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In this minireview, we refer to recent results as far as the Platelet Activating Factor (PAF) inhibitors are concerned. At first, results of organic compounds (natural and synthetic ones and specific and nonspecific) as inhibitors of PAF are reported. Emphasis is given on recent results about a new class of the so-called metal-based inhibitors of PAF. A small library of 30 metal complexes has been thus created; their anti-inflammatory activity has been further evaluated owing to their inhibitory effect against PAF in washed rabbit platelets (WRPs). In addition, emphasis has also been placed on the identification of preliminary structure-activity relationships for the different classes of metal-based inhibitors.

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The halogermylenes (Cp*GeX) n (1a, X ) Cl, n ) 1; 1b, X ) Br, n ) 2; Cp* ) pentamethylcyclopentadienyl) were prepared in high yield by a redistribution reaction of GeCp* 2 with GeX 2 (1,4-dioxane). The ionic compounds [Cp*Ge][GeX 3 ] (2a, X ) Cl; 2b, X ) Br) were also formed to a small extent in this reaction. Treatment of trans-[Mo(dppe) 2 (N 2 ) 2 ] (3) (dppe ) Ph 2 PCH 2 CH 2 PPh 2 ) with 1 equiv of 1a,b affords in refluxing toluene the germylyne complexes trans-[X(dppe) 2 MotGe-(η 1 -Cp*)] (4a, X ) Cl; 4b, X ) Br). Concomitant formation of GeCp* 2 and the dihalo complexes trans-[Mo(dppe) 2 (X) 2 ] (5a, X ) Cl; 5b, X ) Br) is observed in this reaction. In comparison, the reactions of trans-[W(dppe) 2 (N 2 ) 2 ] (6) with 1a,b and (Cp*GeI) ∞ (1c) afford selectively the germylyne complexes trans-[X(dppe) 2 WtGe-(η 1 -Cp*)] (7a-c). The molecular structures of 4a‚0.5pentane and 4b‚0.5pentane reveal very short Mo-Ge bonds, almost linear Mo-Ge-C(Cp*) sequences, and an η 1 -bonded Cp* substituent indicating the presence of a molybdenum-germanium triple bond. The structural features of the germylyne ligand in 4a and 4b are compared with those in the corresponding tungsten complexes trans-[X(dppe) 2 WtGe-(η 1 -Cp*)] (7a-c), and the bonding parameters of the Cp* substituent are shown to be similar to those in the germanes (η 1 -Cp*)GeI 3 ( 8) and (η 1 -Cp*) 2 -GeCl 2 (9).

Plumb line: A series of compounds trans‐[L(PMe3)4WPb(2,6‐Trip2C6H3)]n+ (n=0: L=Br, I; n=1: L=PhCN, PMe3; Trip=2,4,6‐iPr3C6H2; see structure of L=PMe3 derivative) containing WPb triple bonds is reported. Quantum‐chemical analyses of the WPb bond in the plumbylidyne complex [(PMe3)5WPb(2,6‐Trip2C6H3)]+ confirm the electronic analogy with Fischer‐type carbyne complexes.

The first reactions of the germylidyne complexes trans-[X(dppe) 2 WtGe(η 1 -Cp*)]‚ [toluene] (1-Cl‚C 7 H 8 , X ) Cl; 1-I‚C 7 H 8 , X ) I) with nucleophiles and electrophiles are reported. Treatment of 1-I‚C 7 H 8 with KBH 4 in refluxing THF affords selectively the hydridogermylidyne complex trans-[H(dppe) 2 WtGe(η 1 -Cp*)] (2). Similarly, metathetical exchange of 1-I‚C 7 H 8 with an excess of MY (M ) Na, K; Y ) NCO, N 3 , NCS, CN) gives the pseudohalideyields in the presence of acetonitrile the first cationic germylidyne complex, trans-[(MeCN)(dppe) 2 WtGe(η 1 -Cp*)][B(C 6 F 5 ) 4 ] (4). All new complexes were well characterized. The molecular structures of 2‚1.5C 6 D 6 , 3a‚THF, 3d‚0.5C 7 H 8 , and 4 were determined by single-crystal X-ray diffraction studies. The germylidyne complexes reveal very short W-Ge distances (d W-Ge ) 229.91(9)-231.84(6) pm), an almost linear geometry at the triply bonded germanium atom (W-Ge-C Cp* ) 172.0(1)-176.8(1)°) and a η 1 -bonded Cp* substituent.