John N. Bridson

1,7‐Dioxa[7](2,7)pyrenophane: The Pyrene Moiety Is More Bent than That of C70

Themostdistortedpyrenemoietyyetprepared (see picture) has been synthesized by the valence isomerization of a tethered [2.2]metacyclophane-1,9-diene to a 10b,10c-dihydropyrene and in situ dehydrogenation by 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) at 80 °C. The end-to-end bend of the pyrene moiety exceeds that of the corresponding part of the equator of D5h C70.

Zinc(II) and cadmium(II) complexes of the potentially tridentate ligands 2-[[2-pyridinylmethyl)amino]methyl]phenol (HSALAMP) and 2-[[[2-(2-pyridinyl)ethyl]amino]methyl]phenol (HSALAEP). X-ray crystal structures of the [Zn(SALAMP)(NO3)]2 and the [Cd(SALAEP)(NO3)]2 dimers

Abstract Zinc(II) and cadmium(II) complexes with two potentially tridentate (NNO) ligands 2-[[(2-pyridinylmethyl)amino]methyl]phenol (HSALAMP) and 2-[[[2-(2-pyridinyl)ethyl]amino]methyl]phenol (HSALAEP) have been isolated and structurally characterized through 1 H, 13 C and 2-D NMR spectroscopy and in two cases by X-ray crystallography. HSALAMP behaves as a tridentate (NNO) or a bidentate (NN) ligand, depending upon the nature of the anion and the reaction conditions and on reaction with zinc( II ) salts gives three types of complex: (a) [Zn(SALAMP)X] 2 · y C 2 H 5 OH (X = Cl, y = 0 ( I ); X = I, y = 0 ( II ); X = NO 3 y = 1 ( III ); (b) [Zn(HSALAMP)X 2 ]· y H 2 O (X = Cl, y = 1 ( IV ); X = I, y = 0 ( V ); (c) [Zn(HSALAMP) 2 ](CIO 4 ) 2 ·C 2 H 5 OH·H 2 O ( VI ). However HSALAEP, a similar compound with one additional carbon atom in the chain, acts as a tridentate ligand irrespective of the nature of the anion and the reaction conditions, forming compounds with zinc( II ) and Cd(II) salts, [M(SALAEP)X] 2 · y C 2 H 5 OH (M = Zn, X = CI, y = 0 ( VI I); M = Zn, X = I, y = 0 ( VIII) ; M = Zn, X = NO 3 , y = 0 ( IX ) and M = Cd, X = NO 3 , y = l ( X ). The single crystal X-ray structures of the [Zn(SALAMP)(NO 3 )] 2 ( III ) and the [Cd(SALAEP)(NO 3 )] 2 (X) dimers have been determined. III crystallized in the monoclinic system, space group P 2 1 / c , with a = 10.156(4), b = 17.424(4), c = 8.090(4) A, β = 107.56(2)°, V = 1365(2) A 3 and Z = 4. X crystallized in the monoclinic system, space group P 2 1 / n , with a =9.728(2), b =15.132(4), c =10.223(4) A, β = 92.910(10)° V = 1502.9(8) A 3 and Z = 2. The structures of III and X are similar and consist of centrosymmetric dimers in which deprotonated phenolates bridge the two metal atoms and link the two halves of the dimer. In III and X the zinc(II) and cadmium(II) ions have a highly distorted six-coordinate structure, bonded to two oxygen atoms from a bidentate nitrate group, the pyridine nitrogen, an amine nitrogen and a phenolate oxygen. The metal-metal separations are quite short (3.063(1) A ( III ), 3.429(1) A ( X ) with M-O-M angles of 98.33(9) ( III ) and 99.2(1° ( X ). Compounds I and II and VII–IX have been proposed to have dimeric structures similar to those of III and X , with SALAMP or SALAEP acting as tridentate (NNO) ligands with the two zinc(II) ions bridged similarly by phenolate oxygens. Compounds IV , V and VI appear to have four-coordinate, monomeric structures with (HSALAMP) acting as a bidentate ligand (NN).

Polynuclear copper(II) complexes with μ2-1,1-azide bridges. Structural and magnetic properties

Abstract Two novel, weakly antiferromagnetically coupled, tetranuclear copper(II) complexes [Cu4(PAP)2(μ2-1,1-N3)2(μ2-1,3-N3)2(μ2-CH3OH)2(N3)4 (1) (PAP = 1,4-bis-(2′-pyridylamino)phthalazine) and [Cu4(PAP3Me)2 (μ2-1,1-N3)2(μ2-1,3-N3)2(H2O)2(NO2)2]- (NO3)2 (2) (PAP3Me = 1,4-bis-(3′-methyl-2′-pyridyl)aminophthalazine) contain a unique structural with two μ2-1,1-azide intramolecular bridges, and two μ2-1,3-azide intermolecular bridges linking pairs of copper(II) centers. Four terminal azide groups complete the five-coordinate structures in 1, while two terminal waters and two nitrates complete the coordination spheres in 2. The dinuclear complexes [Cu2(PPD)(μ2-1,1-N3)(N3)2(CF3SO3)]CH3OH) (3) and [Cu2(PPD)(μ2-1,1-N3)(N3)2(H2O)(ClO4)] (4) (PPD = 3,6-bis-(1′-pyrazolyl)pyridazine) contain pairs of copper centers with intramolecular μ2-1,1-azid and pyridazine bridges, and exhibit strong antiferromagnetic coupling. A one-dimensional chain structure in 3 occurs through intermolecular μ2-1,1-azide bridging interactions. Intramolecular Cu-N3-Cu bridge angles in 1 and 2 are small (107.9 and 109.4°, respectively), but very large in 3 and 4 (122.5 and 123.2°, respectively), in keeping with the magnetic properties. 2 crystallizes in the monoclinic system, space group C2/c with a = 26.71(1), b = 13.51(3), c = 16.84(1) A , β = 117.35(3)° and R = 0.070, Rw = 0.050. 3 crystallizes in the monoclinic system, space group P21/c with a = 8.42(1), b = 20.808(9), c = 12.615(4) A , β = 102.95(5)° and R = 0.045, Rw = 0.039. 4 crystallizes in the triclinic system, space group P1, with a = 10.253(3), b = 12.338(5), c = 8.072(4) A , α = 100.65(4), β = 101.93(3), γ = 87.82(3)° and R = 0.038, Rw = 0.036 . The magnetic properties of 1 and 2 indicate the presence of weak net antiferromagnetic exchange, as indicated by the presence of a low temperature maximum in χm (80 K (1), 65 K (2)), but the data do not fit the Bleaney-Bowers equation unless the exchange integral is treated as a temperature dependent term. A similar situation has been observed for other related compounds, and various approaches to the problem will be discussed. Magnetically 3 and 4 are well described by the Bleaney-Bowers equation, exhibiting very strong antiferromagnetic exchange (− 2J = 768(24) cm−1 (3); − 2J = 829(11) cm−1 (4)).

Linear dependence of spin exchange coupling constant on bridge angle in phenoxy-bridged dinickel(II) complexes

A magneto-structural relationship showing linear dependence of antiferromagnetic exchange coupling constant (–J) on Ni–O–Ni bridge angle as well as the intramolecular Ni ⋯ Ni distance has been obtained with a series of phenoxy-bridged macrocyclic dinickel(II) complexes with centrosymmetric structures.

A novel antiferromagnetically coupled, dimeric, dodecanuclear copper(II) complex involving two macrocyclic ligands each with a ‘benzene-like’ arrangement of six copper centres

Template condensation of 2,6-diformyl-4-methylphenol with 1,3-diamino-2-hydroxypropane, in the presence of copper(II) nitrate and a base, results in the formation of a novel dimeric, dodecacopper(II) complex of a 30-membered macrocyclic ligand (H6M), with a pseudo-hexagonal, ‘benzene-like’ arrangement of metal centres and an alternating double (µ2-OPh, µ2-OH) and single (µ2-OR) bridge arrangement within each ring.

Copper(II) coordination chemistry of potentially octadentate (N8) tetrapyridyl and tetrapyrazolyl-pyridazine ligands. X-ray crystal structures of [Cu2(PTAPY)Br4]·2DMF and [Cu2(PTAPY)(NO3)2(N3)(H2O)]2(NO3)2·1.2CH3OH

Abstract The structural, electrochemical, ESR and magnetic properties of a series of dinuclear copper(II) complexes of two new polyfunctional pyridazine ligands, 3,6-bis( N,N,N′,N′ -tetrakis(pyridine-2-ylmethyl)-aminoethanethiolato pyridazine (PTAPY), and 3,6-bis( N,N,N′,N′ -tetrakis(pyrazol-1-ylmethyl)-aminoethanethiolato pyridazine (PTAPZ) are discussed. PTAPY and PTAPZ are potentially octadentate (N 8 ) ligands and on reaction with copper(II) salts form dinuclear complexes, [Cu 2 (PTAPY)X 4 ]·yH 2 O (X=NO 3 , y=1 ( I ); X=Br, y=2 ( II )), [Cu 2 (PTAPY)(CH 3 CN) 2 ](ClO 4 ) 4 ·0.5C 2 H 5 OH ( III ), [Cu 2 (PTAPZ)Cl 4 ]·5H 2 O ( V ), and a tetranuclear complex [Cu 2 (PTAPY)(NO 3 ) 2 (N 3 )(H 2 O)] 2 (NO 3 ) 2 ·1.2CH 3 OH ( IV ). The single crystal X-ray structures of compounds II and IV have been determined, and in each case the ligand is hexadentate. II ([Cu 2 (PTAPY)Br 4 ]·2DMF) crystallized in the triclinic system, space group P 1 , with a =14.037(3), b =14.941(4), c =11.782(6) A, α=103.77(3), β=106.08(3), γ=84.59(2)°, V =2305(2) A 3 and Z =2 ( R =0.036 and R w =0.032). Two different five-coordinate (CuN 3 Br 2 ) geometries exist within the same molecule. IV crystallized in the triclinic system, space group P 1 , with a =14.876(5), b =16.172(4), c =10.068(2) A, α=95.45(2), β=108.40(2), γ=64.74(2)° and Z =2 ( R =0.058 and R w =0.051). The two copper atoms are quite different with six- (axially elongated, distorted tetragonal) and five- (distorted square- pyramidal) coordinate arrangements, and dimerization through azido nitrogens results in the formation of a tetranuclear azide bridged molecule. The pyridazine nitrogens remain uncoordinated in all complexes and there is no magnetic interaction between the distant copper centers. Cyclic voltammograms are characterized by the presence of either one ‘two-electron’ or two ‘one-electron’ (overlapping) reversible or quasi-reversible redox processes, associated with the reduction of the dinuclear copper(II) species to dinuclear copper(I) species.

Synthesis and Unusual Crystal Structure of syn-6,15-Dicyano-2,11-dithia[3.3]metacyclophane

Abstract syn-6,15-Dicyano-2,11-dithia[3.3]metacyclophane 4 is the first of its kind to crystallize with both bridges in the pseudo-boat conformation. A number of other unusual features are also apparent in the crystal structure, none of which are predicted by AM1 or ab initio calculations.

Thiopyridyl triazine derivatives and their platinum complexes: A new class of potential antitumor agents

Abstract A novel series of thiopyridyl triazine ligands and their metal(II) complexes have been synthesized. The X-ray structure of the mononuclear copper(II) complex of the ligand 6-thiopyridyl-2,4-bis(dimethylamino)-l,3,5-triazine (L5) has also been determined. The in vitro cytotoxic potency against the human colon cancer cell line (HT-29) has been determined for the ligands and their platinum complexes. All compounds including their ligands have been found to be highly potent against the HT-29 cell line. The ligand 2,4,6-trithiopyridyl-l,3,5-triazine (L2) and its platinum complex were found to be 10–30 times more potent than cisplatin.

Synthesis, structure and solution conformation of some [(η5-indenyl)(I2-n)(R)(Ln)COIII](n-1)+ (n = 1, 2; R = perfluoroalkyl; L P-donor) complexes

Abstract Reaction of (η 5 -indenyl)(I)(R)(CO)Co (R  C 3 F 7 , C 6 F 13 ) with P-donor ligands yields a series of mono- and disubstituted products [(η 5 -indenyl)(I 2- n )(R)(L n )Co] n-1)+ ( n = 1, 2, L  PMe 3 ; n = 1, L  PPhMe 2 , PPh 2 Me, PPh 2 (OMe), PPh 3 ). Product distribution is highly ligand dependent and no disubstituted product forms for bulky P-donor ligands. Solution NMR data ( 1 H, 13 C, 19 F) for the racemic, Co-chiral, monosubstituted derivatives support a slightly distorted η 5 -indenyl piano stool structure with a preferred conformation which places the perfluoroalkyl group trans to the indenyl 6-ring. The structure of [(C 9 H 7 )(C 3 F 7 )(PMe 3 ) 2 Co]I·0.5 CH 2 Cl 2 ( 5 ) was determined by single crystal X-ray diffraction. Compound 5 crystallizes in the monoclinic space group P 2 1 / n with a = 16.760(5) A, b = 10.614(7) A, c = 28.595(5) A, β = 96.61 (2)°, V = 5053(3) A 3 , Z = 4 and was refined to R = 0.040 and R w = 0.036 based on 4097 observations with I > 3.00σ,(I).

In situ oxidation of a copper (I) complex to produce a hydroxy-bridged dinuclear copper (II) complex. Structural, magnetic and electrochemical properties

Abstract The green hydroxo-bridged dicopper (II) complex [Cu2(PTP)(OH)Cl3]∗d2CH3CN (1) was obtained by aerial oxidation of an acetonitrile solution of a red copper (I)/PTP complex (PTP = 3,6-bis(2-pyridylthio)pyridazine). 1 crystallizes in the monoclinic system, space group P21/n, with a = 12.104(1), b = 11.014(4), c = 18.697(2) A , β = 106.372(9) 0 , and four formula units per unit cell. 1 has a triple bridged, distorted five-coordinate structure with a CuCu separation of 3.0514(8) A, and a CuOHCu angle of 106.2(1)0. Variable temperature magnetic studies indicate moderate anti-ferromagnetic coupling between the copper centers (−2J = 296 cm−1). The salt [H2PTPH]2+[CuBr4]2− (2) is also reported from an unusual reaction between CuBr2 and PTPH (PTPH = 1,4-bis(2-pyridylthio)phthalazine) in CH3CN/CHCl3 mixture. 2 crystallizes in the orthorhombic system, space group Pnma, with a = 11.540(5), b = 15.177(6), c = 13.156(4) A , and four formula units per unit cell. The ligand is protonated at both pyridine nitrogens, leading to an essentially flat cation due to internal hydrogen bonding.