Heterobimetallic Coordination Polymers Based on the [Pt(SCN)₄]^2– and [Pt(SeCN)₄]^2– Building Blocks

Abstract

New complexes and the first coordination polymers containing [Pt(SCN)4](2-) of the type [M(L)x][Pt(SCN)4] (where L = 2,2'-bipyridine (bipy), x = 2, M = Co(II), Ni(II), Cu(II); L = ethylenediamine (en), x = 2, M = Ni(II), Cu(II); L = N,N,N',N'-tetramethylethylenediamine (tmeda), x = 1, M = Cu(II); L = 2,2';6',2″-terpyridine (terpy), x = 1, M = Mn(II), Co(II); L = 1,10-phenanthroline (phen), x = 2, M = Pb(II)) were prepared by reacting the appropriate metal-ligand cations with K2[Pt(SCN)4] and structurally characterized. [M(bipy)2Pt(SCN)4]2·2MeOH (M = Co (1), Cu (4)) consist of supramolecular tetranuclear distorted squares containing two [M(bipy)2](2+) and two [Pt(SCN)4](2+) units. [Cu(bipy)2(NCS)]2[Pt(SCN)4] (6) is a double salt of the [Pt(SCN)4](2-) anion and two [Cu(bipy)(NCS)](+) cations. [Cu(en)2Pt(SCN)4] (7, 8) are 1-D coordination polymers that are coordinated in either cis or trans fashion at the [Pt(SCN)4](2-) unit, for 7 and 8, respectively. Complexes [Cu(en)2Pt(SeCN)4] (9) and [Ni(en)2Pt(SCN)4] (10) are similar to 8 and 7, respectively, but complex 9 (prepared using ((n)Bu4N)2[Pt(SeCN)4]) also presents intermolecular Se-Se interactions which resulted in an increased dimensionality. Compounds [M(terpy)Pt(SCN)4] (M = Mn (11), Co (13)) involve 2-D sheets of [M(terpy)](2+) and [Pt(SCN)4](2-) units, whereas [Mn(terpy)2][Pt(SCN)4] (12) is a double salt of one [Mn(terpy)2](2+) unit and one [Pt(SCN)4](2-). [Cu(tmeda)Pt(SCN)4] (14) contains a five-coordinate Cu(2+) metal center coordinated to one tmeda ligand and three different [Pt(SCN)4](2-) units, resulting in 2-D sheets. [Pb(phen)2Pt(SCN)4] (15) contains an 8-coordinate Pb(2+) metal center coordinated to two phen ligands and four [Pt(SCN)4](2-), generating a 3-D network in the solid state. Structural correlations were established between the ancillary ligand, the choice of metal, the structure of the [Pt(SCN)4](2-) building block, and the resulting dimensionality of the coordination polymers.