David J. Phillips

Metal chelates of dithiocarbazic acid and its derivatives. VI. Antiferromagnetic and ferromagnetic interactions in some copper(II) complexes of salicylaldehyde and acetylacetone Schiff bases derived from s-methyldithiocarbazate

Abstract The Schiff base S-methyl-β-N-(2-hydroxyphenyl)methylendithiocarbazate, o -HO.C 6 H 4 CHNNHC(S)SCH 3 , and the corresponding 5chloro, 5-bromo, 5-nitro, and 3-methoxy derivatives were prepared from the appropriate salicylaldehyde and S-methyldithiocarbazate. The acetylacetone Schiff base 2-hydroxy-4-methyl-5,6-diaza-7-thiono-8-thianona-2,4-diene, CH 3 C(OH)CHC(CH 3 )NNHC(S)SCH 3 , was also prepared. By the loss of two protons the ligands behave as doubly negatively charged ONS tridentates. Complexes of the type M(ONS).B (M = Cu,Ni; B = py, H 2 O) and Co III (ONS)(ONSH) were isolated. In addition, the complexes M(ONS) (M = Cu, Ni, Pd, Pt) were obtained. It is suggested that where M = Ni, Pd, Pt, the complexes possess square-planar, dimeric thiolo-bridged structures. The copper complexes Cu(ONS) of the 5-chloro,5-bromo-, and 3-methoxy- salicylaldehyde Schiff bases are red and have anomalously low moments which decrease with decrease in temperature. This behaviour is attributed to antiferromagnetic interaction due to an oxygen-bridged dimeric structure. The moment of the green copper complex of the 5-nitro-salicylaldehyde Schiff base increases with decrease in temperature, indicating ferromagnetic interaction between the copper atoms. The value of the moment at 83′K is 2.43 B.M. and the magnetic data fit the expression for a tetrahedral cluster of four ferromagnetically interacting copper atoms. The green copper complex of the acetylacetone Schiff base is also ferromagnetic.

Metal chelates of dithiocarbazic acid and its derivaties. I. Complexes of dithiocarbazic acid and its S-methyl ester

Abstract The complexes CR(H 2 NNHCS 2 ) 3 . 2H 2 O, Ni(H 2 NNHCS 2 ) 2 . H 2 O, and M(H 2 NNHCS 2 ) 2 (M = Pd, Pt, Zn, Cd, Pb) have been obtained by the reaction of hydrazinium dithiocarbazate with the appropriate metal salt. Infrared and electronic spectral data indicate that the ligand is coordinated via one nitrogen and one sulphur atom. S -Methyldithiocarbazate yields high-spin nickel(II) complexes of two types: [Ni(H 2 NNHCSSCH 3 ) 3 ]X 2 (X = NO 3 , Cl, Br) and Ni(H 2 NNHCSSCH 3 ) 2 X 2 (X = Cl, NCS). Spectral data indicate NS coordination in these compounds. The complexes M(H 2 NN=CSSCH 3 ) 2 (M = Ni, Pd, Pt) containing deprotonated S -methyldithiocarbazate were also isolated; the nickel complex is diamagnetic.

Metal chelates of dithiocarbazic acid and its derivatives. II. Complexes of the schiff bases formed by condensation of S-methyldithiocarbazate with acetone and pyridine-2-aldehyde

Abstract The acetone Schiff base S-methyl-N-isopropylidendithiocarbazate, Me2CNNC(SMe)SH (NSH), forms the stable, crystalline complexes [M(NS)2] (M=Co, Ni, Pd, Pt, Cu), which are non-electrolytes in nitrobenzene. The nickel, palladium, platinum, and copper complexes are square-planar but magnetic and spectral evidence indicates that the cobalt complex is tetrahedral. The pyridine-2-aldehyde Schiff base S-methyl-N-(2-pyridyl)methylendithiocarbazate, C5H4NCHNNC(SMe)SH (N-N-SH), forms the square-planar 1:1 complexes [M(NNS)X] (M = Ni, Pd, Pt, Cu; X = Cl, Br, I, NCS, or NO3) and [Cu(NNS)H2OClO4 and the octahedral 2:1 complexes [M(NNS)2] (M = Fe, Ni). The manganese(III) complex [Mn(NNS)Cl2]. 1 2 H2O is probably octahedral and polymeric. With iron(III) the complexes [Fe(NNS)2ClO4 and [Fe(NNS)2][FeCl4] were obtained. Both the iron(II) complex and the iron(III) complex cation are spin-paired. Bivalent cobalt is oxidized to yield the cobalt(III) complexes ion [Co(NNS)2], which was isolated as [Co(NNS)2]NO3 H2O and [Co(NNS)2[CoX4] (X = Cl, Br, NCS).

Metal chelates of dithiocarbazic acid and its derivatives. III. Complexes of the tridentate schiff base α-N-Methyl-S-methyl-β-N-(2-pyridyl)methylendithiocarbazate with some 3d metal ions

Abstract The Schiff base, α- N -methyl- S -methyl-β- N -(2-pyridyl)methylendithiocarbazate, C 5 H 4 NCHNN(Me)C(SMe)S (NNMeS), behaves as a neutral tridentate ligand, forming stable crystalline complexes with first-row transition metal ions. It forms the monoligand complexes Cr(NNMeS)Cl 3 , Mn(NNMeS)X 2 (X = Cl, NCs), M(NNMeS)X 2 (M = Ni, Cu; X = Cl, Br, I, NCS), and [Cu(NNMeS)(H 2 O)]SO 4 . The manganese and nickel complexes are probably halogen-bridged, octahedral, and polymeric. The structures of the copper complexes are uncertain The bis-ligand complexes, which were isolated, are [M(NNMeS) 2 ](ClO 4 ) 2 (M = Fe, Co, Ni), [Ni(NNmeS) 2 ](BF 4 ) 2 2H 2 O, [M(NNMeS) 2 ][MX 4 ] (M = Fe, Co; X = Cl, Br, I, NCS), and [Fe(NNMeS) 2 ][FeCl 4 ] 2 . In these complexes the iron(II) cation is low-spin and diamagnetic but the cobalt(II) cation is high-spin.

Metal chelates of dithiocarbazic acid and its derivatives. VII. The magnetism of some copper(II) complexes of salicylaldehyde Schiff bases derived from N-methyl-S-methyldithiocarbazate and S,S′-dimethyldithiocarbazate

Abstract The Schiff bases α- N -methyl-{S}-methyl-β- N -(2-hydroxyphenyl)methylendithiocarbazate o-HO.C 6 H 4 .CH = NNMeC(=S)SMe (HONMeS), its 3-methoxy derivative (3-MeOHONMeS), 1-(2-hydroxyphenyl)-2,3-diaza-4-methylthio-5-thiahexa-1,3-diene, o-HO.C 6 H 4 .CH = NNC(SMe) 2 (HONSMe) and its 5-chloro and 5-bromo derivatives (5XHONSMe; X = Cl, Br) were prepared. By the loss of a proton the Schiff bases act as uni-negatively charged ONS tridentate ligands. The complexes Ni(ONMeS)X (X = Cl, Br, NCS) are diamagnetic and square-planar, while the complex Ni(ONMeS) 2 is paramagnetic and octahedral. The palladium complex Pd(ONSMe)Cl was also isolated. the copper complexes Cu(ONMeS)NO 3 , Cu(ONSMe)NO 3 , and [Cu(ONMeS)py]ClO 4 display normal magnetic behaviour. The compound Cu(ONMeS)BF 4 has an anomalously low moment (0.88 B.M.) at room temperature and the moment decrease to 0.38 B.M. at 93°K due to antiferromagnetic interaction. The compound Cu 2 (3MeOONMeS)Cl 3 also displays antiferromagnetic interaction between the two copper atoms of the dimer. The complexes Cu 3 (ONMeS) 2 Cl 4 and Cu 3 (ONSMe) 2 Cl 4 most likely have a linear trimeric structure; the magnetic data for the latter compound fit an equation for a linear trimer with three antiferromagnetically interacting copper atoms. The compounds Cu(5ClONSMe)Cl and Cu(5BrONSMe)Cl are monomeric with normal magnetic moments.

Metal complexes of the 2-hydroxy derivative of pyridine N-oxide

Abstract The 2-hydroxy derivative of pyridine N-oxide exists in the tautomeric form 1-hydroxy-2-pyridone (Hopo). This paper describes the following complexes of the deprotonated ligand (opo): Cu(opo) 2 ; Cu(opo)NO 3 ,H 2 O * ; Cu(opo)Br,0.5CH 3 OH * ; Cu(opo)Cl * ; Ni(opo)Cl,1.5H 2 O; Co(opo)Cl,1.5H 2 O * and Fe(opo) 3 ,H 2 O (new complexes are marked with asterisks). Structures with bidentate opo, are proposed for the complexes, on the basis of measurements of x-ray powder diffraction spectra, Mossbauer, infrared and electronic spectra, and magnetic data down to 89 K. The complex Cu(opo)Br, 0.5CH 3 OH is antiferromagnetic, and its susceptibility data have been fitted to various models.

Metal complexes with 2-aminopyridine N-oxide, including N-oxide-bridged complexes of cobalt(II), nickel(II) and copper(II): further studies on related pyridine N-oxide complexes

Abstract Metal complexes of 2-aminopyridine N-oxide (Hapo) have been characterised by infrared spectra, X-ray powder diffraction spectra, and by magnetic measurements and electronic spectra to liquid nitrogen temperature. Neutral Hapo appears to be an O-donor ligand in almost every case, according to spectroscopic evidence. The [M(Hapo) 6 ]X 2 ] complexes (M = Mn, Co and Ni; X drawn from ClO 4 , BF 4 and NO 3 ) are octahedrally coordinated and [Cu(Hapo) 4 ](BFA 4 ) 2 is square planar. The complexes Co(Hapo) 2 Br 2 ·C 2 H 5 OH, Ni(Hapo) 2 Br 2 , Cu(Hapo) 2 (NO 3 ) 2 , and the copper(II) halide complexes, are all antiferromagnetic and N-oxide bridged. Such bridging pyridine N-oxide, whilst common with copper(II), is rare with cobalt(II) and nickel(II). The temperature dependence of the magnetism of Ni(Hapo) 2 Br 2 has been compared to that for various models. Other Hapo complexes with cobalt(II) and nickel(II) halides appear to be halide-bridged. Some previously reported complexes with pyridine N-oxide (po), of the type M(po)Hal 2 ·H 2 O (M = Co, Ni), have been more fully characterised and are halide-bridged. The complexes [Fe(Hapo) 4 Cl 2 ]Cl and [(Cr(Hapo) 4 Cl 2 ]Cl·H 2 O have trans -MO 4 Cl 2 coordination. The complex Cu(apo) 2 contains deprotonated O,N-bonded ligand. The complexes Cu(apo) 2 , [Cu(Hapo) 4 ](BF 4 ) 2 , Cu(Hapo) 2 (NO 3 ) 2 and the metal perchlorate complexes have been previously reported, the remaining complexes are new.

Metal chelates of dithiocarbazic acid and its derivatives. V. complees of the NNS ligand 2-(2,3-diaza-4-methylthio-5-thiahexa-1,3-dienyl) pyridine with 3d metal ions

Abstract The Schiff base, 2-(2,3-diaza-4-methylthio-5-thiahexa-1,3-dienyl) pyridine, C 5 H 4 NCHNNC(SMe) 2 (NNSMe), forms stable, crystalline complexes with manganese(II), cobalt(II), nickel(II), and copper(II) The complex Mn(NNSMe)Cl 2 is probably halogenbridged and six-coordinate. With cobalt the complexes Co(NNSMe)X 2 (X = Cl, Br, I), Co(NNSMe) 2 (NCS) 2 H 2 O, [Co(NNSMe) 2 NO 3 ]NO 3 , [Co(NNSMe) 2 ](ClO 4 ) 2 H 2 O and [Co(NNSMe) 2 ](BF 4 ) 2 were isolated. The halide complexes are tetrahedral, with bidentate NN-bonded ligand. The nitrato complex is probably five-cordinate, with NN-bonded ligand. The perchlorate and fluoborate complexes are lowspin. All nickel complexes isolated are six-coordinate. The complex [Ni(NNSMe) 2 NO 3 ]NO 3 probably has bidentate ligand and one bidentate nitrate. The other nickel complexes Ni(NNSMe)X 2 (X = Cl, Br, I, NCS) and [Ni(NNSMe) 2 ](ClO 4 ) 2 contain tridentate NNS bonded ligand, and the mono-ligand complexes are anion-bridges. Thi structure of Cu 2 (NNSMe)Cl 4 is uncertain. The complexes Cu(NNSMe)X 2 (X = NO 3 , NCS) have coordinated anion. Bidentate NN-bonded ligand is present in the thiocyanato complex. The complexes [Cu(NNSMe) 2 ](ClO 4 ) 2 4H 2 O, [Cu(NNSMe) 2 ](BF 4 ) 2 and [Cu(NNSMe) 2 I]BF 4 contain bidentate NN-bonded ligand and resemble the complexes of diimine ligands such as 1,10-phenanthroline. The reasons for the predominantly bidentate behavior of NNSMe with cobalt(II) and copper(II), and tridentate behaviour with nickel(II) are discussed.

Metal chelates of dithiocabazic acid and its derivatives. IV. Complexes of the tridentate schiff base α-N-Methyl-S-methyl-β-N-(6-methylpyrid-2-yl)methylendithiocarbazate

Abstract The Schiff base α-N-methyl-S-methyl-β-N-(6-methylpyrid-2-yl)methylendithiocarbazate, 6-MeC5H3NCHNN(Me)C(SMe)S(MeNNMeS), acts as a tridentate ligand and forms stable, crystalline complexes with iron(II), cobalt(II), nickel(II), and copper(II). The bis-ligand complexes [M(MeNNMeS)2](ClO)4)2.nH2O(M = Fe, Co, Ni), [Co(MeNNMeS)2](BF4)2, [Fe(MeNNMES)2][FeI4], [Fe(MeNNMeS)2][FeIIICl4]2, and [Co(MeNNMeS)2][CoX4] (X = C, Br, NCS) were isolated. The iron(II) cation [Fe(MeNNMeS)2]2+ is low-spin. The mono-ligand complexes M(MeNNMeS)(NCS)2 (M = Fe, Ni) are six-coordinate and probably polymeric with thiocyanato bridges. On the other hand, spectral evidence indicated that the halogeno-complexes M(MeNNMeS)X2 (M = Fe, Ni, Cu; X = Cl, Br) are five-coordinate probably with a distorted trigonal bipyramidal structure.

Metal complexes of 2-acetylpyridine n-oxide oxime

Abstract Complexes of 2-acetylpyridine N-oxide oxime (pxo) are reported with Ni(II), Co(II), Cu(II) and Fe(III). Pxo behaves as an O,N donor via the N-oxide oxygen and the oxime nitrogen atoms. The complexes M(pxo)Cl 2 ·CH 3 OH (M = Ni, Co) are antiferromagnetic and are thought to be N-oxide bridged. The temperature dependence of the magnetism of the nickel compound has been compared to that for various models. Complexes of the type M(pxo) 2 X 2 (M = Ni, Co, Cu) have been obtained, in which X is drawn from Br, NO 3 , BF 4 and NCS, depending on the metal; these compounds are all assigned trans -MN 2 O 2 X 2 structures. Halogen-bridged structures are proposed for the complexes Cu(pxo)Hal 2 (Hal = Cl, Br). The compound Fe(pxo)Cl 3 ·CH 3 OH is probably six-coordinate. Magnetic measurements and electronic spectra, to liquid nitrogen temperature, are reported and also infrared spectra, X-ray powder diffraction spectra and Mossbauer spectra.