Try this.

#!/usr/bin/perl

use strict;

my %record;
my $string = "{key_1 : value_1}{key_2 : value_2}{key_n : value_n}";

for ( map { split /\}/ } $string ) {
    $record{$1} = $2 if /\{(\w+)\s:\s(\w+)/;
}
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