Synthesis of binuclear platinum complexes containing the ligands 8-naphthyridine, 2-aminopyridine, and 7-azaindolate. An experimental study of the steric hindrance of the bulky pentafluorophenyl ligands in the synthesis of binuclear complexes.

The bidentate N-donor ligands 2-aminopyridine (2-ampy), 7-azaindolate (aza) and 1,8-naphthyridine (napy) have been used to study the steric effect of pentafluorophenyl groups in the synthesis of binuclear platinum(II) complexes. The 2-ampy and aza ligands bridge two "Pt(C 6F 5) 2" fragments with Pt...Pt distances of 4.1 and 3.4 A, respectively (complexes 1 and 3). Under the same reaction conditions the napy ligand shows chelating behavior and makes the mononuclear complex ( A) highly reactive because of its strained coordination. One of the Pt-N bonds of the chelating complex is broken on reaction with HX {X = Cl ( 4), Br ( 5)} because of protonation while the anion X (-) occupies a created vacant site. The resulting mononuclear complex eliminates C 6F 5H when refluxed, and a binuclear complex ( 6) with two napy ligands bridging two "Pt(C 6F 5)Cl" fragments is obtained. The reaction of A with HPPh 2 affords a mononuclear complex ( 7) analogous to complexes 5 and 6, but reflux gives a binuclear complex ( 8) with the two napy ligands terminally bound and the PPh 2 groups bridging the "Pt(C 6F 5)napy" moieties. The reaction of A with HCCPh gives a binuclear complex; moreover, the final product does not depend on the ratio of complex A to HCCPh. Complexes 1, 4, 6, 9 have been structurally characterized by X-ray diffraction.

Synthesis and Reactivity of (Pentafluorophenyl)platinate(II) Complexes with Bridging 1,8-Naphthyridine (napy) and X Ligands (X = C(6)F(5), OH, Cl, Br, I, SPh). Crystal Structure of [NBu(4)][Pt(2)(&mgr;-napy)(&mgr;-OH)(C(6)F(5))(4)].CHCl(3).

By reaction of [NBu(4)](2)[Pt(2)(&mgr;-C(6)F(5))(2)(C(6)F(5))(4)] with 1,8-naphthyridine (napy), [NBu(4)][Pt(C(6)F(5))(3)(napy)] (1) is obtained. This compound reacts with cis-[Pt(C(6)F(5))(2)(THF)(2)] to give the dinuclear derivative [NBu(4)][Pt(2)(&mgr;-napy)(&mgr;-C(6)F(5))(C(6)F(5))(4)] (2). The reaction of several HX species with 2 results in the substitution of the bridging C(6)F(5) by other ligands (X) such as OH (3), Cl (4), Br (5), I (6), and SPh (7), maintaining in all cases the naphthyridine bridging ligand. The structure of 3 was determined by single-crystal X-ray diffraction. The compound crystallizes in the monoclinic system, space group P2(1)/n, with a = 12.022(2) Å, b = 16.677(3) Å, c = 27.154(5) Å, beta = 98.58(3) degrees, V = 5383.2(16) Å(3), and Z = 4. The structure was refined to residuals of R = 0.0488 and R(w) = 0.0547. The complex consists of two square-planar platinum(II) fragments sharing a naphthyridine and OH bridging ligands, which are in cis positions. The short Pt-Pt distance [3.008(1) Å] seems to be a consequence of the bridging ligands.

Hydrogen-bond mediation of supramolecular aggregation in neutral bis-(C6F5)Pt complexes with aromatic H-bond donating ligands. A synthetic and structural study.

Six pentafluorophenylplatinum(II) complexes containing proton acceptor atoms (F) and pyridine-like aromatic ligands able to act as proton donors have been synthesized and characterized, with emphasis on the factors that mediate their supramolecular aggregation in the solid state--hydrogen bonds and pi-pi interactions. The crystal structure analyses of the mononuclear complexes cis-[Pt(C6F5)2(napy)](1), cis-[Pt(C6F5)2(CH2napy)](3), cis-[Pt(C6F5)2(2-ammpy)](5), and cis-[Pt(C6F5)2(2-bipym)](6) reveal the influence of D-HPt and D-HF (D=C, N) hydrogen bonding on the organization of molecules into stacks, which can be further interconnected to generate channels. The prevalence of hydrogen bonding over pi-pi interactions between aromatic rings in establishing the nature of the observed supramolecular aggregation is demonstrated.