Treatment of Na2PdCl4 or [MCl2(PhCN)2] with bis(4-pyridyl)diselenide yielded an insoluble product of composition [MCl2(4,4′-(C5H4N)2Se2)]n (1). The reactions of Na2PdCl4 with one and two eq. of Na(4-SeC5H4N) afforded insoluble products [PdCl(4-SeC5H4N)]n (2) and [Pd(4-SeC5H4N)2]n (3), respectively. On treatment with PPh3, 2 and 3 gave trans-[PdCl(4-SeC5H4N)(PPh3)2] (4a) and trans-[Pd(4-SeC5H4N)2(PPh3)2] (5a), respectively. The oxidative addition of bis(4-pyridyl)diselenide to Pt(PPh3)4 exclusively yielded trans-[Pt(4-SeC5H4N)2(PPh3)2] (5b). The treatment of two eq. of Na(4-SeC5H4N) with cis-[PtX2(PR3)2] afforded 5b (X = Cl) and trans-[Pt(4-SeC5H4N)2(PEt3)2] (5c) (X = Cl or CF3SO3). The reactions of cis-[MCl2(P∩P)] and [M2Cl2(μ-Cl)2(PR3)2] with two eq. of Na(4-SeC5H4N) exclusively yielded cis-[M(4-SeC5H4N)2(P∩P)] (M/P∩P = Pd/dppe (6a), Pt/dppm (6b) and Pt/dppp (6c)) and [MCl(4-SeC5H4N)(PR3)]n (7), respectively. The complex trans-[PtCl(4-SeC5H4N)(PEt3)2] (4b) was isolated from the redistribution reaction between 5c and cis-[PtCl2(PEt3)2]. The complex [PdCl(4-SeC5H4N)(PPh3)]n (7b) exists in bi- and tri-nuclear forms, whereas [MCl(4-SeC5H4N)(PEt3)]n (7a, 7c) and [PtCl(4-SeC5H4N)(PMe2Ph)]n (7d) retain their trinuclear structure in solution. Molecular structures of 4a, 4b, 5a, 5c, 6a, 6c, 7a, 7b and 7c were established by single crystal X-ray diffraction analyses. The complexes trans-[PdCl(4-SeC5H4N)(PPh3)2] and [PdCl(4-SeC5H4N)(PPh3)]n can act as catalysts for Suzuki C–C cross coupling reaction.

Addition of 1,4-benezenedithiol and 4,4'-biphenyldithiol to M(OTf)2 (M = cis-[Pt(PEt3)2](2+) or cis-[Pd(dppe)](2+)) (dppe = 1,2-bis(diphenylphosphino)ethane) gave self-assembled tetranuclear complexes [M2{S(C6H4)nS}]2(OTf)4 (n = 1, 2). The same reaction with 1,4-benezenedimethanethiol yielded octanuclear supramolecular coordination complexes (SCC) [M2{SCH2C6H4CH2S}]4(OTf)8. These complexes were characterized by NMR, mass, and UV-vis spectroscopies, cyclic voltammetry, as well as density functional theory studies and represent the first examples of SCCs constructed by thiolate groups and square-planar metal ions. The rectangular shape of tetranuclear complexes and square shape of octanuclear complex are confirmed by single-crystal structures and computational studies. The palladium complexes showed excellent catalytic activity in Suzuki C-C cross-coupling reactions with high turnover numbers (2 × 10(7)), even with low catalyst loading.

A series of silver triphenylphosphine complexes containing pyridyl chacogenolate (S, Se) ligands has been synthesized by employing [AgCl(PPh3)3] and [Ag2(μ-Cl)2(PPh3)4].

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The reaction of cis-[Pt(PEt 3 ) 2 (OTf) 2 ] with 4-mercaptobenzoic acid (4-H 2 mba) in the presence of sodium methoxide yielded trans-[Pt(SC 6 H 4 COOH-4) 2 (PEt 3 ) 2 ] (1), the simple addition of 3-/4-mercaptobenzoic acid to cis-[Pt(PEt 3 ) 2 (OTf) 2 ] and cis-[M(_ PP) 2 (OTf) 2 ] gave the self-assembled complexes cis-[Pt(μ-SC 6 H 4 COOH-n)(PEt 3 ) 2 ] 2 (OTf) 2 [n = 3 (2), 4 (3)] and [M(μ-SC 6 H 4 COOH-n)(_ PP)] 2 (OTf) 2 [M/n/_ PP = Pd/3/dppe (4), Pd/4/ dppe (5), Pt/4/dppp (6); dppe = 1,2-bis(diphenylphosphino)ethane, dppp = 1,2-bis(diphenylphosphino)propane], respectively, and the reactions of cis-[PtCl 2 (PR 3 ) 2 ] (R = Et, Ph) and [PtCl 2 (dppm)] with 3-/4-mercaptobenzoic acids in the pres-[a]