Brian K. Nicholson

A novel methodology for the synthesis of complexes containing long carbon chains linking metal centres: molecular structures of {Ru(dppe)Cp*}2(μ-C14) and {Co3(μ-dppm)(CO)7}2(μ3:μ3-C16)

Elimination of AuX(PR3)(X = halogen, R = Ph, tol) occurs readily in reactions between compounds containing C(sp)- or C(sp2)-X bonds and alkynyl or polyynyl gold(I) complexes; this reaction has been applied to the syntheses of complexes containing a variety of metal centres linked by C(n) chains (n up to 16).

Thiourea monoanion and dianion complexes of rhodium(III) and ruthenium(II)

Abstract The versatility of deprotonated thioureas as ligands is shown by the synthesis and characterisation of a range of rhodium(III) complexes of substituted thioureas, with support from a ruthenium(II) analogue in one case. Reaction of the complexes [LMCl(μ-Cl)] 2 [M=Rh, L=η 5 -C 5 Me 5 (Cp*); M=Ru, L=η 6 - p -cymene] with Na[MeNHC(S)NCN] and excess trimethylamine base gives the dinuclear complexes [LM{SC(NCN)NMe}] 2 containing chelate-bridging thiourea dianion ligands. The Ru complex was characterised by an X-ray diffraction study. The mononuclear complexes [Cp*Rh{SC(NCN)NMe}(PPh 3 )] and [Cp*Rh{SC(NPh)NPh}(PPh 3 )], containing chelating thiourea dianion ligands, were prepared by analogous reactions in the presence of triphenylphosphine. Reaction of [Cp*Rh{SC(NCN)NMe}(PPh 3 )] with HCl, or [Cp*RhCl(μ-Cl)] 2 with 2 equiv. of PPh 3 and Na[MeNHC(S)NCN] (with no added base) gave the complex [Cp*RhCl{SC(NCN)NHMe}(PPh 3 )], containing a (monodentate) S-bonded thiourea monoanion ligand, which was characterised by an X-ray diffraction study. The AsPh 3 and SbPh 3 analogues of this complex were also prepared and characterised. Reaction of [Cp*RhCl(μ-Cl)] 2 with 2 equiv. of PPh 3 or SbPh 3 and PhNHC(S)NHPh or various trisubstituted thioureas PhNHC(S)NR 1 R 2 , triethylamine and NaBPh 4 gave a range of cationic complexes [Cp*Rh{SC(NR 1 R 2 )NPh}(EPh 3 )] + (E=P, Sb), as their tetraphenylborate salts, in which the thiourea is bonded as a monoanion through the S and the NPh group. The corresponding reaction utilising 1,6-bis(diphenylphosphino)hexane (dpph) gave the dinuclear complex [Cp*Rh{SC(N(CH 2 CH 2 ) 2 O)NPh}] 2 (μ-η 2 -dpph) (BPh 4 ) 2 .

Gold(III) thiosalicylate complexes containing cycloaurated 2-arylpyridine, 2-anilinopyridine and 2-benzylpyridine ligands

Reactions of the gold(III) dichloride complexes [(N_C)AuCl 2 ] ((N_C)=cycloaurated 2-phenylpyridine, 2-( p -tolyl)pyridine, 2-anilinopyridine or 2-benzylpyridine) with thiosalicylic acid (2-mercaptobenzoic acid, HSC 6 H 4 CO 2 H) and base gives a series of gold(III) thiosalicylate complexes [(N_C)Au(SC 6 H 4 CO 2 )]. A crystal structure determination on the 2- p -tolylpyridine derivative is reported, confirming the presence of a chelating thiosalicylate ligand, with the tolyl and thiolate groups mutually cis , together with a highly puckered gold–thiosalicylate moiety, and a twisted carboxylate group. The activity of the thiosalicylate complexes against P388 leukaemia cells has been determined.

Ortho-manganated arenes in synthesis: IV.Ortho-manganation of substituted acetophenones and of heteroaromatic methyl ketones. The crystal structures of two cyclometallated acetylthiophene derivatives

Abstract A range of acetophenones containing methoxy, methyl and bromo substituents on the ring have been ortho-manganated with PhCH2 Mn(CO)5 in refluxing heptane to give substituted complexes of the type MeC(O)C6H4Mn(CO)4 in good yields. Similarly prepared were the ortho-manganated complexes derived from 2-acetylthiophene, 3-acetyl-2,5-dimethylthiophene, 2-acetyl-N-methylpyrrole, 2-acetylfuran and 3-acetylindole. All new complexes were fully characterised by normal methods, including 13C NMR spectra, the first reported for ortho-manganated ketones, and X-ray crystal structures are described for the two derivatives, η2-(2-acetyl-3-thienyl)tetracarbonylmanganese and η2-(3-acetyl-2,5-di- methyl-4-thienyl)tetracarbonylmanganese.

Bis- and tris-(pyrazolyl)borate complexes of methyltin chlorides and the X-ray structure of five-coordinate [bis(pyrazolyl)borate]chlorodimethyltin(IV)

Abstract The two series of complexes, five-coordinate Me n Cl 3− n Sn[(pz) 2 BH 2 ] and six-coordinate Me n Cl 3− n Sn[(pz) 3 BH] (pz = 1-pyrazolyl, n = 0–3) have been prepared from the appropriate methyltin chlorides and K[(pz) 2 BH 2 ] or K[(pz) 3 BH] in dichloromethane. The complexes have been fully characterised by infrared and mass spectroscopy and by 1 H, 13 C and 119 Sn NMR where solubility permitted. The X-ray crystal structure of Me 2 ClSn[(pz) 2 BH 2 ] shows a distorted trigonal-bipyramidal tin atom with a pyrazolyl-nitrogen and a chlorine atom in the axial sites.

SOLID-STATE AGGREGATION OF MERCURY BIS-ACETYLIDES, HG(CCR)2, R = PH, SIME3

Abstract The structures of Hg(CCR) 2 (R=Ph, SiMe 3 ) show unusual aggregation in the solid state. When R=Ph there are eight independent molecules in the asymmetric unit, while for R=SiMe 3 there are pentameric aggregates. The Hg…Hg distances are 3.7–4.0 A, possibly indicating weak mercuriophilic interactions, but the main driving force for clustering appears to be interactions between Hg atoms and the CC bonds of adjacent molecules.

The synthesis and x-ray structure of tris(pyrazolyl)borate(trimethyl)tin; a six-coordinate trialkyltin complex

Abstract Reaction between Me3SnCl and K[HB(pz)3) (pz= 1-pyrazolyl, C3H3N2) affords [HB(pz)3]SnMe3 which was shown by a full X-ray structure determination (Trigonal, space group P 3 , a = b = 11.722(3), c = 8.211(2) A, γ = 120°, Z = 2) to contain six-coordinate tin bonded to three methyl groups and to three pyrazolyl groups.

Platinum(II) complexes of chelating and monodentate thiourea monoanions incorporating chiral, fluorescent or chromophoric groups

Abstract The reaction of cis-[PtCl2(PPh3)2] with trisubstituted thioureas [R1R2NC(S)NHR3] in refluxing methanol with triethylamine base, followed by addition of NaBPh4 gives the salts [Pt{SC(NR1R2)NR3}(PPh3)2]BPh4 in high yield; a range of thiourea substituents, including chiral, fluorescent and chromophoric groups can be incorporated. The azo dye-derived complex [Pt{SC(N(CH2CH2)2O)NC6H4NNC6H4NMe2}(PPh3)2]BPh4 has been characterised by a single-crystal X-ray diffraction study. The formation of a fluorescein-derivatised platinum–thiourea complex is also described. Reaction of cis-[PtCl2(PPh3)2] with PhNHC(S)NHPh or EtNHC(S)NHEt, triethylamine and NaBPh4 gives, respectively, [Pt{SC(NHPh)NPh}(PPh3)2]+ and the known cation [Pt{SC(NHEt)NEt}(PPh3)2]+, isolated as tetraphenylborate salts. Reaction of cis-[PtCl2(PPh3)2] with an excess of Na[MeNHC(S)NCN] in methanol gives the bis(thiourea monoanion) complex trans-[Pt{SC(NCN)NHMe}2(PPh3)2], characterised by NMR spectroscopy and an X-ray crystal structure determination. When cis-[PtCl2(PPh3)2] is reacted with 1 equiv. of Na[MeNHC(S)NCN] in methanol, with added NaBPh4, a mixture of isomers of the [Pt{SC(NHCN)NMe}(PPh3)2]+ cation is obtained.

Synthesis and electrospray mass spectrometry of platinum(II) complexes derived from thiourea dianions and the x-ray structure of [Pt{NMeC(=NCN)S}(COD)] (COD = CYCLO-OCTA-1,5-DIENE)

Abstract Platinum(II) complexes formally derived from the thiourea dianion [MeNC(S)N(CN)]2 have been synthesized from the platinum-halide complexes cis-[PtCl2L2] [L = tertiary phosphine or L2 = cyclo-octa-1,5-diene (COD)] by reaction with the sodium salt of N-methyl N-cyanothiourea. The complexes have been fully characterized, including an X-ray crystal structure determination of [Pt{NMeC(=NCN)S}(COD)]. The results of an electrospray mass spectrometry study on platinum(II) complexes of thiourea dianions are also reported, including the in situ coordination chemistry with silver(I) ions. Copyright

Ortho-manganated arenes in synthesis: V. Ortho-manganation of N-acyl heteroaromatics, benzamides and substituted benzaldehydes. Crystal structure of (μ2-O,C-1-acetyi-2-indolyl)tetracarbonylmanganese☆

Abstract 1-Benzoylpyrrole has been shown to react with PhCH 2 Mn(CO) 5 in refiuxing heptane to ortho -manganate the heterocyclic ring to give (μ 2 -O,C-1-benzoyl-2-pyrrolyl)tetracarbonylmanganese in good yield. Similarly prepared were the corresponding derivatives of N -acetylpyrrole and of N -acetyl- and N-benzoyl-indole. N,N -Dialkylbenzamides could also be ortho -manganated in good yields, but not the parent benzamide. Benzaldehydes also react provided that they contain p -MeO or p -Me 2 N substituents. The structure of (μ 2 - O,C -1-acetyl-2-indolyl)tetracarbonyl-manganese has been determined by X-ray diffraction.