complexes are fluxional molecules. They have been characterized by elemental analysis, and 1 H NMR, IR and mass spectroscopy.

Duroquinonerhodium(I) complexes. Crystal structure of [Rh(DQ)(C6H5Me)]PF6

The preparation of cationic arenerhodiiim(I) complexes of the type [Rh(DQ)-(arene)]PF6 (DQ = duroquinone; arene = C6H6-nMen, n duroquinone complexes with Group VB donor ligands are described. The crystal structure of [Rh(DQ)(C6H5Me)]PF6 has been determined by X-ray diffraction. The compound crystallizes in the P21/n space group, in a unit cell of dimensions a 15.9866(5), b 11.8438(3), c 9.9968(3) A, β 98.473(4)A. The structure was solved by Patterson and Fourier methods and refined to R and Rw values of 0.062 and 0.076, respectively. The Rh atom is coordinated to a toluene group (η6) and a duroquinone ligand (η4), which eclipse each other. Both ligands are distorted to adopt boat-like conformations.

Rhodium(I) diolefin complexes with polycyclic π-arene ligands. Synthesis of bimetallic complexes with diphenylmethane as bridging ligand

SummaryThe preparation and properties of cationic arenerhodium(I) complexes of general formula [Rh(diolefin)(η6arene)]ClO4 (diolefin=1,5-cyclooctadiene, tetrafluorobenzobarrelene or trimethyltetrafluorobenzobarrelene; arene = biphenyl or diphenylmethane) are described. These complexes react with the solvated intermediate complex [Rh(diolefin)(Me2CO)x]ClO4 to give homobimetallic [(diolefin)Rh(Ph2CH2)Rh(diolefin)](ClO4)2 derivatives. New heterobimetallic complexes of the type [(diolefin)Rh(Ph2CH2)Cr(CO)3]ClO4 have been synthesized by reaction of Cr(CO)3(η6-Ph2CH2) with the solvated complex [Rh(diolefin)(Me2CO)x]ClO4 or, alternatively by treatment of [Rh(diolefin)(η6-arene)]ClO4 with the complex Cr(CO)3(η6Me3B3N3Me3) in chloroform solution.

Homo- and hetero-binuclear complexes containing the anion [Rh(C5Me5){PO(OMe)2}2(pyrazolate)]– as ligand. Crystal structure of [(C5Me5)Rh{µ-PO(OMe)2}2(µ-C3H3N2)-Ru(C6H6)]ClO4·CH2Cl2

The neutral rhodium(III) complex [Rh(C5Me5)I{PO(OMe)2}{P(OH)(OMe)2}] reacts with pyrazole-type ligands [HL = pyrazole (Hpz), 3-methylpyrazole, or 3,5-dimethylpyrazole] in the presence of AgClO4 yielding cationic complexes of the general formula [Rh(C5Me5){PO(OMe)2}{P(OH)(OMe)2}(HL)]ClO4. They react with Na2CO3 in aqueous solutions with formation of the neutral complexes [Rh(C5Me5){PO(OMe)2}2(HL)]. Addition of NaH in tetrahydrofuran to the cationic complexes or thallium acetylacetonate in MeOH to the neutral compounds affords the corresponding bimetallic derivatives [(C5Me5)Rh{PO(OMe)2}2LM](M = Na or Tl). These complexes react with halide compounds such as [{M(ring)Cl2}2][M(ring)= Rh(C5Me5), Ir(C5Me5), Ru(C6H6), Ru(C6H5Me), Ru(MeC6H4Pri-p) or Ru(C6Me6)], [MBr(CO)5], [(PtMe3I)4] or [{Rh(µ–Cl)(cod)}2](cod = cycloocta-1,5-diene) to give cationic or netural complexes of the type [(C5Me5)Rh{µ-PO(OMe)2}2(µ-L)-M(ring)]ClO4 or [(C5Me5)Rh{PO(OMe)2}2(µ-L)MLn][MLn= Re(CO)3, Mn(CO)3, PtMe3 or Rh(cod)]. The crystal structure of [(C5Me5)Rh{µ-PO(OMe)2}2(µ-pz)Ru(C6H6)]ClO4·CH2Cl2 has been determined by X-ray diffraction methods: monoclinic, space group P21/c, a= 11.179(1), b= 17.039(1), c= 18.186(2)A, β= 94.85(1)° and Z= 4. The complex cation consists of one rhodium and one ruthenium atom bridged by two phosphonate and one pyrazolate anion. An η5-C5Me5 and an η6-C6Me6 group complete the co-ordination spheres of the metals, which show no direct intermetallic interaction.

Fluorinated barrelene-ruthenium(II) complexes with anionic chelating ligands

Abstract Reaction of ruthenium(III) chloride with the barrelene diolefins (tetrafluoro-benzobarrelene (TFB) or (trimethyltetrafluorobenzobarrelene) (Me 3 TFB) leads to the formation of the polymeric complexes [RuCl 2 (barrelene)] n . These compounds react with anionic chelating ligands with formation of new hexacoordinated neutral complexes of the general formulae [Rh(chelate) 2 (barrelene)], where chelate = acetylacetonate, tropolonate, salicylal-dehydate and 8-oxyquinolinate. The IR and 1 H NMR spectra of the complexes are given and discussed.

Cationic organometallic complexes with hexaalkylborazines. I: Synthesis and reactivity of cationic hexamethylborazinerhodium complexes with carbonyl ethylene and diolefins as ligands

Abstract The PF 6 salts of the new cationic hexamethylborazinerhodium(I) complexes of general formula [Rh(Me 3 B 3 N 3 Me 3 )(LL′)] + (LL′= 1,5-cyclooctadiene, norbornadiene, tetrafluorobenzobarrelene, trimethyltetrafluorobenzobarrelene, L = L′ = ethylene, CO) have been prepared from the reaction between [RhCl(LL′)] 2 , Me 3 B 3 NMe 3 , and AgPF 6 in dichloromethane. These complexes are very labile, undergoing rapid ring ligand exchange in solution with σ and π-donor ligands. The synthesis of [Rh(η 6 -naphthalene)(COD)]PF 6 is also described. The properties and NMR and IR spectroscopic characteristics of the new compounds are briefly discussed.

Organometallic chelating ligands. Synthesis of a new anionic tripod like ligand with an N,N',O-donor set. X-ray crystal structure of [(η6-C6Me6)Ru{μ-P(O)(OMe)2}(μ-Pz)2Re(CO)3] (Me = methyl, Pz = pyrazolate)

Abstract The synthesis of the new anionic organometallic chelating ligand [(η6-C6Me6)Ru{P(O)(OMe)2}(Pz)2]−L− (Me = methyl, Pz = pyrazolate) is described. This ligand was isolated as its neutral sodium derivative NaL·∼ 0.7NAPF6, which is a new synthetic precursor for obtaining heterobimetallic complexes with phosphonate and pyrazolate groups acting as bridging ligands. The heterobimetallic compound LRe(CO)3 was obtained by reaction of ReBr(CO)5 with NaL·∼0.7NaPF6, in which the anionic complex L− is acting as an N,N′,O-tripod donor ligand. The structure of the title complex was established by X-ray crystallography. The compound crystallizes as monoclinic, space group Cc (No. 9) with a=31.214(6), b=11.111(2), c=15.769(3) A, β=103.14(3)°. The neutral complex has a binuclear structure with the (C6Me6)Ru and Re(CO)3 moieties triply bridged by two pyrazolate groups and one phosphonate group. The synthesis of TIPz is also described.