COMPARISON OF STRUCTURE OF 8-MERCAPTOQUINOLINATES OF TRIVALENT METALS BELONGING TO EIGHT ( Co, Rh, Ir ), FIFTH ( As, Sb, Bi ) AND THIRD ( Ga, In, Tl ) GROUP

Elga Silina1, Yurii Bankovsky1, Vitaly Belsky2, Lucija Pech1, Janis Ashaks1, Janis Lejejs1

1Institute of Inorganic Chemistry, Latvian Academy of Sciences, 34 Miera Street, Salaspils, LV-2169, E-mail: director@iic.iph.sal.lv.
2Karpov Institute of Physical Chemistry, Moscow, Russia.

Keywords: inorganic coordination compounds, trivalent metals, 8-mercapto-quinoline and its derivatives

On the basis of x-ray investigation of the above-mentioned trivalent metal 8-mercaptoquinolinates ( see Table ) the regularities of their structure have been established and generalized. 

Table 
I	Co(C9H6NS)3 				XI 	As(C9H6NS)3 
II 	Rh(C9H6NS)3.CHCl3 		XII 	As[C9H5(4-CH3)NS]3 
III 	Rh(C9H6NS)3.DMFA 		XIII 	Sb(C9H6NS)3 
IV 	Ir[C9H4(4-CH3)NS]3.1.3 CHCl3 	XIV 	Sb[C9H5(2-CH3)NS]3 
V 	Ga(C9H6NS)3.CH3OH 		XV 	Sb[C9H4(2-CH3)(5-SCH3)NS]3 
VI 	In(C9H6NS)3.CHCl3 		XVI 	Sb[C9H5(4-C6H5)NS]3 
VII 	In[C9H5(5-SC6H5)NS]3 		XVII 	Bi(C9H6NS)3 
VIII 	In[C9H5(2-C6H5)NS]3 		      XVIII   Bi[C9H5(2-CH3)NS]3 
IX 	 In[C9H5(2-C3H7)NS]2Cl 		XIX 	Bi[C9H5(2-C6H5)NS]2Cl 
X 	Tl(C9H6NS)3

In the group of 8-mercaptoquinolinates of the 8th group transient elements (I- IV ) the complexes occur to be asymmetric isomers in which all three ligands differ in their position in the coordination sphere of the metal atom. Coordination polyhedron of the metal is a very insignificantly distorted octahedron ( 3S+3N ) it is formed by three bidentic ligands of 8-mercaptoquinoline. The limits of the diagonal angles SMS, SMN, NMN are of 176+- 3o. The lengths of the bonds M-S and M- N are close to the sum of the corresponding covalent radii and essentially depend on the transpartner nature: the most lengthened bonds occur to be the bonds M-S and M-N in transposition to which the sulfur atom is situated. Three coordination planes SMN in the complexes I-IV are practically mutually perpendicular to each other, but inflections of the metal-containing rings along to the S...N line are insignificant.

Asymmetric isomer of the complex is found to exist in the group of 8-mercaptoquinolinates of the third group nontransient elements ( V-VII, X ). Nevertheless the coordination polyhedron of the metal octahedron ( 3S +3N ) is already noticeably distorted. The limits of the diagonal angles are of 166+-6o . The lengths of the bonds M-S are close to the sum of the corresponding covalent radii, but the bonds M-N are noticeably longer. The strengthening of the bonds M-S and M-N is observed on transition from complex V to complex X. In the complexes V VII, X the two shortest and similar with regound to value bonds M-S are situated in trans-position. Three coordination planes SMN are not exactly perpendicular to each other. The inflection of the metal-containing rings does not exceed 10o.

Structure of the fifth group nontransient element 8-mercaptoquinolinates ( XI-XIX) significantly differs due to the presence of the unshared electron pair in the atoms of trivalent metals As, Sb, Bi. The basic coordination polyhedron of the metal is a trigonal pyramid ( M + 3S ) in the apex of which the metal M atom is situated. The M-S bond lengths slightly exceed the sum of the corresponding covalent radii. The surrounding of the metal is complemented by two or three essentially weak coordination bonds M...N. The octahedral surrounding of the metal is strongly distorted the limits of the diagonal angles SMN are of 158+- 4o. Complexes are the symmetric isomers, in which all three ligands are identically located in the coordination sphere of metal.

The analysis of the structure of coordination polyhedron in the complexes XI (swings 3S + N ), XIII (distorted octahedron 3S + 3N ), XVII (pentagonal pyramid 3S + 3N ) has been performed taking into account the unshared electron pair participation of which in formation of isostructural complexes XIV and XVIII has been considered.

On examples of the compounds VII-IX, XII, XIV-XVI, XVIII, XIX the influence of substituents in the quinoline nucleus on the geometry of the complexes is discussed.