Concomitant polymorphic behavior of di-mu-thiocyanato-kappa2N:S;kappa2S:N-bis[bis(tri-p-fluorophenylphosphine-kappaP)silver(I)].
The structures of two polymorphs, both monoclinic P2(1)/n [polymorph (I)] and P2(1)/c [polymorph (II)], of di-mu-thiocyanato-kappa(2)N:S;kappa(2)S:N-bis[bis(tri-p-fluorophenylphosphine-kappaP)silver(I)] complexes have been determined at 100 K. In both polymorphs the complex has a dinuclear structure where the silver(I) coordinates to two phosphine ligands and two bridging thiocyanate anions to form complexes with distorted tetrahedral geometry. Polymorph (I) has just one half of the [Ag(2)(SCN)(2){P(4-FC(6)H(4))(3)}(4)] molecule at (0, 1/2, 0) from the origin in the asymmetric unit. Polymorph (II) has one and a half molecules of [Ag(2)(SCN)(2){P(4-FC(6)H(4))(3)}(4)] in the asymmetric unit; the half molecule is situated at (0, 1, 1/2), while the full molecule is located at (1/3, 1/2, 1/3) from the origin. The Ag-P bond distances range from 2.4437 (4) to 2.4956 (7) A in both polymorphs. The Ag-S distances are 2.5773 (7) A in (I) and 2.5457 (5), 2.5576 (5) and 2.5576 (5) A in (II). The full molecule in polymorph (II) has slightly shorter Ag-N bond distances [2.375 (1) and 2.367 (2) A] compared with the half molecules in both polymorphs [2.409 (2) A in (II) and 2.395 (2) A in (I)]. The two polymorphs are compared using r.m.s. overlay calculations as well as half-normal probability plot analysis.
Omondi
Bernard
B
Department of Chemistry, University of Johannesburg, PO Box 524, Auckland Park 2006, Johannesburg, South Africa.
Meijboom
Reinout
R