Pawlicki Miłosz, Latos-Grazyński Lechosław
Department of Chemistry, University of Wrocław, ul. F. Joliot-Curie 14, 50-383 Wrocław, Poland.
Chemistry. 2003 Oct 6;9(19):4650-60. doi: 10.1002/chem.200304899.
Condensation of 2,4-bis(phenylhydroxymethyl)furan with pyrrole and p-toluylaldehyde formed, instead of the expected 5,20-diphenyl-10,15-di(p-tolyl)-2-oxa-21-carbaporphyrin, a pyrrole addition product [(H,pyr)OCPH]H(2); this product can formally be considered as an effect of hydrogenation of 3-(2'-pyrrolyl)-5,20-diphenyl-10,15-di(p-tolyl)-2-oxa-21-carbaporphyrin ([(pyr)OCPH]H). The new oxacarbaporphyrinoid presents the (1)H NMR spectroscopy features of an aromatic molecule, including the upfield shift of the inner H21 atom. Insertion of NiCl(2) or PdCl(2) into [(H,pyr)OCPH]H(2) gave two structurally related organometallic complexes, [(pyr)OCP]Ni(II)] and [(pyr)OCP]Pd(II)], in which the metal ions are bound by three pyrrolic nitrogens and the trigonally hybridized C21 atom of the inverted furan. The reaction of [(H,pyr)OCPH]H(2) with silver(I) acetate yields a stable Ag(III) complex [(C(2)H(5)O,pyr)OCP]Ag(III)] substituted at the C3 position by the ethoxy and pyrrole moieties. The macrocyclic frame of [(H,pyr)OCPH]H(2) is conserved. Addition of trifluoroacetic acid to [(C(2)H(5)O,pyr)OCP]Ag(III)] yielded a new aromatic complex [(pyr)OCP]Ag(III)](+). The structures of [(pyr)OCP]Ni(II)] and [(C(2)H(5)O,pyr)OCP]Ag(III)] have been determined by X-ray crystallography. In both molecules the macrocycles are only slightly distorted from planarity and the nickel(II) and silver(III) are located in the NNNC plane. The dihedral angle between the macrocyclic and appended-pyrrole planes of [(pyr)OCP]Ni(II)] reflects the biphenyl-like arrangement with the NH group pointing out toward the adjacent phenyl ring on the C5 position. Tetrahedral geometry around the C3 atom was detected for [(C(2)H(5)O,pyr)OCP]Ag(III)]. The Ni[bond]C and Ag[bond]C bond lengths are similar to other nickel(II) or silver(III) carbaporphyrinoids where the trigonal carbon atom coordinates the metal ion. The trend detected in the (13)C chemical shifts for the appended-pyrrole resonances has been rationalized by the extent of effective conjugation between the macrocycle and the appended pyrrole moiety controlled by the hybridization of the C3 atom and the metal ion oxidation state. The dianionic or trianionic macrocyclic core of the pyrrole-appended derivatives is favored to match the oxidation state of nickel(II), palladium(II), or silver(III), respectively.
2,4 - 双（苯基羟甲基）呋喃与吡咯和对甲苯甲醛缩合，并未形成预期的5,20 - 二苯基 - 10,15 - 二（对甲苯基）- 2 - 氧杂 - 21 - 碳卟啉，而是生成了一种吡咯加成产物[（H，pyr）OCPH]H₂；该产物可形式上视为3 - （2'-吡咯基）- 5,20 - 二苯基 - 10,15 - 二（对甲苯基）- 2 - 氧杂 - 21 - 碳卟啉（[（pyr）OCPH]H）氢化的结果。这种新的氧杂碳卟啉类化合物呈现出芳香族分子的¹H NMR光谱特征，包括内部H21原子的高场位移。将NiCl₂或PdCl₂插入[（H，pyr）OCPH]H₂中得到了两种结构相关的有机金属配合物，[（pyr）OCP]Ni（II）]和[（pyr）OCP]Pd（II）]，其中金属离子通过三个吡咯氮原子以及呋喃反转后三角杂化的C21原子配位。[（H，pyr）OCPH]H₂与乙酸银（I）反应生成一种稳定的Ag（III）配合物[（C₂H₅O，pyr）OCP]Ag（III）]，其在C3位置被乙氧基和吡咯部分取代。[（H.pyr）OCPH]H₂的大环骨架得以保留。向[（C₂H₅O，pyr）OCP]Ag（III）]中加入三氟乙酸得到一种新的芳香族配合物[（pyr）OCP]Ag（III）]⁺。[（pyr）OCP]Ni（II）]和[（C₂H₅O，pyr）OCP]Ag（III）]的结构已通过X射线晶体学确定。在这两个分子中，大环仅略微偏离平面，镍（II）和银（III）位于NNNC平面内。[（pyr）OCP]Ni（II）]的大环平面与连接的吡咯平面之间的二面角反映了联苯状排列，其中NH基团指向C5位置的相邻苯环。对于[（C₂H₅O，pyr）OCP]Ag（III）]，检测到C3原子周围的四面体几何结构。Ni—C和Ag—C键长与其他三角碳原子配位金属离子的镍（II）或银（III）碳卟啉类化合物相似。通过C3原子的杂化和金属离子氧化态控制的大环与连接的吡咯部分之间有效共轭程度，对连接的吡咯共振的¹³C化学位移中检测到的趋势进行了合理化解释。吡咯连接衍生物的二价阴离子或三价阴离子大环核心分别有利于匹配镍（II）、钯（II）或银（III）的氧化态。
