First metallamacrocyclic complexes of Pt(iv) with 3,3,3′,3′-tetraalkyl-1,1′-phenylenedicarbonylbis(thioureas): synthesis by direct or electrolytic oxidative addition of I2, Br2 and Cl2

Abstract

Elemental I(2) and Br(2) cleanly react with the 3:3 Pt(ii) metallamacrocycle of 3,3,3',3'-tetra(n-butyl)-1,1'-terephthaloylbis(thiourea)(cis-[Pt(II)(3)(L(p)(1)-S,O)(3)]3), in chloroform at room temperature, to yield oxidative addition products; (195)Pt NMR studies reveal that a stepwise oxidative addition readily occurs to each of the Pt(ii) centres in the metallamacrocycle to yield the mixed valence species cis-[Pt(II)(2)Pt(IV)I(2)(L(p)(1)-S,O)(3)] and cis-[Pt(II)Pt(IV)(2)I(4)(L(p)(1)-S,O)(3)], and the fully oxidised cis-[Pt(IV)(3)I(6)(L(p)(1)-S,O)(3)] in solution, depending on the mole ratio I(2):3. Similar results are obtained on treatment of solutions of 3 with elemental Br(2). Treatment of the corresponding 2:2 Pt(ii) complex of 3,3,3',3'-tetraethyl-1,1'-isophthaloylbis(thiourea)(cis-[Pt(II)(2)(L(m)(1)-S,O)(2)]4) with iodine, results in facile oxidative addition to yield cis-[Pt(IV)(2)(L(m)(1)-S,O)(2)I(4)], with a trans-Pt(iv)-iodo arrangement. Molecules in the crystal structure of 5 have their trans-Pt(iv)-iodo axes essentially aligned, with very close intermolecular iodide contacts (3.775(1)A), resulting in chains of weakly bound metallamacrocycles in the solid. An alternative electrolytic synthesis method, using a simple two-compartment glass cell containing 4 and a chosen halide salt in dichloromethane, led to the formation of cis-[Pt(IV)(2)(L(m)(1)-S,O)(2)Br(4)] 6 and cis-[Pt(IV)(2)(L(m)(1)-S,O)(2)Cl(4)] 7, completing characterization of a series of first-reported trans-Pt(iv)-X (X=I, Br, Cl) metallamacrocyclic complexes.

2,6-Dipicolinoylbis(N,N-dialkylthioureas) as versatile building blocks for oligo- and polynuclear architectures

“…1). [21][22][23] This coordination mode has also been found for the extended tetraalkylisophthaloylbis(thioureas) in binuclear bis-chelates of the type 2 with Cu 2+ , Ni 2+ , Zn 2+ , Co 2+ , Cd 2+ , Pt 2+ and Pd 2+ ions, [24][25][26][27][28] 31 Attempts with corresponding 2,6-dipicolinoylbis(N,Ndialkylthioureas), H 2 L (Fig. 2), seem to be more promising.…”

Bipodal 1,1′-acyl-3,3,3′,3′-tetraalkylbis(thiourea) ligands with flexible C3, C4and C6spacer groups

“…The pyridine adducts of 2:2 and 3:3 nickel(II) complexes of 3,3,3 0 ,3 0 -tetraethyl-1,1 0 -terephthaloylbis(thiourea) show some interesting host-guest chemistry in the solid state (Hallale et al, 2005). Recently, the corresponding diiodidoplatinum(IV) adducts were prepared and characterized after electrochemically induced oxidative addition of I 2 to the corresponding 2:2 and 3:3 Pt II complexes of 3,3,3 0 ,3 0 -tetraethyl-1,1 0 -isophthaloylbis(thiourea) and 3,3,3 0 ,3 0 -tetraethyl-1,1 0 -terephthaloylbis(thiourea) (Westra et al, 2005). A similar bipodal ligand with a 2,6-substituted pyridine ring as spacer and its Ag I coordination polymer has been described (Schrö der et al, 2000).…”

Light-induced cis/trans isomerization of cis-[Pd(L-S,O)2] and cis-[Pt(L-S,O)2] complexes of chelating N,N-dialkyl-N′-acylthioureas: key to the formation and isolation of trans isomers

“…Generally N,N-dialkyl-N'-acylthioureas show a marked tendency to coordinate to d 8 3 ], not easily accessible by other means [12]. In this context the overwhelming tendency to form cis complexes of the numerous complexes of divalent transition metal ions with simple N,N-dialkyl-N'-acyl(aroyl)thioureas which have been structurally characterized is striking [9].…”