Frank C. March

Steric constraints imposed by triazamacrocyclic ligands. Crystal and molecular structure of two copper(II) complexes with triazamacrocyclic ligands : μ-chloro-μ-hydroxo-bis(1,5,9-triazacyclododecane)dicopper(II) perchlorate and bromo-(1,5,9-triazacyclotetradecane)copper(II) perchlorate

Abstract Crystal structures of two complexes of copper(II) with triazamacrocycles have been determined. The dimeric complex [Cu:(L1) 2 (μ-OH)(μ-Cl)](ClO 4 ) 2 (L1=1,5,9-triazacyclododecane) crystallizes in the monoclinic space group P 2 1 / n with a =14.29(1), b =9.292(9), c =25.63(2) A, β=102.23(6)°, Z =4. The structure has been refined to an R of 0.081 ( R w 0.0847). The coordination sphere of the copper(II) is best described as trigonal bipyramidal with two nitrogens of the macrocycle and the O atom occupying the trigonal plane. The CuN bond distances vary from 1.99(1)–2.06(1) A. [Cu(L6)Br](ClO 4 ) (L6=1,5,9- triazacyclotetradecane) crystallizes in the orthorhombic space group Pnma , a =14.365(4), b =11.491(6), c =10.194(3) A, Z =4. The data have been refined to R of 0.077 ( R w 0.075). The copper has a very distorted four-coordinate geometry, the CuN bond distances are equal within experimental error (2.02 A); the bond angles around the copper range from 92–148°. Electrochemical and ESR spectral studies of the [Cu(L6)] 2+ complex are reported.

Crystal and molecular structures of {NN′-[2-(2′-pyridyl)ethyl]ethylenebis(salicylideneiminato)}-iron(II) and -cobalt(II)–ethanol (1/1)

The crystal and molecular structures of the title complexes, [Fe(salpeen)](1) and [Co(salpeen)]·EtOH (2), have been determined using three-dimensional X-ray diffraction data collected on automatic diffractometers. Complex (1) crystallises in the monoclinic space group P21/c with the unit-cell parameters a= 10.572(2), b= 11.465(2), c= 16.640(3)A, β= 90.52(1)°, and Z= 4, and its structure has been refined by conventional least-squares techniques using 1 118 reflections having I > 3σI to give R 0.056 and R′ 0.062. Complex (2) crystallises in the triclinic space group P with the unit-cell parameters a= 15.049(2), b= 15.127(2), c=10.258(1)A, α= 90.53(l), β= 93.53(1), γ= 109.81 (1)°, and Z= 4, and its structure has been refined using 1 237 reflections having I > 3σI to give R 0.064 and R′ 0.069. The cobalt complex thus has two crystallographically independent molecules in the asymmetric unit, each hydrogen bonded via an oxygen atom to an ethanol adduct molecule; there are small but significant differences between the two molecules. The iron and cobalt complexes have a similar distorted trigonal-bipyramidal geometry.

Stereochemistry of some organic derivatives of Group Vb elements. Part VI. Crystal and molecular structure of µ-oxo-bis[perchloratotriphenylbismuth(V)]

The structure of the title compound has been determined by X-ray methods. Crystals are monoclinic, space group P21/c, with Z= 4 in a unit cell of dimensions a= 18·750(3), b= 10·108(2), c= 18·927(3)A, β= 92·19(1)°. The structure was solved by the heavy-atom method and refined by block-diagonal least-squares methods to a residual R of 0·070 for 3145 data considered observed. The structure contains well separated discrete molecules. The two bismuth atoms are linked by an oxygen bridge [mean Bi–O(br) 2·065(10)A, Bi–O–Bi 142·4(7)°]. The configuration about the bismuth atoms is distorted trigonal bipyramidal with the oxygen atoms apical and phenyl groups equatorial. The perchlorate groups are weakly co-ordinated to the metal [mean Bi–O(perchlorate) 2·65(1)A], one being disordered. Other mean dimensions: Bi–C(Ph) 2·19(2)A, O(br)–Bi–C(Ph) 97·1(1)°, Bi–O–Cl 132·3(8)°.

Stereochemistry of some organic derivatives of Group Vb elements. Part VIII. Crystal and molecular structure of µ-chloro-bis[hydroxytriphenylarsenic](1+) dichloroiodate(1–)

Crystals of the title compound are monoclinic, space group P21/c, with Z= 4 in a unit cell of dimensions: a= 14.259(2), b= 14.374(2), c= 17.653(3)A. β= 90.15(1)°. The structure was solved by the heavy-atom method and refined by least-squares techniques to R= 0.046 for 2441 observed intensities. The compound is correctly formulated as [Ph3As–O–H ⋯ Cl ⋯ H–O–AsPh3]+ ICl2–. The chloride ion bridges the hydroxy groups via strong hydrogen bonds. The stereochemistry of the arsenic atoms is very slightly distorted tetrahedral. Mean dimensions are: As–C(Ph) 1.901 (10), As–O 1.727(7) and 1.716(7), I–Cl 2.513(3) and 2.542(4)A. The hydrogen atoms involved in the bridging have been located, with mean distances O–H 0.89 and H ⋯ Cl–2.13 A.

Dipyrromethene complexes of transition metals. Part II. Stereochemistry of complexes of cobalt(II), nickel(II), copper(II), zinc(II), cadmium(II), mercury(II), and palladium(II) and crystal structure analysis of the palladium complex

Complexes have been formed between bivalent ions of cobalt, nickel, copper, zinc, mercury, and palladium and the the ligands 4,4′-dicarboxyethyl-3,3′,5,5′-tetramethyldipyrromethene (mpmH) and 3,4′-dicarboxyethyl-5-chloro-3′,4,5′-trimethyldipyrromethene (cpmH). The stereochemistry of these complexes has been investigated by measurement of magnetic susceptibility, and 1H n.m.r. spectra, and u.v. visible spectra. An X-ray determination of the crystal and molecular structure of the complex Pd(mpm)2 is reported. The palladium atom lies on a crystallographic centre of symmetry and is necessarily coplanar with the four co-ordinated nitrogen atoms of the ligand. The unique bidentate ligand is not planar.

Dipyrromethene complexes of transition metals. Part III. Physical properties and crystal and molecular structure of a mixed-ligand complex of palladium(II)

Complexes have been formed between bivalent palladium and the dipyrromethene ligands 4,4′-bis(ethoxycarbonyl)-3,3′,5,5′-tetramethyldipyrromethene (mpmH) and 3,4′-bis(ethoxycarbonyl)-5-chloro-3′,4,5′-trimethyldipyrromethene (cpmH) of the type Pd2Cl2L2(L = mpm or cpm) and PdXL(LH)(X = Cl or Br; L = mpm or cpm; LH = mpmH or cpmH). The latter complexes contain both bi- and uni-dentate co-ordinated dipyrromethene ligands. The 1H n.m.r. and u.v.–visible spectra of these complexes have been investigated and an X-ray determination (diffractometer data) of the crystal and molecular structure of PdCl(cpm)(cpmH) is reported. The palladium atom is in an essentially square planar environment bonded to three nitrogen atoms and one chlorine atom. The uni- and bi-dentate dipyrromethene ligands deviate considerably from planar configurations. The unco-ordinated nitrogen atom lies above the palladium square plane but does not seem chemically bonded to any atom in the plane. Crystals are monoclinic, space group Cc, Z= 4, a= 1782(1), b= 2096(1), c= 1038(6) pm, β= 95·47(3)°. The structure was solved by Patterson and Fourier methods and refined by least-squares techniques to R 5·7%(2257 independent reflections).