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The Cobalticinium Cation [Co III (η 5 ‐C 5 H 5 ) 2 ] + : A metal‐organic complex as a novel template for the synthesis of clathrasils
Author(s) -
van de Goor Gianpietro,
Freyhardt Clemens C.,
Behrens Peter
Publication year - 1995
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.19956210218
Subject(s) - orthorhombic crystal system , crystallography , steric effects , hydrothermal synthesis , crystal structure , extended x ray absorption fine structure , microporous material , thermal stability , hydrothermal circulation , metal , materials science , chemistry , stereochemistry , absorption spectroscopy , organic chemistry , physics , quantum mechanics , seismology , geology
The cobalticinium cation [Co III (η 5 ‐C 5 H 5 ) 2 ] + Cocp 2 + is the first metal‐organic complex that acts as a structure‐directing template in the hydrothermal synthesis of microporous solids. Three different clathrasil framework structures – nonasil (NON), octadecasil (AST) and dodecasil 1H (DOH) – crystallize during hydrothermal treatment from the synthesis system SiO 2 NH 4 FCocp 2 PF 6 H 2 O at 420–470 K. From infrared, optical and x‐ray absorption (XANES, EXAFS) spectroscopic measurements, it is evident that the cobalticinium cation remains unchanged upon incorporation into the crystallizing silica framework proving its role as a template. Thermal analysis demonstrates that Cocp 2 + entrapped in silica frameworks possesses a much higher thermal stability than the cation in simple salts. An X‐ray single‐crystal structure determination of cobalticinium nonasil was performed at 220 K: [Cocp 2 F] 4 · 88 SiO 2 , orthorhombic, space group Pccn , a = 22.125(2) Å, b = 13.612(3) Å, c = 14.889(2) Å, Z = 1. Each of the large [5 8 6 12 ]‐cages of the nonasil structure is occupied by a Cocp 2 + cation in staggered conformation which does not show any orientational or rotational disorder but is fixed due to steric confinement and weak CH … O(host) interactions. Fluoride anions that compensate the charge of the Cocp 2 + cations reside in half of the small [4 1 5 8 ] cages in front of the four‐membered rings. They coordinate to the neighbouring framework atom Si1 ( d (Si1F): 1.836(6) Å), causing a distortion of the tetrahedral oxygen environment to a nearly ideal trigonal‐bipyramidal penta‐coordination of Si1.