Terminal Azido Research Articles

Preparation, crystal structure and spectroscopic study of azido(N,O-quinaldato)triaquamanganese(II) monohydrate andthiocyanato(N,O-quinaldato)-(O-quinaldic acid)diaquamanganese(II), [Mn(NC 9H 6COO) (N 3(H 2O) 3]·H 2O and [Mn(NC 9H 6COO)(NC 9H 6COOH)(NCS)(H 2O) 2

Two mixed ligand complexes of quinaldic acid and manganese(II) azide or thiocyanate, namely azido(N,O-quinaldato)triaquamanganese(II) monohydrate ( 1) and thiocyanato(N,O-quinaldato)(O-quinaldic acid)diaquamanganese(II) ( 2), have been prepared and characterized by single-crystal X-ray methods. The coordination environment of the manganese(II) atom in complex 1 is a distorted octahedron. Each metal atom is chelated by a quinaldate anion [via its nitrogen atom, MnN = 2.292(3) Å, and a carboxylate oxygen atom, MnO = 2.147(3) Å] and links three aqua molecules [MnO distances from 2.189(3) to 2.217(3) Å] and a terminal azido ligand [MnN = 2.181(3) Å]. The structure of complex 2 features distorted octahedral manganese(II) coordination geometry, chelated quinaldate anion [MnN = 2.271(7) Å and MnO = 2.158(5) Å], O-bonded neutral quinaldic acid molecule [MnO = 2.228(5) Å], two aqua molecules [MnO = 2.180(5) and 2.203(6) Å] and a terminal N-thiocyanato group at an MnN distance of 2.119(7) Å. The IR spectra of these two complexes are presented and discussed in relation to their structures.

Crystal Structures of mer-Cr(pyridine)3(N3)3 and Polymeric NaCr(pyridine)4(N3)4. A Structure Containing μ(1,3) Bridging Azido Ligands between Chromium-and Sodium-Centered Polyhedra

The structures of mer-Cr(py)3(N3)3 (1) and polymeric NaCr(py)4(N3)4 (2) were determined by X-ray crystallography. Crystal data; 1, C15H15N12Cr, triclinic, space group P1̄, a = 895.3(2), b = 999.1(3), c = 1269.9(5) pm , α = 106.76(3), β = 96.69(3), γ = 116.30(2)°, V = 943.8(6) · 106 pm3, Z = 2 and Rw = 0.038 for 1736 observed MoKα diffractometer data; 2, C20H20N16CrNa, monoclinic, space group C2/c, a = 1561.2(3), b = 1028.8(2), c = 1573.6(4) pm, β = 90.70(2)°, V = 2 527.3(9) · 106 pm3, Z = 4 and = 0.033 for 1272 MoKα diffractometer data. The coordination around the chromium (III) ion in the discrete molecules of 1 is six-coordinate with mean distances Cr-N(py) of 210.2(4) pm and Cr-N(N3) of 200.8(4) pm. The terminal azido ligands are almost linear and asymmetric, the N-N bonds nearer to the metal (118.8(6) to 120.5(7) pm) being significantly longer than the terminal ones (114.7(7) to 115.5(7) pm). In compound 2, each chromium or sodium cation is six-coordinated by four azido groups and two pyridine molecules. The azido groups act as μ(1,3) bridging ligands between chromium and sodium octahedra to form a three-dimensional network structure. The chromium atoms are trans-coordinated by the pyridine ligands whereas the sodium cations are cis-coordinated.