Alcohol and Aldehyde Adducts of Zinc Thiolates: Structural Modeling of Alcoholdehydrogenase

Bis(pentafluorothiophenolato)zinc (1) and bis(2,4,6-triisopropylthiophenolato)zinc (2) can be combined with
nitrogen-containing derivatives of benzyl alcohol and benzaldehyde to form (N,O-chelate) zinc thiolates.
2-Pyridylmethanol as well as 2-quinolylmethanol (HetMeOH) yield [(HetMeO)Zn(SR)]4 (3, 4) having a cyclo-Zn4(μ-O)4 backbone and only terminal SR. Likewise, thiolate 1 and 2-(dimethylamino)benzyl alcohol form
zwitterionic [(dimethylammoniobenzylato)Zn(SR)2]2 (5) with bridging alkoxide and terminal thiolate. In contrast,
6-picolylmethanol (PicMeOH) and thiolate 1 result in [(PicMeOH)Zn(SC6F5)2] (6) containing zinc in a tetrahedral
ZnNS2O, environment. Simple aromatic aldehydes form polymeric complexes [(RCHO)Zn(SC6F5)2] (7:  R =
p-tolyl, 8:  R = mesityl) with a [Zn−S]∞ backbone. Chelating aldehydes (CA) yield mononuclear complexes
with tetrahedral ZnNS2O coordination [(CA)Zn(SC6F5)2] (9, CA = pyridine-2-carbaldehyde; 10, CA =
6-methylpyridine-2-carbaldehyde; 11, CA = 6-methoxypyridine-2-carbaldehyde; 12, CA = quinoline-2-carbaldehyde; 13, CA = 2-(dimethylamino)benzaldehyde). In contrast, N-methylimidazole-2-carbaldehyde (ImA)
is coordinated twice in tetrahedral [(ImA)2Zn(SC6F5)2] (14) lacking any Zn−O interactions. Pyridine-2,6-dicarbaldehyde (PDA) forms trigonal bipyramidal [(PDA)Zn(SC6F5)2] (15) with ZnNO2S2 ligation. The structures
of 3, 4, 6, 8, 10, 11, 13, and 14 were determined crystallographically, and the structures of 5 and 15 were deduced
from those of the corresponding ZnBr2 complexes. The ZnNS2O coordination pattern observed for the enzyme
has been reproduced to a very good approximation. In complexes 6 and 10, which are almost superimposable, it
is realized for both the corresponding alcohol and aldehyde.

双(五氟硫代苯酚酸根)锌(1)与双(2,4,6-三异丙基硫代苯酚酸根)锌(2)可与苄醇和苯甲醛的含氮衍生物相结合，形成(N,O-螯合)锌硫醇盐。2-吡啶甲醇以及2-喹啉甲醇(异MeOH)可生成具有环状Zn4(μ-O)4骨架和仅末端SR的[(异MeO)Zn(SR)]4(3, 4)。类似地，硫醇盐1和2-(二甲氨基)苄醇形成具有桥连醇氧和末端硫醇盐的阳离子[(二甲氨基苄基酸根)Zn(SR)2](5)。相反，6-吡啶甲醇(吡MeOH)和硫醇盐1产生含有四面体ZnNS2O环境的[(吡MeOH)Zn(SC6F5)2](6)。简单的芳香醛形成具有[Zn-S]∞骨架的聚合物配合物[(RCHO)Zn(SC6F5)2](7: R = 对甲苯基, 8: R = 甲基异丙基苯基)。螯合醛(CA)产生具有四面体ZnNS2O配位的单核配合物[(CA)Zn(SC6F5)2](9, CA = 吡啶-2-甲醛; 10, CA = 6-甲基吡啶-2-甲醛; 11, CA = 6-甲氧基吡啶-2-甲醛; 12, CA = 喹啉-2-甲醛; 13, CA = 2-(二甲氨基)苯甲醛)。相反，N-甲基咪唑-2-甲醛(ImA)在四面体[(ImA)2Zn(SC6F5)2](14)中配位两次，没有任何Zn-O相互作用。吡啶-2,6-二甲醛(PDA)形成具有ZnNO2S2配位的三角双锥[(PDA)Zn(SC6F5)2](15)。3, 4, 6, 8, 10, 11, 13和14的结构通过晶体学方法确定，而5和15的结构则是从相应的ZnBr2配合物的结构中推断出来的。对于酶观察到的ZnNS2O配位模式已经以极高的精度被再现。在几乎可以重叠的6和10这两个配合物中，对于相应的醇和醛都实现了这一目标。