Aggregation control of copper(I) thiolates through substituent size and ancillary chelate ligands: closely related mono-, di-, tri- and tetranuclear complexes

The choice of thiolates and of ancillary nitrogen chelate ligands N <^> N d etermines the aggregation state of copper(I) thiolate compounds [(RS)(x)Cu- y(N <^> N)(z)](k). Starting from electrogenerated [(RS)Cu](n), the species obtained and structurally characterized include (i) mononuclear (RS)Cu(Me(4 )phen), Me(4)phen = 3,4,7,8-tetramethyl-1,10-phenanthroline, with 2,6-diorg anophenyl thiolates RS-, (ii) dinuclear [(mu -RS)Cu(Me(2)phen)](2), Me(2)ph en = 2,9-dimethyl-1,10-phenanthroline, with R = phenyl or o-tolyl, (iii) tr inuclear (mu -RS)(3)Cu-3(Me(4)phen)(2) with R = mesityl, (iv) tetranuclear (mu -RS)(4)Cu-4(bpy)(2) with R = 2,4,6-i-Pr3C6H2, and (v) the tetranuclear dianion [(mu -RS)(6)Cu-4](2-) where the added chelate ligand N <^> N = bis( 2-imidazolyl)ketone occurs in the [(N N)(2)Cu](+) counterions. The new trin uclear (mu -MesS)(3)Cu-3(Me(4)phen)(2) exhibits an unsymmetrical Cu3S3 six- membered ring in which the dicoordinate copper(I) center has a nearly linea r configuration (angle S-Cu-S 173.93(13)degrees). Both tetracoordinate copp er(I) atom sites exhibit a characteristic distortion from a tetrahedral tow ards a trigonal pyramidal CuN2S2 arrangement which is reminiscent of the ge ometry observed for the rhombic variants of type 1 Cu centers in blue coppe r proteins. (C) 2001 Elsevier Science B.V. All rights reserved.