Concomitant polymorphic behavior of di-μ-thiocyanato-κ² N:S;κ² S:N-bis[bis(tri-p-fluorophenylphosphine-κP)silver(I)]

Abstract

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.

Silver(i) complexes with 1′-(diphenylphosphino)-1-cyanoferrocene: the art of improvisation in coordination

“…In the crystal, its molecules are arranged around the inversion centers and, hence, only their half is structurally independent. Analogous structures have been reported for [L 2 Ag(µ-SCN-S,N)] 2 with various monophosphine (L = PPh 3 , 37 P(C 6 H 4 Me-4) 3 , 38 P(C 6 H 4 F-4) 3 39 and Ph 2 PPy) 35 The eight-membered ring in the structure of 8 is rectangular in shape due to the presence of the rigid, rod-like SCN bridges and the fact that the S-Ag-N angle of 93.79(4)° departs considerably from the tetrahedral value, being diminished due to the steric demands of the Ag-bound phosphines. The central (AgSCN) 2 ring has a chair-like conformation ( Figure S11) with the silver atoms displaced by 0.541(1) Å above and below the "central" (SCN) 2 plane.…”

Oligo-nuclear silver thiocyanate complexes with monodentate tertiary phosphine ligands, including novel ‘cubane’ and ‘step’ tetramer forms of AgSCN : PR3 (1 : 1)4

“…comprising the asymmetric unit), 27 with a 'pseudomorph' as the 0.35H 2 O solvate 28 and an interesting pair of polymorphs, both monoclinic P2 1 /x, of AgSCN : P(C 6 H 4 -4F) 3 ) (1 : 2) 2 (see above, 9), one with one half of the centrosymmetric dimer in the asymmetric unit (P2 1 /n, Z = 2 dimers description) and the other with one full and one-half dimer in the asymmetric unit (P2 1 /c, Z = 6 dimers description). 10 A further member is added in the present work, AgSCN : PPh 2 py (1 : 2) 2 , 3, also dimeric. In complexes of the P-monodentate PPh 2 py ligand with the pyridyl component uncoordinated, it is not unusual to find that the crystalline form adopted is that of the PPh 3 analogue, and, further, that the pyridyl group nitrogen atom may be disordered over some or all of the six available sites within the ligand.…”

“…SYNTHESIS OF AgSCN : P(C 6 H 4 -4F) 3 (1 : 1) X , (10). To a solution of AgSCN (0.0497 g, 0.3 mmol) in 30 ml of acetonitrile, P (C 6 H 4 -4F) 3 (0.0948 g, 0.3 mmol) was added.…”

“…C 55 H 45 AgNP 3 S. C 2 H 8 N 2 , M = 1012.9. Triclinic, space group P1 ˉ, a = 13.276( 7), b = 13.780 (10), c = 14.313(3) Å, α = 89.17(5), β = 79.22(3), γ = 80.40(6)°, V = 2536 Å 3 (T ca. 300 K).…”

“…D c (Z = 2) = § This was the subject of a single crystal X-ray study, the results of which are harmonious with those recently reported in ref. 10, wherein two monoclinic P2 1 /x (C 5 2h , no. 14) polymorphs are described, both obtained from the same solvent (acetonitrile); the results of our study conform to those presented for the form with the Z = 6 cell, set as P2 1 /c.…”