Reaction of the nine-nuclear cluster Ni9(HOOCCMe3)4(μ4-ΟΗ)3(μ3-OH)3 (OOCCMe3)12 (1) with pyridine results in the binuclear species Py4Ni2(OOCCMe3)2(μ-OOCCMe3)2(μ-OH2) (2). Thermolysis of 2 at 100−140 °C in toluene or xylene leads to complex Py2Ni2(HOOCCMe3)2(OOCCMe3)2(μ-OOCCMe3)2(μ-OH2) (3). This complex can be converted back in 2 by the reaction of 3 with 2 equiv of pyridine. Thermolysis of solid 3 in vacuo at 170 °C gives the binuclear tetra-bridged trimethylacetate Py2Ni2(μ-OOCCMe3)4 (4) which can be reverted in 3 by reaction with 1 equiv of H2O and 2 equiv of HOOCCMe3. Compound 4 might be also prepared by the reaction of the complexs L2Ni2(μ-OOCCMe3)4 (L = 2,3-lutidine (5), Et3N (6)) with pyridine at 40−80 °C in hexane or benzene solution. Complexes 5 and 6 are formed in an one-step reaction by interaction of complex 1 and ligand L. Complex Dipy2Ni2(OOCCMe3)2(μ-OOCCMe3)2(μ-OH2) (7), an isoelectronic analogue of complex 2, was prepared by reacting 1 with Dipy. Thermolysis of solid 7 at 170 °C in vacuo gives monomer DipyNi(OOCCMe3)2 (8). Hetero-ligand complex DipyNi(NH2Ph)(OOCCMe3)2 (9) was obtained upon the reaction of PhNH2 with complex 7 at 20 °C in benzene or MeCN. Reaction of 1 with α,α‘,α‘ ‘-tripyridyl leads to the formation of the monomeric TerpyNi(OOCCMe3)2 (10). Complexes 4−10 were characterized with X-ray data. Magnetic properties of the synthesized complexes are discussed.

The reaction of NiCI 2 9 6H20 with Me3CCOOH and KOH taken in a molar ratio of 1 : 2 : 2 in water afforded the nonanuclear anti.ferromagnetic complex [Nig(Me3CCOOH)4(p4-O)3(I~3-OH)3(OOCCMe3)I2], which apparently contains Ni II and Ni III atoms. The complex was isolated by extraction with CH2C12, benzene, or hexane. The reactions of this complex with pyridine bases (pyridine (Py), 3,4-1utidine (Lut), and nicorandil (Nic)) gave the adducts L4Ni2(OOCCMe3)2(~t-OOCCMe3)2(tt-OH) (L = Py, Lut, or Nic, respectively). According to magnetic measurements, intramolecular ferromagnetic exchange interactions in these adducts are complemented by intermoleeular antiferromagnetic interactions. Pyrolysis of the pyridine adduct in air or under an inert atmosphere in xylene yielded the antiferromagnetie complex Py2Ni2(Me3CCOOH)2(OOCCMe3)2(~t-OOCCMe3)2(~.-OH2), which contains Ni 11 atoms. The structures of all the complexes synthesized were established by X-ray diffraction analysis. The electronic absorption spectra of these compounds are considered.

The reactions of dicopper tetrapivalate complex Cu 2 (μ-OOC-t-Bu) 4 (NCMe) 2 (1) with triphenylphosphine oxide and diethyl phosphite allow paddle-wheel (PW) copper(II) complexes with phosphorus-containing axial ligands (2, 3) to be obtained. When meso-bis-(diethoxyphosphoryl)porphyrins 4M were employed in this ligand exchange reaction, a series of one-dimensional (1D) homo-and heterometallic coordination polymers 5M composed of PW subunits and organophosphonate diesters were prepared and characterized by means of single crystal Xray analysis. Planar porphyrinate 4Pd and nonplanar metalloporphyrinates 4Cu and 4Ni proved to be appropriate molecular structural blocks for assembly of coordination polymers. The structural parameters of the tetrapyrrolic macrocycles incorporated into the polymer chain are determined by the nature of the metal center of the porphyrin moiety. While the geometry of palladium(II) and nickel(II) porphyrinates 4Pd and 4Ni does not change significantly in the polymer chain, saddle-shaped Cu(II) porphyrinate 4Cu exhibits a nearly planar core configuration, being coordinated to the copper centers of PW fragments by two peripheral phosphoryl groups in the polymer chain. The geometry of the tetrapyrrolic core is a key parameter influencing the structural properties of the polymeric materials. For 5Pd and for isostructural 5Cu, all metal centers of the polymeric chain are aligned. The planar macrocycles of adjacent chains are parallel and are shifted one to another in such a way that the angle between the Pd•••P and Pd•••Pd directions is 40.4°, and the distance between the nearest palladium(II) atoms of neighboring chains is 11.668 Å. There is no free volume in these crystals. In the crystals of 5Ni, formed by nonplanar porphyrinates, only copper atoms of the PW pivalate moiety are located in one plane, and zigzag chains are formed so that two adjacent tetrapyrrolic macrocycles are located in alternating positions with respect to this plane, the nickel atoms being displaced from this plane by 1.548 Å. This arrangement naturally leads to the formation of regular pores. The resulting channels have an effective cross-section of about 10 × 12 Å and represent ca. 18% of the volume of the crystal. The exchange reaction between the free-base porphyrin 4H 2 and an excess of copper(II) pivalate complex 1 is accompanied by the metalation of the porphyrin core affording the polymer 5Cu. Moreover, self-assembly of metalloporphyrinate 4Zn is observed under studied experimental conditions, which interferes with the formation of the target mixed coordination polymers.

Extraction of polymer (1). formed in the reaction of CoCI~ with KOOCBu t, with boiling hexane gives crystals of hexamer Co6(~.3-OH)2(OOCBu~)I0(HOOCBut)4 (2). According to data of X-ray study, four Co H atoms in the hexanuclear molecule 2 have an octahedral ligand environment and two Co H atoms have a tetrahedral one. Dissolution of polymer 1 in EtOH results in its splitting into Co4(~t3-OH)~(OOCBut)~(HOEt)6 tetramers (3). In molecule 3, two asymmetric dimeric (q2-OOCBur fragments are bound by two tridentate bridging OH groups.Key words: cobalt trimethylacetates, polynuclear complexes, carboxylate ligands, synthesis. X-i-ay araalysis.Polynuclear transition-metal complexes with carboxylate bridging ligands often have unusual structures and possess unique chemical and physical (first of all, magnetic) properties. Lz In particular, trimethylacetate derivatives, which are highly volatile and readily soluble in organic solvents, can be of interest as initial compounds for preparing thin films (e.g., oxide films) and immobilized catalysts. Particular attention is paid to these compounds because of structural analogies between some of their metal fragments and those of the active sites of natural enzymes. 3-13Recently, we have shown that the action of various amines on the nonanuclear hydroxocarboxylate Nig(HOOCBu~)4(Ft4-O)3(I-t3-OH)3(. tt-OOCBut) 12, which is readily obtained in 70--90% yields in the reaction of NiCt2-6H20 with potassium pivalate, results in various nickel(10 trimethytacetates whose structure and magnetic properties can be deliberately modified. 14 in this context, the availability of the starting oligomeric cobalt complex and relatively easy "control" over reactions also were prerequisites to extending the approaches found to transformations of cobalt trimethylacetates. In this work, we report the results of our studies on the synthesis of the first hexa-and tetranuclear cobalt(n) trimethylacetates.

Durch Erwärmen von Rh2(HCOO)4°C H2O mit einem Überschuß von Thioessigsäure läßt sich das Thioacetat (Ia) darstellen.