Utilization of mixtures of aromatic N-donor ligands of different coordination ability for the solvothermal synthesis of thiostannate containing molecules

Abstract

Utilization of mixtures of differently coordinating aromatic N-donor ligands leads to the formation of the two new compounds {[Ni(phen)2]2Sn2S6}·4,4'-bipy·½H2O I and {[Ni(phen)2]2Sn2S6}·2,2'-bipy II that could be prepared under solvothermal conditions (4,4'-bipy = 4,4'-bipyridine, C10H8N2; phen = 1,10-phenanthroline, C12H8N2; 2,2'-bipy = 2,2'-bipyridine, C10H8N2). In the structures of both compounds Ni-S bond formation is observed which is highly unusual when only bidentate N-donor ligands are applied in the reaction mixture. The detailed analysis of the crystal structure indicates that the presence of 4,4'-bipy and 2,2'-bipy molecules are essential for the stabilization of the arrangement of the constituents. The main structural motif {[Ni(phen)2]2Sn2S6} is arranged generating off center parallel stacking of the phen ligands. The empty spaces between the {[Ni(phen)2]2Sn2S6} moieties are occupied by either 2,2'-bipy (I) or 4,4'-bipy (II) molecules which are oriented towards the phen ligands to form intermolecular π-π interactions.

Transition Metal Complexes with Linkage to the Thiostannate Units Forced by Suitable Amine Molecules

“…In compounds 1 , 2 , and 5 the S atoms are located in cis position. The rigid positions of the biting angles of the N‐donor atoms of the amine ligands (phen or 2,2′‐bipy) and the [Sn 2 S 6 ] 4– unit cause a distinct distortion of the ideal octahedral arrangement [N–TM–N/N–TM–S: 71.25(12)–95.23(8)°; 153.4(2)–173.95(10)°] (Supporting Information, Tables S6 and S7), comparable to literature data for similar compounds . In compounds 3 and 4 the S atoms are located in trans position in the octahedron and the TM ions are on special positions leading to ideal angles [N–TM–N/S–TM–S: 180.00(17)–180.00(3)°], whereas the cis angles significantly deviate from ideal values [80.21(8)–99.79(8)°] (Supporting Information, Table S8), as observed in similar compounds …”

“…[Ni(phen) 2 ] 2 [Sn 2 S 6 ]} · biph ( 1 ) was synthesized analogous to the compounds {[Ni(phen) 2 ] 2 [Sn 2 S 6 ]} · 2,2′‐bipy and {[Ni(phen) 2 ] 2 [Sn 2 S 6 ]} · 4,4′‐bipy · ½H 2 O . In the latter two compounds the aromatic amines 2,2′‐bipy and 4,4′‐bipy were added for stabilization of the structure of {[Ni(phen) 2 ] 2 [Sn 2 S 6 ]} via π–π bonding interactions.…”

“…In the latter two compounds the aromatic amines 2,2′‐bipy and 4,4′‐bipy were added for stabilization of the structure of {[Ni(phen) 2 ] 2 [Sn 2 S 6 ]} via π–π bonding interactions. Syntheses without these amine molecules led to formation of [Ni(phen) 3 ]Cl 2 complexes . Therefore, the concept of stabilizing thiostannate containing compounds by addition of an aromatic amine molecule could be verified by applying biphenyl during the syntheses of 1 .…”

“…The charge compensation in these compounds can be achieved in different ways: (a) inorganic cations, (b) inorganic‐organic hybrid compounds with protonated amine molecules as counterions, (c) compounds with integrated transition metal ions (TM) in the thiostannate unit and protonated amines as counterions, and finally (d) compounds containing [TM(amine) n ] m + or [ Ln (amine) n ] m + complexes for charge compensation as summarized in several review articles , , . In the latter group mainly the [Sn 2 S 6 ] 4– unit is observed, whereas the [SnS 4 ] 4– anion is less common , , , . Other thiostannate ions like for example [Sn 3 S 7 ] 2– , [Sn 4 S 9 ] 2– ,, [Sn 5 S 12 ] 4– , [Sn 3 S 9 ] 6– , or [Sn 4 S 10 ] 4– are only found in pure inorganic or inorganic‐organic hybrid compounds so far.…”

“…using amines like tetraethylenepentamine (tepa) in {[Ni(tepa)] 2 [Sn 2 S 6 ]}, or tris(2‐aminoethyl)amine (tren) in {[Ni(tren)] 2 [Sn 2 S 6 ]} n , which cannot saturate the coordination sphere of the central metal atom. Aromatic or cyclic amines with rigid positions of the amine groups like 1,10‐phenanthroline (phen) in {[TM(phen) 2 ] 2 [Sn 2 S 6 ]} · (TM = Fe, Co), and {[Ni(phen) 2 ] 2 [Sn 2 S 6 ]} · amine (amine = 2,2′‐bipyridine (2,2′‐bipy), 4,4′‐bipyridine (4,4′‐bipy)) and 1,2‐diaminocyclohexane (1,2‐dach) in the related class of thioantimonates in {[Fe(1,2‐dach) 2 ][Sb 6 S 10 ]} seem to be exceptions: in principal these amine ligands could satisfy the coordination requirements of the central TM 2+ atoms, but interestingly TM–S bonds have been observed, even with Fe 2+ and Co 2+ which normally prefer bonds to N donor ligands. A further observation is that only few [TM(amine) n ] 2+ containing tin‐sulfur compounds exhibit a dimensionality larger than zero.…”