Studies on synthesis and coordination chemistry of catechol based phosphine oxides (original) (raw)
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RSC Adv., 2014
Some selected aminophosphine oxides (AmPOs) of the type OP(NMe 2 ) 3 , OPPh(NMe 2 ) 2 , OP(NC 2 H 4 O) 3 , OPPh(NC 2 H 4 O) 2 and their corresponding La(III) and Th(IV) complexes are synthesized and analyzed by FT-IR, 1 H-NMR, 31 P{ 1 H}-NMR, elemental analysis and TGA data. The coordination behavior of AmPOs was compared with some of the known ligands that include trioctylphosphine oxide (TOPO), tributylphosphate (TBP) and diethylphosphite (DEP). Thermogravimetric analysis of these complexes showed a distinct decomposition trend either by a single step or multi-step elimination of ligand species, which are strongly dependent on the electronic and steric behaviour of substituents on the P]O group and the nature of the metal. Phosphine oxide based La(III) and Th(IV) complexes undergo three unique intermolecular ligand exchange reactions at room temperature: relative competition among phosphine oxides to form a strong complex by exchanging the weaker ligand and complete ligand transfer from La(III) to Th(IV) metal centers. Ligand crossover is well controlled by priority rules and the trend is TOPO > TBP > DEP > AmPO > Ph 3 PO. This tendency closely agrees with the stability constants of metal complexes. On comparison, Th(IV) complexes showed slightly higher stability than La(III) analogues.
Polyhedron, 1995
The syntheses and characterizations of the new trifunctional ligand bis(2-ethoxyethyl)benzylphosphine (OPO; 1) and some new group 10 metal complexes are described. Reactions of this potentially hemilabile ligand with the nickel, palladium and platinum chlorides have been studied, resulting in isolation of the series, MCI2(OPO)2, where M = Ni (2), Pd (3) or Pt (4). The X-ray crystal structure of 2 shows the metal to have a square planar trans arrangement with r/l-bonding of the ligand through the phosphorus centre. Compounds 3 and 4 are also trans. The attempted formation of an oxygen/phosphorus chelate with nickel using NaBPh4 resulted in the new complex trans-NiCIPh(OPO)2 (5), which has been shown to be square planar, with trans chloro and phenyl groups, by X-ray crystallography. The dibromo analogue of 2 has also been prepared (6), from which bromide abstraction has been attempted.
2007
The present work deals with the syntheses of flexible, ditopic catechol phosphines and their self-assembly to produce di- or multinuclear complexes. A set of bidentate ligands with a phosphine functionality at one end and a catechol unit at the other end was synthesised via hydrophosphanation followed by LiAlH4 reduction. The rationale behind the design was to have ligands which can differentiate between hard and soft metals, and react with a combination of both selectively to produce hetero di- or multi-nuclear assemblies in a single step. Reaction of the catechol phosphine with boronic acid produced a phosphine functionalised benzo-1,3,2-dioxaborol. The ability of this species to act as a Lewis-base via the P-centered donor and as Lewis-acid via the B centered acceptor was demonstrated in reactions with (COD)PdCl2 and some nitrogen donors. Reaction of a palladium complex of the phosphine functionalised benzo-1,3,2-dioxaborol with DABCO gave a triple Lewis acid/base complex which c...
Russian Chemical Bulletin, 2012
The reactions of (2 methyl 4 oxopent 2 yl)diphenylphosphine oxide (L) with uranyl and neodymium nitrates afforded complexes with compositions M : L = 1 : 2 and 1 : 3. These com plexes were characterized by X ray diffraction, IR spectroscopy, and elemental analysis. In the solid complexes, phosphine oxide L has a variable denticity. Studies by 1 H and 31 P NMR and IR spectroscopy showed that in chloroform, the mononuclear complexes [UO 2 (O L) 2 (O,O NO 3) 2 ], [Nd(O L) 2 (O,O NO 3) 3 ] and [Nd(O L) 3 (O,O NO 3) 3 ] are neutral, and the ligand molecules are coordinated to the metal cation through the phosphoryl oxygen atom.
Synthesis and coordination properties of novel polyfunctional phosphine ligands
Tetrahedron Letters, 1993
4'-formyl-2-diphenylphosphino-acetophenone 6 has been prepared in four steps (50%) starting from terephtalaldehyde mono_(diethylacetal) 1. Condensation of 5 with the parasubstituted aniline8 HaNA-i gives quantitatively the phosphine-imines 6-8. Phosphines 4-6 instantaneously react with Pdrt(acac)a to yield the bis-enolato complexes cis-[Pd"([4'-(R)CsH,lC(O)=CHPPh2)21 GkCH(OC2H&,
Dalton Transactions, 2009
The coordination properties of the b-keto phosphine ligands R 2 PCH 2 C(O)Ph (HL 1 , R = i-Pr; HL 2 , R = Ph), of the new acetamide-derived phosphine ligand (i-Pr) 2 PNHC(O)Me (HL 3 ) and of Ph 2 PNHC(O)Me (HL 4 ) have been examined towards Ni(II) complexes. Comparisons are made between systems in which the PCH 2 function of the ketophosphine has been replaced with an isoelectronic PNH group in amide-derived ligands, or the PCH functionality of phosphinoenolates with a PN group in phosphinoiminolate complexes. Furthermore, ligands HL 2 and HL 4 reacted with [(h 5 -C 5 H 5 )CoI 2 (CO)] to afford the phosphine mono-adducts [(h 5 -C 5 H 5 )CoI 2 {Ph 2 PCH 2 C(O)Ph}] (1) and [(h 5 -C 5 H 5 )CoI 2 {Ph 2 PNHC(O)Me}] (3), respectively, which upon reaction with excess NEt 3 yielded the phosphinoenolate complex [(h 5 -C 5 H 5 )CoI{Ph 2 PCH ···C( ···O)Ph}] (2) and the phosphinoiminolate complex [(h 5 -C 5 H 5 )CoI{Ph 2 PN ···C( ···O)Me}] (4), respectively. The complexes cis-[Ni{(i-Pr) 2 PN ···C( ···O)Me} 2 ] (6) and cis-[Ni{Ph 2 PN ···C( ···O)Me} 2 ] were obtained similarly from NiCl 2 and HL 3 and HL 4 , respectively, in the presence of a base. The phosphinoenolate complex [Ni{(i-Pr) 2 PCH ···C( ···O)Ph} 2 ] (5) exists in ethanol as a mixture of the cis and trans isomers, in contrast to cis-[Ni{(Ph 2 PCH ···C( ···O)Ph} 2 ], and the solid-state structure of the trans isomer of 5 was established by X-ray diffraction. The structures of the ligand HL 3 and of the complexes 1, 3 in 3·3/2CH 2 Cl 2 , 4, 6 and 7 have also been determined by X-ray diffraction and are compared with those of related complexes. Complexes 4, 6 and 7 contain a five-membered heteroatomic metallocyclic moiety, which is constituted by five different chemical elements. The structural consequences of the steric bulk of the P substituents and of the electronic characteristics of the P,O chelates are discussed.
Polyhedron, 2003
The crystal structures of bis[2-(bromodimethylstannyl)ethyl]phenylphosphine oxide 3 (X ¼ Br), and t-butyl[3-(iododimethylstannyl)propyl]phenylphosphine oxide 7 (X ¼ I), have been determined. Compound 7 (X ¼ I), grown from EtOH solution, is a chelated complex as a consequence of an intramolecular Sn-O interaction and hence contrasts with the previously reported [3-(iododimethylstannyl)propyl]diphenylphosphine oxide, grown from alcohol media solution, which has an intermolecular Sn-O linked chain structure. Molecules of 7 (X ¼ I) are linked into double chains via C-H-I and C-H-p interactions. Compound 3 (X ¼ Br), isostructural with previously reported 3 (X ¼ Cl) obtained from CH 2 Cl 2 solution, contains two distinct trigonal bipyramidal tin centres. One Sn centre is intramolecularly bound to the O, i.e., one PhP(O)CH 2 CH 2 fragment is acting as a C,O-chelating unit, while the other Sn centre is weakly bonded to a Br ligand from another molecule to set up zig zag chains of molecules. Intermolecular interactions, C-H-Br and C-H-p, create a double layer of molecules. Detailed 1 H NMR spectra of 3 are reported.