Jesús A. Miguel

Highly Fluorescent Platinum(II) Organometallic Complexes of Perylene and Perylene Monoimide, with Pt σ-Bonded Directly to the Perylene Core

3-Bromoperylene (BrPer) or N-(2,5-di-tert-butylphenyl)-9-bromo-perylene-3,4-dicarboximide (BrPMI) react with [Pt(PEt(3))(4)] to yield trans-[PtR(PEt(3))(2)Br] (R = Per, 1a; R = PMI, 1b). Neutral and cationic perylenyl complexes containing a Pt(PEt(3))X group have been prepared from 1a,b by substitution of the Br ligand by a variety of other ligands (NCS, CN, NO(3), CN(t)Bu, PyMe). The X-ray structures of trans-[PtR(PEt(3))(2)X] (R = Per, X = NCS (2a); R = PMI, X = NO(3) (4b); R = Per, X = CN(t)Bu (5a)) show that the perylenyl fragment remains nearly planar and is arranged almost orthogonal to the coordination plane: The three molecules appear as individual entities in the solid state, with no π-π stacking of perylenyl rings. Each platinum complex exhibits fluorescence associated to the perylene or PMI fragments with emission quantum yields, in solution at room temperature, in the range 0.30-0.80 and emission lifetimes ∼4 ns, but with significantly different emission maxima, by influence of the X ligands on Pt. The similarity of the overall luminescence spectra of these metalated complexes with the perylene or PMI strongly suggests a perylene-dominated intraligand π-π*emissive state, metal-perturbed by interaction of the platinum fragment mostly via polarization of the Ar-Pt bond.

Ferroelectric liquid crystal behavior in platinum orthometallated complexes

Di-μ-chloro-bis[(η3-2-methylallyl)platinum] reacts with chiral imines, p-R1C6H4CHNC6H4OR2-p [HL*; with R1, R2, or both equal to either (R)- or (S)-1-methylheptyl], to yield the C,N-cyclometallated platinum(II) compounds [Pt2(μ-Cl)2(L*)2] (2). Treatment of 2 with Tl[(p-H21C10OC6H4CO)2CH] produces mononuclear orthoplatinated complexes (3) incorporating a β-diketonate. Both complexes 2 and 3 are mesomorphic materials that display smectic A (SmA) and chiral smectic C (SmC*) phases. Their mesogenic properties are compared with those of their palladium analogues, reported previously. The platinum complexes show somewhat more stable mesophases. A study of the ferroelectric properties of compounds 2 and 3 has been performed.

Ring opening and closing in (CO)n(L)MnI complexes where L = S2CPCy3 or diphosphine. Novel complexes containing the Mn(μ-L)AuC6F5 entity where L = S2CPCy3 or dppm

Abstract The four-membered Mc-S-C-S ring in complexes containing S 2 CPCy 3 chelate ligands are opened very easily when the complexes are treated with phosphites, isocyanides or diphosphines, to give complexes in which the S 2 CPCy 3 entity is monodentate. In some cases, the resulting complexes undergo intramolecular displacement of CO by the uncoordinated sulfur with closing of the Mn-S-C-S ring. The uncoordinated sulfur in cationic complexes in which S 2 CpCy 3 is monodentate, appears to be a poor nucleophile, and fails to bind a second metal to give four-electron bridges. Treatment of fac -[Mn(CO) 3 (dppm){SC(S)PCy 3 }]PF 6 with [(tht)AuC 6 F 5 ), causes opening of the chelate ring of the diphosphine dppm, and simultaneous closing of the ring of the S 2 CPCy 3 ligand to give [S 2 CPCy 3 )(CO) 3 Mn(μ-dppm)Au(C 6 F 5 )[PF 6 . However, the complex [(η 5 -C 5 H 4 -Me)(CO) 2 MnSC(PCy 3 )SAu(C 6 F 5 )], containing the first example of a η 1 (S′), S 2 CPCy 3 four-electron bridge between two different metals, can be prepared from [Mn(η 5 -C 5 H 4 Me)(CO) 2 (SC(S)PCy 3 )] and [Au(C 6 F 5 )(tht)].

Manganese(I) complexes with (tricyclohexylphosphonio)dithiocarboxylate as chelate and unidentate ligand. X-Ray crystal structure of fac-[Mn(CO)3{S2CP(C6H11)3}2]ClO4·H2O

[Mn(CO)5Br] reacts with S2CP(C6H11)3(C6H11= cyclohexyl) in refluxing CS2 to give fac-[Mn(CO)3{S2CP(C6H11)3}Br](1) which can be also obtained by refluxing cis-[Mn(CO)4{P(C6H11)3}Br] in CS2. Halide abstraction from (1) with AgClO4, and subsequent treatment with neutral ligands L affords fac-[Mn(CO)3L{S2CP(C6H11)3}]ClO4 with L = CO, P(OMe)3, P(C6H11)3, S2CP(C6H11)3. In the case of L = S2CP(C6H11)3 an X-ray structure determination shows that the resulting compound fac-[Mn(CO)3{S2CP(C6H11)3}2]ClO4 contains one S2CP(C6H11)3 acting as a chelate (SS′) ligand and another acting in a unidentate σ-(S) fashion. Compounds [Mn(CO)5{S2CP(C6H11)3}]ClO4 and fac-[Mn(CO)3(L–L){S2CP(C6H11)3}]ClO4(L–L = Ph2PCH2PPh2 or 2,2′-bipyridyl) containing unidentate S2CP(C6H11)3 ligands can be obtained by displacement of OClO3– from perchlorate complexes.

New bonding mode of tricyclohexylphosphoniodithiocarboxylate (S2CPCy3) as an eight-electron donor. Synthesis, reactivity, and X-ray crystal structure of [Mn2(CO)6(S2CPCy3)]

The reaction of Mn2(CO)10 with the tricyclohexylphosphine–carbon disulphide adduct S2CPCy3 in refluxing toluene affords the dinuclear complex [Mn2(CO)6(S2CPCy3)](1) in good yield, the structure of which, determined by X-ray crystallography, shows a new mode of co-ordination of the S2CPCy3 ligand which is bonded to an Mn atom by two sulphur atoms and to the other Mn atom by two sulphur and one carbon atom donating 8 electrons; thermal reactions of (1) with neutral monodentate ligands L yield [Mn2(CO)5(S2CPCy3)(L)]via CO displacement.

Syntheses of cationic tri- and di-carbonyl complexes of manganese(I) with diphosphines from the appropriate neutral bromocarbonyls

Reaction of the complexes fac-[MnBr(CO)3(L–L)][L–L = Ph2P(CH2)nPPh2, n= 1 (dppm) or 2 (dppe)] with phosphorus-donor ligands, L, leads to the complexes cis,cis-[MnBr(CO)2(L–L)L]. These neutral dicarbonyls are oxidized by NO2 or [NO][PF6] to the unstable cationic species trans-[MnBr(CO)2(L–L)L]+ which may be isolated as hexafluorophosphate salts and which lead to the neutral trans-[MnBr(CO)2(L–L)L] when reduced by hydrazine. Replacement of the bromo-ligand in either cis,cis- or trans-[MnBr(CO)2(L–L)L], using TI[PF6] in the presence of another ligand L′(N or P donor), results in the formation of cis,cis- or trans-[Mn(CO)2(L–L)LL′][PF6] respectively, or of mer-[Mn(CO)3(L–L)L][PF6] if L′= CO. However, using Ag[CIO4] as the halogen abstracter, the perchlorate salts of the cis,cis-cationic dicarbonyls (or the mer tricarbonyls) are obtained regardless of the neutral bromocarbonyl isomer used.

Manganese complexes with S2CPEt3 ligands. X-Ray crystal structures of cis-trans-[Mn(CO)2(PEt3)2(S2CPEt3)]ClO4 and cis-trans-[Mn(CO)2(PEt3)2(S2CH)]

A variety of manganese(I) carbonyl complexes containing triethylphosphine and monodentate or chelate triethylphosphoniodithiocarboxylato ligands can be obtained by substitution reactions either under mild conditions or by thermal or photochemical methods. The products resulting from the thermal reactions between bromo carbonyls and S2CPEt3 are very different from those obtained with S2CP(C6H11)3 under similar conditions, and this can be attributed to the difference in electronic and steric properties of the phosphines concerned. The X-ray structure of cis,trans-[Mn(CO)2(PEt3)2(S2CPEt3)]ClO4 has been determined. Reduction of this compound with NaBH4 affords the neutral dithioformate complex cis,trans-[Mn(CO)2(PEt3)2(S2CH)] which has been characterized by spectroscopic methods and by X-ray crystallography.