We have studied 52 new HHV8 strains by sequencing the complete hypervariable K1 gene and genotyping the K14.1/K15 loci located at both sides, respectively, of the viral genome. The samples originated from 49 patients with Kaposi's sarcoma (KS; 32 patients), multicentric Castleman's disease (MCD; 12 patients), or primary effusion lymphoma (PEL; 5 patients). Among these patients, 32 were of African origin (West and Central African countries and Creoles from French Guiana) and the 17 others were mostly French homosexuals. Comprehensive phylogenetic studies allowed the identification of distinct groups within the three already known main subtypes. Interestingly, two new sequences that did not cluster within a known subtype or group could be considered as prototypes of early/ancient variants of the C subtype and A/C set, respectively. Among the 32 African strains, the majority were either of the B subtype (13 cases) or of the A5 group (11 cases), indicating that this latter genotype is frequent and widespread in Africa. In contrast, a subtype C strain infected most of the 17 other patients. PCR-based genotyping of the K14.1/K15 loci revealed an overall predominance of P subtype, except in the A5 and B K1 groups, in which the P and M alleles were equally represented. The implications of these data on the evolution and spread of HHV8 among human African populations are discussed.

The reaction of thiosemicarbazones 4-MeC 6 H 4 C(Me)᎐ ᎐ NN(H)C(᎐ ᎐ S)NH 2 a, C 6 H 5 C(Et)᎐ ᎐ NN(H)C(᎐ ᎐ S)NH 2 b and 4-MeC 6 H 4 C(Me)᎐ ᎐ NN(H)C(᎐ ᎐ S)NHMe c with K 2 [PdCl 4 ] led to tetranuclear palladiumthe ligands are tridentate through the [C, N, S ] atoms and they are deprotonated at the NH group. The Pd-S chelating bond is sufficiently strong for the complexes to undergo reactions with nucleophiles without bond cleavage. The molecular structure of 1b has been determined by single-crystal diffraction, confirming the formation of the tetranuclear moieties. Hydrogen bonding N ؒ ؒ ؒ H and S ؒ ؒ ؒ H links Pd 4 clusters into strands in the solid state. Reaction of 1a and 1b with phosphines gave mono-and di-nuclear species, 2a, 2b, 3b and 5a, 5b, respectively. Treatment with 1,1Ј-bis(diphenylphosphino)ferrocene led to trimetallic compounds 6a and 6b. The molecular structure of 3b has been determined by X-ray crystallography; dimer units are present through N ؒ ؒ ؒ H hydrogen bonds. The reaction of 2b with hydrochloric acid resulted in a 1 : 1 electrolyte, 4b, with NH and C᎐ ᎐ S groups. Alternatively, treatment of 1a, 1b and 1c with strong chelating phosphines produced mononuclear compounds with only cleavage of the Pd-S bridging bonds, 7a, 7b, 7c and 8c with the diphosphine monodentate; 7a and 7b were obtained with the dinuclear species 7aЈ and 7bЈ, respectively, as impurities, where the bidentate phosphine ligand bridges two metallated units. The crystal structure of one such compound, 7bЈ, with a bridging bis(diphenylphosphino)methane ligand, is also described.

Treatment of the thiosemicarbazone ligands 4‐MeC6H4C(Me)=NN(H)C(=S)NHMe (a), 4‐MeC6H4C(Me)=NN(H)C(=S)NHEt (b), and 4‐MeC6H4C(Me)=NN(H)C(=S)NHPh (c) with K2[PdCl4] produced the tetranuclear palladium(II) compounds [Pd{4‐MeC6H3C(Me)=NNC(=S)NHMe}]4 (1a), [Pd{4‐MeC6H3C(Me)=NNC(=S)NHEt}]4 (1b), and [Pd{4‐MeC6H3C(Me)=NNC(=S)NHPh}]4 (1c) with deprotonation of the NH group. Treatment of thiosemicarbazones 4‐MeOC6H4C(H)=NN(Me)C(=S)NH2 (d) and 3‐MeOC6H4C(H)=NN(Me)C(=S)NH2 (e) with K2[PdCl4] gave the mononuclear palladium(II) compounds [Pd{4‐MeOC6H3C(H)=NN(Me)C(=S)NH2}(Cl)] (1d) and [Pd{3‐MeOC6H3C(H)=NN(Me)C(=S)NH2}(Cl)] (1e). Treatment of the Schiff base 4‐MeOC6H4C(H)=N[2‐(SMe)C6H4] (f) with Li2[PdCl4] afforded [Pd{4‐MeOC6H3C(H)=N[2‐(SMe)C6H4]}(Cl)] (1f). All the ligands are terdentate through the [C,N,S] atoms and the Pd−S bond formed is sufficiently strong to tolerate treatment with nucleophiles without bond cleavage. Treatment of 1a, 1b, and 1c with triphenylphosphane gave the mononuclear species 2a, 2b, and 2c, which upon treatment with hydrochloric acid resulted in the 1:1 electrolytes 3a, 3b, and 3c, with NH and C=S groups. Coordination of PPh3 to Pd in 1f was achieved by treatment of the compound with sodium perchlorate, followed by the nucleophile in a 1:1 molar ratio, to yield 2f. The crystal structures of compounds 2a and 1f are described.

The palladium(II) compound [Pd{3,4-(MeO)2C6H2C(H)NCy}{(Ph2PCH2CH2)2PPh-P,P,P}][PF6] was synthesized and characterized by elemental analysis (C, H, N) and by 1H and 31P{1H} NMR spectroscopy in CDCl3 and 31P{1H} solid-state NMR spectroscopy. The molecular structure was determined by X-ray crystallography, showing it to be the first pentacoordinated cyclometalated palladium(II) complex.

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